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Now showing items 1602-1620 of 1747

• #### Supertropical Quadratic Forms I

[OWP-2013-27] (Mathematisches Forschungsinstitut Oberwolfach, 2013)
We initiate the theory of a quadratic form q over a semiring $R$. As customary, one can write $q(x+y)=q(x)+q(y)+b(x,y)$, where b is a companion bilinear form. But in contrast to the ring-theoretic case, the companion ...
• #### Supertropical semirings and supervaluations

[OWP-2010-05] (Mathematisches Forschungsinstitut Oberwolfach, 2010)
We interpret a valuation $\upsilon$ on a ring $R$ as a map $\upsilon:R \rightarrow M$ into a so called bipotent semiring $M$ (the usual max-plus setting), and then define a supervaluation $\varphi$ as a suitable map into ...
• #### Sur le Minimum de la Fonction de Brjuno

[OWP-2018-26] (Mathematisches Forschungsinstitut Oberwolfach, 2018-12-11)
The Brjuno function attains a strict global minimum at the golden section.
• #### 1649 - Surface Bundles

[OWR-2016-56] (2016) - (04 Dec - 10 Dec 2016)
This workshop brought together specialists in algebraic topology, low dimensional topology, geometric group theory, algebraic geometry and neighboring fields. It provided a good overview of the current developments, and ...
• #### 1904 - Surface, Bulk, and Geometric Partial Differential Equations: Interfacial, stochastic, non-local and discrete structures

[OWR-2019-3] (2019) - (20 Jan - 26 Jan 2019)
Partial differential equations in complex domains with free\linebreak boundaries and interfaces continue to be flourishing research areas at the interfaces between PDE theory, differential geometry, numerical analysis ...
• #### Surgery theory and geometry of representations

[OWS-11] (Birkhäuser Basel, 1988)
These notes were prepared for the DMV-Seminar held in Dusseldorf, Schloss Mickeln from June 28 to July 5, 1987. They consist of two parts which can be read independently. The reader is presumed to have a basic education ...
• #### A surprising connection between quantum mechanics and shallow water waves

[SNAP-2019-018-EN] (Mathematisches Forschungsinstitut Oberwolfach, 2019-12-11)
We describe a connection between quantum mechanics and nonlinear wave equations and highlight a few problems at the forefront of modern research in the intersection of these areas.
• #### Swallowtail on the shore

[SNAP-2014-007-EN] (Mathematisches Forschungsinstitut Oberwolfach, 2014)
Platonic solids, Felix Klein, H.S.M. Coxeter and a flap of a swallowtail: The five Platonic solids tetrahedron, cube, octahedron, icosahedron and dodecahedron have always attracted much curiosity from mathematicians, not ...
• #### Swarming robots

[SNAP-2016-001-EN] (Mathematisches Forschungsinstitut Oberwolfach, 2016)
When lots of robots come together to form shapes, spread in an area, or move in one direction, their motion has to be planned carefully. We discuss how mathematicians devise strategies to help swarms of robots behave like ...
• #### The Sylow Structure of Scalar Automorphism Groups

[OWP-2018-05] (Mathematisches Forschungsinstitut Oberwolfach, 2018-03-22)
For any locally compact abelian periodic group A its automorphism group contains as a subgroup those automorphisms that leave invariant every closed subgroup of A, to be denoted by SAut(A). This subgroup is again a locally ...
• #### Symmetry and characters of finite groups

[SNAP-2016-005-EN] (Mathematisches Forschungsinstitut Oberwolfach, 2016)
Over the last two centuries mathematicians have developed an elegant abstract framework to study the natural idea of symmetry. The aim of this snapshot is to gently guide the interested reader through these ideas. In ...
• #### The T-Graph of a Multigraded Hilbert Scheme

[OWP-2011-34] (Mathematisches Forschungsinstitut Oberwolfach, 2011)
The $T$-graph of a multigraded Hilbert scheme records the zero and one-dimensional orbits of the $T=(K^*)^n$ action on the Hilbert scheme induced from the $T$-action on $\mathbb{A}^n$. It has vertices the $T$-fixed points, ...
• #### 0622 - Teichmüller Space (Classical and Quantum)

[OWR-2006-26] (2006) - (28 May - 03 Jun 2006)
This is a short report on the conference “Teichmüller Space (Classical and Quantum) ” held in Oberwolfach from May 28th to June 3rd, 2006.
• #### 1048 - Teichmüller Theory

[OWR-2010-53] (2010) - (28 Nov - 04 Dec 2010)
This is a report on the workshop on Teichmüller theory held in Oberwolfach, from November 28 to December 4, 2010. The workshop brought together people working in various aspects of the field, with a focus on recent ...
• #### Ten lectures on random media

[OWS-32] (Birkhäuser Basel, 2002)
The following notes grew out oflectures held during the DMV-Seminar on Random Media in November 1999 at the Mathematics Research Institute of Oberwolfach, and in February-March 2000 at the Ecole Normale Superieure in Paris. ...
• #### Tensor Representations of q(∞)

[OWP-2016-09] (Mathematisches Forschungsinstitut Oberwolfach, 2016-06-17)
We introduce a symmetric monoidal category of modules over the direct limit queer superalgebra $\mathfrak{q}(\infty)$. The category can be defined in two equivalent ways with the aid of the large annihilator condition. ...
• #### The ternary Goldbach problem

[SNAP-2014-003-ENSNAP-2014-003-DE] (Mathematisches Forschungsinstitut Oberwolfach, 2014)
[also available in German] Leonhard Euler (1707–1783) – one of the greatest mathematicians of the eighteenth century and of all times – often corresponded with a friend of his, Christian Goldbach (1690–1764), an amateur ...
• #### 1135 - The Analytic Theory of Automorphic Forms

[OWR-2011-43] (2011) - (28 Aug - 03 Sep 2011)
The workshop brought together leading experts in the theory of automorphic forms. Recently developed analytic, geometric and ergodic methods have enabled several important results in the theory for $GL(2)$, and also made ...
• #### 0606 - The Arithmetic of Fields

[OWR-2006-6] (2006) - (05 Feb - 11 Feb 2006)
This is the report on the Oberwolfach workshop The Arithmetic of Fields, held in February 2006. Field Arithmetic (MSC 12E30) is a branch of mathematics concerned with studying the inner structure (orderings, valuations, ...


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# Speed, distance and time

is a measure of how far an object moves. Distance refers only to how far an object moves - it does not include an object's direction. This means that distance is a quantity. Smaller distances can be measured with a ruler, a tape measure or a trundle wheel. Larger distances can be measured with or aerial photography.

is the of distance - it is the distance travelled per unit time. Like distance, speed is also a scalar quantity, as it does not refer to direction. To measure speed in the laboratory, a distance value and a time value are needed. The time value can be measured accurately with light gates, although a stopwatch can also be used.

### Measuring distance, time and speed

To calculate speed, use the equation:

$speed = \frac{distance}{time}$

This is when:

• speed is measured in metres per second (m/s)
• distance is measured in metres (m)
• time is measured in seconds (s)

### Example

A toy car rolls down a ramp. The car takes 0.4 s to complete the final 30 cm of the ramp. Calculate the speed of the car as it rolls down the final 30 cm of the ramp.

First convert the distance from centimetres to metres:

30 cm = 0.3 m

Then substitute the values into the equation:

$speed = \frac{distance}{time}$

$speed = 0.3 \div 0.4$

$speed = 0.75~m/s$

format: plain


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# basic probability question - effect of repetition on odds

If I have a 5% chance of catching a cold by hugging someone with a cold, what are the odds that I will catch a cold if I hug someone 150 times? Sorry, basic question.

-

This is a common question where calculating the inverse (not catching a cold) is much easier. The probability of not catching a cold when hugging someone is $0.95$, so the probability of not getting a cold after $150$ hugs is
$$0.95^{150} \approx 0.000455$$
$$1 - 0.95^{150} \approx 0.999544 = 99.9544\%$$


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Question

# ∫x+2(x2+3x+3)√x+1dx

A
B
C
D

Solution

## The correct option is C This is an another form of special irrational algebraic functions. To solve this we’ll substitute x+1=t2 or x=t2−1 & dx = 2t.dt ∫t2−1+2((t2−1)2+3(t2−1)+3)√t2−1+12t.dt ∫(t2+1).2t((t2−1)2+3(t2−1)+3).t 2∫t2+1t4+t2+1.dt Now we are familiar with the form we have, this is ∫x2±1x4+Kx2+1dx form and to solve this we’ll have to divide numerator and denominator by t2. So, we'll have -  2∫1+1t2t2+1+1t2dt =2∫1+1t2(t−1t)2+3dt Substitute t−1t=u 1+1t2 .dt = du So, the integral will be = 2∫1(u)2+(√3)2du Which is a standard form. And we can apply the corresponding formula On substituting u = t−1t and using standard formula, the integral becomes 2.1√3tan−1(t−1t√3)+C On substituting t=√x+1 2√3tan−1(x√3(x+1))+CMathematics

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# Synthesizeable D Flip flop for FPGA

Having played around with Verilog for some time now, I decided to graduate to implementing designs on Alltera CycloneIV FPGA using the Quartus suite.

Starting with a simple D flip flop, I face the first road block.

Problem Statement: The output(Q) of a D-FF is required follow the input signal (as it should be), and here goes the code:

//----------------------------------------
//module D flip flip
//-----------------------------------------

module d(q_w,q0_w,d,c);
output q_w,q0_w;
input c,d;

//wire c;
reg q,q0;
wire q_w,q0_w;
assign q_w=q;
assign q0_w=q0;

initial
begin
q=1'b0; q0=1'b1;
end
always @ (posedge c)
begin
q<=d;
q0<= ~d;
end
endmodule

The input signal 'd' also transitions at the same positive edge of a common clock signal ('c' for module D-FF). This is causing the circuit to not behave properly as the transition and testing happens at same edge of clock. Also that I have read it is better to stick to one edge of clock in designs (as a good practice) and am hence abstained from using negative edge of the clock.

Having encountered the same issue when simulating I used a delay to do away with the problem

always @ (posedge c)
begin
#2 q=d;
q0= ~d;
end

Despite searching a lot I cant figure out a way to implement the functionality as required in the hardware. I tried adding buffer elements before the clock signal enters D-FF module but in vain.

PS: I haven't yet burnt any of this on the FPGA yet. My apprehensions are marked by the results of Quartus Simulation.

I have manually tweaked the input D at point to check the follow up of the circuit

What @duskwuff is pointing out is that when you implemented your test waveform (c and d) you have d transitioning at the exact same time as c. This is not how whatever is driving your flip-flop will really work. The input has to be set up before the clock edge. If the input is transitioning at the clock edge--remember that while the edges look square in the logic analyzer, in reality the voltage takes a certain amount of time to transition from one state to another--your flip-flop may read high, low, or some intermediate voltage that may really confuse your logic.

At the first positive clock edge, d transitions from low to high. But because the new value of d (high) was not set up before the clock edge, your flip-flop sees the original value (low) and outputs that on q. The same thing happens on the second positive clock edge.

However, between the second and third positive clock edges, at 140ns, you change d from low to high. So when the clock goes positive the third time at 150ns, it sees the high value, and then q goes high about 8ns later.

Your test sequence should look something like:

1. set clock high
2. wait 1/4 clock cycle
3. set d to some value
4. wait 1/4 clock cycle
5. set clock low
6. wait 1/2 clock cycle
7. set clock high (it's now been one full cycle from last positive edge)
8. wait 1/4 clock cycle
9. check q
• Thanks for the elaborate explanation. It helped. I may change the test waveforms as per what you mentioned. But still, how do I make sure that the waveform is actually shifted in the hardware so as to avoid the problem. Or will this code run just fine on hardware as there will automatically be delays? – Prateek Sharma Mar 11 '16 at 5:20
• As long as everything is driven from the same clock you'll be fine. It's trickier when dealing with asynchronous signals, like from an external serial line. Cross that bridge when you come to it. – Willis Blackburn Mar 11 '16 at 12:19
• How about an up vote? :-) – Willis Blackburn Mar 11 '16 at 12:19
• Sry was away over the weekend. Anywho, just to clarify one last time. This piece of code will run perfectly on the hardware without me requiring any changes? is that right. Thanks again – Prateek Sharma Mar 14 '16 at 8:36
• It should work. But don't take my word for it, synthesize it and see for yourself. – Willis Blackburn Mar 14 '16 at 11:47

First: don't use delays in implementations. Delays cannot be synthesized in hardware; they should be confined to testbench code.

Second: the situation you're testing, where d changes at a clock edge, is a timing violation. Failing under these circumstances is perfectly normal; virtually all flip-flops will fail or exhibit inconsistent behavior when subjected to this input. Adjust your testbench to move the transitions of d such that they don't coincide with the clock edges.

• So do you mean to say that if I run my contentious code on actual FPGA then the result would be consistent?Secondly, aren't tetstbenches, purely simulation tool? If yes, whats the point of tweaking the testbench code. If not necessarily, then how so I 'move the transitions of d such that they don't coincide with the clock edges' if not by using delays. Thanks – Prateek Sharma Mar 11 '16 at 2:16
• Having run on simulation tools earlier, I am now looking only to make it work on actual hardware. Beats me. – Prateek Sharma Mar 11 '16 at 2:32
• Changing the D input to any flip-flop during a clock transition will cause unpredictable behavior. Don't do this in your tests. Edit the input waveform such that this doesn't happen. – duskwuff -inactive- Mar 11 '16 at 3:12
• Thanks. Even though, I may edit the wave form for testing, how do I make sure that the waveform is actually 'shifted' when run on the hardware. – Prateek Sharma Mar 11 '16 at 5:18
• Checking for these timing violations is a part of standard timing analysis, and the software will take care of that for you under most circumstances. – duskwuff -inactive- Mar 11 '16 at 5:55


text:
# IsProductOperator

 Other toolboxes required IsProductOperator Determines if an operator is an elementary tensor none IsProductVectorOperatorSchmidtDecompositionOperatorSchmidtRank Entanglement and separability

IsProductOperator is a function that determines if a bipartite or multipartite operator is an elementary tensor or not. If it is an elementary tensor, its tensor decomposition can be provided.

## Syntax

• IPO = IsProductOperator(X)
• IPO = IsProductOperator(X,DIM)
• [IPO,DEC] = IsProductOperator(X,DIM)

## Argument descriptions

### Input arguments

• X: An operator that acts on a bipartite or multipartite Hilbert space.
• DIM (optional, by default has all subsystems of equal dimension): A specification of the dimensions of the subsystems that X lives on. DIM can be provided in one of three ways:
• If DIM is a scalar, it is assumed that X lives on the tensor product of two spaces, the first of which has dimension DIM and the second of which has dimension length(X)/DIM.
• If $X \in M_{n_1} \otimes \cdots \otimes M_{n_p}$ then DIM should be a row vector containing the dimensions (i.e., DIM = [n_1, ..., n_p]).
• If the subsystems aren't square (i.e., $X \in M_{m_1, n_1} \otimes \cdots \otimes M_{m_p, n_p}$) then DIM should be a matrix with two rows. The first row of DIM should contain the row dimensions of the subsystems (i.e., the mi's) and its second row should contain the column dimensions (i.e., the ni's). In other words, you should set DIM = [m_1, ..., m_p; n_1, ..., n_p].

### Output arguments

• IPO: Either 1 or 0, indicating that X is or is not an elementary tensor.
• DEC (optional): If IPO = 1 (i.e., X is an elementary tensor), then DEC is a cell containing two or more operators, the tensor product of which is X. If IPO = 0 then DEC is meaningless.

## Examples

The following code verifies that the 8-by-8 identity operator (interpreted as living in 3-qubit space) is indeed a product operator:

>> [ipo,dec] = IsProductOperator(eye(8),[2,2,2])

ipo =

1

dec =

[2x2 double]    [2x2 double]    [2x2 double]

>> celldisp(dec)

dec{1} =

0.9170         0
0    0.9170

dec{2} =

-0.9170         0
0   -0.9170

dec{3} =

-1.1892         0
0   -1.1892

As we can see, the tensor decomposition that is returned is not always the "cleanest" one that exists. However, we can verify that it is indeed a valid tensor decomposition of the identity operator:

>> Tensor(dec)

ans =

1.0000         0         0         0         0         0         0         0
0    1.0000         0         0         0         0         0         0
0         0    1.0000         0         0         0         0         0
0         0         0    1.0000         0         0         0         0
0         0         0         0    1.0000         0         0         0
0         0         0         0         0    1.0000         0         0
0         0         0         0         0         0    1.0000         0
0         0         0         0         0         0         0    1.0000

## Source code

Click here to view this function's source code on github.


text:
# Circle A has a center at (2 ,5 ) and a radius of 2 . Circle B has a center at (4 ,2 ) and a radius of 3 . Do the circles overlap? If not, what is the smallest distance between them?

Sep 9, 2016

Yes, the circles do overlap. See explanation.

#### Explanation:

Circle A, center(2,3), r=2.
Circle B, center(4,2), r=3

In the graph above, the red one is Circle A, and the green one Circle B. The white line is the distance between the two center points.

Distance between the centers of the two circles =
$\sqrt{{\left(4 - 2\right)}^{2} + {\left(2 - 5\right)}^{2}} = \sqrt{{2}^{2} + {3}^{2}} = \sqrt{13} = 3.61$

As the distance between the two centers (3.61) is smaller than the sum of the two radii (2+3=5), the two circles overlap.


text:
# Subcomplexes of the infinitely-dimensional sphere

I'm trying to understand better what Hatcher does in the beginning chapter on cell complexes and so in this sense I would really like someone to elucidate for me what are the subcomplexes of $S^{\infty}$, with the cell structure described in the book, having two cells in each dimension.

The clearer the explanation the better! Thanks

-
Have you tried making the list of subcomplexes yourself? For example. What are the 1-dimensional subcomplexes? – Mariano Suárez-Alvarez Feb 8 '13 at 6:32
of course i tried; I'm pretty sure the subcomplexes are the $n$-dimensional spheres and the $n$-dimensional spheres, each along with an $n+1$ cell attached to the previous sphere along its boundary. but i was hoping for a detailed answer... – TJIF Feb 8 '13 at 6:47
Why don't you write what you did in the question? – Mariano Suárez-Alvarez Feb 8 '13 at 6:50
@TJIF - do you understand how to make, for example, $S^2$ with two cells in each dimension (less than 3). – Joe Tait Feb 8 '13 at 9:39
got it, thanks. – TJIF Feb 21 '13 at 2:45


text:
# Applications of the Pythagorean Theorem, and the Midpoint Formula

Objective:
At the end of this lesson you will be able to:

1. Use right triangles to solve some simple applications.
2. Use the Midpoint Formula to find the point that is midway between two points on a line.

Prior Knowledge
Before you begin this lesson, you should know how to:

• Simplify and approximate square roots.
• Graph points and lines on the coordinate plane.
• Work with exponents.
• Understand the Pythagorean Theorem

### LESSON SUMMARY

Many practical problems can be solved using the Pythagorean Theorem. Here’s an example: Your suitcase is 22″ long, 14″ wide and 9″ deep. What is the length of the longest object you can lay flat on the bottom of your suitcase?

Using a diagram is often helpful in solving problems like this. The bottom of a suitcase is a rectangle. The longest object fits on the diagonal. We can represent this diagonal object with a dotted line. The sides of the suitcase and this dotted line form the sides of a right triangle.

Use the Pythagorean Theorem to find the length of the diagonal. Substitute 22 for “a” and 14 for
b“. Solve the equation for “c“.

222 + 142 = c2
484 + 196 = c2
680 = c2
26.07 = c

The longest object you can fit on the bottom of your suitcase is a little more than 26 inches.

In the final part of this lesson, we work with the Midpoint Formula.

Using the Midpoint Formula, we can find the point midway between two coordinates. The
formula is:

$$\left(x,y\right)=\left(\frac{\left(x_1+x_2\right)}2,\frac{\left(y_1+y_2\right)}2\right)$$

To use the formula to find the point midway between (5, 10) and (-3, -5), we’ll label the points as
shown below.

$$\left(5,10\right)\;\;\;\;\left(-3,-5\right)$$
$$\left(x_1,\;y_1\right)\;\;\;\;\left(x_2,\;y_2\right)$$

Now substitute the coordinates in the formula and simplify the resulting equation.

$$\left(x,y\right)=\left(\frac{\left(5+\left(-3\right)\right)}2\right),\left(\frac{\left(10+\left(-5\right)\right)}2\right)$$
$$=\left(\frac22,\frac52\right)$$
$$=\left(1,2.5\right)$$

The point midway between (5, 10) and (-3, -5) is (1, 2.5).

Examples

These examples can help you master the new ideas in this lesson.

1. A ladder is leaning against a building. When the base of the ladder is 7.2 feet from the base of the building, it reaches to a point 9.6 feet high. If the ladder is moved so that its base is 3 feet from the wall, how far up the building will it reach?

Solution: First, find the length of the ladder. The ladder, the side of the building and the base (or ground) form a right triangle. In the diagram below, the hypotenuse is the ladder. The bottom of the ladder is 7.2 feet from the building. In this position, the top of the ladder reaches to 9.6 feet on the building.

These distances are the legs in a right triangle, so we can substitute them into the Pythagorean theorem.

a2 + b2 = c2

9.62 + 7.22 = c2

92.16 + 51.84 = c2

144 = c2

12 = c

The ladder is 12 feet. Next, find the new height of the ladder when its base is moved 3 feet from the building. If it helps, use the diagram.

The hypotenuse is 12 feet and one leg is 3 feet. Substitute these values into the Pythagorean Theorem. Then solve the resulting equation to find the length of the other leg, b.

a2 + b2 = c2

32 + b2 = 122

9 + b2 = 144

b2 = 135

b = 11.6

The top of the ladder is 11.6 feet high.

2. Use the points (-6, 5) and (8, -1) to find the point midway between the points.

Solution: Use the point (-6, 5) as (x1, y1) . Use (8, -1) as (x2, y2). Then substitute the points into the midpoint formula.

$$\left(x,y\right)=\left(\frac{\left(-6+8\right)}2\right),\left(\frac{\left(5+\left(-1\right)\right)}2\right)$$
$$=\left(\frac22,\frac42\right)$$
$$=\left(1,2\right)$$

The midpoint is (1, 2).

Practice Problems

These problems will give you more experience with the material in this lesson.

1. A decorator is planning to place ribbons diagonally on a rectangular tablecloth. If the
cloth measures 50″ by 70″, how long should each ribbon be cut? (Round your answer to
the nearest tenth.)
2. The trunk of Sam’s car is about 40″ wide and 45″ long. What is the longest object Sam
can fit into the bottom of the trunk? (Round off your answer to the nearest tenth.)
3. Find the point that is midway between the following points.
a) (-8, 3) and (-17, -9)
b) (2, 3) and (-5, 11)

1. 86”
2. 60.2”
3. (-12.5, 3)
4. (-1.5, 7)

R

R

R

R

R

R

R

R

R

R

R

R


text:
In thermodynamics, Carl Neumann (1832-1925) was a German mathematical physicist noted for his 1875 Lectures on the Mechanical Theory of Heat in which he introduction of the now-standard symbol notation $\bar{d} \,$(d-hat), otherwise known as Neumann notation, or δ (Greek delta), in latter usages by others, to represent an inexact differential, i.e. one that is path dependent, such as are differentials of heat δQ and work δW. [1]

Neumann supposedly used his own methods, by passing the need for introducing the entropy function, to script his own version of thermodynamics. [2] His book on heat supposedly used methods on heat similar to German physicist Gustav Kirchhoff. [5]

Neumann seems to have developed an interested in thermodynamics via the overlap of heat and electricity. His 1873 book Explanation of Electrical Forces and Expansion gives evidence to this. [2] Neumann thought that mechanical explanations in physics were incomplete, contradictory, and overly complex. Having studied the analogies between electrodynamics and mechanics, specifically hydrodynamics, which Hermann Helmholtz, Gustav Kirchhoff, and Ludwig Boltzmann, and others had developed, Neumann convinced himself that the analogies lacked “deep foundations”. Moreover, the explanation of heat phenomena requires thermal principles and since heat is intimately related to electricity, he did not expect “merely mechanical principles” to succeed with electricity either. [2]

Inexact differential
See main: Inexact differential
German physicist Georg Helm seems to have been the first to point this origin out, specifically in his 1898 History of Energetics, wherein he comments Neumann was the one that suggested that the special differential sign $\bar{d}Q \,$ (d hat Q) should be used as a way of always keeping in mind the differentials, such as heat, that do not fit the condition for an exact differential. [8]

Economic thermodynamics
Neumann, supposedly, had views on how thermodynamics applied to economy. [6] Neumann argued that all economic life could be expressed by an exchange of energy or by “the transfer of energy of physical bodies”. Neumann, according to the 1887 views of Georg Helm, considered the “energy of the self as the capital of the body”, such that the body contained an energetic component considered as a commodity. [7] The actual citation used by Helm, in the Final Section to his The Doctrine of Energy is:

 "Carl Neumann nennt die eigenenergie gelegentlich das Kapital des Körpers, und dass bei der Ausbildung der Energievorstellungen wirtschaftliche Analogien mitgewirkt haben, ist S. 18 von mir hervorgehoben worden (78)."Note 78Bezeichnend sind die Worte, die Du Bois Reymond (Berl. Monatsberichte 1870) von Leibniz anführt: „Les forces ne sont (pas) detruites, mais dissip6es parmi les parties menues. Ce n'est pas les perdre, mais c'est faire comme font ceux, qui changent la grosse monnaie en petite." Sie sind eben so merkwürdig hinsichtlich des Dissipationsgedankens, wie hinsichtlich der wirtschaftlichen Analogie. "Carl Neumann sets out on occasional discussion of the internal energy capital of the body, and that have participated in the training of energy performances economic analogies, p. 18 worden is highlighted by me (78)."Note 78 Typical are the words quoted by Du Bois Reymond (Berl. monthly reports in 1870) by Leibniz: "The forces are (not) destroyed, but among the minor parties disperses. This is not to lose them, but do like are those that change the currency in small wide." They are just as curious as to the Dissipationsgedankens as economic terms the analogy.

The term 'eigenenergy' (of translated as self-energy) may actually mean internal energy, possibly, as used in the sense of Helm? The exact article (or book) that Helm made these economic speculations using thermodynamic theory still needs to be tracked down; but, nevertheless, the above quote does seem to indicate that Neumann's thermo-economic views predate those of Helm?

References
1. (a) Neumann, Carl. (1875). Vorlesungen über die mechanische Theorie der Wärme (Lectures on the Mechanical Theory of Heat). Germany.
(c) Anon. (1877). “Science (Review: Lectures on the Mechanical Theory of Heat by Carl Neumann, 1875)”, The Westminster Review (pg. 250-), Jan-Apr.
(b) Laider, Keith, J. (1993). The World of Physical Chemistry. Oxford University Press.
2. Aris, Rutherford, David, Howard T, and Stuewer, Roger H. (1983). Springs of Scientific Creativity: Essays on the Founders of Modern Science (ch. 5: The Scientific Style of Josiah Willard Gibbs, pgs. 142-62; esp. pg. 150). University of Minnesota Press.
3. Ampere, A., Neumann F., Weber W., and Kirchhoff, G. (1873). Elektrischen Krafte Darlegung und Erweiterung der von A. Ampere, F. Neumann, W. Weber, G. Kirchhoff, Entwickelten Mathematischen Theorieen (Explanation of Electrical Forces and Expansion on the Mathematical Theories of A. Ampere, F. Neumann, W. Weber, and G. Kirchhoff). Leipzig.
4. (a) Jungnickel, Christa. (1986). Intellectual Mastery of Nature: Theoretical Physics form Ohm to Einstein, Volume 2, 1870-1925 (Footnote 53: pg. 228). University of Chicago Press.
(b) Neumann, Carl. (1873?) Beitrage zu einzelnen Theilen der Mathematischen Physik, insbesondere zur Elektordynamik und Hydrodynamik, Elektrostatik und magnetischen Induction (Individual contributions to Theoretical Mathematical Physics, in particular to Electrodynamics and Hydrodynamics, Electrostatics and Magnetic induction) (Leipzig, 1893), iii-iv, 205-6.
5. Maxwell, James C., Elizabeth Garber, Stephen G. Brush, C. W. Francis Everitt. (1995). Maxwell on Heat and Statistical Mechanics: On "avoiding All Personal Enquiries of Molecules" (pgs. 255, 257). Lehigh University Press.
6. Wallace, Thomas P. (2009). Wealth, Energy, and Human Values: the Dynamics of Decaying Civilizations from Ancient Greece to America (Carl Neumann, pgs. 59, 104-05). AuthorHouse.
7. (a) Helm, Georg. (1887). The Theory of Energy: Historical-Critical Development (Die Lehre von der Energie: Historisch-kritisch Entwickelt) (pg. 72). Leipzig.
(b) Rabinbach, Anson. (1990). The Human Motor - Energy, Fatigue, and the Origins of Modernity (pg. 71). Berkeley: University of California Press.
(c) Wallace, Thomas. (2009). Wealth, Energy, and Human Values: the Dynamics of Decaying Civilizations (Carl Neumann, pgs. 59, 104-05). Author House.
8. (a) Helm, Georg F. (1898). Die Energetik: Nach Ihrer Geschichtlichen Entwickelung (Energetics: Historical Development). Leipzig.
(b) Helm, Georg F. (2000). The Historical Development of Energetics (Carl Neumann: special differential sign, pg. 130). Kluwer Academic Press.


text:
f

#### AttributeError: 'list' object has no attribute 'lower'

On page 77 of the book natural language processing with Python, we have such an exercise: The polysemy of a word is the number of senses it has. Using WordNet, we can determine that the noun doghas seven senses with len(wn.synsets('dog', 'n')).

I wrote the following function to solve it. However, it pops up "AttributeError: 'list' object has no attribute 'lower'". Quite confused, I supposed [synset.lemma_names for synset in synset_list] has made all the lemma into a list, hasn't it?

>>> def average_polysemy(pos):
synset_list = list(wn.all_synsets(pos))
lemma_list = [synset.lemma_names for synset in synset_list]
sense_number = 0
for lemma in lemma_list:
sense_number_new = len(wn.synsets(lemma, pos))
sense_number = sense_number + sense_number_new
return sense_number/len(synset_list)

>>> average_polysemy('n')

Traceback (most recent call last):
File "<pyshell#54>", line 1, in <module>
average_polysemy('n')
File "<pyshell#53>", line 6, in average_polysemy
sense_number_new = len(wn.synsets(lemma, pos))
File "C:\Python27\lib\site-packages\nltk\corpus\reader\wordnet.py", line 1191, in synsets
lemma = lemma.lower()
AttributeError: 'list' object has no attribute 'lower'

 0
typetoken (19)
9/8/2012 5:13:21 PM
comp.lang.python 77058 articles. 6 followers.

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I don't know why lemma_list = [synset.lemma_names for synset in synset_list] will lead to such an error.

I have to use extend to solve the problem for lemma_list. The following codes are successful, take all the nouns as an example:

>>> def average_polysemy(pos):
synset_list = list(wn.all_synsets(pos))
sense_number = 0
lemma_list = []
for synset in synset_list:
lemma_list.extend(synset.lemma_names)
for lemma in lemma_list:
sense_number_new = len(wn.synsets(lemma, pos))
sense_number = sense_number + sense_number_new
return sense_number/len(synset_list)

>>> average_polysemy('n')
3

>
> I wrote the following function to solve it. However, it pops up "AttributeError: 'list' object has no attribute 'lower'". Quite confused, I supposed [synset.lemma_names for synset in synset_list] has made all the lemma into a list, hasn't it?
>
>
>
> >>> def average_polysemy(pos):
>
> 	synset_list = list(wn.all_synsets(pos))
>
> 	lemma_list = [synset.lemma_names for synset in synset_list]
>
> 	sense_number = 0
>
> 	for lemma in lemma_list:
>
> 		sense_number_new = len(wn.synsets(lemma, pos))
>
> 		sense_number = sense_number + sense_number_new
>
> 	return sense_number/len(synset_list)
>
>
>
> >>> average_polysemy('n')
>
>
>
> Traceback (most recent call last):
>
>   File "<pyshell#54>", line 1, in <module>
>
>     average_polysemy('n')
>
>   File "<pyshell#53>", line 6, in average_polysemy
>
>     sense_number_new = len(wn.synsets(lemma, pos))
>
>   File "C:\Python27\lib\site-packages\nltk\corpus\reader\wordnet.py", line 1191, in synsets
>
>     lemma = lemma.lower()
>
> AttributeError: 'list' object has no attribute 'lower'
>
>
>

 0
typetoken (19)
9/8/2012 5:32:59 PM
In article <df7ab5f7-c273-4a62-b79a-f364f9c2d3b0@googlegroups.com>,
Token Type <typetoken@gmail.com> wrote:

> I wrote the following function to solve it. However, it pops up
> "AttributeError: 'list' object has no attribute 'lower'". Quite confused, I
> supposed [synset.lemma_names for synset in synset_list] has made all the
> lemma into a list, hasn't it?

I'm not familiar with that library, but here's a few general ideas to

First, I don't understand this code:

> 	synset_list = list(wn.all_synsets(pos))
> 	lemma_list = [synset.lemma_names for synset in synset_list]

It looks like you're taking an iterable, converting it to a list, just
so you can iterate over it again.  Why not the simpler:

> lemma_list = [synset.lemma_names for synset in wn.all_synsets(pos)]

?  But, I'm also confused about what lemma_list is supposed to end up
being.  The name "lemma_names" is plural, making me think it returns a
list of something.  And then you build those up into a list of lists?

In fact, I'm guessing that's your problem.  I think you're ending up
with a list of lists of strings, when you think you're getting a list of
strings.

My suggestion is to print out all the intermediate data structures
(synset_list, lemma_list, etc) and see what they look like.  If the
structures are simple, just plain print will work, but for more
complicated structures, pprint.pprint() is a life saver.

Another possibility is to assert that things are what you expect them to
be.  Something like:

assert isinstance(synset_list, list)
assert isinstance(lemma_list, list)
assert isinstance(lemma_list[0], str)

and so on.

> 	for lemma in lemma_list:
> 		sense_number_new = len(wn.synsets(lemma, pos))
> 		sense_number = sense_number + sense_number_new
> 	return sense_number/len(synset_list)
>
> >>> average_polysemy('n')
>
> Traceback (most recent call last):
>   File "<pyshell#54>", line 1, in <module>
>     average_polysemy('n')
>   File "<pyshell#53>", line 6, in average_polysemy
>     sense_number_new = len(wn.synsets(lemma, pos))
>   1191, in synsets
>     lemma = lemma.lower()
> AttributeError: 'list' object has no attribute 'lower'
>

 0
roy (2295)
9/8/2012 5:45:39 PM
Thanks very much for all of your tips. Take noun as an example. First, I ne=
ed find all the lemma_names in all the synsets whose pos is 'n'. Second, fo=
r each lemma_name, I will check all their sense number.=20

1)  Surely,we can know the number of synset whose pos is noun by=20
>>> len([synset for synset in wn.all_synsets('n')])
82115

However, confusingly it is unsuccessful to get a list of lemma names of the=
se synsets by=20
>>> lemma_list =3D [synset.lemma_names for synset in wn.all_synsets('n')]
>>> lemma_list[:20]
[['entity'], ['physical_entity'], ['abstraction', 'abstract_entity'], ['thi=
ng'], ['object', 'physical_object'], ['whole', 'unit'], ['congener'], ['liv=
ing_thing', 'animate_thing'], ['organism', 'being'], ['benthos'], ['dwarf']=
, ['heterotroph'], ['parent'], ['life'], ['biont'], ['cell'], ['causal_agen=
t', 'cause', 'causal_agency'], ['person', 'individual', 'someone', 'somebod=
y', 'mortal', 'soul'], ['animal', 'animate_being', 'beast', 'brute', 'creat=
ure', 'fauna'], ['plant', 'flora', 'plant_life']]
>>> type(lemma_list)
<type 'list'>

Though the lemma_list is a list in the above codes, it contains so many unn=
ecessary [ and ]. How come it is like this? But what we desire and expect i=
s a list without this brackets. Confused, I am really curious to know why.

2)  Then I have to use a loop and extend to get all the lemma_names from sy=
nset:
>>> synset_list =3D list(wn.all_synsets('n'))
>>> lemma_list =3D []
>>> for synset in synset_list:
lemma_list.extend(synset.lemma_names)
>>> lemma_list[:20]
['entity', 'physical_entity', 'abstraction', 'abstract_entity', 'thing', 'o=
bject', 'physical_object', 'whole', 'unit', 'congener', 'living_thing', 'an=
imate_thing', 'organism', 'being', 'benthos', 'dwarf', 'heterotroph', 'pare=
nt', 'life', 'biont']

3) In this case, I have to use loop to get all the lemma_names instead of [=
synset.lemma_names for synset in wn.all_synsets('n')]. The following is a w=
orking solution:

>>> def average_polysemy(pos):
synset_list =3D list(wn.all_synsets(pos))
sense_number =3D 0
lemma_list =3D []
for synset in synset_list:
lemma_list.extend(synset.lemma_names)
for lemma in lemma_list:
sense_number_new =3D len(wn.synsets(lemma, pos))
sense_number =3D sense_number + sense_number_new
return sense_number/len(synset_list)

>>> average_polysemy('n')
3

Thanks again.

 0
typetoken (19)
9/9/2012 1:50:16 PM
> In fact, I'm guessing that's your problem.  I think you're ending up
>
> with a list of lists of strings, when you think you're getting a list of
>
> strings.
>
Thanks. You guess right. It turns out that lemma_list is a list of list, as I tested in the previous post.

 0
typetoken (19)
9/9/2012 2:00:34 PM
> structures are simple, just plain print will work, but for more
>
> complicated structures, pprint.pprint() is a life saver.
>

I did try . However,

>>> pprint.pprint(lemma_list)

Traceback (most recent call last):
File "<pyshell#74>", line 1, in <module>
pprint.pprint(lemma_list)
NameError: name 'pprint' is not defined
>>> pprint.pprint(synset_list)

Traceback (most recent call last):
File "<pyshell#75>", line 1, in <module>
pprint.pprint(synset_list)
NameError: name 'pprint' is not defined
>>>

 0
typetoken (19)
9/9/2012 2:19:42 PM
In article <43a68990-d6cf-4362-8c47-b13ce780b068@googlegroups.com>,
Token Type <typetoken@gmail.com> wrote:

> Thanks very much for all of your tips. Take noun as an example. First, I need
> find all the lemma_names in all the synsets whose pos is 'n'. Second, for
> each lemma_name, I will check all their sense number.
>
> 1)  Surely,we can know the number of synset whose pos is noun by
> >>> len([synset for synset in wn.all_synsets('n')])
> 82115
>
> However, confusingly it is unsuccessful to get a list of lemma names of these
> synsets by
> >>> lemma_list = [synset.lemma_names for synset in wn.all_synsets('n')]
> >>> lemma_list[:20]
> [['entity'], ['physical_entity'], ['abstraction', 'abstract_entity'],
> ['thing'], ['object', 'physical_object'], ['whole', 'unit'], ['congener'],
> ['living_thing', 'animate_thing'], ['organism', 'being'], ['benthos'],
> ['dwarf'], ['heterotroph'], ['parent'], ['life'], ['biont'], ['cell'],
> ['causal_agent', 'cause', 'causal_agency'], ['person', 'individual',
> 'someone', 'somebody', 'mortal', 'soul'], ['animal', 'animate_being',
> 'beast', 'brute', 'creature', 'fauna'], ['plant', 'flora', 'plant_life']]
> >>> type(lemma_list)
> <type 'list'>
>

> Though the lemma_list is a list in the above codes, it contains so many
> unnecessary [ and ]. How come it is like this? But what we desire and expect
> is a list without this brackets. Confused, I am really curious to know why.

It looks like synset.lemma_names gets you a list.  And then you're
taking all those lists and forming them into a list of lists:

>>> lemma_list = [synset.lemma_names for synset in wn.all_synsets('n')]

I think what you want to study is the difference between list.append()
and list.extend().  When you use the list builder syntax, you're
essentially writing a loop which does append operations.  The above is
the same as if you wrote:

lemma_list = list()
for synset in wn.all_synsets('n'):
lemma_list.append(synset.lemma_names)

and I think what you're looking for is:

lemma_list = list()
for synset in wn.all_synsets('n'):
lemma_list.extend(synset.lemma_names)

 0
roy (2295)
9/9/2012 2:29:11 PM
In article <dea2fdd1-ad19-4254-b3bf-4104ce0cb241@googlegroups.com>,
Token Type <typetoken@gmail.com> wrote:

> > structures are simple, just plain print will work, but for more
> >
> > complicated structures, pprint.pprint() is a life saver.
> >
>
> I did try . However,
>
> >>> pprint.pprint(lemma_list)
>
> Traceback (most recent call last):
>   File "<pyshell#74>", line 1, in <module>
>     pprint.pprint(lemma_list)
> NameError: name 'pprint' is not defined
> >>> pprint.pprint(synset_list)
>
> Traceback (most recent call last):
>   File "<pyshell#75>", line 1, in <module>
>     pprint.pprint(synset_list)
> NameError: name 'pprint' is not defined
> >>>

OK, I can see how this can be confusing.  In "pprint.pprint()", the two
"pprint"s mean different things.  The first one is the name of a module.
The second one is the name of a function in that module.  In general, I
dislike this style of naming since it just leads to this kind of
confusion.

In any case, you need to do one of two things.

Style 1:

import pprint
pprint.pprint(foo)

Style 2:

from pprint import pprint
pprint(foo)

 0
roy (2295)
9/9/2012 2:32:33 PM
Token Type wrote:
>> In fact, I'm guessing that's your problem.  I think you're ending up
>>
>> with a list of lists of strings, when you think you're getting a list of
>>
>> strings.
>>
>>
> Thanks. You guess right. It turns out that lemma_list is a list of list, as I tested in the previous post.
>

I often noticed people around me that are not that familiar with python
are dismissing the error stack so quickly ; they probably knows the
machine is trying to communicate with them but they don't seem to
understand the message. Error stacks may be difficult to read at first
glance but you can solve a lot of problems just by reading it.

So next time you see 'X' has no attribute 'Y', you'll know that you've
accessed an attribute/method of an object that does not exist, either
you made a typo in the attribute name, or you object is not actually
what you think it is.

Advice : if you have so time, install ipython and execute your scripts
in an ipython shell with the %pdb faeture on. This will automatically
call the debugger upon unhandled exceptions and you'll be able to
inspect your objects live from the prompt.

JM

 0
jeanmichel (487)
9/10/2012 9:52:34 AM
Thanks. By the way, do we have a list of explanations of error message? If so, whenever we come across error message, we can refer to it and solve the problem accordingly.

 0
typetoken (19)
9/14/2012 3:01:11 PM
Thanks. By the way, do we have a list of explanations of error message? If so, whenever we come across error message, we can refer to it and solve the problem accordingly.

 0
typetoken (19)
9/14/2012 3:01:11 PM
On Fri, 14 Sep 2012 08:01:11 -0700, Token Type wrote:

> Thanks. By the way, do we have a list of explanations of error message?
> If so, whenever we come across error message, we can refer to it and
> solve the problem accordingly.

Forget about a "list of explanations of error message[s]". There is no
such list, and there never will be, because there is no limit to the
number and kind of possible error messages.

Instead, you should actually read the error message you see. Python is
telling you what the problem is. Pay attention to it.

AttributeError: 'list' object has no attribute 'lower'

This tells you that you tried to access something.lower, but "something"
is a list, and lists don't have an attribute or method "lower".

Normally, Python will show you the line of source code with the error, so
you will even see the name of the variable.

--
Steven

 0
9/14/2012 3:18:27 PM
On Sat, Sep 15, 2012 at 1:01 AM, Token Type <typetoken@gmail.com> wrote:
> Thanks. By the way, do we have a list of explanations of error message? If so, whenever we come across error message, we can refer to it and solve the problem accordingly.

Not really, but if you paste the message into Google or DuckDuckGo or
another web search engine, you'll usually find something helpful.
Possibly add a few keywords about what you're doing, if the message
alone is too general.

By the way, you don't need to include both comp.lang.python and
one will make it arrive on the other too.

Have fun!

ChrisA

 0
rosuav (4324)
9/14/2012 3:19:24 PM

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AttributeError: 'gr_hier_block2_sptr' object has no attribute 'set_callback' ------=_Part_1122770_31157900.1360876583037 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit I am using ubuntu 12.10 and python version 2.7.3. i run the following command in terminal: matt@matt-Inspiron-1525:~$ python -m trace --count -C . op25_grc.py Here is the output with an error: Imported legacy fsk4 Using Volk machine: ssse3_32 Traceback (most recent call last): File "/usr/lib/python2.7/runpy.py", line 162, in _run_module_as_main "__main__", fname, loader, pkg_name) File "/usr/lib/python2.7/runpy.py", line 72, in _run_code exec code in run_globals File "/usr/lib/python2.7/trace.py", line 819, in <module> main() File "/usr/lib/python2.7/trace.py", line 807, in main t.runctx(code, globs, globs) File "/usr/lib/python2.7/trace.py", line 513, in runctx exec cmd in globals, locals File "op25_grc.py", line 493, in <module> tb = op25_grc() File "op25_grc.py", line 231, in __init__ self.wxgui_fftsink2_0_0.set_callback(wxgui_fftsink2_0_0_callback) File "/usr/local/lib/python2.7/dist-packages/gnuradio/gr/hier_block2.py", line 54, in __getattr__ return getattr(self._hb, name) AttributeError: 'gr_hier_block2_sptr' object has no attribute 'set_callback' here is the code for "hier_block2_.py": # Copyright 2006,2007 Free Software Foundation, Inc. # # This file is part of GNU Radio # # GNU Radi...

AttributeError: 'module' object has no attribute 'urlopen'
Hey, I am trying to run the following example from diveintopython import urllib sock = urllib.urlopen("http://diveintopython.org/") htmlSource = sock.read() sock.close() print htmlSource I have Python 2.3.3 but when i run the above code I get the following error: raceback (most recent call last): File "urllib.py", line 1, in ? import urllib File "/home/shalen/programming/python/tutorials/py/urllib.py", line 2, in ? sock = urllib.urlopen("http://diveintopython.org/") AttributeError: 'module' object has no attribute 'urlopen' Anyone knows how to fix this and why I am getting this error? Thanks Dont ~ ~ ~ ~ __________________________________ Do you Yahoo!? Yahoo! Mail SpamGuard - Read only the mail you want. http://antispam.yahoo.com/tools dont bother wrote: > import urllib > sock = urllib.urlopen("http://diveintopython.org/") > htmlSource = sock.read() > sock.close() > print htmlSource > > I have Python 2.3.3 but when i run the above code I > get the following error: > > raceback (most recent call last): > File "urllib.py", line 1, in ? > import urllib > File > "/home/shalen/programming/python/tutorials/py/urllib.py", > line 2, in ? > sock = > urllib.urlopen("http://diveintopython.org/") > AttributeError: 'module' object has no attribute > 'urlopen' > This is a name cl...

AttributeError: 'module' object has no attribute 'pack'
Dear List, I have a freshly installed opensuse 11.2 and I am experiencing the following problem with the module "subprocess": sampsa@linux-912g:~> python Python 2.6 (r26:66714, Feb 3 2009, 20:52:03) [GCC 4.3.2 [gcc-4_3-branch revision 141291]] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> import subprocess Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/usr/lib/python2.6/subprocess.py", line 404, in <module> import p...

AttributeError: 'module' object has no attribute 'setdefaulttimeout'
I get those errors when I run: /usr/local/bin/SquidClamAV_Redirector.py -c /etc/squid/SquidClamAV_Redirector.conf ################## Traceback (most recent call last): File "/usr/local/bin/SquidClamAV_Redirector.py", line 573, in ? redirector = SquidClamAV_Redirector(config) File "/usr/local/bin/SquidClamAV_Redirector.py", line 145, in __init__ self.__start_urlhandler__() File "/usr/local/bin/SquidClamAV_Redirector.py", line 454, in __start_urlhandler__ urllib.socket.setdefaulttimeout(self.timeout) AttributeError: 'module' object has no attribute 'setdefaulttimeout' ################# the line that is the problem looks like this: ############# urllib.socket.setdefaulttimeout(self.timeout) ############# from the global sintax: ############## def __start_urlhandler__(self): """ create the urlhandler object """ # set timeout urllib.socket.setdefaulttimeout(self.timeout) self.urlhandler = urllib.URLopener() if self.proxy != {}: self.urlhandler.proxies = self.proxy self.urlhandler.addheaders = [('User-agent', ModuleName + ' ' + str(version))] ############## can you give me a hint with this matter? adrian wrote: > urllib.socket.setdefaulttimeout(self.timeout) > AttributeError: 'module' object has no attribute 'setdef...

AttributeError: 'module' object has no attribute 'letters'
what does this error mean? i am trying to use mark hammonds win32 package. Traceback (most recent call last): File "aui2.py", line 11, in <module> import win32com.client File "C:\Python25\lib\site-packages\win32com\client\__init__.py", line 12, in <module> import dynamic, gencache, pythoncom File "C:\Python25\Lib\site-packages\win32com\client\dynamic.py", line 24, in <module> import build File "C:\Python25\lib\site-packages\win32com\client\build.py", line 507, in <module> valid_identifier_chars = string.le...

'''''''''''''The Running Update/Append Queries Using VBA code Ordeal'''''''''''''' #2

if str_mo not in ('','.') and str_da not in ('','.') and str_yy not in ('','.') Any shorter ?
Hi, there. =20 I'm just curious if it ever dawned on anybody how to abbreviate this line : if str_mo not in ('','.') and str_da not in ('','.') and str_yy not in ('','.')=20 =20 Igor Kurbeko Clinical Programmer Analyst 678 336 4328 ikurbeko@atherogenics.com =20 no brain no pain =20 how about: if not (str_mo in ('','.') or str_da in ('','.') or str_yy in ('','.')) OR if not (missing(str_mo) or missing(str_da) or missing(str_yy)) Eric On 22 Oct 03 21:13:37 GMT, ikurbeko@ATHER...

M2Crypto: AttributeError: 'CSR' object has no attribute 'pkey'
Hello python-guys I am trying to build a python based certificate authority using m2crypto. I am quite new to python and I am asking myself why my code snippets below throw the following Traceback: $python csr.py ....++++++++++++ ................++++++++++++ Traceback (most recent call last): File "csr.py", line 48, in <module> csr.create_cert_signing_request(pubkey, cert_name) File "csr.py", line 17, in create_cert_signing_request cert_request.set_pubkey(keypair) File "/usr/lib64/python2.6/site-packages/M2Crypto/X509.py", line 926, in set_... A function with 'and' , 'not' , 'null' , 'car' and 'cdr' What's this ? (defun enigma (x) (and (not (null x)) (or (null (car x)) (enigma (cdr x))))) "I suppose I should learn Lisp, but it seems so foreign." - Paul Graham, Nov 1983 On Wed, Oct 07 2015, CAI GENGYANG wrote: > What's this ? > > > (defun enigma (x) > (and (not (null x)) > (or (null (car x)) > (enigma (cdr x))))) Bad taste? It returns T if the list X contains nil as an element. It would be clearer to write (some #'null x). Helmut CAI GENGYANG ... AttributeError: 'module' object has no attribute 'DatagramHandler' (ubuntu-8.10, python 2.5.2)$ ~/devel/ice/snoip/freespeech$python Python 2.5.2 (r252:60911, Oct 5 2008, 19:24:49) [GCC 4.3.2] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> import logging >>> logging.DatagramHandler Traceback (most recent call last): File "<stdin>", line 1, in <module> AttributeError: 'module' object has no attribute 'DatagramHandler' >>> That is odd since the documentation says there is DatagramHandler for module logging On Mon, Dec 29, 2008 at 4:08 AM, Tz... When I do from lxml import etree I've this error : AttributeError: 'module' object has no attribute 'BytesIO' Hi, I'm on Ubuntu 8.04.1 I've installed lxml with easy_install lxml command. Now, when I load etree I've this error :$ python Python 2.5.2 (r252:60911, Apr 21 2008, 11:12:42) [GCC 4.2.3 (Ubuntu 4.2.3-2ubuntu7)] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>> from lxml import etree Traceback (most recent call last): File "<stdin>", line 1, in <module> File "lxml.etree.pyx", line 40, in lxml.etree (src/lxml/ lxml.etree.c:119415) AttributeError: 'module&#...

error: expected '=', ',', ';', 'asm' or '__attrib
Hi I'm trying to compile an ADC Driver & come acrosss the following error. I've no experience writing drivers before, and hence have no clue how to fix it. Hope someone out there has encountered the problem & suggesst a fix for the same. The Error is I get is : qadc.c: At top level: qadc.c:97: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'qadc_read' make: *** [qadc.o] Error 1 [root@localhost qadc]# ########################################################################### ADC Driver Code ##...

Override 'and' and 'or'
Is it possible to override 'and' and/or 'or'? I cannot find a special method for it... __and__ and __rand__ and __or__ and __ror__ are for binary manipulation... any proposals? Have marvelous sunday, Marco Dekker <m.aschwanden@gmail.com> wrote: > Is it possible to override 'and' and/or 'or'? I cannot find a special > method for it... __and__ and __rand__ and __or__ and __ror__ are for > binary manipulation... any proposals? If you want to customize the truth value testing you have to implement __nonzero__ " __nonzero__( self) Call...

logical to 'on' / 'off'
Hi, is there a function implemented doing this conversion? my Problem is, that I want to use the following code: set(handles.edit_curr_trq_sl,'Enable',get(hObject,'Value')) where get(hObject,'Value') gives the state of a checkbox thank you! function [str]=tf2oo(logic) switch logic case 0 str='off'; case 1 str='on'; end%switch end%function tf2oo() while i do not know a built in function, I use my own:) meisterbartsch wrote: > > > function [str]=tf2oo(logic) > switch logic > case 0 > str='off'; &g...

'a'..'z'
Is it possible to achieve something like this? switch (mystring.charAt(0)) { case 'a'..'z': // do something break; } "cruster" <cruster@gmail.com> wrote in message news:1151319731.988814.326200@m73g2000cwd.googlegroups.com... > Is it possible to achieve something like this? > > switch (mystring.charAt(0)) { > case 'a'..'z': > // do something > break; > } > There are times when an if statement may be more appropriate ;) Sorry - java is not VB :) -- LTP :) cruster schreef: > Is it possible to achieve somethi...

replacement for '{' and '}' ?
I am still playing around with what kind of syntax I would like to mark up my documents. Are there equivalent long substitutes for { and } when they are not used to describe arguments to functions? Something like \begin{group} and \end{group}. In other words, if I could force myself to write, say, \begin{group} \it ... \end{group} instead of {\it ... }, then I believe I could identify from the markup context what is an argument that belongs to a just invoked macro and what is text. {Of course, in this context, \textit{...} would be better.} No more ambiguity whether a in \myfunction{a} is an argument or just text. Is there a way to make latex barf when it sees an ordinary '{' in text, rather than \begin{group}, but not barf when I want it (to denote macro arguments)? Regards, /iaw On Aug 16, 6:01=A0pm, "ivo...@gmail.com" <ivo...@gmail.com> wrote: > Is there a way to make latex barf when it sees an ordinary '{' in > text, rather than \begin{group}, but not barf when I want it (to > denote macro arguments)? What do you mean exactly? I don't understand. Do you have in mind your- to-be-new-syntax or just regular latex? Cheers, Tomek ivowel@gmail.com wrote: > I am still playing around with what kind of syntax I would like to > mark up my documents. > > Are there equivalent long substitutes for { and } when they are not > used to describe arguments to functions? Something like \begin{group} > and \end{gr...

'[OFF]' as in 'offensive'???
Hi, given that 'off-topicness' is indicated as '[OT]' and taking a look at those postings that started the threads indicated as '[OFF]' (which may both be seen as being somewhat offensive) may lead to the conclusion that '[OFF]' stands for offensiveness. I don't think that this is the intended meaning so what actually *does* '[OFF]' mean? I never came across that abbreviation before (although I have been around on the USENET for quite some time) but maybe it is worth knowing? Josef 'Jupp' Schugt NOTE: mails >100 KiB ...

Web resources about - AttributeError: 'list' object has no attribute 'lower' - comp.lang.python

Resources last updated: 3/13/2016 7:02:43 AM


text:
In Progress
Skill 13 of 13
In Progress

# Summary of the Existence discipline

You have finished the 2st half and have completed the Existence discipline! Continue to to Motion discipline, starting with .

All learned properties and mechanisms are stored as memories on your profile, where you can always go to brush them up. Don’t forget the Existence classroom for aid, questions and guidance while doing the finishing tasks.

New properties
Time$t$
Position$\vec s$
Length / distance$L$
Area$A$
Volume$V$
Angle$\theta$
Quantity$n$
Curvature$k$
Gaussian curvature$G$
New mechanisms
Curvature conservation$G_\text{before}=G_\text{after}$
New phenomena
Shape(arrangement of positions)


text:
It’s common to define the possible choices for a character field on Django models like this (from the docs):

from django.db import models

class Student(models.Model):
FRESHMAN = 'FR'
SOPHOMORE = 'SO'
JUNIOR = 'JR'
SENIOR = 'SR'
YEAR_IN_SCHOOL_CHOICES = (
(FRESHMAN, 'Freshman'),
(SOPHOMORE, 'Sophomore'),
(JUNIOR, 'Junior'),
(SENIOR, 'Senior'),
)
year_in_school = models.CharField(
max_length=2,
choices=YEAR_IN_SCHOOL_CHOICES,
default=FRESHMAN,
)

This works fine and it makes constants available for the values, so that elsewhere you can refer to Student.FRESHMAN. It is quite verbose, though, and doesn’t group the constants together very well.

One way to group the constants more clearly is to use an inner class:

from django.db import models

class Student(models.Model):
class Years:
FRESHMAN = 'FR'
SOPHOMORE = 'SO'
JUNIOR = 'JR'
SENIOR = 'SR'
CHOICES = (
(FRESHMAN, 'Freshman'),
(SOPHOMORE, 'Sophomore'),
(JUNIOR, 'Junior'),
(SENIOR, 'Senior'),
)
year_in_school = models.CharField(
max_length=2,
choices=Years.CHOICES,
default=FRESHMAN,
)

Now the constants are clearly part of one group. We can also refer to them intuitively elsewhere with Student.Years.FRESHMAN. It’s still a little verbose, though, as we have to manually re-define the constants as a choices tuple.

We can make one further improvement on this by using an enum for the inner class:

from enum import Enum
from django.db import models

class ChoiceEnum(Enum):
@classmethod
def choices(cls):
return [(choice.name, choice.value) for choice in cls]

class Student(models.Model):
class Years(ChoiceEnum):
FR = 'Freshman'
SO = 'Sophomore'
JR = 'Junior'
SR = 'Senior'

year_in_school = models.CharField(
max_length=2,
choices=Years.choices(),
default=FRESHMAN,
)

Now we can easily refer to Student.Years.FR.value elsewhere, and the Student model is kept simple and readable.

It also has the nice consequence that we can use the enum as a type-hint elsewhere:

from some_module import Student

def find_students_by_year(year: Student.Year):
pass


text:
# Film Review: Les Misérables (2012)

“Life has dropped you at the bottom of the heap”

For many people, myself included, it is nigh on impossible to approach a film version of stage behemoth Les Misérables with a blank slate. It’s been a mainstay of the musical theatre world since its 1985 London debut – it is most likely the show I have seen the most times throughout my lifetime – and after celebrating its 25th anniversary with an extraordinarily good touring production, has been riding high with a revitalised energy. So Tom Hooper’s film has a lot to contend with in terms of preconceptions, expectations and long-ingrained ideas of how it should be done. And he has attacked it with gusto, aiming to reinvent notions of cinematic musicals by having his actors sing live to camera and bringing his inimitable close-up directorial style to bear thus creating a film which is epic in scale but largely intimate in focus.

In short, I liked it but I didn’t love it. I’m not so sure that Hooper’s take on the piece as a whole is entirely suited to the material, or rather my idea of how best it works. Claude-Michel Schönberg’s score has a sweeping grandeur which is already quasi-cinematic in its scope but Hooper never really embraces it fully as he works in his customary solo shots and close-ups into the numbers so well known as ensemble masterpieces.  ‘At The End Of The Day’ and ‘One Day More’ both suffer this fate of being presented as individually sung segments stitched together but for me, the pieces never really added up to more than the sum of their parts to gain the substantial power that they possess on the stage.

And oddly enough for me, considering how often I have shed tears whilst watching it, I remained largely dry-eyed throughout. I welled up once or twice but to my immense surprise, not a single tear rolled down my cheek. I wonder if expectation had its part to play in this, I know that the removal of a couple of the trigger points from the score did – the second chorus of ‘Drink With Me’ when the female voices join in, the moment when Éponine joins Fantine to harmonise gorgeously in the finale – but there was also an emotional distance to the presentation of some of the bigger solo numbers that didn’t quite work for me. Samantha Barks’ ‘On My Own’ really fell flat here despite being well sung and even Eddie Redmayne’s ‘Empty Chairs…’ and the much-fêted ‘I Dreamed A Dream’, in which Anne Hathaway makes a definitive grab for an Oscar, didn’t transcend from their undoubted poignancy to the genuine show-stopping moments I craved.

Where the film really excels is in the grand scale of the ensemble moments. Helena Bonham Carter and Sacha Baron Cohen as the Thénardiers leading a raucous ‘Master of the House’, the lascivious lovely ladies, the impassioned student revolutionaries, Hooper revels in the opportunities granted by putting together such a talented and ginormous supporting cast and placing them in scenes of epic grandeur. I also loved how he really gave a sense of how limited, in the grand scheme of things, the size of the protest actually was in terms of the scale of the city, ramming home the futility of their efforts as even the city-folk for whom they were fighting turned a blind eye to them – it’s always nice to see a fresh angle on material so familiar.

For the more eagle-eyed among you, there surely cannot be a film filled with more thesp spotting opportunities that you could hope to see, with almost every scene jam-packed with familiar faces from the stage. Amongst my favourite spots were Bertie Carvel’s sleazy Bamatabois, Nicola Sloane’s hair-hungry crone and Gabriel Vick as one of the revolutionaries, but the top one has to be the factory scene in which Kate Fleetwood and Hannah Waddingham lead the other workers, who include Clare Foster and Kirsty Hoiles, in making Fantine’s life a misery – so much female fierceness is almost too much to bear! I’ve included the cast list in all its glory below so that you too can spot any familiar names and when you might spot them in the film.

But a film needs big names in order to be made in the harsh economic climate of today (and of Hollywood in general) and this leads to mixed results. Hugh Jackman commands the screen (when Hooper’s camera allows him to…) as Valjean, with a performance of steely intensity and bearded earnestness that never fails to convince, Anne Hathaway really does bring a majestic rawness to the virtuous but unfortunate Fantine and Eddie Redmayne is surprisingly effective as a sweet and sweet-voiced Marius. Russell Crowe’s Javert is certainly well acted but the vocal demands of the role feel a little beyond him and Amanda Seyfried’s Cosette is a little too tremulously breathy, the result of a vocal part pitched a little too high as much as anything.

But as I started off by saying, so few of us can really approach this film with a genuinely clean slate – so much of the discussion that I’ve had with other people, and indeed my own thoughts, are predicated on an already established idea of how it should be done or how it should sound. Which is fine, we all carry baggage, but I do think that we all ought to remember this a bit more. Russell Crowe may not be the strongest singer but comparing him to one’s favourite stage Javert helps no-one in the end, he is doing a different job here. And for my own part, perhaps I lay too much expectation on being moved by the film in the same way as the theatrical version so perhaps a second viewing to test the tear ducts may be in order.

Full cast list

Jean Valjean . . . . . . . . . . . . . . . . . . . . . . HUGH JACKMAN
Javert  . . . . . . . . . . . . . . . . . . . . . . . . . . RUSSELL CROWE
Fantine  . . . . . . . . . . . . . . . . . . . . . . . . . .ANNE HATHAWAY
Cosette. . . . . . . . . . . . . . . . . . . . . . . .AMANDA SEYFRIED
Thénardier  . . . . . . . . . . . . . . . . . .SACHA BARON COHEN
Madame Thénardier . . . . . . . .HELENA BONHAM CARTER
Marius. . . . . . . . . . . . . . . . . . . . . . . . . . EDDIE REDMAYNE
Enjolras. . . . . . . . . . . . . . . . . . . . . . . . . . . . . AARON TVEIT
Éponine  . . . . . . . . . . . . . . . . . . . . . . . SAMANTHA BARKS
Gavroche  . . . . . . . . . . . . . . . . . . . DANIEL HUTTLESTONE
Convict 1  . . . . . . . . . . . . . . . . . . . . . . .CAVIN CORNWALL
Convict 2  . . . . . . . . . . . . . . . . . . . . . . . . . . . .JOSEF ALTIN
Convict 3  . . . . . . . . . . . . . . . . . . . . . . . . . DAVID HAWLEY
Convict 4  . . . . . . . . . . . . . . . . . . . . . . . . . . . ADAM JONES
Convict 5  . . . . . . . . . . . . . . . . . . . . . . . . . . . . JOHN BARR
Overseer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . TONY ROHR
Mairie Officer  . . . . . . . . . . . . . . . . . . . . . .RICHARD DIXON
Innkeeper  . . . . . . . . . . . . . . . . . . . . . . . .ANDY BECKWITH
Jailer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . STEPHEN BENT
Bishop  . . . . . . . . . . . . . . . . . . . . . . . . . COLM WILKINSON
Madame Baptistine  . . . . . . . . . . . . . . . . . GEORGIE GLEN
Madame Magloire. . . . . . . . . . . . . . . . .HEATHER CHASEN
Constable 1  . . . . . . . . . . . . . . . . . . . . . . PAUL THORNLEY
Constable 2  . . . . . . . . . . . . . . . . . . . . . . . . PAUL HOWELL
Fauchelevent  . . . . . . . . . . . . . . . . . . . . . . .STEPHEN TATE
Foreman . . . . . . . . . . . . . . . . . . . . . . . . .MICHAEL JIBSON
Factory Woman 1 . . . . . . . . . . . . . . . . .KATE FLEETWOOD
Factory Woman 2 . . . . . . . . . . . . HANNAH WADDINGHAM
Factory Woman 3 . . . . . . . . . . . . . . . . . . . CLARE FOSTER
Factory Woman 4 . . . . . . . . . . . . . . . . . . . KIRSTY HOILES
Factory Woman 5 . . . . . . . . . . . . . . . . . . . . . JENNA BOYD
Factory Woman 6 . . . . . . . . . . . . . . . . . . . . . ALICE FEARN
Factory Woman 7 . . . . . . . . . . . . . . . . . ALISON TENNANT
Factory Woman 8 . . . . . . . . . . . . . . . . . . MARILYN CUTTS
Factory Woman 9 . . . . . . . . . . . . . . . . . . . CATHY BREEZE
Factory Onlooker  . . . . . . . . . . . . . . . . . . JOHN ALBASINY
Bamatabois  . . . . . . . . . . . . . . . . . . . . . . . BERTIE CARVEL
Brevet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .TIM DOWNIE
Cochepaille. . . . . . . . . . . . . . . . . . . . . . . ANDREW HAVILL
Bamatabois’ Valet  . . . . . . . . . . . . . . . . . . . . . DICK WARD
Hair Crone  . . . . . . . . . . . . . . . . . . . . . . . NICOLA SLOANE
Pimp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . DANIEL EVANS
Sailor 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . DAVID STOLLER
Sailor 2 . . . . . . . . . . . . . . . . . . . . . . . ROSS MccORMACK
Sailor 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . JAYGANN AYEH
Toothman  . . . . . . . . . . . . . . . . . ADRIAN SCARBOROUGH
Whore 1  . . . . . . . . . . . . . . . . . . . . . . FRANCES RUFFELLE
Whore 2  . . . . . . . . . . . . . . . . . . . . . . . . . . LYNNE WILMOT
Whore 3  . . . . . . . . . . . . . . . . . . . . CHARLOTTE SPENCER
Head Whore . . . . . . . . . . . . . . . . . . . . . . JULIA WORSLEY
Client  . . . . . . . . . . . . . . . . . . . . . . . . . . . . KEITH DUNPHY
Pawn Broker. . . . . . . . . . . . . . . . . . . . . . . ASHLEY ARTUS
Organ-Grinder  . . . . . . . . . . . . . . . . . . . . . JOHN SURMAN
Magistrate  . . . . . . . . . . . . . . . . . . . . . . . . . . .DAVID CANN
Champmathieu. . . . . . . . . . . . . . . . . . . JAMES SIMMONS
Nursing Sister. . . . . . . . . . . . . . . . . . . . . . . . POLLY KEMP
Babet  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .IAN PIRIE
Brujon. . . . . . . . . . . . . . . . . . . . . . . . . . . . .ADAM PEARCE
Clacquesous. . . . . . . . . . . . . . . . . . . . . . .JULIAN BLEACH
Montparnasse  . . . . . . . . . . . . . . . . . . . MARC PICKERING
Young Cosette  . . . . . . . . . . . . . . . . . . . . ISABELLE ALLEN
Young Éponine . . . . . . . . . . . . . . . . . . NATALYA WALLACE
Customer 1. . . . . . . . . . . . . . . . . . . . . . . . PHIL SNOWDEN
Customer 2. . . . . . . . . . . . . . . . . . . . . HADRIAN DELACEY
Baby . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LOTTIE STEER
Tall Customer  . . . . . . . . . . . . . . . . . . . . . . . . . SAM PARKS
Portly Customer . . . . . . . . . . . . . . . . . . . MARK DONOVAN
Handsome Soldier 1. . . . . . . . . . . . . . . . . . . . LEWIS KIRK
Handsome Soldier 2. . . . . . . . . . . . LEIGHTON RAFFERTY
Father Christmas 1. . . . . . . . . . . . . . . . . . . . . PETER MAIR
Father Christmas 2. . . . . . . . . . . . . . . . . . JACK CHISSICK
Inn Whore 1  . . . . . . . . . . . . . . . . . . .DIANNE PILKINGTON
Inn Whore 2  . . . . . . . . . . . . . . . . . . . . . . . ROBYN NORTH
Mother Whore. . . . . . . . . . . . . . . . . . . . . NORMA ATALLAH
Gillenormand  . . . . . . . . . . . . . . . . . . . PATRICK GODFREY
Citizens. . . . . . . . . . . . . . . . . . . . . . . . . . . . .MARK ROPER, PAUL LEONARD
Gavroche’s Urchins  . . . . . . . . . . . . . . . MILES ROUGHLEY, CAMERON STREFFORD, ALFIE DAVIS, JOSEPH WEST
Beggar 1. . . . . . . . . . . . . . . . . . . . . . . . JOEL PHILLIMORE
Beggar 2. . . . . . . . . . . . . . . . JACQUELINE DANKWORTH
Beggar 3. . . . . . . . . . . . . . . . . . . . . . . . .AMELIA JEFFORD
Beggar 4. . . . . . . . . . . . . . . . . . . . . . . . . . CHRIS BARNES
Duc De Raguse  . . . . . . . . . . . . . . . . RICHARD CORDERY
Combeferre  . . . . . . . . . . . . . . . . . . . . KILLIAN DONNELLY
Courfeyrac  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . FRA FEE
Feuilly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GABRIEL VICK
Grantaire. . . . . . . . . . . . . . . . . . . . . . . GEORGE BLAGDEN
Joly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . HUGH SKINNER
Lesgles . . . . . . . . . . . . . . . . . . . . . . . . . . . . .STUART NEAL
Prouvaire  . . . . . . . . . . . . . . . . . . . . . ALISTAIR BRAMMER
Madame Hucheloup. . . . . . . . . . . . . . . . .KATY SECOMBE
Army Officer . . . . . . . . . . . . . . . . . . . . . . HADLEY FRASER
Turning Woman 1 . . . . . . . . . . . . . . . . . . . . LINZI HATELEY
Turning Woman 2 . . . . . . . . . . . . . . . . . . GEMMA WARDLE
Turning Woman 3 . . . . . . . . . . . . . . . . . . . . . . . GINA BECK
Turning Woman 4 . . . . . . . . . . . . . . . . . . . . . . .KATIE HALL
Turning Woman 5 . . . . . . . . . . . . . . . . . . . . . . . .LISA HULL
Turning Woman 6 . . . . . . . . . . . . . . . . . . . . ANDREA DECK
Turning Woman 7 . . . . . . . . . . . . . . . . . JESSICA DUNCAN
Turning Woman 8 . . . . . . . . . . . . . . . . . . . KERRY INGRAM
Majordomo . . . . . . . . . . . . . . . . . . . . . . . JOHN WARNABY
Father Mabeuf  . . . . . . . . . . . . . . . . . . . . . . . .MIKE SARNE
Café Barmaid . . . . . . . . . . . . . . . . . . . . . . . .FREYA PARKS
Mother  . . . . . . . . . . . . . . . . . . . . . . . . . . . . ELLIE BEAVEN
Ensemble “At the End of the Day” . . RICHARD BREMMER, ALEXANDER BROOKS, ELEANOR BRUCE, EMMA DUKES, STEPHEN MATTHEWS, PETER SARACEN, SEBASTIAN SYKES, PHIL ZIMMERMAN
Ensemble Factory Women . . . . . . . . . . . .BESSIE CARTER, HELEN COTTERILL, TRICIA DEIGHTON, MANDY HOLLIDAY, CHARLOTTE HOPE, JACKIE MARKS, SARA PELOSI, MARY ROSCOE, AMELIA SCARAMUCCI, CAROLINE SHEEN
Ensemble “Lovely Ladies”  . . . . . . . . . RACHAEL ARCHER, LORNA BROWN, ANTONIA CLARKE, MARY CORMACK, SONYA CULLINGFORD, HOLLY DALE SPENCER, AMY GRIFFITHS, FANIA GRIGORIOU, AMANDA HENDERSON, ALEXIA KHADIME, LUISA LAZZARO, GEMMA O’DUFFY, ROSA O’REILLY, AMY ELLEN RICHARDSON, OLIVIA ROSE-AARON, ROBYN MIRANDA SIMPSON, RACHEL STANLEY, NANCY SULLIVAN, REBECCA SUTHERLAND, TABITHA WEBB
Ensemble “Master of the House”. . . . . GERARD BENTALL, TONY BIGNELL , MICHAEL CAHILL, RICHARD COLSON , KERRY ELLIS, SIMON FISHER-BECKER , SARAH FLIND, KELLY-ANNE GOWER, JAMES GREENE, NICK HOLDER, CHRIS HOWELL, ALISON JIEAR, TERENCE KEELY, MARTIN MARQUEZ, SALLY MATES, JEFF NICHOLSON, ADAM SEARLES, SIMON SHORTEN
Ensemble Paris Beggars  . . . . . . . . . . . .JULIET ALDERICE, SEAN BUCKLEY, VALERIE CUTKO, SPIKE GRIMSEY, MATT HARROP, GEORGINA JACKSON, PERRY MILLWARD, PHIL PHILMAR, JOYCE SPRINGER, JULIE STARK
Ensemble Students  . . . . . . . . . . . DOMINIC APPLEWHITE, MATTHEW CORNER, ANDY COXON, JONATHAN D. DUDLEY, RHIDIAN MARK, CHRIS MILFORD, JAMIE MUSCATO, JOSEPH PETERS, JONNY PURCHASE, DAVID ROBERTS, STEVEEE ROSS-DAVIES, MATT SEADON YOUNG, JOS SLOVICK, SAMUEL J. WEIR
Ensemble Turning Women  . . . . . . . .SOPHIE HUCHINSON, ELLA HUNT, CLAIRE MACHIN, BRENDA MOORE, MISCHA PURNELL, ANNETTE YEO


text:
# Prove that this is a Banach space

Let $I=[0,1]$ and let $\displaystyle X:=\left\{f: I\times \mathbb R\to \mathbb R\colon \sup_{(t,x)}\frac{|f(t,x)|}{1+|x|}<\infty\right\}$. Prove that $X$, equipped with the norm $\displaystyle \|f\|:=\sup_{(t,x)}\frac{|f(t,x)|}{1+|x|}$ is a Banach space.

My first attempt was to use the characterization that $X$ is a Banach space if and only if every absolutely convergent series converges, but no success.

Then I've noticed that I can prove convergence on every Ball of arbitrarily large radius, however still i cannot conclude on the whole $I\times \mathbb R$. Maybe Ascoli Arzela, but, honestly, i don't know.

Hope you can help me. Thank you.

-
But Arzelà-Ascoli is a theorem about $C(K)$ endowed with the sup norm. Here you have a different norm. So I'm not sure how to apply Arzelà-Ascoli in this case. –  Rudy the Reindeer Jul 28 '12 at 14:32

• The fact that $X$ is a normed space follows from the properties of supremum.
• Take $\{f_k\}\subset X$ a Cauchy sequence. In particular, for each $(t,x)\in [0,1]\times \Bbb R$, the sequence $\{f_k(t,x)\}$ is Cauchy, hence converges to some $f(t,x)$. Fix $\varepsilon>0$, and take $N=n(\varepsilon)$ such that the norm of $f_k-f_j$ is $\leq \varepsilon$ whenever $j,k\geq N$. We have for all $(t,x)\in I\times \Bbb R$ and $k,j\geq N$ that $$|f_j(t,x)-f_k(t,x)|\leq (1+|x|)\varepsilon.$$ We can take the limit in the last equation to show that $f\in X$. Further more, we can show that this gives the convergence of $f_j$ to $f$.
An alternative way is the following. First show that if $X$ is a non-emptyset, the set of bounded real-valued functions defined on $X$, $B(X)$, endowed with the supremum norm is a Banach space. In this particular case, show that $X$ is a closed subspace of $B(X)$.


text:
# Low Pass Filter Transfer Function

I'm trying to get the transfer function of a simple passive pi low pass filter, but I'm a little bit confused about the result.

It comes out that it is a second order filter, but it should be a first order filter. What I'm doing wrong? How should I proceed? I know that I could find the transfer function just by putting the two impedances of the capacitor and the inductor equals, but I would like to find it using another method. Thank you.

• but it should be a first order filter. No, it should be a third order filter as there are 3 reactive components in the circuit. However C1 is in parallel with the input voltage Vin so C1 effectively does nothing making this a second order filter. Oct 6 '17 at 9:24
• So in the frequency response plot there should be three pole? Oct 6 '17 at 9:29
• In an RC filter, R between input and output, C between output and ground. How many reactive components are there. If you do not know the term reactive component then Google that. Why would there be three poles? What is a pole and how does it relate to the transfer function? Does the transfer function have 3 poles? Oct 6 '17 at 9:30
• Yes sorry, I've immediately deleted my comment because I realized that I was wrong, anyway I still does not understand why it comes out that it is a second order filter from the formula. Oct 6 '17 at 9:34
• Normally the CLC filter as in your drawing is used with a source having an output resistance and not like this, input directly at Vin. Because if you define Vin at the input, C1 just follows that voltage and does nothing else. Oct 6 '17 at 9:34

Unfortunately, I could not visualize the circuit you have posted but according to the comments and answer left by Bimpelrekkie, this is a pi filter. Indeed, if there are three energy-storing elements with independent state variables, you have a 3rd-order system. In your case, without a source impedance, the first capacitor plays no role in the input-to-output transfer function. It would indeed if you were to calculate $Z_{in}$ but with a 0-ohm source impedance, it is transparent to determine $H(s)=\frac{V_{out(s)}}{V_{in(s)}}$.

To determine a transfer function swiftly, nothing can beat the Fast Analytical Techniques or FACTs as described here and here. Please consider the below drawing where I have added the basic parasitic elements found in simple inductive and capacitive models. These elements play a role in the frequency response and cannot be neglected if you work in the RF field or in switching converters. These models can of course be made more complicated but then you increase the system order and the difficulty to solve the transfer function goes up significantly.

First, you start with $s = 0$: open the caps and short the inductor. The gain in this mode is 1. Then, to determine the circuit time constants, reduce the excitation $V_{in}$ to 0 V (replace the source by a short circuit) and determine the resistance "seen" from each of the energy storing elements in this mode (assume in your head that you probe the component terminals with an ohm-meter). Inspecting the sketches we have:

$\tau_1=\frac{L_1}{R_{inf}}$ and $\tau_2=C_2(r_L+r_C)$

Then, put one of the energy-storing elements in its high-frequency state (a cap is short circuit and an inductor is open circuited) and "look" at the resistance offered by the other element:

$\tau_{12}=C_2R_{inf}$ and $\tau_{21}=\frac{L_1}{(r_L+r_C)}$

The denominator $D(s)$ of this transfer function is given by:

$D(s)=1+s(\tau_1+\tau_2)+s^2\tau_1\tau_{12}=1+s(\tau_1+\tau_2)+s^2\tau_2\tau_{21}$. If you assemble the above results, you obtain the denominator expression:

$D(s)=1+sC_2(r_L+r_C)+s^2L_1C_2$

For the zero, consider the circuit with the excitation back in place. What condition in this circuit would null the response despite the presence of an excitation? When the series combination of $r_C$ and $\frac{1}{sC_2}$ forms a transformed short circuit: $r_C+\frac{1}{sC_2}=0$ which ends up in a zero defined as $\omega_z=\frac{1}{r_CC_2}$. This is it, we have it all and can express the complete transfer function:

$H(s)=\frac{1+sr_CC_2}{1+sC_2(r_L+r_C)+s^2L_1C_2}$. You must of course put it under the canonical form

$H(s)=\frac{1+\frac{s}{\omega_z}}{1+\frac{s}{Q\omega_0}+(\frac{s}{\omega_0})^2}$ but I leave it to you.

The cool thing with the FACTs is that I did not write a single equation but did just inspect the circuit to determine its time constants. I can go back to the drawings in case I spot a mistake and corrections are easy and fast. A highly-recommended skill to acquire if you have to determine transfer functions! : )

You are effectively solving a second order filter as the first capacitor is in parallel with Vin. There is nothing that C1 can do, it can have a lower impedance at higher frequencies but then voltage source Vin would simply deliver more current. You could remove C1 and at Vout nothing would change.

simulate this circuit – Schematic created using CircuitLab

This is how such a filter is really supposed to be used. Note that I added R1 which allows C1 to do some low-pass filtering.

simulate this circuit

I realize that I offered a simplified expression in which the first capacitor was removed. Actually, as correctly pointed out by Bimpelrekkie, this filter is associated with a source featuring an output resistance so that it combines with the first capacitor and forms a true 3rd-order filter. As a matter of fact, it does not change the path to determine the transfer function using the FACTs as shown below.

Just by determining the time constant of the circuit when the excitation is set to 0 V (replace $V_{in}$ by a short circuit, you can step by step, determine the transfer function of this 3rd-order circuit without writing a single line of algebra! If you made a mistake at the end, spot the guilty drawing, fix it and you're all set. The below Mathcad sheet shows the final result with a formula put under a nice polynomial form.

I have derived a reference transfer function using Thévenin but it would be quite difficult to develop and rearrange it under a meaningful form. With the FACTs, this is easy and swift. Give it a try and you won't go back to classical analysis : )


text:
# Three-Body Problem Problem ( Astronomers )

1. Jan 15, 2010

### choppu

Three-Body Problem Problem ("Astronomers")

Hi,

I am having quite a few problems with the three-body problem. First of all "my" Three-body problem consists of

a static sun (mass 200000 * 1024kg) in the middle of the programme, and two non static planets that revolve around the sun.

I believe this version of the problem is called the "Astronomers" version.

I am not able to find out the differential equation for my version, and would be glad if somebody could point it out to me (preferably with explainations...).

Thanks

choppu

2. Jan 15, 2010

### ideasrule

Re: Three-Body Problem Problem ("Astronomers")

Writing out the differential equations is easy: just write out Newton's second law for all three objects in vector form. Solving them analytically is impossible, as discussed in Wikipedia's article on the n-body problem:

http://en.wikipedia.org/wiki/N-body_problem

3. Jan 15, 2010

### Chronos

Re: Three-Body Problem Problem ("Astronomers")

The n-body problem is incredibly complicated. Even n=3 has not been completely solved. Fortunately, good approximations have be derived. Even large n's can be reasonably approximated with high end computers.

4. Jan 16, 2010

### D H

Staff Emeritus
Re: Three-Body Problem Problem ("Astronomers")

Not quite true. The three-body problem can be deemed fully solved in the sense that an infinite series representation does exist. Karl Sundman developed this series in the early 1900s. He was awarded with the Pontécoulant prize for this work. However (http://scienceworld.wolfram.com/physics/RestrictedThree-BodyProblem.html)
Sundman found a uniformly convergent infinite series involving known functions that "solves" the restricted three-body problem in the whole plane (once singularities are removed through the process of regularization). Since such global regularizations are available for this problem, the restricted problem of three bodies can be considered to be complete "solved." However, this "solution" does not address issues of stability, allowed regions of motion, and so on, and so is of limited practical utility (Szebehely 1967, p. 42). Furthermore, an unreasonably large number of terms (of order 108,000,000) of Sundman's series are required in to attain anything like the accuracy required for astronomical observations.

It doesn't take that high-end a computer. The typical desktop computer or laptop has plenty of oomph. Think of it this way: A 21st century programmable calculator has a lot more computing power than the computers of the 1960s that were used to design trajectories for vehicles that took people to the Moon and took probes to other planets.

Where a lot of computing power is needed is in grinding through the myriad of observations of the planets made over the course of hundreds of years and eclipses made over the course of thousands of years to determine a best-fit state for all the planets at some epoch time. This is a boundary value problem from Hades. Numerically propagating a given state over time is far a simpler problem.

5. Jan 16, 2010

### twofish-quant

Re: Three-Body Problem Problem ("Astronomers")

Also there are restricted three body problems whose solutions are very well known. One common problem for which simple solutions do exist is the problem of two bodies and a spaceship.

6. Jan 16, 2010

### D H

Staff Emeritus
Re: Three-Body Problem Problem ("Astronomers")

Only if the spaceship is at one of the libration points. The general problem of a spaceship subject to the gravitational force of two bodies is the restricted three body problem. The restricted three body problem, like the unrestricted three body body, is insoluble in terms of elementary functions.

7. Jan 16, 2010

### choppu

Re: Three-Body Problem Problem ("Astronomers")

Hi guys,

I do not quite understand how I can write out F=ma for all three objects in vector form. Can you maybe demonstrate it to me with an example please?

8. Jan 16, 2010

### Matterwave

Re: Three-Body Problem Problem ("Astronomers")

F=ma and F=-GMm/r^2 is needed (in vector form).

Now, for one object, you have

$$F_1=m_1a_1=\frac{-Gm_1m_2}{r_{12}^2}-\frac{Gm_1m_3}{r_{13}^2}$$
(Put the vectors in there, I'm too lazy atm)

So, that one object is affected by the gravitational forces on it due to the other two objects.

You get 3 such equations.

9. Jan 17, 2010

### choppu

Re: Three-Body Problem Problem ("Astronomers")

Ok, thanks for explaining.

I still do not understand how I can split up these equations to gain two (six?) first order differential equations.

Can anybody point it out to me please?

10. Jan 17, 2010

### D H

Staff Emeritus
Re: Three-Body Problem Problem ("Astronomers")

One common way to express Newton's law of gravitation vectorially is

$$\vec F_{i,j} = \frac {Gm_im_j}{||\vec r_j - \vec r_i||^3}(\vec r_j - \vec r_i)$$

where
• $$\vec F_{i,j}$$ is the gravitational force exerted on body i by body j.
• $$G$$ is the universal gravitational coefficient.
• $$m_i$$ and $$m_j$$ are the masses of bodies i and j.
• $$\vec r_i$$ and $$\vec r_j$$ are the position vectors of bodies i and j expressed in some inertial coordinates and with respect to the origin of some inertial reference frame, which is typically the ensemble center of mass.

Acceleration rather than force is needed to propagate state. On combining the above with Newton's 2nd law the mass of body i cancels out. The component of the acceleration on body i as induced by body j is thus

$$\vec a_i = \frac {\mu_j}{||\vec r_j - \vec r_i||^3}(\vec r_j - \vec r_i)$$

Here, $$\mu_j$$ is the "standard gravitational coefficient" for body j. Conceptually, this is just the product of the universal gravitational coefficient G and the mass of body j. However, solar system astrophysicists *never* use this product, G*mj. The reason is twofold. First, the standard gravitational coefficients for many of the bodies in the solar system are observable quantities. The masses of the Sun and the planets are not directly observable. The second reason is precision. The uncertainty in G is a lousy 1 part in of 10,000. The standard gravitational parameters for the Sun and the eight planets are known to much greater precision (e.g., 1 part in 1010 for the Sun). See [thread=271501]this thread[/thread] for details.

To find the total acceleration of body i, just sum the accelerations induced by all of the other bodies in the simulation:

$$\vec a_i = \sum_{j\ne i} \frac {\mu_j}{||\vec r_i - \vec r_j||^3}(\vec r_i - \vec r_j)$$

Last edited: Jan 17, 2010
11. Jan 17, 2010

### Chronos

Re: Three-Body Problem Problem ("Astronomers")

Apologies, I do not see a simple n=3 solution in this mix. I confess to being dense.

12. Jan 17, 2010

### choppu

Re: Three-Body Problem Problem ("Astronomers")

Hi and thanks D H,

I was attempting to use a numerical solution on this problem, however I do not see how to begin. How to attempt to solve these two differential equations numerically (by example eulers method) ?

All you got is the equation for the accelerations...

13. Jan 17, 2010

### D H

Staff Emeritus
Re: Three-Body Problem Problem ("Astronomers")

What else do you need? Remember, acceleration is the derivative of velocity, and velocity is the derivative of position.

14. Jan 17, 2010

### choppu

Re: Three-Body Problem Problem ("Astronomers")

So i need to integrate the equations two times?

15. Jan 17, 2010

### D H

Staff Emeritus
Re: Three-Body Problem Problem ("Astronomers")

You will definitely need to integrate N*6 scalar states, where N is the number of bodies. If you want to look at this as integrating twice, then the answer is "yes".

However, a second-order differential equation can always be reduced to a first-order differential equation. For example, Newton's second law is a second order differential equation. Ignoring the vectorial nature of things for a bit, Newton's second law for a constant-mass object subject to some external force is

$$\ddot x(t) = \frac{F(t)}{m}$$

To convert this to a first-order differential equation, construct a state vector u that comprises the object's position x and velocity v:

$$\vec u \equiv \bmatrix x \\ v \endbmatrix$$

The derivative of this vector is

$$\frac{d}{dt}\vec u(t) = \bmatrix u_2(t) \\ F(t)/m \endbmatrix$$

where u2 is just the second element (the velocity element) of the vector u.

Bottom line: Augmenting the state with the velocity changed the initial second order differential equation to a first order differential equation.1 This technique also works for vectors as well as scalars. Instead of adding 1 element to the state, you simply add n elements to the state -- the time derivatives of each of the n elements of the vector. This is exactly what you are going to need to do if you want to use a Runge-Kutta method to propagate the state of the system.

To answer the question posed in your last post: If you envision the position & velocity vectors for all N bodies in your simulation as forming one big vector with N*6 elements, you will only have to integrate once.2

There is a problem with this augmented state approach. Suppose you use this approach and you use Euler's method to perform the integration. Your simulated solar system won't hang together for long. This basic use of Euler's method fails to conserve energy. There is a simple solution variously called symplectic Euler, Euler–Cromer, semi-implicit Euler (and others). Calculate all of the accelerations (see the second footnote). Then for each body, integrate the velocity vector using the calculated acceleration for that body and then integrate the position vector using the integrated velocity.3 This simple change makes a huge difference. Energy is conserved and orbits are bounded (more-or-less).4

==============

1 This technique works for any order differential equation. For example, see http://en.wikipedia.org/wiki/Ordinary_differential_equation#Reduction_to_a_first_order_system.

2 One advantage of this "big honkin state vector" approach is that it ensures that the accelerations are time synchronous. If you integrate each body separately you will need to ensure that you calculate all of the accelerations before you propagate any of the positions.

3 Using the Euler method to integrate the augmented state essentially does this in reverse order: It integrates the position vectors using the current velocity vectors and then integrates the velocity vectors (but using the accelerations calculated from the position vectors prior to the update).

4 If you want to know more about these kinds of techniques, google the terms "symplectic integrator" and "geometric integrator". Just as basic Euler method is a starting point for numerical integration in general, the symplectic Euler method is a starting point for integration methods that conserve some quantity of interest (e.g., energy) in some dynamic system.

16. Jan 17, 2010

### choppu

Re: Three-Body Problem Problem ("Astronomers")

However I still don't understand how I can figure out the x and y coordinates... as in the "current" x and y position. Because all there is now is that first order Differential equation. How do I figure out the X and Y coordinates? Is there a way to split them up or some other way?

Thanks

17. Jan 18, 2010

### Redbelly98

Staff Emeritus
Re: Three-Body Problem Problem ("Astronomers")

You'll need to supply initial values for x, y, vx, vy for each planet. Then use a numerical procedure (eg. Runge-Kutta) to work out how x and y evolve over time for each planet.