text:
Table tennis exercise builder

I am trying to create a builder for table tennis exercises. User Blindman67 helped me here. Now I'm trying to clean up the code before continuing to work on it. Please tell me how to clean up the code so JSLint does not give any more warnings. If you notice any other things, feel free to tell me. I'm a newbie :)

My main problems are:

• Using "use strict"; and this in the same function gives a "strict violation". I would like to use "use strict";, but does that mean every this has to be rewritten to something else?
• JSLint doesn't like the bitwise operators. What is the "JSLint-approved"-way to say |= and &= (lines 292 and 294)?
• JSLint also doesn't recognize the arrow operator => (lines 530 and 533). I managed to replace one in line 318 with an extra function, but I cant figure out how to do it in the lines 530 and 533.
• The createAddTable function depends on drawEmpty, drawEmpty depends on addTable and addTable depends on createAddTable. Now JSLint tells me to put one in front of the other so I dont call something I dont have defined yet. How can I solve this?

// contains an array of tables.
var tableArray = [];
// App constants all up top
var GLOBAL_SCALE = 1;
var SHOW_HELP = true; // set to false to have the help turned off
var WHITE = "white";
var TABLE_REFRESH_DELAY = 50; // Time in millisecond befor updating DOM for table add and remove
var FONT = {
face: "px Arial",
size: Math.max(10, 18 * GLOBAL_SCALE),
fill: WHITE
};
var TABLE = {
width: 223 * GLOBAL_SCALE, // size of table
height: 314 * GLOBAL_SCALE,
tables: document.getElementById("tables"),
image: { // table image styles
fill: "#2e3f73",
lines: WHITE,
font: FONT,
cursor: "default"
},
empty: { // empty table styles
inset: 30 * GLOBAL_SCALE, // amount box is inset
lines: 'rgba(255,255,255,0.5)',
lineWidth: 8 * GLOBAL_SCALE,
font: FONT,
cursor: "pointer",
highlightAmount: 0.3 // amount to highlight empty table when mouse over 0 none 1 full
},
arrow: { // arrow styles
width: 15 * GLOBAL_SCALE, // arrow width
// custom cursor
fill: "#ffb900",
highlight: "#ffdc44",
lineWidth: 1,
line: "#ffdc44",
lineHigh: "#ffed55",
minSize: 5 // min size arrow can be if smaller then arrow is not created
},
DOM: { // variouse dom setting for table canvas and div tags
display: "inline-block",
canvasClass: "table",
zIndex: 1
},
closeIcon: { // styles for reandering and display close icon
size: 32 * GLOBAL_SCALE,
fill: "red",
lines: WHITE,
lineWidth: Math.max(1, 2 * GLOBAL_SCALE),
cursor: "pointer",
pos: {
x: 1, // as fractions
y: 0
}
},
help: { // text help
active: ["Click to drag arrows"],
activeArrow: ["Right click on arrow", "to remove it"],
closeTable: ["close table", "move to top right", "click Close Icon"]
}
};
var MOUSE = { // event contains a list of mouse event to listen to
buttonMasks: [1, 2, 4, 6, 5, 3],
events: ["mousemove", "mousedown", "mouseup", "mouseout", "mouseover", "contextmenu"]
}; // contextmenu is included as that needs to be blocked for right button events
var helpItemsUsed = {
empty: false,
active: false,
activeArrow: false,
closeTable: false
};
var turnOffHelp = function() {
"use strict";
helpItemsUsed.empty = true;
helpItemsUsed.active = true;
helpItemsUsed.activeArrow = true;
helpItemsUsed.closeTable = true;
};
if (!SHOW_HELP) {
turnOffHelp();
}
// returns distance of point p to line segment x, y,xx,yy
var distFromLine = function(px, py, x, y, xx, yy) {
"use strict";
var vx, vy, pvx, pvy, lx, ly, u;
vx = xx - x;
vy = yy - y;
pvx = px - x;
pvy = py - y;
u = (pvx * vx + pvy * vy) / (vy * vy + vx * vx);
if (u >= 0 && u <= 1) {
lx = vx * u;
ly = vy * u;
return Math.sqrt(Math.pow(ly - pvy, 2) + Math.pow(lx - pvx, 2));
}
// closest point past ends of line so get dist to closest end
return Math.min(Math.sqrt(Math.pow(xx - px, 2) + Math.pow(yy - py, 2)), Math.sqrt(Math.pow(x - px, 2) + Math.pow(y - py, 2)));
};
// set up functions create images and do other general setup
function setupContext(ctx, descript) { // sets common context settings
"use strict";
ctx.strokeStyle = descript.lines;
ctx.fillStyle = descript.fill;
ctx.lineWidth = descript.lineWidth;
ctx.lineCap = "round";
if (descript.font) {
ctx.font = descript.font.size + descript.font.face;
}
}

function createTableImage() { // create image of table but why write a comment when the function tells it all???
"use strict";
var table = document.createElement("canvas"),
ctx = table.getContext("2d"),
scaleX = TABLE.width / 223, // get the scale compared to original layout
scaleY = TABLE.height / 314; // get the scale compared to original layout

table.height = TABLE.height;
setupContext(ctx, TABLE.image);

ctx.fillStyle = TABLE.image.fill;
ctx.fillRect(35.25 * scaleX, 20 * scaleY, 152.5 * scaleX, 274 * scaleY);
ctx.fillStyle = TABLE.image.lines; // lines
ctx.fillRect(111.35 * scaleX, 20 * scaleY, 0.3, 274 * scaleY); // middle line
ctx.fillRect(35.25 * scaleX, 20 * scaleY, 2, 274 * scaleY); // left side
ctx.fillRect(185.75 * scaleX, 20 * scaleY, 2, 274 * scaleY); // right side
ctx.fillRect(35.25 * scaleX, 20 * scaleY, 152.5 * scaleX, 2); // top base line
ctx.fillRect(35.25 * scaleX, 292 * scaleY, 152.5 * scaleX, 2); // bottom base line
ctx.fillRect(20 * scaleX, 156 * scaleY, 183 * scaleX, 2); // net
return table;
}

function createEmptyImage() { // empty table image
"use strict";
var i = TABLE.empty.inset,
image = document.createElement("canvas"),
w = image.width = TABLE.width,
h = image.height = TABLE.height,
ctx = image.getContext("2d");
setupContext(ctx, TABLE.empty);
ctx.strokeRect(i, i, w - i * 2, h - i * 2);
ctx.beginPath();
ctx.moveTo(i * 2, i * 2);
ctx.lineTo(w - i * 2, h - i * 2);
ctx.moveTo(i * 2, h - i * 2);
ctx.lineTo(w - i * 2, i * 2);
ctx.stroke();
return image;
}

function createCloseImage() { // create close icon
"use strict";
var S = TABLE.closeIcon.size,
s = S * 0.5,
c = s * 0.4, // cross dist from center
l = TABLE.closeIcon.lineWidth,
image = document.createElement("canvas"),
cx = s + sb / 2, // add half blur to get center
cy = s + sb / 2,
ctx = image.getContext("2d");
image.width = S + sb; // add blur to size
image.height = S + sb;
setupContext(ctx, TABLE.closeIcon);
ctx.beginPath();
ctx.arc(cx, cy, s - l, 0, Math.PI * 2);
ctx.fill();
ctx.stroke();
ctx.beginPath();
ctx.moveTo(cx - c, cy - c);
ctx.lineTo(cx + c, cy + c);
ctx.moveTo(cx - c, cy + c);
ctx.lineTo(cx + c, cy - c);
ctx.stroke();
return image;
}
// create the images
var tableImage = createTableImage();
var closeIcon = createCloseImage();
var emptyTableImage = createEmptyImage();
// draws a arrow a is the arrow object
function drawArrow(ctx, a) {
"use strict";
var s = TABLE.arrow, // get arrow style
x = a.x,
y = a.y,
vx = a.xx - x,
vy = a.yy - y,
dir = Math.atan2(vy, vx),
len = Math.sqrt(vx * vx + vy * vy),
w = s.width / 2,
h = Math.min(len, s.head); // ensure arrow head no bigger than arrow length
// ctx.save();
ctx.setTransform(1, 0, 0, 1, x, y);
ctx.rotate(dir);
h /= 2;
if (a.highlight) {
ctx.fillStyle = s.highlight;
ctx.strokeStyle = s.lineHigh;
} else {
ctx.fillStyle = s.fill;
ctx.strokeStyle = s.line;
}
ctx.lineWidth = s.lineWidth;
ctx.save();
ctx.beginPath();
ctx.moveTo(0, -w / 2);
ctx.lineTo(len - h - h, -w);
ctx.lineTo(len - h - h, -h);
ctx.lineTo(len, 0);
ctx.lineTo(len - h - h, h);
ctx.lineTo(len - h - h, w);
ctx.lineTo(0, w / 2);
ctx.closePath();
ctx.fill();
ctx.stroke();
ctx.restore();
}
// display help text for table

function drawHelpText(ctx, text, style) {
"use strict";
var i,
len = text.length,
y = ctx.canvas.height / 2 - len * style.font.size * 1.2,
yy = y + 1;
ctx.font = style.font.size + style.font.face;
ctx.textAlign = "center";
ctx.textBaseline = "middle";
ctx.strokeStyle = "#000";
ctx.lineWidth = 2;
for (i = 0; i < len; i += 1) {
ctx.strokeText(text[i], ctx.canvas.width / 2 + 1, yy);
yy += TABLE.empty.font.size * 1.2;
}
ctx.fillStyle = style.font.fill;
for (i = 0; i < len; i += 1) {
ctx.fillText(text[i], ctx.canvas.width / 2, y);
y += TABLE.empty.font.size * 1.2;
}
}
//------------------------------------------------------------
// functions for table

function drawClose() { // draws close icon. Fades in the close mouse is
var ctx = this.ctx,
w = closeIcon.width,
grow = w * 0.1,
x = (this.width - w) * TABLE.closeIcon.pos.x,
y = (this.height - w) * TABLE.closeIcon.pos.y,
ic_x = x + w / 2, // icon x and y
ic_y = y + w / 2,
dist = Math.sqrt(Math.pow(this.mouse.x - ic_x, 2) + Math.pow(this.mouse.y - ic_y, 2));

if (dist < TABLE.closeIcon.size / 2) {
this.mouseOverClose = true;
} else {
this.mouseOverClose = false;
}
ctx.globalAlpha = 1 - (Math.min(100, (dist - w * 2)) / 100);
if (this.mouseOverClose) {
ctx.drawImage(closeIcon, x - grow, y - grow, w + grow * 2, w + grow * 2);
} else {
ctx.drawImage(closeIcon, x, y);
}
ctx.globalAlpha = 1;
}

function mouseEvent(e) {
var m = this, // lazy programer short cut
t = e.type,
bounds = m.element.getBoundingClientRect();
m.x = e.clientX - bounds.left;
m.y = e.clientY - bounds.top;
if (t === "mousedown") {
} else if (t === "mouseup") {
} else if (t === "mouseout") {
m.button = 0;
m.over = false;
m.table.mouseOver();
} else if (t === "mouseover") {
m.over = true;
m.table.mouseOver();
}
e.preventDefault();
}

function removeTable(table) { // remove table from dom
"use strict";
table.mouse.remove(); // deactivate moue events
TABLE.tables.removeChild(table.div); // remove from DOM
table.dead = true; // flag as dead to be removed from table array
}

function updateTables() { // Updates tables. Removes any dead tables from table array
"use strict";
var closeTables = [],
i;

closeTables = tableArray.filter(function(t) {
return !t.active;
});
while (closeTables.length > 1) {
removeTable(closeTables.shift());
}
for (i = 0; i < tableArray.length; i += 1) {
tableArray.splice(i, 1);
i -= 1;
}
}
}

function drawTable() { // darw the table all states
var ctx = this.ctx,
minDist = TABLE.arrow.width, // this sets the max distance mouse can be for it to highlight an arrow
dist = 0,
i;

ctx.clearRect(0, 0, ctx.canvas.width, ctx.canvas.height);
if (this.active) {
ctx.drawImage(tableImage, 0, 0);
if (this.mouse.over) {
if (!this.dragging) { // Dont draw close icon while draggin
this.drawCloseIcon();
}
if (this.mouseOverClose && !this.dragging) { // if not dragging and mouse over close
this.cursor = TABLE.closeIcon.cursor; // set cursor
if (this.mouse.button === 1) { // bit field  is mouse left down
this.buttonDown = true;
} else if (this.buttonDown) { // only close if mouse moves up while over close.
this.active = false;
helpItemsUsed.closeTable = true;
this.buttonDown = false;
setTimeout(updateTables, TABLE_REFRESH_DELAY);
}
} else { // not over close
// if near a arrow and mouse button right is down delete the arrow
if (this.closestArrowIndex > -1 && this.mouse.button === 4) { // but field Only button right down
this.arrows.splice(this.closestArrowIndex, 1);
this.closestArrowIndex = -1;
this.mouse.button = 0; // turn mouse click off
helpItemsUsed.activeArrow = true; // flag arrow delete help as used
} else if (this.mouse.button === 1) { // bit field  if down start dragging new arroe
if (!this.dragging) { // Start of drag create arrow
this.arrows.push({
x: this.mouse.x,
y: this.mouse.y,
xx: this.mouse.x,
yy: this.mouse.y
});
this.currentArrow = this.arrows[this.arrows.length - 1];
this.dragging = true;
} else { // during drag move arrow endpoint
helpItemsUsed.active = true; // flag arrow help as used
this.currentArrow.xx = this.mouse.x;
this.currentArrow.yy = this.mouse.y;
}
} else { // mouse up
if (this.dragging) { // is dragging then must be a arrow
// if arrow added is smaller than 2 pixels then remove it;
if (Math.abs(this.currentArrow.xx - this.currentArrow.x) < TABLE.arrow.minSize && Math.abs(this.currentArrow.y - this.currentArrow.yy) < TABLE.arrow.minSize) {
this.arrows.length -= 1;
}
this.currentArrow = null;
this.dragging = false;
}
}
this.cursor = TABLE.image.cursor; // set cursor tp table standard
}
}
if (this.closestArrowIndex > -1 && !this.dragging) { // is mouse near arrow
this.cursor = TABLE.arrow.cursor; // yes set cursor for arrow
}
this.closestArrowIndex = -1;
for (i = 0; i < this.arrows.length; i += 1) { // test all arrow
var a = this.arrows[i];
drawArrow(ctx, a); // draw the arrow
a.highlight = false; // turn off highlight
dist = distFromLine(this.mouse.x, this.mouse.y, a.x, a.y, a.xx, a.yy); // get distance from mouse
if (dist < minDist) { // is closer than any other arrow
this.closestArrowIndex = i; // yes remember the index
minDist = dist;
}
}
if (this.closestArrowIndex > -1 && this.mouse.over) { // is a arror close to mouse
this.arrows[this.closestArrowIndex].highlight = true; // highlight it
}
ctx.setTransform(1, 0, 0, 1, 0, 0); // reset transform after arrows drawn
// show help
if (this.mouse.over) {
if (this.arrows.length === 0 && !helpItemsUsed.active) {
drawHelpText(ctx, TABLE.help.active, TABLE.image);
} else if (this.closestArrowIndex > -1 && !helpItemsUsed.activeArrow) {
drawHelpText(ctx, TABLE.help.activeArrow, TABLE.image);
} else if (this.closestArrowIndex === -1 && !helpItemsUsed.closeTable) {
drawHelpText(ctx, TABLE.help.closeTable, TABLE.image);
}
}
} else {
this.drawEmpty();
}
}

// renders a table. Stops rendering if the mouse is not over
function tableUpdate() {
if (this.mouse.over) {
this.updating = true;
requestAnimationFrame(this.update);
} else {
this.buttonDown = false; // turn of button if dragged off
this.div.style.cursor = "default";
this.updating = false;
this.draw(); // draw another time. This alows for the visual state to be correct
}
this.draw();
this.div.style.cursor = this.cursor;
}

// Mousecallback starts a table rendering if not allready doing so.
function mouseInOutCallback() {
if (this.mouse.over) {
if (!this.updating) {
this.update();
}
} else {
this.div.style.cursor = "default";
}
}

function createAddTable() { // Creates a table. Tables default in inactive
"use strict";
var table = {},
div = document.createElement("div"),
canvas = document.createElement("canvas");
div.style.width = TABLE.width + "px";
div.style.height = TABLE.height + "px";
div.style.display = TABLE.DOM.display;
canvas.width = TABLE.width;
canvas.height = TABLE.height;
canvas.className = TABLE.DOM.tableClass;
canvas.style.zIndex = TABLE.DOM.zIndex;
table.div = div;
table.canvas = canvas;
table.ctx = canvas.getContext("2d");
table.arrows = [];
table.width = TABLE.width;
table.height = TABLE.height;
table.mouseOverClose = false;
table.drawCloseIcon = drawClose;
table.draw = drawTable;
table.dragging = false;
table.active = false;
table.update = tableUpdate.bind(table);
table.mouseOver = mouseInOutCallback; // called by mouseEvent when mouse over out
table.drawEmpty = drawEmpty.bind(table);
table.dead = false; // when removed and not needed it is dead and can then be removed from table array
table.updating = false; // true is animation requests are happening
table.mouse = createMouse(table);
table.draw();
return table;
}

function addTable() { // Adds a table to table array and DOM
"use strict";
var table = createAddTable(); // create new table
TABLE.tables.appendChild(table.div); // add to the dom
table.mouse.start(); // start the mouse
tableArray.push(table); // add to table array
return table;
}

function drawEmpty() { // draw empty table and handle click on empty table
var ctx = this.ctx;
ctx.drawImage(emptyTableImage, 0, 0);
if (this.mouse.over) {
ctx.globalCompositeOperation = "lighter";
ctx.globalAlpha = TABLE.empty.highlightAmount;
ctx.drawImage(emptyTableImage, 0, 0);
ctx.globalAlpha = 1;
ctx.globalCompositeOperation = "source-over";
if (!helpItemsUsed.empty) { // show help is the help action has not yet been done
drawHelpText(ctx, TABLE.help.empty, TABLE.empty);
}
this.cursor = TABLE.empty.cursor;
if (this.mouse.button === 1) { // bit field
this.buttonDown = true;
} else if (this.buttonDown) {
this.active = true;
this.buttonDown = false;
helpItemsUsed.empty = true; // flag this help as not needed as user has complete that task
}
} else {
this.cursor = "default";
}
}

// create the mouse inteface for a table
function createMouse(table) {
var mouse = {
x: 0,
y: 0,
over: false,
table: table,
element: table.div,
button: 0
};
mouse.event = mouseEvent.bind(mouse);
mouse.start = function() {
MOUSE.events.forEach(n => {
});
}
mouse.remove = function() {
MOUSE.events.forEach(n => {
this.element.removeEventListener(n, this.event);
});
}
return mouse;
}

addTable();
body {
background-color: #982439;
}
#table {
}
canvas {
position: absolute;
}
<div id="tables">
</div>

This turned out to be a bit lengthy. I am not sure if I covered everything, but this should help you with cleaning up your code.

JSLint

Strings

In Javascript strings can be surrounded by both double quotes and single quotes. JSLint wants you to turn all single quoted strings into double quoted strings to make strings uniform. If you need to use a double quote in such a string, escape it (\").

Variable declaration

JSLint expects you to declare one variable per line, per var keyword. While you can chain variable declarations together with commas, doing so makes it harder to find the declaration of a particular variable, and is error prone if the declarations are split over multiple lines. Forgetting a comma will cause automatic insertion of a semicolon (ASI), which will drop the following variables in the global scope. This will produce hard to debug bugs. Modifying such a continued statement is harder, because removing or adding a variable does not only involve that variable, but also the variables around it.

Trailing space

JSLint complains about a trailing space, because it is invisible without an other character behind it. It's hardly an error, but easy to correct with a global replace in your editor/IDE.

for-loops

JSLint recommends usage of the array functions over a raw for-loop. For example, you can rewrite the following for-loop:

for (i = 0; i < len; i += 1) {
ctx.strokeText(text[i], ctx.canvas.width / 2 + 1, yy);
yy += TABLE.empty.font.size * 1.2;
}

to use Array.prototype.forEach(..) instead.

text.forEach(function(cur) {
ctx.strokeText(cur, ctx.canvas.width / 2 + 1, yy);
yy += TABLE.empty.font.size * 1.2;
});

The following for-loop is actually a complicated filter:

  for (i = 0; i < tableArray.length; i += 1) {
tableArray.splice(i, 1);
i -= 1;
}
}

  tableArray = tableArray.filter(function(cur) {
});

You will see that it is much easier to see what you are doing with the for-loop when you write it with one of the array functions instead. In some cases it will only add clarity which array you are looping through, while in some cases it will clean up the code a lot and makes it trivial to verify that your code is actually doing what you expect it to do.

this

JSLint wants you to avoid this regardless if you use strict mode. this has it's uses, but you don't need to use it usually. There is this answer on SO that goes in great detail on this. Avoiding this will prevent problems where you suddenly can't reference a variable, because the code is inside a handler, causing you to have to alias this. Similarly, it avoids ambiguity in the code when reading it later, because you don't have to remember which contexts are using their own this.

In strict mode, this is... stricter. It no longer exposes the window object and no longer boxes everything into an object. You can read mdn and this answer on why it impacts anonymous functions.

The "strict violation" may not actually cause a problem when the code is run. JSLint does not have the luxery of evaluating this at run-time, and will return an error when it thinks it might cause a problem. You can read this answer about why it is illegal to use this in that context. To get rid of the error, simply avoid this altogether.

Some added explanation at the end.

Bitwise operators

The bitwise operators are rarily used in javascript, and JSLint will report usage of each and every one of them, because often usage of one is simply a typo. I am not sure why you are using e.which near that code, but it is non-standard and should not be used.

In any case, review each case of this error manually, and ignore those that actually make sense in your code.

Arrow functions

JSLint only wants arrow functions when the arguments are surounded by parenthesis, and the body of the function does not have braces around it. That means that arrow functions according to JSLint may only consist of one statement, and that it returns whatever the return value of that one statement is. If you don't care if it returns anything or not, remove the braces. Otherwise just create a regular anonymous function.

Circular references

Your problem has everything to do with circular references. The best solution is always to refactor the code in such a way that these circular references are not needed.

If you are just out to get rid of jslint errors, you can do it with forward declaration:

var a;
var b = function() {
a();
};
a = function() {
b();
};

Chained assignment

You have two chained assignment statements. JSLint complains about them. I am not a huge fan of them, because it adds extra work when one of the chained variables needs to have a different value.

Other issues

These are issues that JSLint does not complain about, but are things that should be improved in my opinion.

Variable names

You are using a lot of one letter variable names. Remember that by not typing out variables now will produce a headache when you read it back in 2 days time. Do yourself and other maintainers a favour and type out all the variable names.

ES6

You are using arrow functions, which means you are using ES6. Another useful thing in ES6 are the const and let keywords. Where var is subject to variable hoisting, and leaks out of loops they were defined in, let behaves a lot better and is only defined from the moment you declare it, and only lives to the end of the current block. const is used for constants. If you use ES6 features, I recommend using let everywhere you can't use const, and use const everywhere else. Instead of doing this:

// App constants all up top
var GLOBAL_SCALE = 1;
var SHOW_HELP = true; // set to false to have the help turned off

do this:

// App constants all up top
const GLOBAL_SCALE = 1;
const SHOW_HELP = true; // set to false to have the help turned off

You can not assign a new value to constants, not even accidentally. What you assign to a constant is by default not immutable, but in case of objects you can for example freeze it.

Code between function declarations

Between createCloseImage(..) and drawArrow(..) you did hide some code. Don't do this. Instead move this code up towards the rest of the code, or into a constructor.

Classes

Speaking of which... It looks like the code was once in a class, but no longer is. I recommend encapsulating this code in a class. Your use of this makes no sense in this context, but likely used to point to your class instance. Since you use ES6, you can use the syntactic sugar added for classes. In any case, you can then add "use strict"; to the top of that class instead of in each method.

Non-standard use of MouseEvent

You are using MouseEvent.which, which is non-standard. Instead use MouseEvent.buttons if you wanted to detect simultanious pressed mouse buttons, or MouseEvent.button if you are only interested in one button. In the latter case, just check if a particular button is pressed with === instead of bitwise operators.

Magic numbers

Your moved some of your magic numbers to constants, but your code still contains a lot of numbers that make no immediate sense to me. For example, what is 223 in var scaleX = TABLE.width / 223? Or 35.25 in ctx.fillRect(35.25 * scaleX, 20 * scaleY, 152.5 * scaleX, 274 * scaleY);.

Edit: In the comments you let me know that 223 is the width of a table tennis table. Make this clear in the code too, by having a constant with such a name. Now, instead of scaleX being an operation on numbers that don't make immediate sense to me, you can write scaleX = TABLE.width / TABLE_TENNIS_TABLE_WIDTH;. Without me needing to know the dimensions of a table tennis table, the code still makes sense to me.

Some added explanation for the removal of this. A normal class looked something like this.

var PolarBear = function (name) {
//Public data
this.name = name;

//Private data
var MAX_SIZE = 300; //cm
var size = Math.floor(Math.random() * MAX_SIZE);

//Because "this" depends on the context
var self = this;

//Private function
var growl = function () {
console.log(self.name + " growls.");
};

//Public functions
this.pet = function () {
console.log("You decide to pet your polar bear named " + this.name);
growl();
};

this.getSize = function () {
return size;
};
};

You'll notice that the private function does not actually use this., because this in that function actually points to the window object, because we are not in strict mode. Instead of aliasing this we could refer to name directly, but that would mean that if we changed the (public) name of our PolarBear, the private function would use the old name. All in all, it is needlessly messy and harder to write without testing. We could instead do it this way:

var PolarBear = function (name) {
"use strict";

//Public data
let polarbear = {}
polarbear.name = name;

//Private data
const MAX_SIZE = 300; //cm
let size = Math.floor(Math.random() * MAX_SIZE);

//Private function
let growl = function () {
console.log(polarbear.name + " growls.");
};

//Public functions
polarbear.pet = function () {
console.log("You decide to pet your polar bear named " + polarbear.name);
growl();
};

polarbear.getSize = function () {
return size;
};

//Public functions and data
return polarbear;
};

Now if we test it with this, you see they work the same way.

var myPet = new PolarBear("Jack");
myPet.pet();

console.log(myPet.getSize());
myPet.name = "Elizabeth the 4th";
myPet.pet();

//These don't work, because they are private
console.log(myPet.size); //undefined
myPet.growl(); //TypeError

In the second example, instead of using this, we use one object that we return. This object polarbear is the public interface of our PolarBear class. In the end it works better, because we don't really have to worry about the actual scope of this, or if we need to replace it with an alias that is guaranteed the this we expected it to be. You can write the second example without needing to know the nuances of how this works, which makes it less error-prone to write it. You know the scope of polarbear, because you defined its scope.

• Thank you very much for your answer! Only part of this code is mine, thats why some things are done in two different ways. The "magic numbers" are the actual sizes of a table tennis table in cm. width/223 is the scale of the current drawing. Can you give me an example on how to replace "this" in a proper way? Is it ok to contact you if I have more questions? :) – Tweakimp Aug 22 '16 at 3:05
• I have added some text to my answer. If you don't understand something I have written, try to see if googling the terms I used clarifies something. If after you have revised your code you want people to review it again, post a follow up question. This meta question explains how to do this. – Sumurai8 Aug 22 '16 at 10:00
• Oh, and if you have a question about the site in general, or what you can and cannot do on the site or just want to say hi, feel free to drop by in the second monitor. – Sumurai8 Aug 22 '16 at 10:29


text:
## Electronic Journal of Statistics

### Exchangeable Markov survival processes and weak continuity of predictive distributions

#### Abstract

We study exchangeable, Markov survival processes – stochastic processes giving rise to infinitely exchangeable non-negative sequences $(T_{1},T_{2},\ldots)$. We show how these are determined by their characteristic index $\{\zeta_{n}\}_{n=1}^{\infty}$. We identify the harmonic process as the family of exchangeable, Markov survival processes that compose the natural set of statistical models for time-to-event data. In particular, this two-dimensional family comprises the set of exchangeable, Markov survival processes with weakly continuous predictive distributions. The harmonic process is easy to generate sequentially, and a simple expression exists for both the joint probability distribution and multivariate survivor function. We show a close connection with the Kaplan-Meier estimator of the survival distribution. Embedded within the process is an infinitely exchangeable ordered partition. Aspects of the process, such as the distribution of the number of blocks, are investigated.

#### Article information

Source
Electron. J. Statist., Volume 11, Number 2 (2017), 5406-5451.

Dates
First available in Project Euclid: 28 December 2017

https://projecteuclid.org/euclid.ejs/1514430423

Digital Object Identifier
doi:10.1214/17-EJS1381

Mathematical Reviews number (MathSciNet)
MR3743735

Zentralblatt MATH identifier
06825051

#### Citation

Dempsey, Walter; McCullagh, Peter. Exchangeable Markov survival processes and weak continuity of predictive distributions. Electron. J. Statist. 11 (2017), no. 2, 5406--5451. doi:10.1214/17-EJS1381. https://projecteuclid.org/euclid.ejs/1514430423

#### References

• Aldous, D. (1985), Exchangeability and related topics. In Ecole D’été de Probáilités de Saint-Flour, 1983. Lecture Notes in Math 1117, 1–198.
• Aldous, D. (1996), Probability distributions on cladograms. In Random Discrete Structures 76, 1–18.
• Anderson, P. K., Borgan, O., Gill, R. D. and Keiding, N. (1993)., Statistical models based on counting processes. New York: Springer.
• Clayton, D. G. (1991) A Monte Carlo method for Bayesian inference in frailty models., Biometrics 47, 467–485.
• Cornfield, J., and Detre, K. (1977), Bayesian life table analysis. J. Roy. Statist. Soc. B 39, 264–296.
• Doksum, K. A. (1974), Tailfree and neutral random probabilities and their posterior distributions. Annals of Probability 2, 183–201.
• Cox, D. R. and Oakes, D. (1978), Analysis of Survival Data. London, Chapman & Hall.
• Ford, D. J. (2005) Probabilities on cladograms: Introduction to the alpha model. Preprint., arXiv:math.PR/0511246
• Ferguson, T. S. (1973) A Bayesian analysis of some nonparametric problems., Annals of Statistics 1, 209–230.
• Gehan, E. A. (1975) A generalized Wilcoxon test for comparing arbitrarily singly-censored samples., Biometrika 52, 203–233.
• Gnedin, A. and Pitman, J. (2005), Regenerative composition structures. Annals of Probability 33, 445–479.
• Ghosal, L. and van der Vaart, A. (2017) Fundamentals of Bayesian nonparametric inference. Cambridge University, Press.
• Hjort, N. L. (1990) Nonparametric Bayes estimators based on beta processes in models for life history data., Annals of Statistics 18, 1259–1294.
• James, Lancelot F. (2006) Poisson calculus for spatial neutral to the right processes. Preprint., arXiv:math.PR/0604266
• James, Lancelot F. (2006) Spatial Neutral to the Right Species Sampling Mixture Model, The Annals of Statistics 34, 416–440
• James, Lancelot F. (2007) Neutral-to-the-right species sampling mixture models. In:, Advances in Statistical Modeling and Inference , 425–439. World Sci. Publ., Hackensack, N.J.
• Kalbfleisch, J. D. (1978), Nonparametric Bayesian analysis of survival time data. J. Roy. Statist. Soc. B 40, 214–221.
• Kaplan, E. L. and Meier, P. (1958), Nonparametric estimation from incomplete observations. J. Amer. Statist. Assn. 53, 457—481.
• Kingman, J. F. C (1993), Poisson Processes. Oxford Scientific Publications.
• Lijoi, A., Prunster, I., and Walker, S. (2008), Posterior analysis for some classes of nonparametric models. J. Nonparametr. Statist. 20, 447–457.
• McCullagh, P., Pitman, J., and Winkel, M. (2008), Gibbs fragmentation trees. Bernoulli 14, 988–1002.
• Müller, P., and Quintana, F. (2004), Nonparametric Bayesian data analysis. Statistical Science 19, 95–110.
• Pitman, J. (2006), Combinatorial Stochastic Processes. Lecture Notes Math. Springer, New York.
• Walker, S., Damien, P., Laud, P., and Smith, A. (1999), Bayesian nonparametric inference for random functions and related functions. J. Roy. Statist. Soc. B 61, 485–527.
• Walker, S. and Muliere, P. (1997), Beta-Stacy processes and a generalization of the Polya-urn scheme. Ann. Statist. 25, 1762–1780.

format: plain


text:
## how to explain e commerce project in interview

ionic bond. Positively charged ions move to the negative electrode during electrolysis. On the other hand, the valence electrons of the chloride ions reside in the 3p orbital. To learn more, see our tips on writing great answers. Covalent Bonding. They receive electrons and are reduced . Then only can we say that it is the high polarising power of lead (IV) cation etc. Most bromide compounds are highly soluble in water, but lead(II) bromide is an exception. It also is made of a metal (lead) and a non-metal (iodine) which is characteristic of ionic compounds. Fe2O3 6. Is it ok to lie to players rolling an insight? Answer and Explanation: PbBr2 is insoluble in water. Can you name the Ionic or Covalent Bonds? Chemical bond A chemical bond is a lasting attraction between atoms, ions or molecules that enables the formation of chemical compounds. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Thanks for contributing an answer to Chemistry Stack Exchange! Is this a common thing? MathJax reference. When a crystal of an ionic compound dissolves in water, the ions separate. Lead (II) Sulfide ( PbS ) is Ionic I'll tell you the ionic or Covalent bond list below. Ionic bond, also called electrovalent bond, type of linkage formed from the electrostatic attraction between oppositely charged ions in a chemical compound. Stack Exchange network consists of 176 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. noun. Why is lead (IV) chloride covalent while lead (II) chloride ionic? Covalent bonds other then 2-center, 2-electron bonds. When Tin and chlorine combine it creates either:-SnCl2, called tin(II) chloride, stannous chloride. How to reveal a time limit without videogaming it? It is an ionic compound. Water consists of a covalent bond containing hydrogen and oxygen bonding together to make H2O. How can ionic bonding in lanthanides occur without valence orbitals available for overlap? It's probably best represented by 4x dative bonds from chloride into 6s + 6p orbitals of Pb, which have covalent character because of strong polarisation. Ionic compounds are composed of a non-metal and a metal element. Ionic bonding is a type of chemical bond that involves the electrostatic attraction between oppositely charged ions, and is the primary interaction occurring in ionic compounds. LiBr - Lithium Bromide. Why does my cat lay down with me whenever I need to or I’m about to get up? Use MathJax to format equations. Another example is vulcanized rubber. On the other hand, the valence electrons of the chloride ions reside in the 3p orbital. Bi (group 5A) forms ionic Bi3+ 5cpds and covalent Bi + cpds. (NH 4) 2S ammonium sulfide 19. Identify each compound as Ionic or Covalent Write the appropriate chemical name for the compounds: 1. SnBr 4 tin (IV) bromide 18. How did Trump's January 6 speech call for insurrection and violence? Ions exert electrostatic force on each other, which forms ionic bonds. Answer and Explanation: CO2 is a molecular compound. Pb(IV) can't form bonds with a fully filled 5d subshell, btw, unless you invoke some kind of d-s hybridisation. But no compound is perfectly ionic or covalent. Just under 0.5 g of lead(II). Remember to first determine whether the compound is ionic or molecular! Tin forms tin(II) chloride, SnCl 2, which is an ionic compound and tin(IV) chloride SnCl 4 which is a covalent compound. NaF - Sodium Fluoride. Asking for help, clarification, or responding to other answers. Why does my fridge keep tripping the fuse? Answer : Lead (II) Sulfate ( PbSO4 ) is an Ionic bond What is chemical bond, ionic bond, covalent bond? Were there any computers that did not support virtual memory? cucl2 ionic or covalent, CaCl2 is ionic. site design / logo © 2021 Stack Exchange Inc; user contributions licensed under cc by-sa. Firstly, we must note that their valence electronic configurations are different: lead(II) has its valence electrons in 6s orbital while the valence electrons of lead (IV) reside in the 5d orbital. Bromine is a nonmetal element. Is sodium chloride ionic or covalent? I mean the electronegativity of lead is invariant in whatever compound it forms. LiI - Lithium Iodide. Lead(II) bromide, also known as plumbous bromide, is a chemical compound. It contains lead and bromide ions. Lead is a bluish-white lustrous metal. It is very soft, highly malleable, ductile, and a relatively poor conductor of electricity. )(NH 42O ammonium oxide 16. For example in the ionic compound sodium chloride NaCl, the chlorine ion (Cl 1– ) gains one electron that was given by the sodium ion (Na 1+ ). By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy. lead II iodide is named as if it is an ionic compound. calcium chloride is not a covalent bond. The positively charged electrode in electrolysis is called the anode . Usually when this compound occurs it makes Lead (iv) chloride, which is composed of one lead atom and four chlorine atoms. This seems reasonable as the anode is the source of electrons and cathode is where the electrons flow. Pb ... 12. lead (II) phospha 3(PO 4) 2 te 13. Bromine is the only nonmetal element that naturally takes form as a liquid under normal circumstances. An example is water. Answer and Explanation: Water is made up of covalent bonds, rather than ionic bonds. Would tin (II) sulfide be considered a covalent network solid? Negatively charged ions move towards the anode. Â¿CuÃ¡les son los 10 mandamientos de la Biblia Reina Valera 1960? Question : Is Lead (II) Sulfate ( PbSO4 ) an ionic or covalent bond ? Ionic compounds, such as sodium chloride (NaCl), are formed by a transfer of electrons that creates ions. Front Tire & Downtube Clearance - Extremely Dangerous? Question = Is ICl3 polar or nonpolar ? Based on what I have read from Clayden's Organic Chemistry, I understand that atomic orbitals of similar energy interact strongly to produce strong covalent … The atom that loses the electrons becomes a positively charged ion (cation), while the one that gains them becomes a negatively charged ion (anion). Why are ionic substances able to be Electrolysed. Get Smart Results For Bromine Is A Metal Or Nonmetal. How would one compare the magnitude of covalent character between SnCl4 and SnF2 using Fajan's Rules? Simply so, is Lead II bromide ionic or covalent? Why do ionic compounds dissociate whereas coordinate complexes won't? It only takes a minute to sign up. You will then determine a number of properties of these compounds and on thatClassify each of these compounds as molecular or ionic PtO2 SrI2 NH4Br K2CO3 NI3 C5H10O5 Ba(OH)2. Is it possible to explain this in a "less ionic" manner, meaning that we do not invoke the concept of charges and polarisation. I was thinking that since the interacting orbitals of the lead (IV) cation and the chloride ions are closer in energy, a favourable covalent interaction would occur. NaI - Sodium Iodide. Multiple valence: … Now what? The definition of ionic bond is when a positively charged ion forms a bond with a negatively charged ions and one atom transfers electrons to another. Lead(II) bromide, also known as plumbous bromide, is a chemical compound. • ionic compounds are pure substances that form when metal and non-metal atoms are chemically bonded together by an ionic bond (electrostatic attraction). The ions are atoms that have gained one or more electrons (known as anions, which are negatively charged) and atoms that have lost one or more electrons (known as cations, which are positively charged). Beside this, is Lead II bromide ionic or covalent? In $\ce{PbCl4}$ the lead is in $\ce{Pb^{IV}}$ state and $\ce{Cl}$ is having a considerable, not very large - but enough to be polarised easily, and the high charge density on lead polarizes the anion much more efficiently, so that the electron density is shifted and partially shared, in effect the compund is much covalent.You would like to see Fajan's rule, if you didn't knew them before. 3) 2 zinc bicarbonate / zinc hydrogen carbonate 17. Get the best of Sporcle when you Go Orange.This ad-free experience offers more features, more stats, and more fun while also helping to support Sporcle. Children’s poem about a boy stuck between the tracks on the underground, The first published picture of the Mandelbrot set. The ions in a compound such as sodium chloride are arranged in a lattice structure. A diamond is an example of Giant Covalent bond of carbon. Excess income after fully funding all retirement accounts. The ions must be free to move, which is possible when an ionic substance is dissolved in water or it is melted. Why is the melting point of magnesium oxide higher than aluminium oxide? Can I bring a single shot of live ammo onto the plane from US to UK as a souvenir? Lead (ii) chloride is a special compound because it only has two atoms connected to it but it usually would need four to satisfy the lead atom. HNO3+HI--->HIO3+NO2+H2O. It is very resistant to corrosion but tarnishes upon exposure to air. On a side note, how would we explain that titanium (IV) iodide is covalent? This activity focused on molecular (covalent) compounds, while an earlier activity addressed ionic compounds. Its chemical formula is PbBr 2. It contains lead and bromide ions. Thank you for becoming a member. Ionic compounds, such as sodium chloride (NaCl), are formed by a transfer of electrons that creates ions. Lead isotopes are the end products of each of the three series of naturally occurring radioactive elements. Therefore, molten ionic compounds do conduct electricity. Click to see full answer. Keeping this in consideration, is lead bromide an ionic compound? Using the periodic table, predict whether the following chlorides are ionic or covalent: SiCl 4, PCl 3, CaCl 2, CsCl, CuCl 2, and CrCl 3. Covalent bonding offers no particular advantage in the case of SnCl2 because tin wouldn't have a full shell. rev 2021.1.14.38315, The best answers are voted up and rise to the top, Chemistry Stack Exchange works best with JavaScript enabled, Start here for a quick overview of the site, Detailed answers to any questions you might have, Discuss the workings and policies of this site, Learn more about Stack Overflow the company, Learn more about hiring developers or posting ads with us. @orthocresol Ok. That sounds simple enough. P 2O 5 ous pentoxide 14. An example of an ionic bond is the chemical compound Sodium Chloride. Since this process uses only water as a source, it can produce up to 99.9995% pure hydrogen and oxygen. This is because lead bromide has a relatively low melting point. LiCl - Lithium Chloride. What are the names of Santa's 12 reindeers? Writing the net ionic equation for sodium fluoride+hydrochloride, magnesium iodide + lead (II) acetate sliver (I) acetate + potassium iodide nickel (II) sulfate + barium chloride barium acetate + ammonium sulfate barium hydroxide +aluminum bromide zinc iodide + potassium hydroxide 52,964 results My explanation is as follows: I consider the interaction between the atomic orbitals of the lead (II) and lead (IV) cations with the chloride ions. I would like to find out more about what makes a compound ionic and what makes one covalent. What (in the US) do you call the type of wrench that is made from a steel tube? Examples of Covalent Bond: Water. Similarly, is lead bromide soluble? Electrolysis uses direct current (DC) electricity to split water into its basic elements of hydrogen and oxygen. The hydrogen and oxygen atoms in a water molecule, however, are bonded by sharing electrons rather than by transferring them. Covalent Bonding. A diamond has a giant molecular structure. Same applies to Pb(II) and its fully filled 6s orbital. Thickening letters for tefillin and mezuzos. Naming Ionic and Covalent Compounds This will test your ability to name ionic and molecular compounds. Firstly, we must note that their valence electronic configurations are different: lead(II) has its valence electrons in 6s orbital while the valence electrons of lead (IV) reside in the 5d orbital. Replacing a random ith row and column from a matrix. Lead(II) bromide, also known as plumbous bromide, is a chemical. Making statements based on opinion; back them up with references or personal experience. Why does magnesium form covalent bonds with carbon? I have already come up with an explanation of my own, which I have provided below. Chemistry Stack Exchange is a question and answer site for scientists, academics, teachers, and students in the field of chemistry. Naming compounds and Writing Formulas Learn with flashcards, games, and more — for free. At its simplest it is just more positive charge -> more polarising -> more covalent bond. ReplacePart to substitute a row in a Matrix. Ionic and Covalent Bonding 2 | 1 ... Tin (Sn) and lead (Pb) (group 4A) commonly form ionic compounds with 2+ ions. Please feel free to point out any inaccuracies. So why would believe that the lead atom in lead (IV) compounds is more polarising than in lead (II) compounds. I am not confident that this is correct. Which wire goes to which terminal on this single pole switch? What is internal and external criticism of historical sources? How to determine stable electron states in ionic and covalent bonds? What does the expression "go to the vet's" mean? Lead bromide is an ionic compound and can conduct electricity when the ions are free to move - either molten or in aqueous solution. If you want to quickly find the word you want to search, use Ctrl + F, then type the word you want to search. Diamonds. But when an ionic compound melts, the charged ions are free to move. Why are diamond shapes forming from these evenly-spaced lines? Its chemical formula is PbBr2. NaCl - Sodium Chloride. Vulcanized rubber. Ca(ClO 3) 2 cium chlorate 15. naming ionic and covalent compounds ... (2,4) Lead Plumbum Plumbic PlumbousSn (2,4) Tin Stannum Stannic Stannous Metals that do not have latin namesCo (2,3) Cobalt - Cobaltic CobaltousCr (2,3) Chromium - Chromic ChromousMn (2,3) Manganese - Manganic Manganous Metals that have latin names but use english rootHg (1,2) Mercury Hydrargyrum Mercuric Mercurous 8. Can a private company refuse to sell a franchise to someone solely based on being black? NiI 2 20. The product is the ionic compound, sodium chloride. Know and understand the definitions of: metal, non-metal, ionic compound, covalent (molecular) compound, binary compound and electrolyte. This is molecular in the gas phase and forms polymeric covalent chains in the solid (mp. What are the characteristics of agape love? The hydrogen atoms share electrons with the oxygen atom, which makes it covalent. How to make a square with circles using tikz? Can scratches be removed from sterling silver? Ionic bond examples include: LiF - Lithium Fluoride. However, I felt this was too general a question so I thought that asking about the chlorides of lead would be more appropriate. Does a Bugbear PC take damage when holding an enemy on the other side of a Wall of Fire with Grapple? Negatively charged ions move to the positive electrode during electrolysis. Calcium hydroxide--ionic, but the hydroxide ion has a covalent bond in it. In a galvanic (voltaic) cell, the anode is considered negative and the cathode is considered positive. © AskingLot.com LTD 2021 All Rights Reserved. Review for Quiz 2: Ionic and Covalent Compounds 1. @orthocresol Actually, if you think about it, the argument using positive charge seems to fail when we consider neutral atoms in the first step. NAMING WORKSHEET #1 Formula of Compound Ionic, Covalent, or Acid? However, in an electrolytic cell, the anode is taken to be positive while the cathode is now negative. Calcium Chloride: ionic Citric Acid: covalent Phenyl Salicylate: covalent Potassium Iodide: ionic Sodium Chloride: ionic Sucrose: covalent good. Based on what I have read from Clayden's Organic Chemistry, I understand that atomic orbitals of similar energy interact strongly to produce strong covalent bonds. Positive lead ions (cations) move to the cathode and gain electrons to become lead metal. However, I would also like to hear the opinions of others. Electrolysis is commonly used in energy for the production of hydrogen. This argument only works if you first assume that the interacting species are all ions, not neutral atoms. The negatively charged electrode in electrolysis is called the cathode . 6. Numerically stable way to compute sqrt((b²*c²) / (1-c²)) for c in [-1, 1]. ionic bond. It takes a liquid form at normal room temperature and has a brownish-red color in both its gaseous and liquid state. Why calcium fluoride has a higher melting point than chlorine fluoride? However, in the case of lead (II), covalent bond formation is not favoured since the orbital energies are considered to be too far apart. NaBr - Sodium Bromide. The bond may result from the electrostatic force of attraction between oppositely charged ions as in ionic bonds; or through the sharing of electrons as in covalent … chemistry.stackexchange.com/questions/19763/…, chemistry.stackexchange.com/questions/42784/…, chemistry.stackexchange.com/questions/9038/….

#### Related

how to explain e commerce project in interview 2021


text:
# How do you solve 2(x-1) + 3= x -3(x+1)?

$x = - 1$
$2 x - 2 + 3 = x - 3 x - 3$
$2 x + 1 = - 2 x - 3$
$2 x + 2 x = - 3 - 1$
$4 x = - 4$
$x = - 1$


text:
# Vector Identity Rules Ax(BxC)

1. Aug 25, 2009

### omegacore

1. The problem statement, all variables and given/known data

Regarding the identity Ax(BxC)

2. Relevant equations

Does this identity only hold when A != B != C?

2. Aug 25, 2009

### queenofbabes

Which identity are you referring to? Whatever the identity it would work for any vector....but of course the cross product of 2 equal vectors is zero =)

3. Aug 25, 2009

### omegacore

Ah yes, I forgot the identifying portion of the identity:

Ax(BxC) = B(A dot C) - C(A dot B)

Same qualifying question as before. Obviously this identity does not just fall out of the sky and is the product of a process. I am wondering if the process is disrupted (invalid identity) by having A = B... it seems like it wouldn't be.

4. Aug 25, 2009

### queenofbabes

No it wouldn't, I wonder what makes you think so?

5. Aug 25, 2009

### Hurkyl

Staff Emeritus
It's fair to wonder, because some sources tend to be somewhat sloppy about explicitly stating hypotheses.

6. Aug 25, 2009

### kuruman

An identity holds for any choice of vectors. That's what makes it an "identity".

7. Aug 25, 2009

### Hurkyl

Staff Emeritus
Not all identities are universal. For example,
sin arcsin x = x
is only valid on the interval $[-\pi/2, \pi/2]$.


text:
+0

The golden rectangle is inscribed in a circle with a radius of 10cm. Find the area of that rectangle.

0
323
6

The golden rectangle is inscribed in a circle with a radius of 10cm. Find the area of that rectangle.

Guest Jun 8, 2015

#2
+1068
+10

The golden rectangle is inscribed in a circle with a radius of 10cm. Find the area of that rectangle.

The ratio of the sides a and b of the golden rectangle is calculated by the upper formula.

Because the ratio of the sides of this rectangle is constant,  so must be the ratio of the angles that these sides form with rectangle's diagonal!

a = 1,   b = 1/1.61803398874989485 = 0.61803398874989484752

tan(B) = 1/ 0.61803398874989484752

B = ≈58.28o        A = ≈31.72o

Circle's radius  r = 10cm,    rectangle's diagonal  d = 20cm      a = ?,   b = ?  and  A = ?

cos(A) = a/d             b = sqrt(d2 - a2 )                      A = a*b

a = d*cos(A)            b = sqrt(202 - 17.0132)             A = 17.013*10.515

a = 17.013cm           b = 10.515cm                          A =  ≈178.88cm2

civonamzuk  Jun 8, 2015
Sort:

#1
+81007
+10

Call x one side of the rectangle......then the adjacent side will be (Phi)x

And the diameter of this circle will  = 20cm    ......and by the Pythagorean Theorem, we have.......

x ^2  +  [(Phi)x]^2  = 400

x^2 [ 1 + (Phi)^2]  = 400      and we can note that Phi^2  =  1 + Phi.......so we have

x^2 ( 1 + 1 + Phi)  = 400

x^2 (2 + Phi )  = 400

x^2  =   400 / (2 + Phi)        take the  positive square root of both sides

x = 20 / √(2 + Phi)

So....the area of this rectangle  = (20/√(2 + Phi))* (Phi * 20/ √(2 + Phi) ) = 400Phi / (2 + Phi)  = about

178.88 cm^2

CPhill  Jun 8, 2015
#2
+1068
+10

The golden rectangle is inscribed in a circle with a radius of 10cm. Find the area of that rectangle.

The ratio of the sides a and b of the golden rectangle is calculated by the upper formula.

Because the ratio of the sides of this rectangle is constant,  so must be the ratio of the angles that these sides form with rectangle's diagonal!

a = 1,   b = 1/1.61803398874989485 = 0.61803398874989484752

tan(B) = 1/ 0.61803398874989484752

B = ≈58.28o        A = ≈31.72o

Circle's radius  r = 10cm,    rectangle's diagonal  d = 20cm      a = ?,   b = ?  and  A = ?

cos(A) = a/d             b = sqrt(d2 - a2 )                      A = a*b

a = d*cos(A)            b = sqrt(202 - 17.0132)             A = 17.013*10.515

a = 17.013cm           b = 10.515cm                          A =  ≈178.88cm2

civonamzuk  Jun 8, 2015
#3
+91451
0

Why is it a golden rectangle?  What is so special about phi ?

Melody  Jun 9, 2015
#4
+5

http://en.wikipedia.org/wiki/Golden_rectangle

Guest Jun 9, 2015
#5
+5

http://en.wikipedia.org/wiki/Golden_ratio

Guest Jun 9, 2015
#6
+91451
0

Thanks anon

Melody  Jun 9, 2015

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text:
## Frank Gutch Jr: Up-and-Comers for 2013, Why All the Covers, Mental Tracks, and Notes…..

Posted in Opinion with tags , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , on February 20, 2013 by segarini

Remember when I said 2012 was the best year ever in music?  2013 is even at this early date biting  2012 on the ass.  Artists are lining up with what I am sure is going to be a run and a half of outstanding and, in some cases, mindblowing offerings.  Rather than wait and write about them pretty much after the fact, let us dig in now in a sort of anticipatory way, shall we?

## Frank Gutch Jr: Lost & Found

Posted in Opinion with tags , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , on December 12, 2012 by segarini

A few days ago, I saw a picture of a couple of Darrell Vickers‘ friends and fellow band members standing before a wall of vinyl, only a small portion of a collection which more than likely takes up a whole house.  Vickers has been digitizing and posting the most rare (and most odd) of the records under the guise of Radio Vickers, a hobby which thus far has handed many a fan of oddities music that which they might not have ever found.  You never know what you’re going to find when Darrell points the finger, but one thing I did find and am thrilled to have found, actually, is a collection of odd bands from down under recreating the original Nuggets: Artyfacts from the First Psychedelic Era, this one titled Antipodean Interpolations of the First Psychedelic Era.  Bands like Velociraptor and The Gooch Palms and King Gizzard and the Wizard Lizard and The Murlocs serving up covers of The StandellsDirty Water and  Sagittarius‘s My World Fell Down and The LeavesHey Joe.  And that’s just the tip of the Vickers iceberg.


text:
If six pennies are … - QuestionCove
OpenStudy (anonymous):

If six pennies are tossed onto the table, what is the probability of seeing two heads and four tails?

2 years ago
OpenStudy (amistre64):

how many ways can you arrange them?

2 years ago
OpenStudy (amistre64):

$\binom{n}{r}p^rq^{n-r}$

2 years ago
OpenStudy (amistre64):

if p=q this amounts to:$\binom{n}{r}p^n$

2 years ago
OpenStudy (anonymous):

they're being tossed all at the same time, not one by one

2 years ago
OpenStudy (amistre64):

doesnt really matter

2 years ago
OpenStudy (amistre64):

one by one we can get: t h h t t t or if we throw them all at once t h h t t t

2 years ago
OpenStudy (anonymous):

ok thx i see, so it's 0.234375?

2 years ago
OpenStudy (amistre64):

what is 6 choose 2? the rest is 1/2^6 of course

2 years ago
OpenStudy (amistre64):

15 * 1/2^6 whatever that turns out to be eh

2 years ago
OpenStudy (anonymous):

well as a fraction it'd be 15/64

2 years ago
OpenStudy (amistre64):

yeah, thatll be it

2 years ago
OpenStudy (anonymous):

ah ty that's what i got

2 years ago


text:
# Navier Stokes Github

ow oscillations found by Khalighi et al. SU2 solves the compressible Navier-Stokes equations expressed in differential form as. com/JamieMJohns/Navier This youtube channel is for the purpose of a digital portfolio, and not necessarily for the purpose of sharing/providing code. In 2013, I was invited to teach a 2 day mini-course in the Latin-American School in High-Performance Computing, in Argentina. CFDPython, 一系列具有"12 Steps to Navier Stokes" http功能的IPython笔记本 0 赞 0 评论 文章标签: HTTP STEP Sequence Ipython SEQ Ipython Notebook. We consider the Navier-Stokes equations in a channel with varying Reynolds numbers. Specifically, since they have been used for the Navier-Stokes equations, they will also be applicable to the Stokes equations, much as for most any other flow problem. Navier-Stokes viscosity. Like any non-linear system, in order to find a solution for a given time step, we must undergo an iteration process to obtain a solution that reduces the residual (i. View on GitHub Download this project as a. The solver is designed with the object-oriented methodology. SU2 is a suite of open-source software tools written in C++ for the numerical solution of partial differential equations (PDE) and performing PDE constrained optimization. 2D/3D Compressible Euler, RANS, Laminar Navier-Stokes. Asymptote, a TeX/LaTeX aware vector graphics language. The theory of compressive turbulence lags behind the study of the incompressible Navier-Stokes equations. GitHub Gist: instantly share code, notes, and snippets. MiniAero is an explicit (using RK4) unstructured finite volume code that solves the compressible Navier-Stokes equations. View On GitHub LESGO solves the filtered Navier-Stokes equations in the high-Reynolds number limit on a Cartesian mesh. Case files. Navier-Stokes equations by P. For the Navier-Stokes equation, Teko has implementations of SIMPLE, PCD and LSC. The code solves Navier Stokes equations in a 2D lid driven cavity, with computation of the rotational as well. This file is part of the hIPPYlib library. Commercial CFD packages use nite volume methods (a form of nite di erencing), which integrate and discretise equations in an. $$This means that the pressure is instantaneously determined by the velocity field (the pressure is no longer an independent hydrodynamic variable). The software solves numerically a form of the Navier-Stokes equations appropriate for low-speed, thermally-driven flow, with an emphasis on smoke and heat transport from fires. 今や流体力学を Navier-Stokes まで計算機で速習できるオンラインコースウェアがあるという. 2014) CFD Python has a new home on GitHub. Graphs or timing analysis to show speedup from the sequential implementation. CGNS CFD Data Standard by John Steinbrenner / Pointwise on behalf of CGNS Steering Committee What is CGNS? CFD General Notation System A standard for recording & recovering CFD data. Below there is a selection of audio-visual projects developed over the last few years using OpenFrameworks (C++), Python and Processing (Java). The PNP Solver Finite Element Methods for the Poisson-Nernst-Planck equations coupled with Navier-Stokes Solver GitHub The code We are developing, in Python and C++, solvers for simulating charge-transport systems with an arbitrary number of charge-carrying species. Nonlinear. MIE 1210: Computational Fluid Mechanics - LinkWIP Course from University of Toronto for teaching me Navier Stokes equations and how to implement them. エントリーの編集は 全ユーザーに共通 の機能です。 必ずガイドラインを一読の上ご利用ください。. Note: you may apply or follow the edits on the code here in this GitHub Gist I'm trying to follow this post to solve Navier-Stokes equations for a compressible viscous flow in a 2D axisymmetric st. Unstructured mesh methods for the Navier-Stokes equations, (D. The Navier-Stokes equations provide a theoretical description of the ﬂow of a ﬂuid around an object [2], ˆ @v @t +ˆ(v r)v = r p+ r2v; (2) where pdenotes the pressure and the viscosity coefﬁcient. Follow Instituto Navier Stokes para la Mecánica de Fluidos on WordPress. com La liberación del conocimiento ya comenzó Este obra está bajo una licencia de Creative Commons Reconocimiento-NoComercial-CompartirIgual 3. The equations are mapped to a general body-fitted coordinate system. Bonetb and J. Navier Stokes equations lost their Revelation worth 4,003,084,104. Distinguishing features. of the 45th AIAA Aerospace Sciences Meeting and Exhibit, January 2007. A CodePen by Fabrice Weinberg. Wubs rallelaP multilevel incomplete factorization of saddle point matrices. Iterations – Number of time-steps to use in Navier-Stokes diffusion. Multigrid solution of the navier–stokes equations at low speeds with large temperature variations. GPU whisperer. Semi-implicit BDF time discretization of the Navier-Stokes equations with VMS-LES modeling in a high performance computing framework. Fluid simulation project with the Navier Stokes. txt) or read online for free. Perssona J. In this example we solve the Navier-Stokes equation past a cylinder with the Uzawa algorithm preconditioned by the Cahouet-Chabart method (see [GLOWINSKI2003] for all the details). I present the equations that are solved, how the discretization is performed, how the constraints are handled, and how the actual code is structured and implemented. Default value = 10. Extensibility. Originally designed to simulate flow in the atmospheric boundary layer, LESGO has been extended and used to simulate flow over tree canopies, wall-mounted cubes, and wind turbine arrays, among other things. Therefore, though this tool does not produce time-series that obey fluid-flow equations (i. spectralDNS. If it is a time-dependent problem, the frequency is based on the time iterations, while for steady-state problems it is based on the outer or inner iterations, depending on whether it is a multi-zone or single-zone problem, respectively. , Discrete functional analysis tools for discontinuous Galerkin methods with application to the incompressible Navier-Stokes equations. To increase performance, I solved for the velocity vector field of the fluid at a lower resolution than I used to compute the distribution of material moving through the fluid (shown in black and white). Fluid Simulation with Navier Stokes - index. Saleri, and A. Our model exploits the fact, according to Plateau's laws, that the steady state of a film is a union of constant mean curvature surfaces and minimal surfaces. Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. Both inviscid and viscous terms are included. Problem setup and solution methodology. A spectral-element solver for the incompressible Navier-Stokes equations with thermal coupling Instructor : Prof. Unlike previous approaches where optical. Praveen Chandrashekar. By treating the full Navier--Stokes equation as a perturbation of this model equation, we obtain new conditional blowup results for solutions of the Navier--Stokes equation. Si la demostración de Otelbaev es correcta, la turbulencia no está descrita por las ecuaciones de Navier-Stokes. A more complete list can be found on my github, bitbucket and gitlab pages. And a paper that claims to solve the problem should probably say up front what the new insight is. based on the Navier Stokes equations. University Pompeu Fabra 08003 Barcelona, SPAIN A. Yiyuan has 4 jobs listed on their profile. Ref: Ghia, Urmila, Kirti N. The Navier-Stokes equations are to be solved in a spatial domain for t2(0;T]. task_7()" Show/Hide Code. Navier-Stokes implementation from Jos Stam in 3D. 257-286 (2017). Bertozzi Mathematics Dept. (2007-2008) Real-time Navier-Stokes 3D smoke with OpenSceneGraph (OpenGL) rendered as particle system. Einkemmer, M. Sapiro Elec. MagIC is a numerical code that can simulate fluid dynamics in a spherical shell. Modern fluid simulators treat viscosity and pressure in separate solver stages, which reduces accuracy and yields incorrect free surface behavior. Abstract: With this study we investigate the accuracy of deep learning models for the inference of Reynolds-Averaged Navier-Stokes solutions. Spectral methods in python; deal. k= 8;8 8 mesh, ﬁnal value. There's no need to compile in modules, then navier stokes, and then in your app. Navier-Stokes equation will ﬁnd nowhere for this term, since it is actually hidden inside fext. The code solves Navier Stokes equations in a 2D lid driven cavity, with computation of the rotational as well. During submarine landslides, strong free surface deformation,. Reviews and High-level Presentations. Download DUNS 2d/3d structured multi-block CFD for free. Ghia, and C. com/JamieMJohns/Navier This youtube channel is for the purpose of a digital portfolio, and not necessarily for the purpose of sharing/providing code. Live demo here, code on Github. The equations are usually solved on a regular structured grid, in most cases using a second order projection method where the solution is rst updated without accounting for the pressure, the pressure is found from the. NSERC CREATE summer school on clean combustion engines, Ryerson University, Toronto, 2017. k= 8;8 8 mesh, initial value. The grid is partitioned into subgrids load balanced for the number of MPI ranks requested by the user. Sign in Sign up Instantly share code, notes, and. The course structure is outlined in the project’s github page which you can take a look at here. Duke University Durham, NC 27708 G. Mu – Weight parmeter from Navier-Stokes diffusion - weights divergence and Laplacian terms. Therefore, though this tool does not produce time-series that obey fluid-flow equations (i. , sole distributors for the U. I extended and tested the scope of the Navier-Stokes solver developed during the master's thesis. Nonlinear. 7 CFL3D is a structured-grid, cell-centered, upwind-biased, Reynolds-averaged Navier-Stokes (RANS) code. Iterations – Number of time-steps to use in Navier-Stokes diffusion. Hidden Fluid Mechanics: A Navier-Stokes Informed Deep Learning Framework for Assimilating Flow Visualization Data Alireza / October 16, 2018 / 1 Comment / Uncategorized Our new work on physics-informed machine learning has been published online. If it is a time-dependent problem, the frequency is based on the time iterations, while for steady-state problems it is based on the outer or inner iterations, depending on whether it is a multi-zone or single-zone problem, respectively. Although it is not possible to derive an analytical solution to this test case, very accurate numerical solutions to benchmark reference quantities have been established for the pressure difference, drag, and lift coefficient [1],[2]. 18 // You should have received a copy of the GNU Lesser General Public. Then the continuity equation implies$$ abla\cdot u = 0. To benefit from parallism you can run the unsteady Navier-Stokes part of the code below on, say, eight cores: mpirun -n 8 python3 -c "import dfg; dfg. de · Beolingus Deutsch-Englisch OpenThesaurus ist ein freies deutsches Wörterbuch für Synonyme, bei dem jeder mitmachen kann. FEST-3D (Finite-volume Explicit STructured 3-Dimensional) is computational fluid dynamic solver written in Fortran 90 for solving the Navier-Stokes equations on structured grids using state-of-the-art finite-volume methods. This work studies the hierarchy for the vorticity and the vorticity increments in two-dimensional ﬂows. in May 18, 2018 1 Navier Stokes Equation and Finite Volume discretized equations. Extending the resulting equations to differnt fluids and circumstances requires substantial physical modeling, but the equations for Newtonian incompressible fluids are somewhat. The main focus of OpenSBLI is on the solution of the compressible Navier-Stokes equations with application to shock-boundary layer interactions (SBLI). A spectral-element solver for the incompressible Navier-Stokes equations with thermal coupling Instructor : Prof. Poisson in a hundred ways; Heat equation; Navier-Stokes equations. Matrix details for Goodwin/Goodwin_127. In another word, the Reynolds number, Re, is quite small, i. ows governed by the Navier-Stokes equations 3 2. Praveen Chandrashekar. Both SPRNT and Frehd were developed within my research group (the former in collaboration with IBM Research Austin). Bestsellers. In weather modelling, one of the models used for convection is the Navier-Stokes equation, which model fluids, with the heat is coupled to according to the Boussinesq approximation which treats the change in temperature as a small forcing term to the Navier-Stokes equation. Solving the compressible Navier-Stokes equations means that acoustic waves are included in the solution (if the resolution is fine enough and if the accuracy of the numerical scheme is high enough to be able to be able to represent the high-frequency low-amplitude acoustic perturbations). Home People Codes Talks Teaching Publications For students Around CAM Calendar Contact. Smokeview (SMV) is a visualization program that is used to display the output of FDS and CFAST simulations. OLAFOAM is the evolution of IHFOAM, a well-known three-dimensional Navier-Stokes solver for free surface flows, and is born with the spirit of providing the latest advances for the simulation of wave dynamics to the OpenFOAM and FOAM-extend communities. An interesting research item, which has led to relevant scientific publications, concerns the development of new preliminary design methodologies, obtained through numerous CFD Navier-Stokes aerodynamic analyses. a simpliﬁed 3D Navier–Stokes model for full scale landslide sce-nario in the Gulf of Mexico, the East-Breaks underwater landslide. I'm posting in the mailing list first, because I wanted to make sure that this is a problem with the Navier Stokes module before I create an issue on Github. Fluid Simulation with Navier Stokes - index. It has been developed by Prof. The primary applications are computational fluid dynamics and aerodynamic shape optimization, but has been extended to treat more general equations such as electrodynamics and chemically reacting fl. Read through the first couple chapters of “Learning IPython for Interactive Computing and Data Visualization”, which is attached. It is parallelised using MPI and is capable of scaling to many thousands of processors. to the impact of a falling rigid block. Isotropic turbulence with Re_lambda=128 computed using the NS solver and a mesh of size 300**3 is physical space. The Cauchy momentum equation is a. We simulate the Navier-Stokes equations describing the two-dimensional fluid flow past a circular cylinder at Reynolds number 100 using the Immersed. It is based on Fast Marching Method. My research project consisted of creating a three-dimensional fluid simulation using a Navier-Stokes solver, and a volumetric renderer to display the results on-screen. where denotes the vorticity, the -component of the velocity field, and the -component. The problem is discretized with the finite difference method on a uniform mesh. The sample demonstrates shallow water solver implemented with the OpenCL™ technology. Stokes’ Law is a proposition that relates the drag force experienced by a falling sphere to the sphere’s (constant) velocity in a liquid of known viscosity. to the impact of a falling rigid block. Are you sure you want to remove Theory of the Navier-Stokes equations from your list? Theory of the Navier-Stokes equations Published 1998 by World Scientific in Singapore , River Edge, N. A finite volume scheme is implemented to solve the vorticity transport equation with a vorticity boundary condition. Here, we focus only on the incompressible version. View alirezayazdani1’s profile on GitHub; Upcoming Events. 257-286 (2017). For more information and source code availability see https://hippylib. For those wishing to use the "bleeding edge" version of Fluidity, feel free to download the 'master' branch of the repository. Figure 1: Navier-Stokes informed neural networks: A plain vanilla densely connected (physics uninformed) neural network, with 10 hidden layers and 50 neurons per hidden layer per output variable (i. SPRNT is available on GitHub under an open-source license. Iterations – Number of time-steps to use in Navier-Stokes diffusion. Bertozzi Mathematics Dept. and Raviart, P. The sorts of things that move in games are restricted to either small, discrete objects such as vehicles and people, or sometimes some larger, mechanical or pre-scripted objects. The Navier-Stokes equations in their full and simplified forms help with the design of aircraft and cars, the study of blood flow, the. Module Graph. Reynolds number in the Navier-Stokes simulations (Re= 3000) is in characteristic of insect ight, we expect this study to provide general insight into the applicability of the numerical methods across a wide range of animals, including insects, bats and birds. In this solver, the full Navier-Stokes equations have been solved numerically in the physical plane itself without using any transformation to the computational plane. GIT-ting Started Developing SU2 on GitHub (Internal Developers) Running Regression Tests Code Review Code Structure Style Guide Advanced AD Techniques v7 Docs Build SU2 From Source Solver Setup Markers and Boundary Conditions Customizing the output of the simulation Basics of Multi-Zone Computations Guide to Version v7. Let us consider the Navier-Stokes equation in two dimensions (2D) given explicitly by. It currently has the following features 2-d compressible NS; Quadrilateral meshes; Isoparametric elements using Winslow equations; Steady state, BDF1, BDF2 time stepping schemes. ABSTRACT: The VIC model is a large-scale, semi-distributed hydrologic model. It is written in standard (compliant) Fortran 2008 by means of OOP paradigm. Navier Stokes（纳维叶－斯托克斯）方程是流体力学中描述粘性牛顿流体的方程，是目前为止尚未被完全解决的方程，目前只有大约一百多个特解被解出来，是最复杂的方程之一。. Finite element discretization of the Navier-Stokes and similar transport equations on various geometries from Ralph Goodwin. Isotropic turbulence with Re_lambda=128 computed using the NS solver and a mesh of size 300**3 is physical space. Posted on 07. A simple and clear visual representation of this fluid simulation in real time. The theory of compressive turbulence lags behind the study of the incompressible Navier-Stokes equations. zip file Download this project as a tar. OFF is a CFD code designed to be accurate, efficient and modular for solving, numerically, the Navier-Stokes equations of fluid dynamics by means of Finite Volume technique. GitHub Gist: star and fork lcw's gists by creating an account on GitHub. (6 July 2012). For more details, feel free to contact me directly. Like any non-linear system, in order to find a solution for a given time step, we must undergo an iteration process to obtain a solution that reduces the residual (i. • The algorithm tells the user what hands should be kept or not. The fluid motion is governed by the incompressible Navier-Stokes equations while the dynamics of the structure is described in a general form involving displacement, velocity, and acceleration terms. OpenCoarrays is a Coarray Fortran (CAF) implementation supporting Fortran 2008 and 2015 features. Time analyticity for the heat equation and Navier-Stokes equations We prove the analyticity in time for non-decaying solutions of two parabolic equations in the whole space. The closure terms in the Navier-Stokes equations are formulated in terms of linear, nonlinear and transient components. navier_stokes_mesh3d, data files which define meshes for several 3D test problems involving the Navier Stokes equations (NSE) for fluid flow, provided by Leo Rebholz. The finite differences solver is a rewritten version of Lorena Barba’s 12 steps to Navier-Stokes computations. Stable Fluids - a paper about stable numerical methods for evaluating Navier-Stokes on a discrete grid. Hydro3D is a finite difference Navier Stokes solver that permits accurate and efficient Large Eddy Simulation (LES) of turbulent flows. Chandrashekar. A Navier-Stokes Informed Deep Learning Framework for Assimilating Flow. A Series of Example Programs The following series of example programs have been designed to get you started on the right foot. Given the initial conditions of the fluid (which could be parameters in our implementation), we can solve this equation at each time step to find the state of the fluid at the next step. The assembled coefficients are exported as sparse matrices for use in scipy. Let us consider the Navier-Stokes equation in two dimensions (2D) given explicitly by. It is written in standard (compliant) Fortran 2008 by means of OOP paradigm. Hidden Fluid Mechanics: A Navier-Stokes Informed Deep Learning Framework for Assimilating Flow Visualization Data Alireza / October 16, 2018 / Leave a comment / Uncategorized Our new work on physics-informed machine learning has been published online. FEniCS: separate boundary conditions in normal and tangential direction of mesh boundary. We propose an alternative formulation inspired by geometric flow. Willis/SoftwareX6(2017)124–127 127 hasbeenusedbyseveralgroupsaroundtheworldtomakean importantcontributiontodevelopmentsinourunderstandingof. Stokes’ Law is only valid for non-turbulent flow, so Reynolds number for the falling ball viscometer was also determined. This gives rise to a complete pressure and velocity proﬁle of the simulated environment. License; Prolog; Class material. Unlike previous approaches where optical. The "12 steps to Navier-Stokes" lessons have proved effectiveness. 2 •Github repo 10. The course structure is outlined in the project’s github page which you can take a look at here. Recently activities have been carried out on Tecnam P2012 and on new regional 90 seats aircraft. Navier-Stokes equations by P. Graphs or timing analysis to show speedup from the sequential implementation. 15 This approach was. The Cauchy momentum equation is a. MUSCL 2nd- and high-order scheme, with a wide choice of limiters. Translation of proposed Navier-Stokes solution by Mukhtarbay Otelbaev. redbKIT consists of three main packages FEM_library provides 2D/3D finite elements approximations of advection-diffusion-reaction equations, Navier-Stokes equations, nonlinear elastostatic and elastodynamics, and fluid-structure interaction problems. Compact-Reconstruction Weighted Essentially Non-Oscillatory Schemes for the Unsteady Navier-Stokes Equations Debojyoti Ghosh, Shivaji Medidayand James D. Navier (1758-1836) and English Mathematician Sir G. Used for smoothing/denoising a gradient field. A 2D solution generated in Mathematica. The Navier-Stokes equations are solved using a Fourier pseudo-spectral discretization. A general multiblock grid is used to model complex configurations. • Realised a machine learning project on GitHub to help people learn how to play the game "Magic The Gathering" using python and decision trees. CGNS CFD Data Standard by John Steinbrenner / Pointwise on behalf of CGNS Steering Committee What is CGNS? CFD General Notation System A standard for recording & recovering CFD data. It can be directly obtained from the Navier–Stokes equations. I was trying to use the Navier-Stokes equation and got stuck. Research projects at Ecole Centrale Paris September 2015 – June 2017. Presentation of the shape optimization problem 4 2. mantaflow is an open-source framework targeted at fluid simulation research in Computer Graphics. Below there is a selection of audio-visual projects developed over the last few years using OpenFrameworks (C++), Python and Processing (Java). Cauchy momentum equation. Navier Stokes Github. However, it's necessary to define it and provide it to the the solver object ( HyPar ) so that it can then send it to interpolation functions for a characteristic-based reconstruction. NSERC CREATE summer school on clean combustion engines, Ryerson University, Toronto, 2017. The second test problem is an incompressible 3D Navier-Stokes problem discretized on a non uniform 3D mesh with a finite element method:. FEATool Multiphysics is a fully integrated physics and PDE simulation environment where the modeling process is subdivided into six steps; preprocessing (CAD and geometry modeling), mesh and grid generation, physics and PDE specification, boundary condition specification, solution, and postprocessing and visualization. The assembled coefficients are exported as sparse matrices for use in scipy. Get IAMR. PDF | We present hidden fluid mechanics (HFM), a physics informed deep learning framework capable of encoding an important class of physical laws governing fluid motions, namely the Navier-Stokes. Mendl Technische Universit at Dresden. Solid arrows point from a parent (sub)module to the submodule which is descended from it. The Model for Prediction Across Scales (MPAS) is a collaborative project for developing atmosphere, ocean and other earth-system simulation components for use in climate, regional climate and weather studies. Fluid Simulation with Navier Stokes. Both SPRNT and Frehd were developed within my research group (the former in collaboration with IBM Research Austin). Home People Codes Talks Teaching Publications For students Around CAM Calendar Contact. Analytic Results from Shell Models of Turbulence Shell models of turbulence are simpler to deal with analytically and numerically than the full Navier{Stokes equations. The Zalesak’s test case is a common benchmark to evaluate the reconstruction of the interface while the Zalesak sphere is rotating. Las ecuaciones de Navier-Stokes se cree que describen la transición de flujo laminar a flujo turbulento (hay indicios numéricos, pero el problema del milenio exige una demostración matemática). SUNTANS – Stanford University Unstructured Nonhydrostatic Terrain-following Adaptive Navier-Stokes Simulator, OpenFOAM – Open-source 3-dimensional CFD model. When applying the DD strategy, the sequential algorithm of discretization is mainly kept and each processor computes part. Invariant measures for the Stochastic Navier-Stokes equation on a 2D rotating sphere with stable Lévy noise ArXiv Preprint November 29, 2018. Perssona J. In 2013, I was invited to teach a 2 day mini-course in the Latin-American School in High-Performance Computing, in Argentina. Derivation ¶ The derivation of the Navier-Stokes equations contains some equations that are useful for alternative formulations of numerical methods, so we shall briefly recover the steps to arrive at (1) and (2). Range: [ 0:016; 89]. A Variational Approach to Estimate Incompressible Fluid Flows. A more complete list can be found on my github, bitbucket and gitlab pages. Figure 1: Navier-Stokes informed neural networks: A plain vanilla densely connected (physics uninformed) neural network, with 10 hidden layers and 50 neurons per hidden layer per output variable (i. com/JamieMJohns/Navier This youtube channel is for the purpose of a digital portfolio, and not necessarily for the purpose of sharing/providing code. Navier-Stokes equation. OLAFOAM is the evolution of IHFOAM, a well-known three-dimensional Navier-Stokes solver for free surface flows, and is born with the spirit of providing the latest advances for the simulation of wave dynamics to the OpenFOAM and FOAM-extend communities. RNS is a block-structured AMR code that solves the compressible reactive Navier-Stokes equations with detailed models for the chemistry, and is based on high-order numerical methods (AMLSDC and WENO) that achieve fourth-order accuracy in both time and space. The model involves a Navier-Stokes equations physics mode, representing the fluid flow with solid wall or no-slip boundary conditions everywhere. The theory of compressive turbulence lags behind the study of the incompressible Navier-Stokes equations. Models based on a direct solution of Navier-Stokes (NS) equations, and featuring a free surface tracking algorithm, have also been used. The inlet velocity is given as u inlet = 4u max (y-h step )(1-y)/h inlet 2 where h inlet is the channel height, hstep the expansion step height, and u max = 1 the maximum velocity. But I'm getting my Ph. based solver of the incompressible Navier-Stokes equations on unstructured two dimensional triangular meshes. 3 EULER EQUATIONS In the context of ﬂuid dynamics, the Euler equations are a simpliﬁcation of the Navier-Stokes equations, with no viscosity or thermal conductivity ("˘k ˘0). Generally, the user needs to select the best-fit values according to their experimental or theoretical data. You’ll want to use the IPython shell instead of a regular Python shell (which is a pain). NAS Software. I'm currently working through some tutorials to understand the idea of of the discretized Navier-Stokes equations for numerical simulati. Flusi, a program for performing simulations of Navier-Stokes and MHD flows in complex geometries using penalisation. This gives rise to a complete pressure and velocity proﬁle of the simulated environment. We will prove the existence of blowup for solutions to the Navier--Stokes equation for a wide class of initial data, so long as certain scale critical quantities remain small up until blowup time. Navier-Stokes; Solving for Pressure; Iteratively Solving the Pressure Equation; All Together Now! Implementation; References; The Velocity Field. Section 4 is concerned with the diagnosis of the pressure field required to. Fluidity is an open source, general purpose, multiphase computational fluid dynamics code capable of numerically solving the Navier-Stokes equation and accompanying field equations on arbitrary unstructured finite element meshes in one, two and three dimensions. There are inequivalent formulations of the Navier Stokes equation on manifolds due to the different possibilities for the Laplacian operator acting on vector fields on a Riemannian manifold. A Variational Approach to Estimate Incompressible Fluid Flows. As such, it shares several basic features with the other land surface models (LSMs) that are commonly coupled to global circulation models (GCMs):. In the present research work, an incompressible unsteady two-dimensional finite volume Navier-Stokes solver is developed to investigate viscous flow past two-dimensional geometries. Linear elastic eigenvalue problem; Interior penalty method; Visualize Argyris basis; Poisson using linear tetrahedra; Nonlinear Poisson equation. Default value = 5. The 5-week module develops worked examples that build on each other to incrementally guide the learner to create a program to solve the Navier-Stokes equations of fluid dynamics, in 12 steps. FEST-3D (Finite-volume Explicit STructured 3-Dimensional) is computational fluid dynamic solver written in Fortran 90 for solving the Navier-Stokes equations on structured grids using state-of-the-art finite-volume methods. Commercial CFD packages use nite volume methods (a form of nite di erencing), which integrate and discretise equations in an. GPU whisperer. Using Python to Solve Partial Differential Equations This article describes two Python modules for solving partial differential equations (PDEs): PyCC is designed as a Matlab-like environment for writing algorithms for solving PDEs, and SyFi creates matrices based on symbolic mathematics, code generation, and the ﬁnite element method. We propose an alternative formulation inspired by geometric flow. Derivation The derivation of the Navier-Stokes equations contains some equations that are useful for alternative formulations of numerical methods, so we shall briefly recover the steps to arrive at \eqref{ns:NS:mom} and \eqref{ns:NS:mass}. Sign up Navier-Stokes fluid simulation in various languages (C, Fortran, and Haskell using Repa). Let us consider the Navier-Stokes equation in two dimensions (2D) given explicitly by. Depicted above is a Kelvin-Helmholtz instability using 3 total levels of refinement generated by the publicly available IAMR code (available HERE) for solving the variable-density incompressible Navier-Stokes equations. Navier-Stokes This project is a WebGL incompressible fluid simulation running entirely on your GPU. GPU whisperer. Stokes (1819-1903) formulated the Navier-Stokes Equations by. Hydro3D is a finite difference Navier Stokes solver that permits accurate and efficient Large Eddy Simulation (LES) of turbulent flows. Isotropic turbulence with Re_lambda=128 computed using the NS solver and a mesh of size 300**3 is physical space. Pressure Transfer between linear & angular motion External forces / torques. Proceedings of the 13th International Congress on Mathematical Education ICME13, ICME 13 Monographs, Springer-Nature, Berlin-Heidelberg-New York 2018 Gabriele Kaiser Rainer und Weiss, Ysette Kaenders article MR3868736. Computer graphics enthusiast. Cavity flow solution at Reynolds number of 200 with a 41x41 mesh. Tweet with a location. Jonathan Tompson, Kristofer Schlachter, Pablo Sprechmann, Ken Perlin ICML 2017 A learning-based system for simulating Navier-Stokes Equations in real-time. The module was part of a course taught by Prof. Clone via HTTPS Clone with Git or checkout with SVN using the repository's web address. The DUNS (Diagonalized Upwind Navier-Stokes)code is a 2D/3D, structured, multi-block, multi-species,reacting, steady/unsteady, Navier Stokes fluid dynamics code with q-omega turbulence model. The Navier-Stokes equations are to be solved in a spatial domain $$\Omega$$ for $$t\in (0,T]$$. Hello World! I thought it would be fun to show a bit of what I do on my spare time. One is a cell-centered approximate projection method-based solver that uses an explicit second-order Godunov scheme to handle the nonlinear advection terms that appear in the momentum equation. Navier-Stokes equation will ﬁnd nowhere for this term, since it is actually hidden inside fext. de · Beolingus Deutsch-Englisch OpenThesaurus ist ein freies deutsches Wörterbuch für Synonyme, bei dem jeder mitmachen kann. Then the motion of the fluid is determinded by the uncompressible Navier-Stokes equation. navier_stokes_mesh3d, data files which define meshes for several 3D test problems involving the Navier Stokes equations (NSE) for fluid flow, provided by Leo Rebholz. https://github. home documentation community source code gallery events try it online donate documentation community source code gallery events try it online donate. problem of solving Navier-Stokes equations is rather easy. edu/cse/codes/mit18086. proximation of the Navier-Stokes equations converges to the solution of the incompressible Navier-Stokes equations as the Mach number goes to 0 [5{7]. Realism is provided through a ﬁnite difference approximation to the incompressible Navier-Stokes equations. University Pompeu Fabra 08003 Barcelona, SPAIN A. Current game environments are too static. Algebraic fractional-step schemes with spectral methods for the incompressible Navier-Stokes equations. Similar to Newton's laws of motion, the Navier-Stokes equation expresses how velocity changes as a result of forces: Here, is the velocity at a point in time and space, t is time, p is pressure at a point, p is the density of the fluid at a point, µ is viscosity, and are external forces, such as gravity, acting on the fluid. Multigrid solution of the navier-stokes equations at low speeds with large temperature variations. Cauchy momentum equation. Hidden Fluid Mechanics: A Navier-Stokes Informed Deep Learning Framework for Assimilating Flow Visualization Data Alireza / October 16, 2018 / Leave a comment / Uncategorized Our new work on physics-informed machine learning has been published online. When applying the DD strategy, the sequential algorithm of discretization is mainly kept and each processor computes part. « 254A, Notes 0: Physical derivation of the incompressible Euler and Navier-Stokes equations The structure of correlations of multiplicative functions at almost all scales, with applications to the Chowla and Elliott conjectures ». The default value of OUTPUT_FILES is (RESTART, PARAVIEW, SURFACE_PARAVIEW). Navier-Stokes implementation from Jos Stam in 3D. $\endgroup$ - Stephen Montgomery-Smith Jan 26 '14 at 19:20. In this work, we look the continuum limit of the DN and GOY shell models and reproduce results from Kolmogorov theory for the stationary case.


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Elastic scattering of nuclear systems induced by weakly bound projectiles
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10.1063/1.3688787
/content/aip/proceeding/aipcp/10.1063/1.3688787
http://aip.metastore.ingenta.com/content/aip/proceeding/aipcp/10.1063/1.3688787
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Scitation: Elastic scattering of nuclear systems induced by weakly bound projectiles
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10.1063/1.3688787
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