content: /*******************************************************************************
   * Copyright (c) 2010 Haifeng Li
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   *******************************************************************************/
  
  package smile.math.matrix;
  
  import java.lang.reflect.Constructor;
  
  /**
   * An abstract interface of dense matrix.
   *
   * @author Haifeng Li
   */
  class Factory {
      private static Class<?> nlmatrix;
      private static Constructor<?> nlmatrixArray;
      private static Constructor<?> nlmatrixArray2D;
      private static Constructor<?> nlmatrixZeros;
      private static Constructor<?> nlmatrixOnes;
  
      static {
          try {
              nlmatrix = Class.forName("smile.netlib.NLMatrix");
  
              try {
                  nlmatrixArray2D = nlmatrix.getConstructor(double[][].class);
              } catch (NoSuchMethodException e) {
                  System.err.println("NLMatrix(double[][]) does not exist");
              }
  
              try {
                  nlmatrixArray = nlmatrix.getConstructor(double[].class);
              } catch (NoSuchMethodException e) {
                  System.err.println("NLMatrix(double[]) does not exist");
              }
  
              try {
                  nlmatrixZeros = nlmatrix.getConstructor(Integer.TYPE, Integer.TYPE);
              } catch (NoSuchMethodException e) {
                  System.err.println("NLMatrix(int, int) does not exist");
              }
  
              try {
                  nlmatrixOnes = nlmatrix.getConstructor(Integer.TYPE, Integer.TYPE, Double.TYPE);
              } catch (NoSuchMethodException e) {
                  System.err.println("NLMatrix(int, int, double) does not exist");
              }
          } catch (ClassNotFoundException e) {
              System.out.println("smile-netlib module is not available in the classpath. Pure Java matrix library will be employed.");
          }
      }
  
      /** Creates a matrix initialized by A. */
      public static DenseMatrix matrix(double[][] A) {
          if (nlmatrixZeros != null) {
              try {
                  return (DenseMatrix) nlmatrixArray2D.newInstance((Object) A);
              } catch (Exception e) {
                  System.err.println("Failed to call NLMatrix(double[][]): "+e);
              }
          }
  
          return new JMatrix(A);
      }
  
      /** Creates a column vector/matrix initialized by A. */
      public static DenseMatrix matrix(double[] A) {
          if (nlmatrixZeros != null) {
              try {
                  return (DenseMatrix) nlmatrixArray.newInstance(A);
              } catch (Exception e) {
                  System.err.println("Failed to call NLMatrix(double[]): "+e);
              }
          }
  
          return new JMatrix(A);
      }
  
      /** Creates a matrix of all zeros. */
      public static DenseMatrix matrix(int nrows, int ncols) {
          if (nlmatrixZeros != null) {
              try {
                  return (DenseMatrix) nlmatrixZeros.newInstance(nrows, ncols);
              } catch (Exception e) {
                  System.err.println("Failed to call NLMatrix(int, int): "+e);
              }
          }
  
          return new JMatrix(nrows, ncols);
      }
  
      /** Creates a matrix filled with given value. */
      public static DenseMatrix matrix(int nrows, int ncols, double value) {
          if (nlmatrixOnes != null) {
              try {
                  return (DenseMatrix) nlmatrixOnes.newInstance(nrows, ncols, value);
              } catch (Exception e) {
                  System.err.println("Failed to call NLMatrix(int, int, double): "+e);
              }
          }
  
          return new JMatrix(nrows, ncols, value);
      }
  }
  