Here you can find the source of multiply(final double[][] A, final double[][] B)
| Parameter | Description |
|---|---|
| A | a parameter |
| B | a parameter |
public static final double[][] multiply(final double[][] A, final double[][] B)
//package com.java2s; /**// ww w.ja v a 2 s . c om * Copyright (C) 2012 Fredrik Ekelund <fredrik@ipx.se> * * This file is part of Decision Trees. * * 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. */ public class Main { /** * * @param A * @param B * @return */ public static final double[][] multiply(final double[][] A, final double[][] B) { final int n = A.length; final int m = B.length; if (m == 0 || n == 0) { return new double[0][0]; } final int p = B[0].length; if (m != A[0].length) { throw new IllegalArgumentException( String.format("Non-conformant matrix dimensions: [%d x %d] * [%d x %d]", n, A[0].length, m, p)); } if (p == 0) { return new double[0][0]; } // return uncheckedMultiply(A, B, n, m, p); return uncheckedMultiplyJAMA(A, B, n, m, p); } static double[][] uncheckedMultiplyJAMA(final double[][] A, final double[][] B, final int n, final int m, final int p) { final double[][] C = new double[n][p]; final double[] bCol = new double[m]; for (int j = 0; j < p; j++) { for (int k = 0; k < m; k++) bCol[k] = B[k][j]; for (int i = 0; i < n; i++) { final double[] aRow = A[i]; double sum = 0.0; for (int k = 0; k < m; k++) { sum += aRow[k] * bCol[k]; } C[i][j] = sum; } } return C; } }