Vector Matrix multiplication - Android java.lang

Android examples for java.lang:Math Matrix

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Description

Vector Matrix multiplication

Demo Code


//package com.java2s;

public class Main {
    /**/*from   w ww . ja v  a  2 s. c  o  m*/
     * Cache matrix
     */
    private final static float[] sTemp = new float[32];

    /**
     * Vector Matrix multiplication 
     * 
     * @param result The float array that holds the result.
     * @param resultOffset The offset into result array
     * @param lhs The float array that holds the left-hand-side matrix.
     * @param lhsOffset The offset into the lhs array where the lhs is stored
     * @param rhs The float array that holds the right-hand-side matrix
     * @param rhsOffset The offset into the rhs array where the rhs is stored.
     */
    public static void multiplyMV(final float[] result,
            final int resultOffset, final float[] lhs, final int lhsOffset,
            final float[] rhs, final int rhsOffset) {
        //android.util.Log.d(TAG,"multiplyMV()");
        synchronized (sTemp) {
            sTemp[0] = rhs[rhsOffset];
            sTemp[1] = rhs[rhsOffset + 1];
            sTemp[2] = rhs[rhsOffset + 2];
            sTemp[3] = rhs[rhsOffset + 3];
            System.arraycopy(lhs, lhsOffset, sTemp, 4, 16);
            result[3 + resultOffset] = (sTemp[7] * sTemp[0])
                    + (sTemp[11] * sTemp[1]) + (sTemp[15] * sTemp[2])
                    + (sTemp[19] * sTemp[3]);
            result[2 + resultOffset] = (sTemp[6] * sTemp[0])
                    + (sTemp[10] * sTemp[1]) + (sTemp[14] * sTemp[2])
                    + (sTemp[18] * sTemp[3]);
            result[1 + resultOffset] = (sTemp[5] * sTemp[0])
                    + (sTemp[9] * sTemp[1]) + (sTemp[13] * sTemp[2])
                    + (sTemp[17] * sTemp[3]);
            result[0 + resultOffset] = (sTemp[4] * sTemp[0])
                    + (sTemp[8] * sTemp[1]) + (sTemp[12] * sTemp[2])
                    + (sTemp[16] * sTemp[3]);
        }
    }
}

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