/*
Copyright (C) 1999 CERN - European Organization for Nuclear Research.
Permission to use, copy, modify, distribute and sell this software and its documentation for any purpose 
is hereby granted without fee, provided that the above copyright notice appear in all copies and 
that both that copyright notice and this permission notice appear in supporting documentation. 
CERN makes no representations about the suitability of this software for any purpose. 
It is provided "as is" without expressed or implied warranty.
 */
package cern.jet.math.tfcomplex;

/**
 * Only for performance tuning of compute intensive linear algebraic
 * computations. Constructs functions that return one of
 * 

 * 
a * constant
 * 
a / constant
 * 
 * a is variable, constant is fixed, but for performance
 * reasons publicly accessible. Intended to be passed to
 * matrix.assign(function) methods.
 */
public final class FComplexMult implements cern.colt.function.tfcomplex.FComplexFComplexFunction {
    /**
     * Public read/write access to avoid frequent object construction.
     */
    public float[] multiplicator;

    protected FComplexMult(final float[] multiplicator) {
        this.multiplicator = multiplicator;
    }

    /**
     * Returns the result of the function evaluation.
     */
    public final float[] apply(float[] a) {
        float[] z = new float[2];
        z[0] = a[0] * multiplicator[0] - a[1] * multiplicator[1];
        z[1] = a[1] * multiplicator[0] + a[0] * multiplicator[1];
        return z;
    }

    /**
     * Returns the result of the function evaluation.
     */
    public final float[] apply(float re, float im) {
        float[] z = new float[2];
        z[0] = re * multiplicator[0] - im * multiplicator[1];
        z[1] = im * multiplicator[0] + re * multiplicator[1];
        return z;
    }

    /**
     * a / constant.
     */
    public static FComplexMult div(final float[] constant) {
        return mult(FComplex.inv(constant));
    }

    /**
     * a * constant.
     */
    public static FComplexMult mult(final float[] constant) {
        return new FComplexMult(constant);
    }
}