org.apfloat.internal.DoubleScramble Maven / Gradle / Ivy
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package org.apfloat.internal;
/**
* Functions to perform bit-reverse ordering of double data.
*
* @version 1.0
* @author Mikko Tommila
*/
public class DoubleScramble
{
private DoubleScramble()
{
}
/**
* Permute the data in the table to bit-reversed order.
*
* The permutation table argument should contain pairs of indexes
* that indicate array elements whose contents are swapped.
*
* @param data The array to permute.
* @param offset The offset within the array to permute.
* @param permutationTable Table of indexes indicating, which elements in the data are to be swapped.
*/
public static void scramble(double[] data, int offset, int[] permutationTable)
{
for (int k = 0; k < permutationTable.length; k += 2)
{
int i = offset + permutationTable[k],
j = offset + permutationTable[k + 1];
double tmp = data[i];
data[i] = data[j];
data[j] = tmp;
}
}
}