org.apfloat.spi.NTTStepStrategy Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of apfloat Show documentation

High performance arbitrary precision arithmetic library

There is a newer version: 1.14.0

package org.apfloat.spi;

import org.apfloat.ApfloatContext;
import org.apfloat.ApfloatRuntimeException;

/**
 * Steps for the six-step or two-pass NTT.
 *
 * @since 1.7.0
 * @version 1.7.0
 * @author Mikko Tommila
 */

public interface NTTStepStrategy
{
    /**
     * Multiply each matrix element (i, j) by w^{i * j} / totalTransformLength.
     * The matrix size is n₁ x n₂.
     *
     * @param arrayAccess The memory array to multiply.
     * @param startRow Which row in the whole matrix the starting row in the arrayAccess is.
     * @param startColumn Which column in the whole matrix the starting column in the arrayAccess is.
     * @param rows The number of rows in the arrayAccess to multiply.
     * @param columns The number of columns in the matrix (= n₂).
     * @param length The length of data in the matrix being transformed.
     * @param totalTransformLength The total transform length, for the scaling factor. Used only for the inverse case.
     * @param isInverse If the multiplication is done for the inverse transform or not.
     * @param modulus Index of the modulus.
     */

    public void multiplyElements(ArrayAccess arrayAccess, int startRow, int startColumn, int rows, int columns, long length, long totalTransformLength, boolean isInverse, int modulus)
        throws ApfloatRuntimeException;

    /**
     * Transform the rows of the data matrix.
     * If only one processor is available, it runs all transforms in the current
     * thread. If more than one processor are available, it dispatches the calculations
     * to multiple threads to parallelize the calculation. The number of processors is
     * determined using {@link ApfloatContext#getNumberOfProcessors()}.
     *
     * @param arrayAccess The memory array to split to rows and to transform.
     * @param length Length of one transform (one row).
     * @param count Number of rows.
     * @param isInverse true if an inverse transform is performed, false if a forward transform is performed.
     * @param permute If permutation should be done.
     * @param modulus Index of the modulus.
     */

    public void transformRows(ArrayAccess arrayAccess, int length, int count, boolean isInverse, boolean permute, int modulus)
        throws ApfloatRuntimeException;

    /**
     * Get the maximum transform length.
     *
     * @return The maximum transform length.
     */

    public long getMaxTransformLength();
}