org.ejml.interfaces.decomposition.QRPDecomposition Maven / Gradle / Ivy
/*
* Copyright (c) 2009-2017, Peter Abeles. All Rights Reserved.
*
* This file is part of Efficient Java Matrix Library (EJML).
*
* 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.
*/
package org.ejml.interfaces.decomposition;
import org.ejml.data.Matrix;
/**
*
* Similar to {@link QRDecomposition} but it can handle the rank deficient case by
* performing column pivots during the decomposition. The final decomposition has the
* following structure:
* A*P=Q*R
* where A is the original matrix, P is a pivot matrix, Q is an orthogonal matrix, and R is
* upper triangular.
*
*
* @author Peter Abeles
*/
public interface QRPDecomposition
extends QRDecomposition
{
/**
* Returns the rank as determined by the algorithm. This is dependent upon a fixed threshold
* and might not be appropriate for some applications.
*
* @return Matrix's rank
*/
int getRank();
/**
* Ordering of each column after pivoting. The current column i was original at column pivot[i].
*
* @return Order of columns.
*/
int[] getColPivots();
/**
* Creates the column pivot matrix.
*
* @param P Optional storage for pivot matrix. If null a new matrix will be created.
* @return The pivot matrix.
*/
T getColPivotMatrix(T P);
}