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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.apache.org/licenses/LICENSE-2.0
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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package org.apache.commons.math.linear;
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* An interface to classes that implement an algorithm to calculate the
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* QR-decomposition of a real matrix.
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* <p>This interface is based on the class with similar name from the now defunct
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* <a href="http://math.nist.gov/javanumerics/jama/">JAMA</a> library, with the
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* following changes:</p>
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* <li>a {@link #getQT() getQT} method has been added,</li>
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* <li>the <code>solve</code> and <code>isFullRank</code> methods have been replaced
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* by a {@link #getSolver() getSolver} method and the equivalent methods provided by
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* the returned {@link DecompositionSolver}.</li>
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* @see <a href="http://mathworld.wolfram.com/QRDecomposition.html">MathWorld</a>
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* @see <a href="http://en.wikipedia.org/wiki/QR_decomposition">Wikipedia</a>
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* @version $Revision: 799857 $ $Date: 2009-08-01 09:07:12 -0400 (Sat, 01 Aug 2009) $
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public interface QRDecomposition {
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* Returns the matrix R of the decomposition.
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* <p>R is an upper-triangular matrix</p>
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* @return the R matrix
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* Returns the matrix Q of the decomposition.
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* <p>Q is an orthogonal matrix</p>
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* @return the Q matrix
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* Returns the transpose of the matrix Q of the decomposition.
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* <p>Q is an orthogonal matrix</p>
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* @return the Q matrix
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* Returns the Householder reflector vectors.
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* <p>H is a lower trapezoidal matrix whose columns represent
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* each successive Householder reflector vector. This matrix is used
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* @return a matrix containing the Householder reflector vectors
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* Get a solver for finding the A × X = B solution in least square sense.
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DecompositionSolver getSolver();