org.ejml.dense.row.decomposition.eig.watched.WatchedDoubleStepQREigenvalue_DDRM 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.dense.row.decomposition.eig.watched;
import org.ejml.data.Complex_F64;
import org.ejml.data.DMatrixRMaj;
import org.ejml.dense.row.decomposition.eig.EigenvalueExtractor_DDRM;
/**
* @author Peter Abeles
*/
public class WatchedDoubleStepQREigenvalue_DDRM implements EigenvalueExtractor_DDRM {
WatchedDoubleStepQREigen_DDRM implicitQR;
int splits[];
int numSplits;
int x1;
int x2;
public WatchedDoubleStepQREigenvalue_DDRM() {
implicitQR = new WatchedDoubleStepQREigen_DDRM();
}
public void setup( DMatrixRMaj A ) {
implicitQR.setup(A);
implicitQR.setQ(null);
splits = new int[ A.numRows ];
numSplits = 0;
}
@Override
public boolean process(DMatrixRMaj origA) {
setup(origA);
x1 = 0;
x2 = origA.numRows-1;
while( implicitQR.numEigen < origA.numRows ) {
if( implicitQR.steps > implicitQR.maxIterations )
return false;
implicitQR.incrementSteps();
if( x2 < x1 ) {
moveToNextSplit();
} else if( x2-x1 == 0 ) {
// implicitQR.A.print();
implicitQR.addEigenAt(x1);
x2--;
} else if( x2-x1 == 1 ) {
// implicitQR.A.print();
implicitQR.addComputedEigen2x2(x1,x2);
x2 -= 2;
} else if( implicitQR.steps-implicitQR.lastExceptional > implicitQR.exceptionalThreshold ) {
// see if the matrix blew up
if( Double.isNaN(implicitQR.A.get(x2,x2))) {
return false;
}
implicitQR.exceptionalShift(x1,x2);
} else if( implicitQR.isZero(x2,x2-1) ) {
// implicitQR.A.print();
implicitQR.addEigenAt(x2);
x2--;
}else {
performIteration();
}
}
return true;
}
private void moveToNextSplit() {
if( numSplits <= 0 )
throw new RuntimeException("bad");
x2 = splits[--numSplits];
if( numSplits > 0 ) {
x1 = splits[numSplits-1]+1;
} else {
x1 = 0;
}
}
private void performIteration() {
boolean changed = false;
// see if it can perform a split
for( int i = x2; i > x1; i-- ) {
if( implicitQR.isZero(i,i-1)) {
x1 = i;
splits[numSplits++] = i-1;
changed = true;
// reduce the scope of what it is looking at
break;
}
}
if( !changed )
implicitQR.implicitDoubleStep(x1,x2);
}
@Override
public int getNumberOfEigenvalues() {
return implicitQR.getNumberOfEigenvalues();
}
@Override
public Complex_F64[] getEigenvalues() {
return implicitQR.getEigenvalues();
}
public WatchedDoubleStepQREigen_DDRM getImplicitQR() {
return implicitQR;
}
}