eigen/lapack/eigenvalues.cpp
2011-02-23 09:32:55 +01:00

95 lines
3.0 KiB
C++

// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2011 Gael Guennebaud <gael.guennebaud@inria.fr>
//
// Eigen is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 3 of the License, or (at your option) any later version.
//
// Alternatively, you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 2 of
// the License, or (at your option) any later version.
//
// Eigen is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
// FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License or the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License and a copy of the GNU General Public License along with
// Eigen. If not, see <http://www.gnu.org/licenses/>.
#include "common.h"
#include <Eigen/Eigenvalues>
// computes an LU factorization of a general M-by-N matrix A using partial pivoting with row interchanges
EIGEN_LAPACK_FUNC(syev,(char *jobz, char *uplo, int* n, Scalar* a, int *lda, Scalar* w, Scalar* /*work*/, int* lwork, int *info))
{
// TODO exploit the work buffer
bool query_size = *lwork==-1;
*info = 0;
if(*jobz!='N' && *jobz!='V') *info = -1;
else if(UPLO(*uplo)==INVALID) *info = -2;
else if(*n<0) *info = -3;
else if(*lda<std::max(1,*n)) *info = -5;
else if((!query_size) && *lwork<std::max(1,3**n-1)) *info = -8;
// if(*info==0)
// {
// int nb = ILAENV( 1, 'SSYTRD', UPLO, N, -1, -1, -1 )
// LWKOPT = MAX( 1, ( NB+2 )*N )
// WORK( 1 ) = LWKOPT
// *
// IF( LWORK.LT.MAX( 1, 3*N-1 ) .AND. .NOT.LQUERY )
// $ INFO = -8
// END IF
// *
// IF( INFO.NE.0 ) THEN
// CALL XERBLA( 'SSYEV ', -INFO )
// RETURN
// ELSE IF( LQUERY ) THEN
// RETURN
// END IF
if(*info!=0)
{
int e = -*info;
return xerbla_(SCALAR_SUFFIX_UP"SYEV ", &e, 6);
}
if(query_size)
{
*lwork = 0;
return 0;
}
if(*n==0)
return 0;
PlainMatrixType mat(*n,*n);
if(UPLO(*uplo)==UP) mat = matrix(a,*n,*n,*lda).adjoint();
else mat = matrix(a,*n,*n,*lda);
bool computeVectors = *jobz=='V' || *jobz=='v';
SelfAdjointEigenSolver<PlainMatrixType> eig(mat,computeVectors?ComputeEigenvectors:EigenvaluesOnly);
if(eig.info()==NoConvergence)
{
vector(w,*n).setZero();
if(computeVectors)
matrix(a,*n,*n,*lda).setIdentity();
//*info = 1;
return 0;
}
vector(w,*n) = eig.eigenvalues();
if(computeVectors)
matrix(a,*n,*n,*lda) = eig.eigenvectors();
return 0;
}