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63 lines
1.7 KiB
C++
63 lines
1.7 KiB
C++
// This file is part of Eigen, a lightweight C++ template library
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// for linear algebra.
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//
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// Copyright (C) 2011 Gael Guennebaud <gael.guennebaud@inria.fr>
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//
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// This Source Code Form is subject to the terms of the Mozilla
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// Public License v. 2.0. If a copy of the MPL was not distributed
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// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
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#include "lapack_common.h"
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#include <Eigen/Eigenvalues>
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// computes eigen values and vectors of a general N-by-N matrix A
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EIGEN_LAPACK_FUNC(syev)
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(char* jobz, char* uplo, int* n, Scalar* a, int* lda, Scalar* w, Scalar* /*work*/, int* lwork, int* info) {
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// TODO exploit the work buffer
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bool query_size = *lwork == -1;
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*info = 0;
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if (*jobz != 'N' && *jobz != 'V')
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*info = -1;
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else if (UPLO(*uplo) == INVALID)
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*info = -2;
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else if (*n < 0)
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*info = -3;
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else if (*lda < std::max(1, *n))
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*info = -5;
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else if ((!query_size) && *lwork < std::max(1, 3 * *n - 1))
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*info = -8;
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if (*info != 0) {
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int e = -*info;
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return xerbla_(SCALAR_SUFFIX_UP "SYEV ", &e);
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}
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if (query_size) {
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*lwork = 0;
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return;
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}
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if (*n == 0) return;
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PlainMatrixType mat(*n, *n);
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if (UPLO(*uplo) == UP)
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mat = matrix(a, *n, *n, *lda).adjoint();
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else
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mat = matrix(a, *n, *n, *lda);
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bool computeVectors = *jobz == 'V' || *jobz == 'v';
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Eigen::SelfAdjointEigenSolver<PlainMatrixType> eig(
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mat, computeVectors ? Eigen::ComputeEigenvectors : Eigen::EigenvaluesOnly);
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if (eig.info() == Eigen::NoConvergence) {
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make_vector(w, *n).setZero();
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if (computeVectors) matrix(a, *n, *n, *lda).setIdentity();
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//*info = 1;
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return;
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}
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make_vector(w, *n) = eig.eigenvalues();
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if (computeVectors) matrix(a, *n, *n, *lda) = eig.eigenvectors();
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}
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