mirror of
https://github.com/triqs/dft_tools
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62 lines
2.3 KiB
C++
62 lines
2.3 KiB
C++
/*******************************************************************************
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*
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* TRIQS: a Toolbox for Research in Interacting Quantum Systems
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*
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* Copyright (C) 2012 by O. Parcollet
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*
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* TRIQS is free software: you can redistribute it and/or modify it under the
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* terms of the GNU General Public License as published by the Free Software
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* Foundation, either version 3 of the License, or (at your option) any later
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* version.
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*
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* TRIQS is distributed in the hope that it will be useful, but WITHOUT ANY
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* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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* details.
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*
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* You should have received a copy of the GNU General Public License along with
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* TRIQS. If not, see <http://www.gnu.org/licenses/>.
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*
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******************************************************************************/
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#ifndef TRIQS_ARRAYS_BLAS_LAPACK_DSTEV_H
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#define TRIQS_ARRAYS_BLAS_LAPACK_DSTEV_H
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#include "./tools.hpp"
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namespace triqs { namespace arrays { namespace blas {
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using namespace blas_lapack_tools;
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namespace f77 { // overload
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extern "C" {
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void TRIQS_FORTRAN_MANGLING(dstev)(const char *, const int &N, const double [], const double [], const double [], const int &, double [], int &);
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}
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inline void stev (char J, const int & N, double* D, double* E, double* Z, int ldz, double * work, int & info) {
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TRIQS_FORTRAN_MANGLING(dstev)(&J,N,D,E,Z,ldz,work,info);
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}
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}
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struct tridiag_worker {
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arrays::vector<double> D,E,W;
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matrix<double> Z;
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size_t s;
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tridiag_worker (size_t n){ s=0; resize(n);}
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void resize(size_t n) { if (s<n) {D.resize(n); E.resize(n); W.resize(2*n+1); Z.resize(n,n);} s = n; }
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template<typename VT>
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void operator()(VT const & d, VT const & e) {
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if (e.size() != d.size() -1) TRIQS_RUNTIME_ERROR << " Error in tridiagonal matrix diagonalization size mismatch";
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resize(d.size());
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D(range(0,s)) = d;
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E(range(0,s-1)) = e;
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int info;
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f77::stev ('V',d.size(),D.data_start(),E.data_start(), Z.data_start(), Z.shape(0),W.data_start(), info);
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if (info !=0) TRIQS_RUNTIME_ERROR << " Error in tridiagonal matrix diagonalization "<< info;
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}
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arrays::vector_view<double> values() const { return D(range(0,s));}
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matrix_view<double> vectors() const { return Z(range(0,s),range(0,s));}
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};
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}}}// namespace
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#endif
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