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explicit matrix reconstruction template added to davidson.h

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Jiri Pittner
2026-02-04 17:39:13 +01:00
parent 1407fb9d8e
commit 7441b44251
2 changed files with 30 additions and 2 deletions
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21
davidson.h
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@@ -46,7 +46,7 @@ namespace LA {
template <typename T, typename Matrix>
extern void davidson(const Matrix &bigmat, NRVec<T> &eivals, NRVec<T> *eivecs, const char *eivecsfile,
void davidson(const Matrix &bigmat, NRVec<T> &eivals, NRVec<T> *eivecs, const char *eivecsfile,
int nroots=1, const bool verbose=0, const double eps=1e-6,
const bool incore=1, int maxit=100, const int maxkrylov = 500,
void (*initguess)(NRVec<T> &)=NULL, const typename LA_traits<T>::normtype *target=NULL)
@@ -309,6 +309,25 @@ if(incore) {delete[] v0; delete[] v1;}
else {delete s0; delete s1;}
if(flag) laerror("no convergence in davidson");
} //davidson
//reconstruction of explicit dense matrix from the implicit one (useful for debugging)
template <typename T, typename Matrix>
NRMat<T> explicit_matrix(const Matrix &bigmat)
{
NRMat<T> r(bigmat.nrows(), bigmat.ncols());
for(int i=0; i<bigmat.ncols(); ++i)
{
NRVec<T> ket(bigmat.ncols());
ket.clear();
ket[i]=(T)1;
NRVec<T> hket(bigmat.nrows());
bigmat.gemv((T)0,hket,'n',(T)1,ket);
for(int l=0; l<bigmat.nrows(); ++l) r(l,i) = hket[l];
}
return r;
}
}//namespace