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jiri 2009-12-15 19:41:27 +00:00
parent 5c1505ba19
commit bd843de786
1 changed files with 20 additions and 9 deletions
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29
davidson.h
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@ -36,7 +36,8 @@ namespace LA {
template <typename T, typename Matrix> template <typename T, typename Matrix>
extern void davidson(const Matrix &bigmat, NRVec<T> &eivals, NRVec<T> *eivecs, const char *eivecsfile, extern 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, int nroots=1, const bool verbose=0, const double eps=1e-6,
const bool incore=1, int maxit=100, const int maxkrylov = 500); const bool incore=1, int maxit=100, const int maxkrylov = 500,
void (*initguess)(NRVec<T> &)=NULL);
//@@@options: left eigenvectors by matrix transpose, overridesymmetric (for nrmat) //@@@options: left eigenvectors by matrix transpose, overridesymmetric (for nrmat)
//@@@small matrix gdiagonalize - shift complex roots up (option to gdiagonalize?) //@@@small matrix gdiagonalize - shift complex roots up (option to gdiagonalize?)
@ -50,7 +51,8 @@ extern void davidson(const Matrix &bigmat, NRVec<T> &eivals, NRVec<T> *eivecs, c
template <typename T, typename Matrix> template <typename T, typename Matrix>
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, const bool verbose, const double eps, int nroots, const bool verbose, const double eps,
const bool incore, int maxit, const int maxkrylov) const bool incore, int maxit, const int maxkrylov,
void (*initguess)(NRVec<T> &))
{ {
bool flag=0; bool flag=0;
int n=bigmat.nrows(); int n=bigmat.nrows();
@ -82,12 +84,18 @@ int nroot=0;
int oldnroot; int oldnroot;
smallS=0; smallS=0;
smallH=0; smallH=0;
//guess based on lowest diagonal element of the matrix
const T *diagonal = bigmat.diagonalof(vec2,false,true);
vec1=0; //default guess based on lowest diagonal element of the matrix
{T t=1e100; int i,j; if(initguess) (*initguess)(vec1);
for(i=0, j= -1; i<n; ++i) if(diagonal[i]<t) {t=diagonal[i]; j=i;} else
vec1[j]=1;} {
const T *diagonal = bigmat.diagonalof(vec2,false,true);
T t=1e100; int i,j;
vec1=0;
for(i=0, j= -1; i<n; ++i) if(diagonal[i]<t) {t=diagonal[i]; j=i;}
vec1[j]=1;
}
//init Krylov matrices //init Krylov matrices
bigmat.gemv(0,vec2,'n',1,vec1); //avoid bigmat.operator*(vec), since that needs to allocate another n-sized vector bigmat.gemv(0,vec2,'n',1,vec1); //avoid bigmat.operator*(vec), since that needs to allocate another n-sized vector
@ -192,7 +200,9 @@ for(j=0; j<=krylovsize; ++j)
if(!incore) s1->get(vec2,j); if(!incore) s1->get(vec2,j);
vec1.axpy(smallV(j,nroot),incore?v1[j]:vec2); vec1.axpy(smallV(j,nroot),incore?v1[j]:vec2);
} }
diagonal = bigmat.diagonalof(vec2,false,true);
{
const T *diagonal = bigmat.diagonalof(vec2,false,true);
eival_n = r[nroot]; eival_n = r[nroot];
for(i=0; i<n; ++i) for(i=0; i<n; ++i)
{ {
@ -200,6 +210,7 @@ for(i=0; i<n; ++i)
denom = denom<0?-std::max(0.1,std::abs(denom)):std::max(0.1,std::abs(denom)); denom = denom<0?-std::max(0.1,std::abs(denom)):std::max(0.1,std::abs(denom));
vec1[i] /= denom; vec1[i] /= denom;
} }
}
//orthogonalise to previous vectors //orthogonalise to previous vectors
vec1.normalize(); vec1.normalize();