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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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23
davidson.h
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@ -36,7 +36,8 @@ namespace LA {
template <typename T, typename Matrix>
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,
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)
//@@@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>
void davidson(const Matrix &bigmat, NRVec<T> &eivals, NRVec<T> *eivecs, const char *eivecsfile,
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;
int n=bigmat.nrows();
@ -82,12 +84,18 @@ int nroot=0;
int oldnroot;
smallS=0;
smallH=0;
//guess based on lowest diagonal element of the matrix
//default guess based on lowest diagonal element of the matrix
if(initguess) (*initguess)(vec1);
else
{
const T *diagonal = bigmat.diagonalof(vec2,false,true);
T t=1e100; int i,j;
vec1=0;
{T t=1e100; int i,j;
for(i=0, j= -1; i<n; ++i) if(diagonal[i]<t) {t=diagonal[i]; j=i;}
vec1[j]=1;}
vec1[j]=1;
}
//init Krylov matrices
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);
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];
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));
vec1[i] /= denom;
}
}
//orthogonalise to previous vectors
vec1.normalize();