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Addtional routines for Lanczos (SYM2, Chebyshef)..

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This commit is contained in:
Jung
2016-01-25 01:26:25 -05:00
parent 5c57d4f403
commit b8fb05a422
5 changed files with 66 additions and 11 deletions
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19
lib/algorithms/approx/Chebyshev.h
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@ -83,7 +83,8 @@ namespace Grid {
public:
void csv(std::ostream &out){
for (RealD x=lo; x<hi; x+=(hi-lo)/1000) {
RealD diff = hi-lo;
for (RealD x=lo-0.2*diff; x<hi+0.2*diff; x+=(hi-lo)/1000) {
RealD f = approx(x);
out<< x<<" "<<f<<std::endl;
}
@ -100,10 +101,24 @@ namespace Grid {
Chebyshev(){};
Chebyshev(RealD _lo,RealD _hi,int _order, RealD (* func)(RealD) ) {Init(_lo,_hi,_order,func);};
Chebyshev(RealD _lo,RealD _hi,int _order) {Init(_lo,_hi,_order);};
////////////////////////////////////////////////////////////////////////////////////////////////////
// c.f. numerical recipes "chebft"/"chebev". This is sec 5.8 "Chebyshev approximation".
////////////////////////////////////////////////////////////////////////////////////////////////////
// CJ: the one we need for Lanczos
void Init(RealD _lo,RealD _hi,int _order)
{
lo=_lo;
hi=_hi;
order=_order;
if(order < 2) exit(-1);
Coeffs.resize(order);
Coeffs.assign(0.,order);
Coeffs[order-1] = 1.;
};
void Init(RealD _lo,RealD _hi,int _order, RealD (* func)(RealD))
{
lo=_lo;