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jiri 2020-06-12 12:29:35 +00:00
parent 3c3b28053c
commit 853008caf1
1 changed files with 2 additions and 2 deletions
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matexp.h
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@ -131,7 +131,7 @@ return z;
//general BCH expansion (can be written more efficiently in a specialization for matrices) //general BCH expansion (can be written more efficiently in a specialization for matrices)
template<class T> template<class T>
const T BCHexpansion (const T &h, const T &t, const int nmax, const bool verbose=0) const T BCHexpansion (const T &h, const T &t, const int nmax, const bool verbose=0, const bool right=1)
{ {
T result=h; T result=h;
double factor=1.; double factor=1.;
@ -139,7 +139,7 @@ T z=h;
for(int i=1; i<=nmax; ++i) for(int i=1; i<=nmax; ++i)
{ {
factor/=i; factor/=i;
z= z*t-t*z; if(right) z= z*t-t*z; else z= t*z-z*t;
if(verbose) std::cerr << "BCH contribution at order "<<i<<" : "<<z.norm()*factor<<std::endl; if(verbose) std::cerr << "BCH contribution at order "<<i<<" : "<<z.norm()*factor<<std::endl;
result+= z*factor; result+= z*factor;
} }