jiri/LA_library
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

*** empty log message ***

Browse Source
This commit is contained in:
jiri 2006-09-11 16:21:46 +00:00
parent 5e6a7ea2e9
commit 94945a4f92
1 changed files with 6 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
matexp.h
View File

@ -156,8 +156,8 @@ return int(ceil(log(n)/log2-log(.75)));
}
template<class T>
NRVec<typename LA_traits<T>::elementtype> exp_aux(const T &x, int &power)
template<class T, class C>
NRVec<C> exp_aux(const T &x, int &power)
{
//should better be computed by mathematica to have accurate last digits, chebyshev instead, see exp in glibc
static double exptaylor[]={
@ -183,7 +183,7 @@ static double exptaylor[]={
8.2206352466243294955e-18,
4.1103176233121648441e-19,
0.};
double mnorm= LA_traits<T>::norm(x);
double mnorm= x.norm();
power=nextpow2(mnorm);
double scale=exp(-log(2.)*power);
@ -204,7 +204,7 @@ while(t*exptaylor[n]>precision);//taylor 0 will terminate in any case
int i; //adjust the coefficients in order to avoid scaling the argument
NRVec<typename LA_traits<T>::elementtype> taylor2(n+1);
NRVec<C> taylor2(n+1);
for(i=0,t=1.;i<=n;i++)
{
taylor2[i]=exptaylor[i]*t;
@ -222,7 +222,7 @@ const T exp(const T &x, const bool horner=true)
int power;
//prepare the polynom of and effectively scale T
NRVec<typename LA_traits<T>::elementtype> taylor2=exp_aux(x,power);
NRVec<typename LA_traits<T>::elementtype> taylor2=exp_aux<T,typename LA_traits<T>::elementtype>(x,power);
T r= horner?polynom0(x,taylor2):polynom(x,taylor2);
@ -242,7 +242,7 @@ const V exptimes(const M &mat, V vec) //uses just matrix vector multiplication
if(mat.nrows()!=mat.ncols()||(unsigned int) mat.nrows() != (unsigned int)vec.size()) laerror("inappropriate sizes in exptimes");
int power;
//prepare the polynom of and effectively scale the matrix
NRVec<typename LA_traits<M>::elementtype> taylor2=exp_aux(mat,power);
NRVec<typename LA_traits<V>::elementtype> taylor2=exp_aux<M,typename LA_traits<V>::elementtype>(mat,power);
V result(mat.nrows());
for(int i=1; i<=(1<<power); ++i) //unfortunatelly, here we have to repeat it many times, unlike if the matrix is stored explicitly