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Lattice matrix exponential ok

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neo
2015-06-17 20:41:07 +09:00
parent e31dfa79d1
commit 4eb71d2cd2
9 changed files with 136 additions and 89 deletions
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37
lib/tensors/Tensor_exp.h Normal file
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#ifndef GRID_MATH_EXP_H
#define GRID_MATH_EXP_H
#define DEFAULT_MAT_EXP 12
namespace Grid {
///////////////////////////////////////////////
// Exponentiate function for scalar, vector, matrix
///////////////////////////////////////////////
template<class vtype> inline iScalar<vtype> Exponentiate(const iScalar<vtype>&r, ComplexD alpha , Integer Nexp = DEFAULT_MAT_EXP)
{
iScalar<vtype> ret;
ret._internal = Exponentiate(r._internal, alpha, Nexp);
return ret;
}
template<class vtype,int N, typename std::enable_if< GridTypeMapper<vtype>::TensorLevel == 0 >::type * =nullptr>
inline iMatrix<vtype,N> Exponentiate(const iMatrix<vtype,N> &arg, ComplexD alpha , Integer Nexp = DEFAULT_MAT_EXP )
{
iMatrix<vtype,N> unit(1.0);
iMatrix<vtype,N> temp(unit);
for(int i=Nexp; i>=1;--i){
temp *= alpha/ComplexD(i);
temp = unit + temp*arg;
}
return ProjectOnGroup(temp);//maybe not strictly necessary
}
}
#endif