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class tensor - apply permutation algebra

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This commit is contained in:
Jiri Pittner 2024-05-03 13:57:11 +02:00
parent 3d8386e30a
commit 518c75fb20
3 changed files with 41 additions and 2 deletions
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2
t.cc
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@ -3350,4 +3350,6 @@ for(int i=0; i<n; ++i)
//cout <<c;
}
//test Tensor apply_permutation_algebra
}

33
tensor.cc
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@ -715,6 +715,39 @@ auxmatmult<T>(nn,mm,kk,&data[0],&u.data[0], &rhsu.data[0],alpha,beta);
}
template<typename T>
static const PermutationAlgebra<int,T> *help_pa;
static bool help_inverse;
template<typename T>
static T help_alpha;
template<typename T>
static void permutationalgebra_callback(const SUPERINDEX &I, T *v)
{
FLATINDEX J = superindex2flat(I);
for(int p=0; p<help_pa<T>->size(); ++p)
{
FLATINDEX Jp = J.permuted((*help_pa<T>)[p].perm,help_inverse);
*v += help_alpha<T> * (*help_pa<T>)[p].weight * (*help_t<T>)(Jp);
}
}
template<typename T>
void Tensor<T>::apply_permutation_algebra(const Tensor<T> &rhs, const PermutationAlgebra<int,T> &pa, bool inverse, T alpha, T beta)
{
if(beta!=(T)0) *this *= beta; else clear();
if(alpha==(T)0) return;
help_t<T> = const_cast<Tensor<T> *>(&rhs);
help_pa<T> = &pa;
help_inverse = inverse;
help_alpha<T> = alpha;
loopover(permutationalgebra_callback);
}
template class Tensor<double>;

8
tensor.h
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@ -183,8 +183,12 @@ public:
void addcontraction(const Tensor &rhs1, int group, int index, const Tensor &rhs, int rhsgroup, int rhsindex, T alpha=1, T beta=1, bool doresize=false);
inline Tensor contraction(int group, int index, const Tensor &rhs, int rhsgroup, int rhsindex, T alpha=1) const {Tensor<T> r; r.addcontraction(*this,group,index,rhs,rhsgroup,rhsindex,alpha,0,true); return r; }
//@@@ general antisymmetrization operator Kucharski style - or that will be left to a code generator?
//@@@symmetrize a group, antisymmetrize a group, expand a (anti)symmetric group - obecne symmetry change krome +1 na -1 vse mozne
void apply_permutation_algebra(const Tensor &rhs, const PermutationAlgebra<int,T> &pa, bool inverse=false, T alpha=1, T beta=0); //general (not optimally efficient) symmetrizers, antisymmetrizers etc. acting on the flattened index list:
// this *=beta; for I over this: this(I) += alpha * sum_P c_P rhs(P(I))
// PermutationAlgebra can represent e.g. general_antisymmetrizer in Kucharski-Bartlett notation
//TODO perhaps implement application of a permutation algebra to a product of several tensors
};