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tensor: contractions over severeal indices implemented

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Jiri Pittner
2024-05-16 18:23:30 +02:00
parent 883d201e67
commit 0b91e88dca
4 changed files with 239 additions and 7 deletions
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20
tensor.h
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@@ -36,6 +36,9 @@
#include "smat.h"
#include "miscfunc.h"
//@@@todo - outer product
//@@@permutation of individual indices??? how to treat the symmetry groups
//@@@todo - index names and contraction by named index list
namespace LA {
@@ -98,6 +101,15 @@ class LA_traits<indexgroup> {
typedef NRVec<LA_index> FLATINDEX; //all indices but in a single vector
typedef NRVec<NRVec<LA_index> > SUPERINDEX; //all indices in the INDEXGROUP structure
typedef NRVec<LA_largeindex> GROUPINDEX; //set of indices in the symmetry groups
struct INDEX
{
int group;
int index;
};
typedef NRVec<INDEX> INDEXLIST; //collection of several indices
int flatposition(const INDEX &i, const NRVec<indexgroup> &shape); //position of that index in FLATINDEX
int flatposition(const INDEX &i, const NRVec<indexgroup> &shape);
FLATINDEX superindex2flat(const SUPERINDEX &I);
@@ -184,8 +196,12 @@ public:
Tensor permute_index_groups(const NRPerm<int> &p) const; //rearrange the tensor storage permuting index groups as a whole
Tensor unwind_index(int group, int index) const; //separate an index from a group and expand it to full range as the least significant one
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, bool conjugate=false);
inline Tensor contraction(int group, int index, const Tensor &rhs, int rhsgroup, int rhsindex, T alpha=1, bool conjugate=false) const {Tensor<T> r; r.addcontraction(*this,group,index,rhs,rhsgroup,rhsindex,alpha,0,true, conjugate); return r; }
Tensor unwind_indices(const INDEXLIST &il) const; //the same for a list of indices
void addcontraction(const Tensor &rhs1, int group, int index, const Tensor &rhs2, int rhsgroup, int rhsindex, T alpha=1, T beta=1, bool doresize=false, bool conjugate1=false, bool conjugate=false); //rhs1 will have more significant non-contracted indices in the result than rhs2
inline Tensor contraction(int group, int index, const Tensor &rhs, int rhsgroup, int rhsindex, T alpha=1, bool conjugate1=false, bool conjugate=false) const {Tensor<T> r; r.addcontraction(*this,group,index,rhs,rhsgroup,rhsindex,alpha,0,true, conjugate1, conjugate); return r; };
void addcontractions(const Tensor &rhs1, const INDEXLIST &il1, const Tensor &rhs2, const INDEXLIST &il2, T alpha=1, T beta=1, bool doresize=false, bool conjugate1=false, bool conjugate2=false);
inline Tensor contractions( const INDEXLIST &il1, const Tensor &rhs2, const INDEXLIST &il2, T alpha=1, bool conjugate1=false, bool conjugate2=false) const {Tensor<T> r; r.addcontractions(*this,il1,rhs2,il2,alpha,0,true,conjugate1, conjugate2); return r; };
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))