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tensor-fourindex conversions for some more symemtries

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Jiri Pittner
2025-10-24 14:17:12 +02:00
parent 874c2d5f83
commit f1060245a0
3 changed files with 160 additions and 5 deletions
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118
tensor.h
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@@ -266,22 +266,26 @@ public:
//due to template nesting and specialization limitation, this cannot be class member - the S parameter has to be the outer one
//note also that the class Tnesor does not support symmetry between groups of indices (only symmetry inside each group), the full fourindex symmetry cannot thus be reflected in some cases
//
template<fourindexsymtype S, typename T, typename I>
Tensor<T> fourindex2tensor(const fourindex_dense<S,T,I> &f);
template<fourindexsymtype S, typename T, typename I>
void tensor2fourindex(const Tensor<T> &t, fourindex_dense<S,T,I> &f);
//conversions from/to fourindex specialized by symmetry type
//NOTE also different index order due to tensor's leftmost index being the least significant
template<typename T, typename I>
Tensor<T> fourindex2tensor(const fourindex_dense<nosymmetry,T,I> &f)
{
NRVec<indexgroup> shape(4);
int n=f.nbas();
for(int i=0; i<4; ++i)
{
shape[i].number=1;
shape[i].symmetry-0;
shape[i].offset=0;
shape[i].range=f.nbas();
shape[i].symmetry=0;
shape[i].offset=1;
shape[i].range=n;
}
NRVec<T> data(f);
return Tensor<T>(shape,data);
@@ -303,6 +307,114 @@ f=fourindex_dense<nosymmetry,T,I>(range,NRMat<T>(t.data,range*range,range*range)
}
template<typename T, typename I>
Tensor<T> fourindex2tensor(const fourindex_dense<twoelectronrealmullikanAB,T,I> &f)
{
NRVec<indexgroup> shape(2);
int n=f.nbas();
for(int i=0; i<2; ++i)
{
shape[i].number=2;
shape[i].symmetry=1;
shape[i].offset=1;
shape[i].range=n;
}
NRVec<T> data(f);
return Tensor<T>(shape,data);
}
template<typename T, typename I>
void tensor2fourindex(const Tensor<T> &t, fourindex_dense<twoelectronrealmullikanAB,T,I> &f)
{
if(t.rank()!=4) laerror("wrong rank in tensor2fourindex");
if(t.shape.size()!=2) laerror("wrong symmetry groups in tensor2fourindex");
int range=t.shape[0].range;
int offset=t.shape[0].offset;
for(int i=0; i<t.shape.size(); ++i)
{
if(range!=t.shape[i].range) laerror("range mismatch in tensor2fourindex");
if(offset!=t.shape[i].offset) laerror("offset mismatch in tensor2fourindex");
if(1!=t.shape[i].symmetry) laerror("symmetry mismatch in tensor2fourindex");
}
f=fourindex_dense<twoelectronrealmullikanAB,T,I>(NRMat<T>(t.data,range*(range+1)/2,range*(range+1)/2));
}
template<typename T, typename I>
Tensor<T> fourindex2tensor(const fourindex_dense<twoelectronrealmullikan,T,I> &f)
{
NRVec<indexgroup> shape(2);
int n=f.nbas();
for(int i=0; i<2; ++i)
{
shape[i].number=2;
shape[i].symmetry=1;
shape[i].offset=1;
shape[i].range=n;
}
NRMat<T> mat(f);
NRVec<T> data(mat); //expand symmetric to full matrix for index group symmetry
return Tensor<T>(shape,data);
}
template<typename T, typename I>
void tensor2fourindex(const Tensor<T> &t, fourindex_dense<twoelectronrealmullikan,T,I> &f)
{
if(t.rank()!=4) laerror("wrong rank in tensor2fourindex");
if(t.shape.size()!=2) laerror("wrong symmetry groups in tensor2fourindex");
int range=t.shape[0].range;
int offset=t.shape[0].offset;
for(int i=0; i<t.shape.size(); ++i)
{
if(range!=t.shape[i].range) laerror("range mismatch in tensor2fourindex");
if(offset!=t.shape[i].offset) laerror("offset mismatch in tensor2fourindex");
if(1!=t.shape[i].symmetry) laerror("symmetry mismatch in tensor2fourindex");
}
NRMat<T> mat(t.data,range*(range+1)/2,range*(range+1)/2);
f=fourindex_dense<twoelectronrealmullikan,T,I>(NRSMat<T>(mat)); //symmetrize mat
}
template<typename T, typename I>
Tensor<T> fourindex2tensor(const fourindex_dense<T2IjAb_aces,T,I> &f)
{
NRVec<indexgroup> shape(4);
for(int i=0; i<4; ++i)
{
shape[i].number=1;
shape[i].symmetry=0;
shape[i].offset=1;
}
shape[3].range=f.noca;
shape[2].range=f.nocb;
shape[1].range=f.nvra;
shape[0].range=f.nvrb;
NRVec<T> data(f);
return Tensor<T>(shape,data);
}
template<typename T, typename I>
void tensor2fourindex(const Tensor<T> &t, fourindex_dense<T2IjAb_aces,T,I> &f)
{
if(t.rank()!=4 ||t.shape.size()!=4) laerror("wrong rank/shape in tensor2fourindex");
int noca = t.shape[3].range;
int nocb = t.shape[2].range;
int nvra = t.shape[1].range;
int nvrb = t.shape[0].range;
int offset=t.shape[0].offset;
for(int i=0; i<t.shape.size(); ++i)
{
if(offset!=t.shape[i].offset) laerror("offset mismatch in tensor2fourindex");
if(0!=t.shape[i].symmetry) laerror("symmetry mismatch in tensor2fourindex");
}
NRMat<T> mat(t.data,noca*nocb,nvra*nvrb);
f=fourindex_dense<T2IjAb_aces,T,I>(noca,nocb,nvra,nvrb,mat);
}