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some more fourindex-tensor conversions

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Jiri Pittner
2025-10-24 15:21:51 +02:00
parent f1060245a0
commit f2d392c2a7
3 changed files with 154 additions and 4 deletions
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105
tensor.h
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@@ -47,7 +47,7 @@
//@@@ will not be particularly efficient
//
//@@@conversions to/from fourindex, optional negative range for beta spin handling in some cases
//@@@use the fact that fourindex_dense is inherited from Mat/SMat and construct tensor from the (unsymmetrized) NRMat sharing data, just rewrite then the shape
//@@@check operator() for all fourindex-tensor conversions
//
//@@@?general permutation of individual indices - check the indices in sym groups remain adjacent, calculate result's shape, loopover the result and permute using unwind_callback
//
@@ -414,6 +414,109 @@ f=fourindex_dense<T2IjAb_aces,T,I>(noca,nocb,nvra,nvrb,mat);
template<typename T, typename I>
Tensor<T> fourindex2tensor(const fourindex_dense<T2ijab_aces,T,I> &f)
{
NRVec<indexgroup> shape(2);
for(int i=0; i<2; ++i)
{
shape[i].number=2;
shape[i].symmetry= -1;
shape[i].offset=1;
}
shape[1].range=f.nocc;
shape[0].range=f.nvrt;
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) laerror("wrong rank in tensor2fourindex");
if(t.shape.size()!=2) laerror("wrong symmetry groups in tensor2fourindex");
int nvrt=t.shape[0].range;
int nocc=t.shape[1].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(-1!=t.shape[i].symmetry) laerror("symmetry mismatch in tensor2fourindex");
}
NRMat<T> mat(t.data,nocc*(nocc-1)/2,nvrt*(nvrt-1)/2);
f=fourindex_dense<T2ijab_aces,T,I>(nocc,nvrt,mat);
}
template<typename T, typename I>
Tensor<T> fourindex2tensor(const fourindex_dense<antisymtwoelectronrealdiracAB,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=1;
shape[i].range=n;
}
NRMat<T> data(f); //expand to full matrix
return Tensor<T>(shape,NRVec<T>(data));
}
template<typename T, typename I>
void tensor2fourindex(const Tensor<T> &t, fourindex_dense<antisymtwoelectronrealdiracAB,T,I> &f)
{
if(t.rank()!=4) laerror("wrong rank in tensor2fourindex");
if(t.shape.size()!=4) 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(0!=t.shape[i].symmetry) laerror("symmetry mismatch in tensor2fourindex");
}
NRMat<T> mat(t.data,range*range,range*range);
f=fourindex_dense<antisymtwoelectronrealdiracAB,T,I>(range,NRSMat<T>(mat));
}
template<typename T, typename I>
Tensor<T> fourindex2tensor(const fourindex_dense<antisymtwoelectronrealdirac,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<antisymtwoelectronrealdirac,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<antisymtwoelectronrealdirac,T,I>(range,NRSMat<T>(mat)); //symmetrize mat
}