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tensor: linear_transform implemented

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Jiri Pittner
2025-11-20 18:17:34 +01:00
parent d136c2314d
commit ad1c4ee968
3 changed files with 122 additions and 23 deletions
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51
tensor.cc
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@@ -1785,7 +1785,6 @@ template<typename T>
Tensor<T> Tensor<T>::inverseTucker(const NRVec<NRMat<T> > &x, bool inverseorder) const
{
if(rank()!=x.size()) laerror("input of inverseTucker does not match rank");
NRVec<INDEXNAME> names_saved = names;
Tensor<T> tmp(*this);
Tensor<T> r;
if(!is_flat()) laerror("inverseTucker only for flat tensors as produced by Tucker");
@@ -1818,14 +1817,60 @@ for(int i=rank()-1; i>=0; --i)
if(inverseorder)
{
NRPerm<int> p(rank()); p.identity();
r.names=names_saved.permuted(p.reverse());
r.names=names.permuted(p.reverse());
}
else
r.names=names_saved;
r.names=names;
return r;
}
template<typename T>
Tensor<T> Tensor<T>::linear_transform(const NRVec<NRMat<T> > &x) const
{
if(x.size()!=shape.size()) laerror("wrong number of transformation matrices in linear_transform");
for(int i=0; i<shape.size(); ++i) if(x[i].ncols()!=shape[i].range) laerror("mismatch of transformation matrix size in linear_transform");
Tensor<T> tmp(*this);
Tensor<T> r;
//do the groups in reverse order to preserve index ordering
for(int g=shape.size()-1; g>=0; --g)
{
Tensor<T> mat(x[g],true); //flat tensor from a matrix
for(int i=shape[g].number-1; i>=0; --i) //indices in the group in reverse order
{
r= tmp.contraction(indexposition(rank()-1,tmp.shape),mat,INDEX(0,0),(T)1,false,false); //always the last index
if(i>0)
{
tmp=r;
r.deallocate();
}
}
//the group's indices are now individual ones leftmost in tensor r, restore group size and symmetry
if(shape[g].number>1)
{
INDEXLIST il(shape[g].number);
for(int i=0; i<shape[g].number; ++i)
{
il[i].group=i;
il[i].index=0;
}
r = r.merge_indices(il,shape[g].symmetry);
}
if(g>0)
{
tmp=r;
r.deallocate();
}
}
r.names=names;
return r;
}
template<typename T>
int Tensor<T>::findflatindex(const INDEXNAME nam) const
{