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tensor: working on add_permuted_contractions

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Jiri Pittner
2025-11-15 18:33:36 +01:00
parent 6281449dbb
commit 5505d39b99
2 changed files with 219 additions and 22 deletions
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183
tensor.cc
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@@ -23,6 +23,7 @@
#include "miscfunc.h"
#include <complex>
#include "bitvector.h"
#include <string.h>
namespace LA {
@@ -1908,6 +1909,109 @@ s>>x.group>>x.index;
return s;
}
static NRPerm<int> find_indexperm(const NRVec<INDEXNAME> &what, const NRVec<INDEXNAME> &where)
{
if(what.size()!=where.size()) laerror("sizes of index name vectors do not match in find_indexperm");
NRPerm<int> basicperm(what.size());
basicperm.clear();
for(int i=0; i<what.size(); ++i)
{
for(int j=0; j<what.size(); ++j)
if(what[i] == where[j])
{
basicperm[i+1]=j+1;
break;
}
}
if(!basicperm.is_valid()) laerror("indices mismatch between lhs and rhs in add_permuted_contractions");
return basicperm;
}
static void parse_antisymmetrizer(const char *txt0, NRVec<NRVec_from1<int> > &groups0, NRVec<INDEXNAME> &names0)
{
int igroup= -1;
int iname= -1;
int iclass=0;
char *txt=strdup(txt0);
char *p=txt;
std::list<std::list<int> > groups;
std::list<INDEXNAME> names;
std::list<int> currentgroup;
foundspace:
while(isspace(*p)) ++p;
if(*p==0) goto finished;
if(!isalpha(*p)) laerror("letter expected in parse_antisymmetrizer");
++iname;
++igroup;
++iclass;
foundname:
{
INDEXNAME n;
int i=0;
while(isalnum(*p))
{
n.name[i]=*p;
++i;
if(i>N_INDEXNAME) laerror("too long index name in parse_antisymmetrizer");
++p;
}
if(i>=N_INDEXNAME) laerror("too long index name in parse_antisymmetrizer");
n.name[i]=0;
//store
names.push_back(n);
currentgroup.push_back(iclass);
//now decide based on next character
if(*p==',')
{
++iname;
++p;
if(!isalpha(*p)) laerror("letter expected in parse_antisymmetrizer");
goto foundname;
}
if(*p=='/')
{
++iname;
++p;
++iclass;
if(!isalpha(*p)) laerror("letter expected in parse_antisymmetrizer");
goto foundname;
}
if(isspace(*p))
{
groups.push_back(currentgroup);
currentgroup.clear();
++p;
goto foundspace;
}
if(*p==0)
{
groups.push_back(currentgroup);
goto finished;
}
laerror("unexpected character in parse_antisymmetrizer");
}
finished:
names0= NRVec<INDEXNAME> (names);
std::cout <<"names parsed "<<names0;
groups0.resize(groups.size());
int i=0;
for(typename std::list<std::list<int> >::const_iterator ii=groups.begin(); ii!=groups.end(); ++ii)
{
groups0[i++] = NRVec_from1<int>(*ii);
}
std::cout<<"groups parsed "<<groups0;
free(txt);
}
template<typename T>
void Tensor<T>::add_permuted_contractions(const char *antisymmetrizer, const Tensor &rhs1, const Tensor &rhs2, T alpha, T beta, bool conjugate1, bool conjugate2)
@@ -1945,33 +2049,76 @@ Tensor<T> tmp=rhs1.contractions(il1,rhs2,il2,alpha,conjugate1,conjugate2);
if(rank()!=tmp.rank()) laerror("rank mismatch in add_permuted_contractions");
//generate the antisymmetrizer, adding also indices not involved as a constant subpermutation
//@@@
PermutationAlgebra<int,T> pa(1);
pa[0].weight=1;
pa[0].perm.resize(rank());
pa[0].perm.identity();
//
//first parse the antisymmetrizer
NRVec<INDEXNAME> antinames;
NRVec<NRVec_from1<int> > antigroups;
parse_antisymmetrizer(antisymmetrizer,antigroups,antinames);
//check the names make sense and fill in the possibly missing ones as separate group
if(antinames.size()>tmp.names.size()) laerror("too many indices in the antisymmetrizet");
bitvector isexplicit(tmp.names.size());
isexplicit.clear();
for(int i=0; i<antinames.size(); ++i)
{
for(int j=0; j<i; ++j) if(antinames[i]==antinames[j]) laerror("repeated names in the antisymmetrizer");
for(int j=0; j<tmp.names.size(); ++j)
if(antinames[i]==tmp.names[j])
{
isexplicit.set(j);
goto namefound;
}
laerror("index name from the antisymmetrized not found in tensor");
namefound: ;
}
if(isexplicit.population()!=antinames.size()) laerror("internal error in add_permuted_contractions");
//fill in additional names
if(antinames.size()<tmp.names.size())
{
int lastgroup=antigroups.size()-1;
int lastclass;
if(antigroups.size()==0) lastclass=0;
else lastclass=antigroups[antigroups.size()-1][antigroups[antigroups.size()-1].size()];
int lastname=antinames.size()-1;
antinames.resize(tmp.names.size(),true);
antigroups.resize(antigroups.size()+tmp.names.size()-antinames.size(),true);
for(int j=0; j<names.size(); ++j)
if(!isexplicit[j])
{
++lastclass;
++lastname;
++lastgroup;
antigroups[lastgroup].resize(1);
antigroups[lastgroup][0]=lastclass;
antinames[lastname] = tmp.names[j];
}
}
std::cout <<"final antisymmmetrizer names and groups"<<antinames<<antigroups;
//prepare the antisymmetrizer
PermutationAlgebra<int,int> pa = general_antisymmetrizer(antigroups,-2,true);
//find permutation between antisym and TMP index order
NRPerm<int> antiperm=find_indexperm(antinames,tmp.names);
//@@@conjugate the PA by antiperm or its inverse
//@@@recast the PA
//@@@permutationalgebra::is_identity() a pokd ano, neaplikovat ale vratit tmp tenzor resp. s nim udelat axpy
//std::cout <<"LHS names = "<<names<<std::endl;
//std::cout <<"TMP names = "<<tmp.names<<std::endl;
//find permutation which will bring indices of tmp to the order as in *this: this->names[i] == tmp.names[p[i]]
NRPerm<int> basicperm(rank());
basicperm.clear();
for(int i=0; i<rank(); ++i)
{
for(int j=0; j<tmp.rank(); ++j)
if((* const_cast<const NRVec<INDEXNAME> *>(&names))[i] == tmp.names[j])
{
basicperm[i+1]=j+1;
break;
}
}
if(!basicperm.is_valid()) laerror("indices mismatch between lhs and rhs in add_permuted_contractions");
NRPerm<int> basicperm=find_indexperm(names,tmp.names);
std::cout <<"Basic permutation = "<<basicperm<<std::endl;
//@@@probably only onw of those will work
PermutationAlgebra<int,T> pb = basicperm*pa;
apply_permutation_algebra(tmp,pb,false,(T)1/(T)pb.size(),beta);
//equivalently possible
//equivalently possible (for trivial pa)
//PermutationAlgebra<int,T> pb = basicperm.inverse()*pa;
//apply_permutation_algebra(tmp,pb,true,(T)1/(T)pb.size(),beta);
}