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small additions to permutations

This commit is contained in:
Jiri Pittner 2024-01-24 13:41:39 +01:00
parent 13c23fb85d
commit 1ee984eda2
2 changed files with 42 additions and 5 deletions
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43
permutation.cc
View File

@ -135,11 +135,27 @@ if(n!=q.size()) laerror("product of incompatible permutations");
NRPerm<T> r(n);
for(T i=1; i<=n; ++i) r[i] = (*this)[q[i]];
return r;
}
template <typename T>
NRPerm<T> NRPerm<T>::conjugate_by(const NRPerm<T> &q) const
NRPerm<T> NRPerm<T>::multiply(const NRPerm<T> &q, bool inverse) const
{
#ifdef DEBUG
if(!this->is_valid() || !q.is_valid()) laerror("multiplication of invalid permutation");
#endif
T n=this->size();
if(n!=q.size()) laerror("product of incompatible permutations");
NRPerm<T> r(n);
if(inverse) for(T i=1; i<=n; ++i) r[q[i]] = (*this)[i];
else for(T i=1; i<=n; ++i) r[i] = (*this)[q[i]];
return r;
}
template <typename T>
NRPerm<T> NRPerm<T>::conjugate_by(const NRPerm<T> &q, bool inverse) const
{
#ifdef DEBUG
if(!this->is_valid() || !q.is_valid()) laerror("multiplication of invalid permutation");
@ -149,11 +165,30 @@ T n=this->size();
if(n!=q.size()) laerror("product of incompatible permutations");
NRPerm<T> qi=q.inverse();
NRPerm<T> r(n);
for(T i=1; i<=n; ++i) r[i] = qi[(*this)[q[i]]];
if(inverse) for(T i=1; i<=n; ++i) r[i] = q[(*this)[qi[i]]];
else for(T i=1; i<=n; ++i) r[i] = qi[(*this)[q[i]]];
return r;
}
template <typename T>
NRPerm<T> NRPerm<T>::commutator(const NRPerm<T> &q, bool inverse) const
{
#ifdef DEBUG
if(!this->is_valid() || !q.is_valid()) laerror("multiplication of invalid permutation");
#endif
T n=this->size();
if(n!=q.size()) laerror("product of incompatible permutations");
NRPerm<T> qi=q.inverse();
NRPerm<T> pi=this->inverse();
NRPerm<T> r(n);
if(inverse) for(T i=1; i<=n; ++i) r[i] = qi[pi[q[(*this)[i]]]];
else for(T i=1; i<=n; ++i) r[i] = pi[qi[(*this)[q[i]]]];
return r;
}
template <typename T>
CyclePerm<T> CyclePerm<T>::conjugate_by(const CyclePerm<T> &q) const
{

4
permutation.h
View File

@ -67,7 +67,9 @@ public:
NRPerm operator|(const NRPerm &rhs) const; //concatenate the permutations rhs,this, renumbering rhs (not commutative)
NRPerm operator*(const NRPerm &q) const; //q is rhs and applied first, this applied second
NRPerm operator*(const CyclePerm<T> &r) const;
NRPerm conjugate_by(const NRPerm &q) const; //q^-1 p q
NRPerm multiply(const NRPerm<T> &q, bool inverse) const; //multiplication but optionally q inversed
NRPerm conjugate_by(const NRPerm &q, bool reverse=false) const; //q^-1 p q or q p q^-1
NRPerm commutator(const NRPerm &q, bool inverse=false) const; //p^-1 q^-1 p q or q^-1 p^-1 q p
int parity() const; //returns +/- 1
void randomize(void); //uniformly random by Fisher-Yates shuffle
bool next(); //generate next permutation in lex order