From 60fd23b37c7446ee433f8ab7f4ecac7cd3c2e11a Mon Sep 17 00:00:00 2001
From: Jiri Pittner <jiri@pittnerovi.com>
Date: Thu, 11 Jan 2024 18:04:25 +0100
Subject: [PATCH] introduced permutation group algebra class

---
 permutation.cc | 11 +++++++++--
 permutation.h  | 33 +++++++++++++++++++++++++++++++--
 2 files changed, 40 insertions(+), 4 deletions(-)

diff --git a/permutation.cc b/permutation.cc
index 4798ab7..f7396b3 100644
--- a/permutation.cc
+++ b/permutation.cc
@@ -95,7 +95,7 @@ return q;
 }
 
 template <typename T>
-NRPerm<T> NRPerm<T>::operator+(const NRPerm<T> &q) const
+NRPerm<T> NRPerm<T>::operator&(const NRPerm<T> &q) const
 {
 #ifdef DEBUG
         if(!this->is_valid() || !q.is_valid()) laerror("concatenation of invalid permutation");
@@ -108,7 +108,7 @@ return r;
 }
 
 template <typename T>
-NRPerm<T> NRPerm<T>::operator-(const NRPerm<T> &q) const
+NRPerm<T> NRPerm<T>::operator|(const NRPerm<T> &q) const
 {
 #ifdef DEBUG
         if(!this->is_valid() || !q.is_valid()) laerror("concatenation of invalid permutation");
@@ -1940,9 +1940,16 @@ template T Sn_character(const Partition<T> &irrep, const  Partition<T> &cclass);
 template std::ostream & operator<<(std::ostream &s, const Sn_characters<T> &x); \
 
 
+#define INSTANTIZE2(T,R) \
+template class WeightPermutation<T,R>; \
+template class PermutationAlgebra<T,R>; \
+
+
 INSTANTIZE(int)
 INSTANTIZE(unsigned int)
 
+INSTANTIZE2(int,double)
+
 
 
 
diff --git a/permutation.h b/permutation.h
index 9a9ca69..99eccc1 100644
--- a/permutation.h
+++ b/permutation.h
@@ -37,6 +37,8 @@ template <typename T> class CyclePerm;
 template <typename T> class Partition;
 template <typename T> class CompressedPartition;
 template <typename T> class YoungTableaux;
+template <typename T, typename R> class WeightPermutation;
+template <typename T, typename R> class PermutationAlgebra;
 
 template <typename T>
 class NRPerm : public NRVec_from1<T> {
@@ -56,8 +58,8 @@ public:
 	bool is_identity() const;
 	NRPerm inverse() const;
 	NRPerm reverse() const; //backward order
-	NRPerm operator+(const NRPerm &rhs) const; //concatenate the permutations this,rhs, renumbering rhs (not commutative)
-	NRPerm operator-(const NRPerm &rhs) const; //concatenate the permutations rhs,this, renumbering rhs (not commutative)
+	NRPerm operator&(const NRPerm &rhs) const; //concatenate the permutations this,rhs, renumbering rhs (not commutative)
+	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
@@ -76,6 +78,33 @@ public:
 	NRPerm pow(const int n) const {return power(*this,n);};
 };
 
+template <typename T, typename R> 
+class WeightPermutation {
+public:
+	R weight;
+	NRPerm<T> perm;
+	
+	WeightPermutation() : weight(0) {};
+	WeightPermutation(const R w, const NRPerm<T> &p) : weight(w), perm(p) {};
+	WeightPermutation(const NRPerm<T> &p) : perm(p) {weight= p.parity();};
+	void copyonwrite() {perm.copyonwrite();};
+	
+};
+
+template <typename T, typename R>
+class PermutationAlgebra : public NRVec<WeightPermutation<T,R> >
+{
+public:
+	PermutationAlgebra() {};
+	PermutationAlgebra(const YoungTableaux<T> &y);// Young antisymmetrizer TODO@@@
+	
+};
+
+//TODO@@@ iostream for WeightPermutation and PermutationAlgebra
+
+//TODO@@@ permutationalgebra  for Kucharski style antisymmetrizers
+
+
 extern PERM_RANK_TYPE factorial(const int n);
 extern PERM_RANK_TYPE binom(int n, int k);
 extern PERM_RANK_TYPE longpow(PERM_RANK_TYPE x, int i);