From 9d5790d6d33302afc76fbe0072d3425155888a3d Mon Sep 17 00:00:00 2001
From: kalmar <kalmar@amu.edu.pl>
Date: Wed, 19 Jul 2017 22:54:18 +0200
Subject: [PATCH] allow for pm to be slowly filled when computing products

---
 src/GroupRings.jl | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/GroupRings.jl b/src/GroupRings.jl
index a2ac768..a8c1cd9 100644
--- a/src/GroupRings.jl
+++ b/src/GroupRings.jl
@@ -351,6 +351,10 @@ function mul!{T}(result::GroupRingElem{T}, X::GroupRingElem, Y::GroupRingElem)
       if Y.coeffs[j] != z
          for i in eachindex(X.coeffs)
             if X.coeffs[i] != z
+               if parent(X).pm[i,j] == 0
+                  g = parent(X).basis[i]*parent(Y).basis[j]
+                  parent(X).pm[i,j] = parent(X).basis_dict[g]
+               end
                result.coeffs[parent(X).pm[i,j]] += X[i]*Y[j]
             end
          end