From 0fabd21e5348eedb8163e117d0df8ee026c8ba3f Mon Sep 17 00:00:00 2001
From: kalmarek <kalmar@amu.edu.pl>
Date: Tue, 3 Oct 2017 14:46:05 +0200
Subject: [PATCH] much faster Cstar_repr

---
 src/OrbitDecomposition.jl | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/src/OrbitDecomposition.jl b/src/OrbitDecomposition.jl
index 5939361..91fa680 100644
--- a/src/OrbitDecomposition.jl
+++ b/src/OrbitDecomposition.jl
@@ -188,14 +188,10 @@ function reconstruct_sol{T<:GroupElem}(preps::Dict{T, Generic.perm},
    return recP
 end
 
-function Cstar_repr{T}(x::GroupRingElem{T}, mreps::Dict)
-   res = spzeros(size(mreps[first(keys(mreps))])...)
-
-   for g in parent(x).basis
-      if x[g] != zero(T)
-         res .+= Float64(x[g]).*mreps[g]
-      end
-   end
+function Cstar_repr(x::GroupRingElem{T}, mreps::Dict) where {T}
+   nzindx = [i for i in eachindex(x.coeffs) if x[i] != zero(T)]
+   RG = parent(x)
+   res = sum(Float64(x[i]).*mreps[RG.basis[i]] for i in nzindx)
 
    return res
 end