From c03882ae69d54f941d17b0d52176000dabe44257 Mon Sep 17 00:00:00 2001
From: kalmar <kalmar@amu.edu.pl>
Date: Wed, 17 May 2017 17:46:30 +0200
Subject: [PATCH] add Misc category with: products, generate_balls

---
 src/Groups.jl | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/src/Groups.jl b/src/Groups.jl
index 221e6ed..e306917 100644
--- a/src/Groups.jl
+++ b/src/Groups.jl
@@ -330,6 +330,39 @@ end
 
 replace_all(W::GWord, subst_dict::Dict{GWord, GWord}) = replace_all!(deepcopy(W), subst_dict)
 
+###############################################################################
+#
+#   Misc
+#
+###############################################################################
+
+function products{T}(X::AbstractVector{T}, Y::AbstractVector{T})
+    result = Vector{T}()
+    seen = Set{T}()
+    for x in X
+        for y in Y
+            z = x*y
+            if !in(z, seen)
+                push!(seen, z)
+                push!(result, z)
+            end
+        end
+    end
+    return result
+end
+
+function generate_balls(S, Id; radius=2)
+    sizes = Vector{Int}()
+    S = unshift!(S, Id)
+    B = [Id]
+    for i in 1:radius
+        B = products(B, S);
+        push!(sizes, length(B))
+    end
+    return B, sizes
+end
+
+
 ###############################################################################
 #
 #   Includes