From 43d78c97f840649f28d700a12f225c1d662c48bc Mon Sep 17 00:00:00 2001
From: kalmar <kalmar@amu.edu.pl>
Date: Mon, 5 Jun 2017 23:50:15 +0200
Subject: [PATCH 1/3] parametrise GroupRing by Group and GroupElem

as suggested by thofma
---
 src/GroupRings.jl | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/src/GroupRings.jl b/src/GroupRings.jl
index cc2faab..8073cd4 100644
--- a/src/GroupRings.jl
+++ b/src/GroupRings.jl
@@ -11,13 +11,13 @@ import Base: convert, show, hash, ==, +, -, *, //, /, length, norm, rationalize,
 #
 ###############################################################################
 
-type GroupRing <: Ring
-   group::Group
-   basis::Vector{GroupElem}
-   basis_dict::Dict{GroupElem, Int}
+type GroupRing{Gr<:Group, T<:GroupElem} <: Ring
+   group::Gr
+   basis::Vector{T}
+   basis_dict::Dict{T, Int}
    pm::Array{Int,2}
 
-   function GroupRing(G::Group; initialise=true)
+   function GroupRing(G::Gr; initialise=true)
       A = new(G)
       if initialise
          complete(A)
@@ -25,11 +25,15 @@ type GroupRing <: Ring
       return A
    end
 
-   function GroupRing(G::Group, basis, basis_dict, pm::Array{Int,2})
+   function GroupRing(G::Gr, basis::Vector{T}, basis_dict::Dict{T,Int}, pm::Array{Int,2})
       return new(G, basis, basis_dict, pm)
    end
 end
 
+GroupRing{Gr<:Group}(G::Gr;initialise=true) = GroupRing{Gr, elem_type(G)}(G, initialise=initialise)
+
+GroupRing{Gr<:Group, T<:GroupElem}(G::Gr, b::Vector{T}, b_d::Dict{T,Int}, pm::Array{Int,2}) = GroupRing{Gr, T}(G, b, b_d, pm)
+
 type GroupRingElem{T<:Number} <: RingElem
    coeffs::AbstractVector{T}
    parent::GroupRing

From 4b86d5d075c8bd53b77fbd78d85963ef5d51669d Mon Sep 17 00:00:00 2001
From: kalmar <kalmar@amu.edu.pl>
Date: Tue, 6 Jun 2017 00:03:38 +0200
Subject: [PATCH 2/3] reparametrise parent call overloads

---
 src/GroupRings.jl | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/GroupRings.jl b/src/GroupRings.jl
index 8073cd4..5501d68 100644
--- a/src/GroupRings.jl
+++ b/src/GroupRings.jl
@@ -112,23 +112,23 @@ end
 #
 ###############################################################################
 
-function (RG::GroupRing)(T::Type=Int)
+function {Gr,T}(RG::GroupRing{Gr,T})(S::Type=Int)
    isdefined(RG, :basis) || throw("Complete the definition of GroupRing first")
-   return GroupRingElem(spzeros(T,length(RG.basis)), RG)
+   return GroupRingElem(spzeros(S,length(RG.basis)), RG)
 end
 
-function (RG::GroupRing)(g::GroupElem, T::Type=Int)
+function {Gr,T}(RG::GroupRing{Gr,T})(g::GroupElem, S::Type=Int)
    g = try
       RG.group(g)
    catch
       throw("Can't coerce $g to the underlying group of $RG")
    end
-   result = RG(T)
-   result[g] = one(T)
+   result = RG(S)
+   result[g] = one(S)
    return result
 end
 
-function (RG::GroupRing)(x::AbstractVector)
+function {Gr,T}(RG::GroupRing{Gr,T})(x::AbstractVector)
    length(x) == length(RG.basis) || throw("Can not coerce to $RG: lengths differ")
    result = RG(eltype(x))
    result.coeffs = x

From 61ed1f7870751cbcfdddbbec873b5494adbe0710 Mon Sep 17 00:00:00 2001
From: kalmar <kalmar@amu.edu.pl>
Date: Tue, 6 Jun 2017 11:46:15 +0200
Subject: [PATCH 3/3] rename groupring_mult[!] -> mul[!]

---
 src/GroupRings.jl | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/src/GroupRings.jl b/src/GroupRings.jl
index 9e5ffd9..76b094c 100644
--- a/src/GroupRings.jl
+++ b/src/GroupRings.jl
@@ -296,7 +296,8 @@ end
 (+)(X::GroupRingElem, Y::GroupRingElem) = add(X,Y)
 (-)(X::GroupRingElem, Y::GroupRingElem) = add(X,-Y)
 
-function groupring_mult!(X,Y,pm,result)
+function mul!{T<:Number}(X::AbstractVector{T}, Y::AbstractVector{T},
+   pm::Array{Int,2}, result::AbstractVector{T})
    for (j,y) in enumerate(Y)
       if y != zero(eltype(Y))
          for (i, index) in enumerate(pm[:,j])
@@ -309,17 +310,17 @@ function groupring_mult!(X,Y,pm,result)
    end
 end
 
-function groupring_mult{T<:Number}(X::AbstractVector{T}, Y::AbstractVector{T},
+function mul{T<:Number}(X::AbstractVector{T}, Y::AbstractVector{T},
    pm::Array{Int,2})
    result = zeros(X)
-   groupring_mult!(X,Y,pm,result)
+   mul!(X,Y,pm,result)
    return result
 end
 
-function groupring_mult(X::AbstractVector, Y::AbstractVector, pm::Array{Int,2})
+function mul(X::AbstractVector, Y::AbstractVector, pm::Array{Int,2})
    T = promote_type(eltype(X), eltype(Y))
    result = zeros(T, deepcopy(X))
-   groupring_mult!(X, Y, pm, result)
+   mul!(X, Y, pm, result)
    return result
 end
 
@@ -328,7 +329,7 @@ function *{T<:Number}(X::GroupRingElem{T}, Y::GroupRingElem{T})
    "Elements don't seem to belong to the same Group Ring!"))
    RG = parent(X)
    isdefined(RG, :pm) || complete(RG)
-   result = groupring_mult(X.coeffs, Y.coeffs, RG.pm)
+   result = mul(X.coeffs, Y.coeffs, RG.pm)
    return GroupRingElem(result, RG)
 end
 
@@ -338,7 +339,7 @@ function *{T<:Number, S<:Number}(X::GroupRingElem{T}, Y::GroupRingElem{S})
    warn("Multiplying elements with different base rings!")
    RG = parent(X)
    isdefined(RG, :pm) || complete(RG)
-   result = groupring_mult(X.coeffs, Y.coeffs, RG.pm)
+   result = mul(X.coeffs, Y.coeffs, RG.pm)
    return GroupRingElem(result, RG)
 end