Merge branch 'enh/pmfree_mul'

This commit is contained in:
kalmar 2017-07-21 21:24:50 +02:00
commit b4aa2f3582
2 changed files with 197 additions and 103 deletions

View File

@ -1,7 +1,7 @@
module GroupRings
using Nemo
import Nemo: Group, GroupElem, Ring, RingElem, parent, elem_type, parent_type
import Nemo: Group, GroupElem, Ring, RingElem, parent, elem_type, parent_type, mul!, addeq!, divexact
import Base: convert, show, hash, ==, +, -, *, //, /, length, norm, rationalize, deepcopy_internal, getindex, setindex!, eltype, one, zero
@ -17,23 +17,40 @@ type GroupRing{Gr<:Group, T<:GroupElem} <: Ring
basis_dict::Dict{T, Int}
pm::Array{Int,2}
function GroupRing(G::Gr; initialise=true)
A = new(G)
if initialise
complete(A)
function GroupRing(G::Group, basis::Vector{T}; init::Bool=false)
RG = new(G, basis, reverse_dict(basis))
if init
RG.pm = try
create_pm(RG.basis, RG.basis_dict)
catch err
isa(err, KeyError) && throw("Product is not supported on basis")
throw(err)
end
else
RG.pm = zeros(Int, length(basis), length(basis))
end
return A
return RG
end
function GroupRing(G::Gr, basis::Vector{T}, basis_dict::Dict{T,Int}, pm::Array{Int,2})
return new(G, basis, basis_dict, pm)
end
function GroupRing(G::Gr, pm::Array{Int,2})
RG = new(G)
RG.pm = pm
return RG
end
end
GroupRing{Gr<:Group}(G::Gr;initialise=true) = GroupRing{Gr, elem_type(G)}(G, initialise=initialise)
GroupRing{Gr<:Group, T<:GroupElem}(G::Gr, basis::Vector{T}; init=false) =
GroupRing{Gr, T}(G, basis, init=init)
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)
GroupRing{Gr<:Group}(G::Gr, pm::Array{Int,2}) =
GroupRing{Gr, elem_type(G)}(G, pm)
type GroupRingElem{T<:Number} <: RingElem
coeffs::AbstractVector{T}
parent::GroupRing
@ -52,7 +69,7 @@ type GroupRingElem{T<:Number} <: RingElem
end
end
export GroupRing, GroupRingElem, complete, create_pm
export GroupRing, GroupRingElem, complete!, create_pm, star
###############################################################################
#
@ -65,8 +82,16 @@ elem_type(::GroupRing) = GroupRingElem
parent_type(::GroupRingElem) = GroupRing
parent_type(::Type{GroupRingElem}) = GroupRing
eltype(X::GroupRingElem) = eltype(X.coeffs)
parent{T}(g::GroupRingElem{T}) = g.parent
Base.promote_rule{T<:Number,S<:Number}(::Type{GroupRingElem{T}}, ::Type{GroupRingElem{S}}) = GroupRingElem{promote_type(T,S)}
function convert{T<:Number}(::Type{T}, X::GroupRingElem)
return GroupRingElem(convert(AbstractVector{T}, X.coeffs), parent(X))
end
###############################################################################
#
# GroupRing / GroupRingElem constructors
@ -77,32 +102,13 @@ function GroupRingElem{T<:Number}(c::AbstractVector{T}, RG::GroupRing)
return GroupRingElem{T}(c, RG)
end
function convert{T<:Number}(::Type{T}, X::GroupRingElem)
return GroupRingElem(convert(AbstractVector{T}, X.coeffs), parent(X))
end
function GroupRing(G::Group, pm::Array{Int,2})
size(pm,1) == size(pm,2) || throw("pm must be square, got $(size(pm))")
RG = GroupRing(G, initialise=false)
RG.pm = pm
return RG
end
function GroupRing(G::Group, basis::Vector)
basis_dict = reverse_dict(basis)
pm = try
create_pm(basis, basis_dict)
catch err
isa(err, KeyError) && throw("Products are not supported on basis")
throw(err)
end
return GroupRing(G, basis, basis_dict, pm)
function GroupRing(G::Group; init::Bool=false)
return GroupRing(G, [elements(G)...], init=init)
end
function GroupRing(G::Group, basis::Vector, pm::Array{Int,2})
size(pm,1) == size(pm,2) || throw("pm must be of size (n,n), got
$(size(pm))")
eltype(basis) == elem_type(G) || throw("basis must consist of elements of $G")
size(pm,1) == size(pm,2) || throw("pm must be square, got $(size(pm))")
eltype(basis) == elem_type(G) || throw("Basis must consist of elements of $G")
basis_dict = reverse_dict(basis)
return GroupRing(G, basis, basis_dict, pm)
end
@ -113,23 +119,29 @@ end
#
###############################################################################
zero(RG::GroupRing, T::Type=Int) = RG(T)
one(RG::GroupRing, T::Type=Int) = RG(RG.group(), T)
function (RG::GroupRing)(i::Int, T::Type=Int)
elt = RG(T)
elt[RG.group()] = i
return elt
end
function (RG::GroupRing)(T::Type=Int)
isdefined(RG, :basis) || throw("Complete the definition of GroupRing first")
isdefined(RG, :basis) || throw("Can not coerce without basis of GroupRing")
return GroupRingElem(spzeros(T,length(RG.basis)), RG)
end
function (RG::GroupRing)(g::GroupElem, T::Type=Int)
g = try
RG.group(g)
catch
throw("Can't coerce $g to the underlying group of $RG")
end
g = RG.group(g)
result = RG(T)
result[g] = one(T)
return result
end
function (RG::GroupRing)(x::AbstractVector)
isdefined(RG, :basis) || throw("Can not coerce without basis of GroupRing")
length(x) == length(RG.basis) || throw("Can not coerce to $RG: lengths differ")
result = RG(eltype(x))
result.coeffs = x
@ -142,16 +154,19 @@ function (RG::GroupRing)(X::GroupRingElem)
end
function (RG::GroupRing)(X::GroupRingElem, emb::Function)
result = RG(eltype(X.coeffs))
for g in parent(X).basis
result[emb(g)] = X[g]
end
return result
isdefined(RG, :basis) || throw("Can not coerce without basis of GroupRing")
result = RG(eltype(X.coeffs))
T = typeof(X.coeffs)
result.coeffs = T(result.coeffs)
for g in parent(X).basis
result[emb(g)] = X[g]
end
return result
end
###############################################################################
#
# Basic manipulation
# Basic manipulation && Array protocol
#
###############################################################################
@ -160,7 +175,7 @@ function deepcopy_internal(X::GroupRingElem, dict::ObjectIdDict)
end
function hash(X::GroupRingElem, h::UInt)
return hash(X.coeffs, hash(parent(X), h))
return hash(full(X.coeffs), hash(parent(X), hash(GroupRingElem, h)))
end
function getindex(X::GroupRingElem, n::Int)
@ -184,10 +199,8 @@ function setindex!(X::GroupRingElem, value, g::GroupElem)
X.coeffs[RG.basis_dict[g]] = value
end
eltype(X::GroupRingElem) = eltype(X.coeffs)
one(RG::GroupRing) = RG(RG.group())
zero(RG::GroupRing) = RG()
Base.size(X::GroupRingElem) = size(X.coeffs)
Base.linearindexing{T<:GroupRingElem}(::Type{T}) = Base.LinearFast()
###############################################################################
#
@ -239,8 +252,8 @@ function (==)(A::GroupRing, B::GroupRing)
A.basis == B.basis || return false
else
warn("Bases of GroupRings are not defined, comparing products mats.")
A.pm == B.pm || return false
end
A.pm == B.pm || return false
return true
end
@ -284,16 +297,23 @@ end
#
###############################################################################
function add{T<:Number}(X::GroupRingElem{T}, Y::GroupRingElem{T})
parent(X) == parent(Y) || throw(ArgumentError(
"Elements don't seem to belong to the same Group Ring!"))
function addeq!{T}(X::GroupRingElem{T}, Y::GroupRingElem{T})
X.coeffs .+= Y.coeffs
return X
end
function add{T<:Number}(X::GroupRingElem{T}, Y::GroupRingElem{T}, check::Bool=true)
if check
parent(X) == parent(Y) || throw("Elements don't seem to belong to the same Group Ring!")
end
return GroupRingElem(X.coeffs+Y.coeffs, parent(X))
end
function add{T<:Number, S<:Number}(X::GroupRingElem{T},
Y::GroupRingElem{S})
parent(X) == parent(Y) || throw(ArgumentError(
"Elements don't seem to belong to the same Group Ring!"))
Y::GroupRingElem{S}, check::Bool=true)
if check
parent(X) == parent(Y) || throw("Elements don't seem to belong to the same Group Ring!")
end
warn("Adding elements with different base rings!")
return GroupRingElem(+(promote(X.coeffs, Y.coeffs)...), parent(X))
end
@ -301,7 +321,24 @@ end
(+)(X::GroupRingElem, Y::GroupRingElem) = add(X,Y)
(-)(X::GroupRingElem, Y::GroupRingElem) = add(X,-Y)
function mul!{T}(result::AbstractVector{T}, X::AbstractVector, Y::AbstractVector, pm::Array{Int,2})
doc"""
mul!{T}(result::AbstractArray{T},
X::AbstractVector,
Y::AbstractVector,
pm::Array{Int,2})
> The most specialised multiplication for `X` and `Y` (`coeffs` of
> `GroupRingElems`) using multiplication table `pm`.
> Notes:
> * this method will silently produce false results if `X[k]` is non-zero for
> `k > size(pm,1)`.
> * This method will fail if any zeros (i.e. uninitialised entries) are present
> in `pm`.
> * Use with extreme care!
"""
function mul!{T}(result::AbstractVector{T},
X::AbstractVector,
Y::AbstractVector,
pm::Array{Int,2})
z = zero(T)
result .= z
for j in eachindex(Y)
@ -314,39 +351,95 @@ function mul!{T}(result::AbstractVector{T}, X::AbstractVector, Y::AbstractVector
end
end
end
end
function mul{T<:Number}(X::AbstractVector{T}, Y::AbstractVector{T},
pm::Array{Int,2})
result = zeros(X)
mul!(X,Y,pm,result)
return result
end
function mul(X::AbstractVector, Y::AbstractVector, pm::Array{Int,2})
T = promote_type(eltype(X), eltype(Y))
result = zeros(T, deepcopy(X))
mul!(X, Y, pm, result)
doc"""
mul!{T}(result::GroupRingElem{T},
X::GroupRingElem,
Y::GroupRingElem)
> In-place multiplication for `GroupRingElem`s `X` and `Y`.
> `mul!` will make use the initialised entries of `pm` attribute of
> `parent(X)::GroupRing` (if available), and will compute and store in `pm` the
> remaining products.
> The method will fail with `KeyError` if product `X*Y` is not supported on
> `parent(X).basis`.
"""
function mul!{T}(result::GroupRingElem{T}, X::GroupRingElem, Y::GroupRingElem)
if result === X
result = deepcopy(result)
end
z = zero(T)
result.coeffs .= z
RG = parent(X)
for j::Int in eachindex(Y.coeffs)
if Y.coeffs[j] != z
for i::Int in eachindex(X.coeffs)
if X.coeffs[i] != z
if RG.pm[i,j] == 0
g::elem_type(parent(X).group) = RG.basis[i]*RG.basis[j]
RG.pm[i,j] = RG.basis_dict[g]
end
result.coeffs[RG.pm[i,j]] += X[i]*Y[j]
end
end
end
end
return result
end
function *{T<:Number}(X::GroupRingElem{T}, Y::GroupRingElem{T})
parent(X) == parent(Y) || throw(ArgumentError(
"Elements don't seem to belong to the same Group Ring!"))
RG = parent(X)
isdefined(RG, :pm) || complete(RG)
result = mul(X.coeffs, Y.coeffs, RG.pm)
return GroupRingElem(result, RG)
function *{T<:Number}(X::GroupRingElem{T}, Y::GroupRingElem{T}, check::Bool=true)
if check
parent(X) == parent(Y) || throw("Elements don't seem to belong to the same Group Ring!")
end
if isdefined(parent(X), :basis)
result = parent(X)(similar(X.coeffs))
result = mul!(result, X, Y)
else
result = mul!(similar(X.coeffs), X.coeffs, Y.coeffs, parent(X).pm)
result = GroupRingElem(result, parent(X))
end
return result
end
function *{T<:Number, S<:Number}(X::GroupRingElem{T}, Y::GroupRingElem{S})
parent(X) == parent(Y) || throw("Elements don't seem to belong to the same
Group Ring!")
warn("Multiplying elements with different base rings!")
RG = parent(X)
isdefined(RG, :pm) || complete(RG)
result = mul(X.coeffs, Y.coeffs, RG.pm)
return GroupRingElem(result, RG)
function *{T<:Number, S<:Number}(X::GroupRingElem{T}, Y::GroupRingElem{S}, check::Bool=true)
if true
parent(X) == parent(Y) || throw("Elements don't seem to belong to the same Group Ring!")
end
TT = typeof(first(X.coeffs)*first(Y.coeffs))
warn("Multiplying elements with different base rings! Promoting the result to $TT.")
result = mul!(result, X, Y)
return result
if isdefined(parent(X), :basis)
result = parent(X)(similar(X.coeffs))
result = convert(TT, result)
result = mul!(result, X, Y)
else
result = convert(TT, similar(X.coeffs))
result = mul!(result, X.coeffs, Y.coeffs, parent(X).pm)
result = GroupRingElem(result, parent(X))
end
return result
end
function divexact{T}(X::GroupRingElem{T}, Y::GroupRingElem{T})
if length(Y) != 1
throw("Can not divide by a non-primitive element $(Y)!")
else
idx = findfirst(Y)
c = Y[idx]
c == 0 || throw("Can not invert")
g = parent(Y).basis[idx]
return X*1//c*parent(Y)(inv(g))
end
end
###############################################################################
@ -357,7 +450,7 @@ end
function star{T}(X::GroupRingElem{T})
RG = parent(X)
isdefined(RG, :basis) || complete(RG)
isdefined(RG, :basis) || throw("*-involution without basis is not possible")
result = RG(T)
for (i,c) in enumerate(X.coeffs)
if c != zero(T)
@ -413,22 +506,18 @@ end
create_pm{T<:GroupElem}(b::Vector{T}) = create_pm(b, reverse_dict(b))
function complete(A::GroupRing)
if !isdefined(A, :basis)
A.basis = [elements(A.group)...]
function complete!(RG::GroupRing)
if !isdefined(RG, :basis)
RG.basis = [elements(RG.group)...]
end
if !isdefined(A, :basis_dict)
A.basis_dict = reverse_dict(A.basis)
if !isdefined(RG, :basis_dict)
RG.basis_dict = reverse_dict(RG.basis)
end
if !isdefined(A, :pm)
A.pm = try
create_pm(A.basis, A.basis_dict)
catch err
isa(err, KeyError) && throw("Product is not supported on basis")
throw(err)
end
for linidx in find(RG.pm .== 0)
i,j = ind2sub(size(RG.pm), linidx)
RG.pm[i,j] = RG.basis_dict[RG.basis[i]*RG.basis[j]]
end
return A
return RG
end
end # of module GroupRings

View File

@ -10,14 +10,16 @@ using Nemo
@test isa(GroupRing(G), Nemo.Ring)
@test isa(GroupRing(G), GroupRing)
RG = GroupRing(G, initialise=false)
@test isdefined(RG, :pm) == false
@test isdefined(RG, :basis) == false
@test isdefined(RG, :basis_dict) == false
@test isa(complete(RG), GroupRing)
@test size(RG.pm) == (6,6)
RG = GroupRing(G, init=false)
@test isdefined(RG, :basis) == true
@test length(RG.basis) == 6
@test isdefined(RG, :basis_dict) == true
@test isdefined(RG, :pm) == true
@test RG.pm == zeros(Int, (6,6))
@test isa(complete!(RG), GroupRing)
@test all(RG.pm .> 0)
@test RG.pm == GroupRing(G, init=true).pm
@test RG.basis_dict == GroupRings.reverse_dict(elements(G))
@ -63,7 +65,7 @@ using Nemo
@testset "GroupRingElems constructors/basic manipulation" begin
G = PermutationGroup(3)
RG = GroupRing(G, initialise=true)
RG = GroupRing(G, init=true)
a = rand(6)
@test isa(GroupRingElem(a, RG), GroupRingElem)
@test isa(RG(a), GroupRingElem)
@ -120,6 +122,9 @@ using Nemo
@test eltype(2.0*a) == typeof(2.0)
@test (2.0*a).coeffs == 2.0.*(a.coeffs)
b = RG(1) + GroupRings.star(a)
@test a*b == mul!(a,a,b)
@test isa(a/2, GroupRingElem)
@test eltype(a/2) == typeof(1/2)
@test (a/2).coeffs == 0.5*(a.coeffs)