Merge branch 'master' into enh/julia-v0.6

This commit is contained in:
kalmarek 2017-09-13 10:54:55 +02:00
commit 822067b04c
2 changed files with 280 additions and 130 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
@ -17,24 +17,31 @@ type GroupRing{Gr<:Group, T<:GroupElem} <: Ring
basis_dict::Dict{T, Int}
pm::Array{Int,2}
function GroupRing{Gr, T}(G::Gr; initialise=true) where {Gr <: Group, T<:GroupElem}
A = new(G)
if initialise
complete(A)
end
return A
function GroupRing(G::Group, basis::Vector{T}; fastm::Bool=false)
RG = new(G, basis, reverse_dict(basis))
fastm && fastm!(RG)
return RG
end
function GroupRing{Gr, T}(G::Gr, b::Vector{T}, b_d::Dict{T, Int}, pm::Array{Int,2}) where {Gr <: Group, T<:GroupElem}
return new(G, b, b_d, pm)
end
function GroupRing(G::Gr, pm::Array{Int,2})
RG = new(G)
RG.pm = pm
return RG
end
end
GroupRing(G::Gr;initialise=true) where Gr <:Group = GroupRing{Gr, elem_type(G)}(G, initialise=initialise)
GroupRing{Gr<:Group, T<:GroupElem}(G::Gr, basis::Vector{T}; fastm::Bool=true) =
GroupRing{Gr, T}(G, basis, fastm=fastm)
GroupRing(G::Gr, b::Vector{T}, b_d::Dict{T,Int}, pm::Array{Int,2}) where {Gr<:Group, T<:GroupElem} = 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
@ -53,7 +60,7 @@ type GroupRingElem{T<:Number} <: RingElem
end
end
export GroupRing, GroupRingElem, complete, create_pm
export GroupRing, GroupRingElem, complete!, create_pm, star
###############################################################################
#
@ -61,12 +68,19 @@ export GroupRing, GroupRingElem, complete, create_pm
#
###############################################################################
elem_type(::GroupRing) = GroupRingElem
elem_type{T,S}(::Type{GroupRing{T,S}}) = GroupRingElem
parent_type(::GroupRingElem) = GroupRing
parent_type(::Type{GroupRingElem}) = GroupRing
parent{T}(g::GroupRingElem{T}) = g.parent
eltype(X::GroupRingElem) = eltype(X.coeffs)
parent(g::GroupRingElem) = 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
###############################################################################
#
@ -78,34 +92,14 @@ 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; fastm::Bool=false)
return GroupRing(G, [elements(G)...], fastm=fastm)
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")
basis_dict = reverse_dict(basis)
return GroupRing(G, basis, basis_dict, pm)
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")
return GroupRing(G, basis, reverse_dict(basis), pm)
end
###############################################################################
@ -114,45 +108,71 @@ end
#
###############################################################################
zero(RG::GroupRing, T::Type=Int) = RG(T)
one(RG::GroupRing, T::Type=Int) = RG(RG.group(), T)
one{R<:Nemo.Ring, S<:Nemo.RingElem}(RG::GroupRing{R,S}) = RG(eye(RG.group()))
function (RG::GroupRing)(i::Int, T::Type=Int)
elt = RG(T)
elt[RG.group()] = i
return elt
end
function (RG::GroupRing{R,S}){R<:Ring, S}(i::Int, T::Type=Int)
elt = RG(T)
elt[eye(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)
function (RG::GroupRing){T<:Number}(x::AbstractVector{T})
isdefined(RG, :basis) || throw("Can not coerce without basis of GroupRing")
length(x) == length(RG.basis) || throw("Can not coerce to $RG: lengths differ")
result = RG(eltype(x))
result.coeffs = x
return result
end
function (RG::GroupRing{Gr,T}){Gr<:Nemo.Group, T<:Nemo.GroupElem}(V::Vector{T},
S::Type=Rational{Int}; alt=false)
res = RG(S)
for g in V
c = (alt ? sign(g)*one(S) : one(S))
res[g] += c/length(V)
end
return res
end
function (RG::GroupRing)(X::GroupRingElem)
RG == parent(X) || throw("Can not coerce!")
return RG(X.coeffs)
end
function (RG::GroupRing)(X::GroupRingElem, emb::Function)
result = RG(eltype(X.coeffs))
for g in parent(X).basis
result[emb(g)] = X[g]
end
return result
isdefined(RG, :basis) || throw("Can not coerce without basis of GroupRing")
result = RG(eltype(X.coeffs))
T = typeof(X.coeffs)
result.coeffs = T(result.coeffs)
for g in parent(X).basis
result[emb(g)] = X[g]
end
return result
end
###############################################################################
#
# Basic manipulation
# Basic manipulation && Array protocol
#
###############################################################################
@ -161,7 +181,7 @@ function deepcopy_internal(X::GroupRingElem, dict::ObjectIdDict)
end
function hash(X::GroupRingElem, h::UInt)
return hash(X.coeffs, hash(parent(X), h))
return hash(full(X.coeffs), hash(parent(X), hash(GroupRingElem, h)))
end
function getindex(X::GroupRingElem, n::Int)
@ -181,15 +201,12 @@ function setindex!(X::GroupRingElem, value, g::GroupElem)
typeof(g) == elem_type(RG.group) || throw("$g is not an element of $(RG.group)")
if !(g in keys(RG.basis_dict))
g = (RG.group)(g)
else
X.coeffs[RG.basis_dict[g]] = value
end
X.coeffs[RG.basis_dict[g]] = value
end
eltype(X::GroupRingElem) = eltype(X.coeffs)
one(RG::GroupRing) = RG(RG.group())
zero(RG::GroupRing) = RG()
Base.size(X::GroupRingElem) = size(X.coeffs)
Base.linearindexing{T<:GroupRingElem}(::Type{T}) = Base.LinearFast()
###############################################################################
#
@ -198,7 +215,7 @@ zero(RG::GroupRing) = RG()
###############################################################################
function show(io::IO, A::GroupRing)
print(io, "Group Ring of [$(A.group)]")
print(io, "Group Ring of $(A.group)")
end
function show(io::IO, X::GroupRingElem)
@ -209,10 +226,14 @@ function show(io::IO, X::GroupRingElem)
elseif isdefined(RG, :basis)
non_zeros = ((X.coeffs[i], RG.basis[i]) for i in findn(X.coeffs))
elts = ("$(sign(c)> 0? " + ": " - ")$(abs(c))*$g" for (c,g) in non_zeros)
join(io, elts, "")
str = join(elts, "")[2:end]
if sign(first(non_zeros)[1]) > 0
str = str[3:end]
end
print(io, str)
else
warn("Basis of the parent Group is not defined, showing coeffs")
print(io, X.coeffs)
show(io, MIME("text/plain"), X.coeffs)
end
end
@ -237,8 +258,8 @@ 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
@ -250,6 +271,11 @@ end
(-)(X::GroupRingElem) = GroupRingElem(-X.coeffs, parent(X))
function mul!{T<:Number}(a::T, X::GroupRingElem{T})
X.coeffs .*= a
return X
end
mul{T<:Number}(a::T, X::GroupRingElem{T}) = GroupRingElem(a*X.coeffs, parent(X))
function mul{T<:Number, S<:Number}(a::T, X::GroupRingElem{S})
@ -282,16 +308,23 @@ 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
@ -299,51 +332,143 @@ end
(+)(X::GroupRingElem, Y::GroupRingElem) = add(X,Y)
(-)(X::GroupRingElem, Y::GroupRingElem) = add(X,-Y)
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])
if X[i] != zero(eltype(X))
index == 0 && throw(ArgumentError("The product don't seem to belong to the span of basis!"))
result[index] += X[i]*y
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
lY = length(Y)
s = size(pm,1)
@inbounds for j in 1:lY
if Y[j] != z
for i in 1:s
if X[i] != z
pm[i,j] == 0 && throw(ArgumentError("The product don't seem to be supported on basis!"))
result[pm[i,j]] += X[i]*Y[j]
end
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)
lX = length(X.coeffs)
lY = length(Y.coeffs)
if isdefined(RG, :pm)
s = size(RG.pm)
findlast(X.coeffs) <= s[1] || throw("Element in X outside of support of RG.pm")
findlast(Y.coeffs) <= s[2] || throw("Element in Y outside of support of RG.pm")
for j in 1:lY
if Y.coeffs[j] != z
for i in 1:lX
if X.coeffs[i] != z
if RG.pm[i,j] == 0
RG.pm[i,j] = RG.basis_dict[RG.basis[i]*RG.basis[j]]
end
result.coeffs[RG.pm[i,j]] += X[i]*Y[j]
end
end
end
end
else
for j::Int in 1:lY
if Y.coeffs[j] != z
for i::Int in 1:lX
if X.coeffs[i] != z
result[RG.basis[i]*RG.basis[j]] += X[i]*Y[j]
end
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.")
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: $c not found in $Y")
g = parent(Y).basis[idx]
return X*1//c*parent(Y)(inv(g))
end
end
###############################################################################
@ -354,7 +479,7 @@ 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)
@ -393,16 +518,15 @@ function reverse_dict(iter)
end
function create_pm{T<:GroupElem}(basis::Vector{T}, basis_dict::Dict{T, Int},
limit=length(basis); twisted=false)
limit::Int=length(basis); twisted::Bool=false)
product_matrix = zeros(Int, (limit,limit))
for i in 1:limit
Threads.@threads for i in 1:limit
x = basis[i]
if twisted
x = inv(x)
end
for j in 1:limit
w = x*(basis[j])
product_matrix[i,j] = basis_dict[w]
product_matrix[i,j] = basis_dict[x*(basis[j])]
end
end
return product_matrix
@ -410,22 +534,34 @@ 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)
fastm!(RG, fill=true)
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
if !isdefined(A, :pm)
A.pm = try
create_pm(A.basis, A.basis_dict)
return RG
end
function fastm!(RG::GroupRing; fill::Bool=false)
isdefined(RG, :basis) || throw("For baseless Group Rings You need to provide pm.")
isdefined(RG, :pm) && return RG
if fill
RG.pm = try
create_pm(RG.basis, RG.basis_dict)
catch err
isa(err, KeyError) && throw("Product is not supported on basis")
isa(err, KeyError) && throw("Product is not supported on basis, $err.")
throw(err)
end
else
RG.pm = zeros(Int, length(RG.basis), length(RG.basis))
end
return A
return RG
end
end # of module GroupRings

View File

@ -10,14 +10,19 @@ 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)
@test isdefined(RG, :basis) == true
@test length(RG.basis) == 6
@test isdefined(RG, :basis_dict) == true
@test isdefined(RG, :pm) == false
RG = GroupRing(G, fastm=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 == GroupRings.fastm!(GroupRing(G, fastm=false), fill=true).pm
@test RG.basis_dict == GroupRings.reverse_dict(elements(G))
@ -37,7 +42,7 @@ using Nemo
@testset "GroupRing constructors FreeGroup" begin
using Groups
F = FreeGroup(3)
S = generators(F)
S = gens(F)
append!(S, [inv(s) for s in S])
S = unique(S)
@ -53,18 +58,22 @@ using Nemo
B = GroupRing(F, basis, d, pm)
@test A == B
g = B()
s = S[2]
g[s] = 1
@test g == B(s)
@test g[s^2] == 0
@test_throws KeyError g[s^10]
end
@testset "GroupRingElems constructors/basic manipulation" begin
G = PermutationGroup(3)
RG = GroupRing(G, initialise=true)
RG = GroupRing(G, fastm=true)
a = rand(6)
@test isa(GroupRingElem(a, RG), GroupRingElem)
@test isa(RG(a), GroupRingElem)
for g in elements(G)
@test isa(RG(g), GroupRingElem)
end
@test all(isa(RG(g), GroupRingElem) for g in elements(G))
@test_throws String GroupRingElem([1,2,3], RG)
@test isa(RG(G([2,3,1])), GroupRingElem)
@ -77,7 +86,8 @@ using Nemo
@test a[5] == 1
@test a[p] == 1
@test string(a) == " + 1*[2, 3, 1]"
@test string(a) == "1*[2, 3, 1]"
@test string(-a) == "- 1*[2, 3, 1]"
@test RG([0,0,0,0,1,0]) == a
@ -89,14 +99,15 @@ using Nemo
@test a[1] == 2
@test a[s] == 2
@test string(a) == " + 2*[1, 2, 3] + 1*[2, 3, 1]"
@test string(a) == "2*[1, 2, 3] + 1*[2, 3, 1]"
@test string(-a) == "- 2*[1, 2, 3] - 1*[2, 3, 1]"
@test length(a) == 2
end
@testset "Arithmetic" begin
G = PermutationGroup(3)
RG = GroupRing(G)
RG = GroupRing(G, fastm=true)
a = RG(ones(Int, order(G)))
@testset "scalar operators" begin
@ -157,6 +168,9 @@ using Nemo
@test GroupRings.augmentation((one(RG)-RG(g))) == 0
end
b = RG(1) + GroupRings.star(a)
@test a*b == mul!(a,a,b)
z = sum((one(RG)-RG(g))*GroupRings.star(one(RG)-RG(g)) for g in elements(G))
@test GroupRings.augmentation(z) == 0