Splitted into Groups.jl package

This commit is contained in:
kalmar 2017-01-26 10:28:41 +01:00
parent 56b63058e3
commit e69f5d13b6
2 changed files with 0 additions and 198 deletions

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module FreeGroups
using Groups
import Base: inv, convert
export FGSymbol, IDSymbol
immutable FGSymbol <: GSymbol
gen::String
pow::Int
end
IDSymbol(::Type{FGSymbol}) = FGSymbol("(id)", 0)
FGSymbol(x::String) = FGSymbol(x,1)
inv(s::FGSymbol) = FGSymbol(s.gen, -s.pow)
convert(::Type{FGSymbol}, x::String) = FGSymbol(x)
change_pow(s::FGSymbol, n::Int) = reduce(FGSymbol(s.gen, n))
typealias FGWord GWord{FGSymbol}
FGWord(s::FGSymbol) = FGWord([s])
end #end of module FreeGroups

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Groups.jl
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module Groups
import Base: length, ==, hash, show
import Base: one, inv, reduce, *, ^
export GSymbol, GWord
export IdSymbol, change_pow
abstract GSymbol
function show(io::IO, s::GSymbol)
if s.pow == 0
print(io, "(id)")
elseif s.pow == 1
print(io, s.gen)
else
print(io, (s.gen)*"^$(s.pow)")
end
end
length(s::GSymbol) = (s.pow == 0 ? 0 : 1)
IdSymbol(T::Type{GSymbol}) = throw(ArgumentError("Define IdSymbol(::Type{$T}) which is the identity element for Your type!"))
one{T<:GSymbol}(::Type{T}) = IdSymbol(T)
one(s::GSymbol) = one(typeof(s))
(*){T<:GSymbol}(s::T, t::T) = return GWord{T}([s])*t
change_pow(s::GSymbol, n::Int) = throw(ArgumentError("Define change_pow function for $(typeof(s))!"))
abstract Word
type GWord{T<:GSymbol} <: Word
symbols::Vector{T}
savedhash::UInt
modified::Bool
function GWord(symbols::Vector{T})
return new(symbols, hash(symbols), false)
end
end
GWord{T<:GSymbol}(s::T) = GWord{T}([s])
IDWord{T<:GSymbol}(::Type{T}) = GWord(one(T))
IDWord{T<:GSymbol}(W::GWord{T}) = IDWord(T)
function length(W::GWord)
return sum([abs(s.pow) for s in W.symbols])
end
one{T}(::Type{GWord{T}}) = IDWord(T)
one{T}(w::GWord{T}) = one(GWord{T})
function inv{T}(W::GWord{T})
if length(W) == 0
return W
else
return freegroup_reduce!(GWord{T}(reverse([inv(s) for s in W.symbols])))
end
end
function join_free_symbols!(W::GWord)
reduced = true
for i in 1:length(W.symbols) - 1
if W.symbols[i].gen == W.symbols[i+1].gen
reduced = false
p1 = W.symbols[i].pow
p2 = W.symbols[i+1].pow
W.symbols[i+1] = change_pow(W.symbols[i], p1 + p2)
W.symbols[i] = one(W.symbols[i])
end
end
return reduced
end
function freegroup_reduce!{T}(W::GWord{T})
if length(W) < 2
deleteat!(W.symbols, find(x -> x.pow == 0, W.symbols))
else
reduced = false
while !reduced
reduced = join_free_symbols!(W)
deleteat!(W.symbols, find(x -> x.pow == 0, W.symbols))
end
end
W.modified = false
W.savedhash = hash(W.symbols,hash(typeof(W)))
return W
end
freegroup_reduce(W::GWord) = freegroup_reduce!(deepcopy(W))
hash{T}(W::GWord{T}) = (W.modified && freegroup_reduce!(W); W.savedhash)
function (==){T}(W::GWord{T}, Z::GWord{T})
W.modified && freegroup_reduce!(W) # reduce could actually clear the flag and recalculate the hash
Z.modified && freegroup_reduce!(Z)
return W.savedhash == Z.savedhash && W.symbols == Z.symbols
end
function show(io::IO, W::GWord)
if length(W) == 0
print(io, "(id)")
else
join(io, [string(s) for s in W.symbols], "*")
end
end
function r_multiply!(W::GWord, x; reduced::Bool=true)
if length(x) > 0
push!(W.symbols, x...)
end
if reduced
freegroup_reduce!(W)
end
return W
end
function l_multiply!(W::GWord, x; reduced::Bool=true)
if length(x) > 0
unshift!(W.symbols, reverse(x)...)
end
if reduced
freegroup_reduce!(W)
end
return W
end
r_multiply(W::GWord, x; reduced::Bool=true) =
r_multiply!(deepcopy(W),x, reduced=reduced)
l_multiply(W::GWord, x; reduced::Bool=true) =
l_multiply!(deepcopy(W),x, reduced=reduced)
(*){T}(W::GWord{T}, Z::GWord{T}) = r_multiply(W, Z.symbols)
(*)(W::GWord, s::GSymbol) = W*GWord(s)
(*)(s::GSymbol, W::GWord) = GWord(s)*W
function power_by_squaring{T}(x::GWord{T}, p::Integer)
if p < 0
return power_by_squaring(inv(x), -p)
elseif p == 0
return one(x)
elseif p == 1
return deepcopy(x)
elseif p == 2
return x*x
end
t = trailing_zeros(p) + 1
p >>= t
while (t -= 1) > 0
x *= x
end
y = x
while p > 0
t = trailing_zeros(p) + 1
p >>= t
while (t -= 1) >= 0
x *= x
end
y *= x
end
return freegroup_reduce!(y)
end
(^)(x::GWord, n::Integer) = power_by_squaring(x,n)
end