kalmar/Groups.jl
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new version of reduce! and free_reduce using delete_ids!

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delete_ids requires second pass of W.symbols, but is so much easier to
get it right!
This commit is contained in:
kalmarek 2018-03-29 19:19:34 +02:00
parent eed218da3c
commit 40cf8a4e9f
1 changed files with 16 additions and 3 deletions
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19
src/Groups.jl
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@ -111,24 +111,37 @@ isone(s::GSymbol) = s.pow == 0
length(W::GWord) = sum([length(s) for s in W.symbols]) length(W::GWord) = sum([length(s) for s in W.symbols])
function delete_ids!(W::GWord)
to_delete = Int[]
for i in 1:length(W.symbols)
if W.symbols[i].pow == 0
push!(to_delete, i)
end
end
deleteat!(W.symbols, to_delete)
end
function free_reduce!(W::GWord) function free_reduce!(W::GWord)
reduced = true reduced = true
for i in 1:length(W.symbols) - 1 for i in 1:length(W.symbols) - 1
if W.symbols[i].str == W.symbols[i+1].str if W.symbols[i].pow == 0
continue
elseif W.symbols[i].str == W.symbols[i+1].str
reduced = false reduced = false
p1 = W.symbols[i].pow p1 = W.symbols[i].pow
p2 = W.symbols[i+1].pow p2 = W.symbols[i+1].pow
W.symbols[i+1] = change_pow(W.symbols[i], p1 + p2) W.symbols[i+1] = change_pow(W.symbols[i], p1 + p2)
W.symbols[i] = change_pow(W.symbols[i], 0) W.symbols[i] = change_pow(W.symbols[i], 0)
end end
end end
deleteat!(W.symbols, find(x -> x.pow == 0, W.symbols)) delete_ids!(W)
return reduced return reduced
end end
function reduce!(W::GWord) function reduce!(W::GWord)
if length(W) < 2 if length(W) < 2
deleteat!(W.symbols, find(x -> x.pow == 0, W.symbols)) delete_ids!(W)
else else
reduced = false reduced = false
while !reduced while !reduced