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@carlobaldassi
Created March 22, 2012 15:58
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A very silly Julia bug [NOW FIXED]
# Annotated version
function calc{T<:Float}(X::Matrix{T}, N...) # change the name of the second argument -> the bug goes away
# (type of second argument doesn't matter)
# we might even use a single argument N::Matrix{T}
# it doesn't matter what's left of the T, it might be
# T<:Float64 or T<:Any or even just T
#function calc(X::Matrix{Float64}, N::Int) # use this form -> the bug goes away
# except where noted
println("$(X * X')") # this does _not_ trigger the bug
# and gives correct results
Z = X # remove this -> the bug goes away
# (any assignment involving X triggers the bug)
return
end
function main()
L = 3
M = 2
srand(10) # seed is not important
X = rand(M, L)
calc(X, 0) # removing this -> bug _also_ with alternative getC declaration!
new_perml = cell(1)
#new_perml = Array(Array{Int64,1},1) # use this instead -> the bug goes away
new_perml[1] = randperm(L) # note: the order of these
p = randperm(L) # two assignments doesnt'matter
@assert length(p) == length(new_perml[1])
@assert typeof(p) == typeof(new_perml[1])
p = new_perml[1] # removing this -> the bug goes away
# (using p=copy(newperml[1]) doesn't help)
Xp = X[:, p] # use Xp = X instead -> the bug goes away
# (using Xp = copy(X[:, p]) doesn't help)
calc([X Xp], 0) # remove this (or don't use Xp) -> the bug goes away
end
main()
# Minimal version
function calc{T}(N::Matrix{T})
mN = N
#mX = X # this would also trigger the bug
return
end
function main()
X = rand(3, 2)
pl = cell(1)
pl[1] = randperm(3)
Xp = X[pl[1],:]
Y = [X Xp]
calc(Y)
end
main()
# This is the same as minimal without main()
# and it works!
function calc{T}(N::Matrix{T})
mN = N
return
end
X = rand(3, 2)
pl = cell(1)
pl[1] = randperm(3)
Xp = X[pl[1],:]
Y = [X Xp]
calc(Y)
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