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simdloop.jl
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simdloop.jl
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function simd_loop_example_from_manual(x, y, z)
s = zero(eltype(z))
n = min(length(x),length(y),length(z))
@simd for i in 1:n
@inbounds begin
z[i] = x[i]-y[i]
s += z[i]*z[i]
end
end
s
end
function simd_loop_with_multiple_reductions(x, y, z)
# Use non-zero initial value to make sure reduction values include it.
(s,t) = (one(eltype(x)),one(eltype(y)))
@simd for i in 1:length(z)
@inbounds begin
s += x[i]
t += 2*y[i]
s += z[i] # Two reductions go into s
end
end
(s,t)
end
for T in {Int32,Int64,Float32,Float64}
# Try various lengths to make sure "remainder loop" works
for n in {0,1,2,3,4,255,256,257}
# Dataset chosen so that results will be exact with only 24 bits of mantissa
a = convert(Array{T},[2*j+1 for j in 1:n])
b = convert(Array{T},[3*j+2 for j in 1:n])
c = convert(Array{T},[5*j+3 for j in 1:n])
s = simd_loop_example_from_manual(a,b,c)
@test a==[2*j+1 for j in 1:n]
@test b==[3*j+2 for j in 1:n]
@test c==[-j-1 for j in 1:n]
@test s==sum(c.*c)
(s,t) = simd_loop_with_multiple_reductions(a,b,c)
@test s==sum(a)+sum(c)+1
@test t==2*sum(b)+1
end
end
# Test that scope rules match regular for
let j=4
# Use existing local variable.
@simd for j=1:0 end
@test j==4
@simd for j=1:3 end
@test j==3
# Use global variable
global simd_glob = 4
@simd for simd_glob=1:0 end
@test simd_glob==4
@simd for simd_glob=1:3 end
@test simd_glob==3
# Index that is local to loop
@simd for simd_loop_local=1:0 end
simd_loop_local_present = true
try
simd_loop_local += 1
catch
simd_loop_local_present = false
end
@test !simd_loop_local_present
end