So I was looking at allocations in some code and I noticed I sped things up
significantly by changing map to a list comprehension. Doing some
microbenchmarking I noticed that map allocates far more memory than a list
comprehension. Shouldn't they essentially be doing the same thing?
data = rand(10000000)
function f1(data)
[sin(i) for i in data]
end
function f2(data)
map(sin, data)
end
function f3(data)
out = zeros(data)
for i in 1:length(data)
out[i] = sin(data[i])
end
out
end
f1([0.1, 0.2])
f2([0.1, 0.2])
f3([0.1, 0.2])
sin([0.1, 0.2])
@time f1(data)
@time f2(data)
@time f3(data)
@time sin(data);
elapsed time: 0.375611486 seconds (80000128 bytes allocated)
elapsed time: 1.707264865 seconds (400000128 bytes allocated, 28.03% gc time)
elapsed time: 0.359320195 seconds (80000128 bytes allocated)
elapsed time: 0.307740829 seconds (80000128 bytes allocated)
