Consider the following code snippet which shows the following expect
problem (on v0.5): if I form a tuple of functions, pass this tuple to
another function, then julia cannot infer enough information about them and
runs into a type instability.
MY QUESTION is: is there a work-around? I.e., can I form an array, tuple,
etc of functions and call them without losing type stability?
(declaring return-type did not help, which surprised me since I thought
that would give the additional information about what the two functions f1,
f2 in the tuple do)
function test(N, ff)
r = 0.234; s = 0.0
for n = 1:N, f in ff
s = s + f(r)::Float64
end
return s
end
function test2(N, f1, f2)
r = 0.234; s = 0.0
for n = 1:N
s = s + f1(r) + f2(r)
end
return s
end
f1(r::Float64)::Float64 = r^3
f2(r::Float64)::Float64 = r^5
test(10, (f1,f2))
test(10, (f1,f1))
test2(10, f1,f2)
@time test(1_000_000, (f1,f2)) # 0.079190 seconds (4.00 M allocations...
@time test2(1_000_000, f1, f2) # 0.002279 seconds (5 allocations: 176
bytes)
@time test(1_000_000, (f1,f1)) # 0.002664 seconds (5 allocations: 176
bytes)
