I the `cfunction` necessary here? Since you already have the return type `R`, wouldn't it suffice to annotate the call with a `::R` suffix? I am thinking:
immutable StableFunction{R,A}
f
StableFunction(f) = new(f)
end
call{R,A}(f::StableFunction{R,A}, x) = f(x)::R
-erik
> On Jan 20, 2015, at 17:56 , Jeff Bezanson <jeff.bezan...@gmail.com> wrote:
>
> Oh, I should also mention that the version that calls goo(foo()) takes
> so little time because the entire loop is probably optimized out.
>
> On Tue, Jan 20, 2015 at 5:54 PM, Jeff Bezanson <jeff.bezan...@gmail.com>
> wrote:
>> Here is a hack that basically works by escaping through the C type system:
>>
>> ```
>> immutable CFunction{R,A}
>> f
>> p::Ptr{Void}
>> CFunction(f) = new(f, cfunction(f, R, (A,)))
>> end
>>
>> call{R,A}(f::CFunction{R,A}, x) = ccall(f.p, R, (A,), x)
>>
>> foo(x::Float64) = 0.0
>> goo(x::Float64) = x
>>
>> function test1()
>> for i=1:100000000
>> f = foo
>> r = f(1.0)
>> goo(r)
>> end
>> end
>>
>> function test2()
>> f = CFunction{Float64,Float64}(foo)
>> for i=1:100000000
>> r = f(1.0)
>> goo(r)
>> end
>> end
>> ```
>>
>> I added an argument to `foo` to increase the generality somewhat.
>> test1() is the original test case. test2() is the new version. The
>> CFunction object needs to be constructed outside the loop, but this
>> can be stored in a data structure and reused anywhere.
>>
>> -Jeff
>>
>>
>> On Tue, Jan 20, 2015 at 4:34 PM, Ivar Nesje <iva...@gmail.com> wrote:
>>> Originally posted at https://github.com/JuliaLang/julia/issues/9863
--
Erik Schnetter <schnet...@gmail.com>
http://www.perimeterinstitute.ca/personal/eschnetter/
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