>> is there anyway the modifyWith functions could work on uboxed types?
>
> If they're inlined, the modify functions on boxed types may well end up
> unboxed.
>
> What's the particular problem you're having?
well, after inspecting a little further its not so bad actually. i
was comparing
module Main where
import qualified Data.Vector.Dense.IO as Vector
import Control.Monad
e = exp 1.0
sigmoid xx = 1.0 / (1 + (e ** (1.0 * xx)))
type Vec = Vector.IOVector Int Double
main = do
let size = 100000
ff::Vec <- Vector.newListVector size $ repeat 0.5
replicateM_ 1000 $ Vector.modifyWith (sigmoid) ff
putStrLn $ "done"
to this:
#include "math.h"
#include "stdlib.h"
#include "stdio.h"
double sigmoid(double xx) {
return 1.0 / (1.0 + (pow(M_E, (1.0 * xx))));
}
int main() {
int size = 100000;
int times = 1000;
int ii,jj;
double* array = malloc(sizeof(double)*size);
for(jj = 0; jj < size; ++jj) {
array[jj] = 0.5;
}
for(ii = 0; ii < times; ++ii) {
for(jj = 0; jj < size; ++jj) {
array[jj] = sigmoid(array[jj]);
}
}
printf("done\n");
}
the haskell version does ok, or 0m37.937s vs 0m23.492s in C. I am
compiling with these options: -O2 -fexcess-precision
-funbox-strict-fields -fglasgow-exts -fbang-patterns -prof -auto-all,
and O2 for gcc.
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