> [EMAIL PROTECTED] (Ketil Z. Malde) writes:
>
> > Thanks for all your help, though!
>
> One interesting(?) observation,
>
> using a custom data type of
>
> data STuple = STuple !Int Foo
>
> is slightly less efficient than using a normal tuple
>
> (Int,Foo)
Just checking... with -funbox-strict-fields, right?
> Seems to go against theory, in which STuple should use three words
> plus the Foo, while (,) should use three words plus the Foo, plus two
> for the Int. Perhaps the Ints are constructed anyway, since they are
> inserted from a function parameter? Sounds reasonable, I suppose;
> memory use seemed to be the same (from "top"), and there was only a
> speed difference.
It's possible that the boxed Int is being reconstructed for some reason. You'll be
able to see the difference more accurately using heap profiling.
> And one more thing, would parametrised types make a difference?
> E.g. my array is
>
> data MyArray label elts = MA label (Array Int elts)
>
> which means I have
>
> data Foo l a = Foo (MyArray l a) !Int
>
> and so on. As far as I can see, this shouldn't matter (a heap object
> is a heap object), but am I seeing far enough, I wonder?
A polymorphic strict field can't be unboxed - eg.
data StrictList a = Scons !a | Snil
will never result in the elements being unboxed, even in (StrictList Int). Apart from
that, parameterised data types make no difference to the storage representation.
Cheers,
Simon
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