[Haskell-cafe] Newbie question about tuples

[Bulat Ziganshin]

Hello peterv,

Friday, July 13, 2007, 10:00:48 PM, you wrote:

you still should select between strict algorithm which ghc can compile
to non-lazy code and lazy algorithm which, as you belive, should make
some other benefits :)

actually, for rather large algorithms, strictness doesn't work (some
parts of your code is non-strict) and you get all this
orders-of-magnitude penalty. look for example at
http://www.cse.unsw.edu.au/~chak/papers/afp-arrays.ps.gz or at the
ByteString paper which emphasizes the same problem (and it was the
reason to implementing strict ByteStrings)

> Yes but doesn't GHC have a good "strictness analyzer" (or how is this
> called?)? I haven't looked at the generated assembly code yet (if this is at
> all readable; but good C/C++ compilers *do* generate reasonably readable
> assembly code)

> -----Original Message-----
> From: Bulat Ziganshin [mailto:bulat.ziganshin at gmail.com] 
> Sent: Friday, July 13, 2007 6:43 PM
> To: peterv
> Cc: 'Lukas Mai'; haskell-cafe at haskell.org
> Subject: Re[2]: [Haskell-cafe] Newbie question about tuples

> Hello peterv,

> Friday, July 13, 2007, 5:03:00 PM, you wrote:

>> think the latest compilers are much better). Now when implementing
> something
>> like this in Haskell, I would guess that its laziness would allow to
>> "interleave" many of the math operations, reordering them to be as optimal
>> as possible, removing many intermediate results (like processing streams).

> don't forget that laziness by itself makes programs an orders of
> magnitude slower :)





-- 
Best regards,
 Bulat                            mailto:Bulat.Ziganshin at gmail.com