Dear Haskell-Cafe,
I'm computing a histogram of a bunch of symbols with up to 8 bits of
information each, stored in a unboxed vector of Word8. The histogram is
represented as an unboxed vector of Int with size 2^bits. I compute the
histogram by folding an increment function.
The problem:
Ouch, now I really feel stupid, because I *knew* about the stricter
foldl' version.
But great to know about the new strictness on vars! I really should get
GHC 6.8 RC1 for Windows...
I just got puzzled why mysum worked better than sum for some reason...
mysym looks like an identical
2007/10/6, Peter Verswyvelen [EMAIL PROTECTED]:
But great to know about the new strictness on vars! I really should get GHC
6.8 RC1 for Windows...
Just in case you misunderstood : this functionality was already there
in GHC 6.4, it's just the new syntax to active it that is available
only in
On 10/6/07, Bertram Felgenhauer [EMAIL PROTECTED] wrote:
This is a language extension, you need -fbang-patterns
to allow it, or with a recent ghc (6.7, 6.9 or a 6.8 rc)
a {-# LANGUAGE BangPatterns #-} pragma, or -XBangPatterns.
LANGUAGE pragmas (including BangPatterns) work just fine in 6.6,
Just to be clear, I doubt the difference had anything to do with
tail-recursion per se. My guess is that with the mysum version, ghc was
able to do some strictness analysis/optimization that it wasn't able to do
(for whatever reason) with the first version. The best solution (as others
have
The following code, when compiled with GHC 6.6.1 --make -O gives a stack
overflow when I enter 100 as a command line argument:
(please don't look at the efficiency of the code, it can of course be
improved a lot both in time performance and numeric precision...)
import System
leibnizPI
Peter Verswyvelen wrote:
The following code, when compiled with GHC 6.6.1 --make -O gives a stack
overflow when I enter 100 as a command line argument:
(please don't look at the efficiency of the code, it can of course be
improved a lot both in time performance and numeric precision...)
Can anyone explain the following error message from Hug98
(with extensions enabled)?
I have
class Space t
class Space t = HasY v t
where
assignY :: v - t - t
getY :: t - v
varY :: forall w . Space w = v - (t-t) - (w-w)
I get an error on the last definition quantifier does not
hello,
just skip the forall. free type variables are implicitly
forall-quantified.
the forall keyword is used for functions that need to take polymorphic
functions
as arguments, but that's advanced stuff.
so in short, this should work:
class Space t
class Space t = HasY v t
where
Iavor S. Diatchki wrote:
just skip the forall. free type variables are implicitly
forall-quantified.
Of course! Thanks. The problem is that I actually wanted exists.
However as the type that exists is functionally dependent on other the
parameters to the class I think I can deal with it
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