On Tue, May 29, 2007 at 02:42:22PM -0700, Scott Dillard wrote:
> You're right. I broke them when experimenting to see where the cycles
> were going. I've fixed them, but the other pair of functions, named
> gaussElim2, were correct and the issue remains that unsafeRead appears
> slower than readArr
Why would lists-of-lists be faster than unboxed arrays? No indexing
arithmetic? Deforestation? I'm very curious. The first advice I got
from #haskell when trying to speed up my original code was "get rid of
all those lists."
First, I think lists-of-lists is only faster (if at all) in your spec
Hello Scott,
Wednesday, May 30, 2007, 1:42:22 AM, you wrote:
> I've included your implementation for comparison, as well as a simple
> pure matrix multiplication function, but I'm having trouble tracking
> them down in the profiling. I think all of their cycles are being
> counted under main, but
You're right. I broke them when experimenting to see where the cycles
were going. I've fixed them, but the other pair of functions, named
gaussElim2, were correct and the issue remains that unsafeRead appears
slower than readArray.
I've included your implementation for comparison, as well as a si
instead of (!) (or readArray in stateful code) helped a lot. So then I
went to optimize my gaussian elimination function and found just the
opposite. unsafeRead is slower than readArray. This struck me as very
The functions gaussElimSafe and gaussElimUnsafe are different in their
outputs (*).
| Behalf Of Scott Dillard
| Sent: 29 May 2007 06:22
| To: glasgow-haskell-users@haskell.org
| Subject: readArray is faster than unsafeRead
|
| Hello,
|
| I'm writing some matrix multiplication and inversion functions for
| small matrices (3x3 and 4x4 mostly, for 3d graphics, modeling,
| simulat
Hello,
I'm writing some matrix multiplication and inversion functions for
small matrices (3x3 and 4x4 mostly, for 3d graphics, modeling,
simulation, etc.) I noticed that the matrix multiplication was a
bottleneck so I set out to optimize and found that using unsafeRead
instead of (!) (or readArr
