On 17.07.2013 16:11, Brian Lewis wrote:
On 2013.07.17, at 08:03, Jan-Willem Maessen wrote:
This has all the marks of a 64-bit-only code running on a 32 bit
machine.
This discussion is interesting, but I'm not sure why so much of it is
taking place here instead of on the mwc-random issue
On 10 July 2013 14:10, kudah kudahkuka...@gmail.com wrote:
Yes, it does. Without optimizations the result is
ndgorsfesnywaiqraloa, while with optimizations the result is always
aabb.
Sorry for taking so long. So problem is uniformR. You can reproduce bug
reliably and I cannot.
Test triggers the bug, only zeros and ones like you said, but
only for native-sized types:
-O2:
Int
0 0 0 0 0 1 0 0 1 0 1 1 0 0 0 0 0 0 0 0
Int32
41 37 25 85 27 84 70 8 70 32 36 1 14 92 1 74 17 28 38 76
Int64
37 77 57 75 17 58 28 77 23 51 1 13 50 35 21 11 70 43 6 5
Word
0 0 1 1 0 0 1 0 0 0 0 0
This has all the marks of a 64-bit-only code running on a 32 bit machine.
It looks like you're getting the high bits of the rng with a signed shift
right, ultimately yielding only the sign bit.
I suspect mwc-random needs to use Int64 rather than Int internally in a few
critical places.
On Wed,
On 2013.07.17, at 08:03, Jan-Willem Maessen wrote:
This has all the marks of a 64-bit-only code running on a 32 bit
machine.
This discussion is interesting, but I'm not sure why so much of it is
taking place here instead of on the mwc-random issue tracker:
Yes, it does. Without optimizations the result is
ndgorsfesnywaiqraloa, while with optimizations the result is always
aabb.
On Wed, 10 Jul 2013 02:21:10 +0400 Aleksey Khudyakov
alexey.sklad...@gmail.com wrote:
On 10.07.2013 01:38, kudah wrote:
I've attached the script that I
Same here, I used mwc-random to generate random strings. It works in
ghci and when compiled with -O0, but with -O1 and -O2 I've been getting
exclusively a's and b's.
On Sun, 17 Mar 2013 18:48:06 +0500 Azeem -ul-Hasan aze...@live.com
wrote:
I am using
GHC 7.6.1
mwc-random 0.12.0.1
On 09.07.2013 22:10, kudah wrote:
Same here, I used mwc-random to generate random strings. It works in
ghci and when compiled with -O0, but with -O1 and -O2 I've been getting
exclusively a's and b's.
It looks like MWC generates only 0 and 1 for some reason. I've tried to
write simple test but
I've attached the script that I had trouble with. It tries to replicate
one directory structure in another directory, while replacing filenames
and file contents with random data. When compiled with -O1 or -O2
resulting file and directory names are composed only of a's and b's,
but file contents
On 10.07.2013 01:38, kudah wrote:
I've attached the script that I had trouble with. It tries to replicate
one directory structure in another directory, while replacing filenames
and file contents with random data. When compiled with -O1 or -O2
resulting file and directory names are composed only
On 17 March 2013 21:49, Dominic Steinitz domi...@steinitz.org wrote:
Aleksey Khudyakov alexey.skladnoy at gmail.com writes:
I've tried to run you program and I've got approximately same results
regardless of optimization level. Which versions of GHC, mwc-random,
vector and primitive do you
On 16.03.2013 13:31, Azeem -ul-Hasan wrote:
Nope that isn't the case either. Even if I make use of defaultSeed
through create the problem still remains. The problem seems to be in the
generation of a vector of (a,a) i.e in the part
V.generateM ((round $ p*(fromIntegral $ l*z)) `div` 2) (\i-
I am using
GHC 7.6.1
mwc-random 0.12.0.1
vector 0.9.1
primitive 0.4.1
Azeem
On 16.03.2013 13:31, Azeem -ul-Hasan wrote:
Nope that isn't the case either. Even if I make use of defaultSeed
through create the problem still remains. The problem seems to be in the
generation of a
Aleksey Khudyakov alexey.skladnoy at gmail.com writes:
I've tried to run you program and I've got approximately same results
regardless of optimization level. Which versions of GHC, mwc-random,
vector and primitive do you use?
By approximate do you mean you are getting Monte Carlo noise
from System.Random and it
works fine with optimizations turned on. So any ideas why optimizations are
messing with System.Random.MWC?
Azeem
From: carter.schonw...@gmail.com
Date: Fri, 15 Mar 2013 17:09:36 -0400
Subject: Re: [Haskell-cafe] Optimization flag changing result of code execution
To: aze
ideas
why optimizations are messing with System.Random.MWC?
Azeem
From: carter.schonw...@gmail.com
Date: Fri, 15 Mar 2013 17:09:36 -0400
Subject: Re: [Haskell-cafe] Optimization flag changing result of code
execution
To: aze...@live.com
CC: haskell-cafe@haskell.org
Hey Azeem,have you
16. Thanks again.
Azeem
Date: Sat, 16 Mar 2013 10:58:50 +0200
From: r...@ro-che.info
To: aze...@live.com
CC: carter.schonw...@gmail.com; haskell-cafe@haskell.org
Subject: Re: [Haskell-cafe] Optimization flag changing result of code
execution
Perhaps the problem is in withSystemRandom
I was trying to solve a computational problem form James P Sethna's book
Statistical Mechanics: Entropy, Order Parameters, and Complexity[1]. The
problem is on page 19 of the pdf linked and is titled Six degrees of
separation. For it I came up with this code: http://hpaste.org/84114
It runs
Hey Azeem,
have you tried running the same calculation using rationals? Theres some
subtleties to writing numerically stable code using floats and doubles,
where simple optimizations change the orders of operations in ways that
*significantly* change the result. In this case it looks like you're
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