16 Oct 2009 07:58
Re: RMCL 5.2 on Snow Leopard: floating point issues
The problem manifests itself with returning every float value as 0.0 which is a likely source of causing division by zero float error.
I still do not know what causes this problem. There is no obvious CL code that could explain this. However, there is good news, or at least good enough news. I can now replicate the bug. Tracking the bug in a large code base finally turned up this unlikely culprit:
Welcome to Macintosh Common Lisp Version 5.2!
? 3.3
3.3
? (choose-directory-dialog)
#P"Double Ristretto:Users:alex:Desktop:RMCL 5.2:level-1:"
? 3.3
0.0
?
OS X 10.6.1, Core 2 Duo, 2.6 Ghz MacBook Pro with a fresh copy of RMCL from Google Code.
time to sleep...
Alex
On Oct 15, 2009, at 9:30 PM, Chun Tian wrote:
Hi again,(this is in a Listerner 1 process "initial" breaking after the error
occurring for the first time resulting in float /0 errors)
What does above mean? I try to eval something like (/ 1.0 0.0) first,
but the rest of those float tests are still keep the same.
--binghe
在 2009-10-16，11:26， Chun Tian 写道：Hi, Alexander
Hmmm ... I'm also in Snow Leopard using RMCL 5.2, but your tests are
all fine here:
Welcome to Macintosh Common Lisp Version 5.2!
? 3
3
? 3.0
3.0
? *read-default-float-format*
SINGLE-FLOAT
? (setq *read-default-float-format* 'short-float)
SHORT-FLOAT
? 3
3
? 3.3
3.3
? (float 3)
3.0
? (+ 4.5 5.5)
10.0
?
This is Mac OS X 10.6.1 on Intel Core 2 Duo 2.66GHz (MacBookPro5,2).
I just want to clarify that not everyone met the same issue as you
(I'm sorry for that).
Regards,
Chun Tian (binghe)
在 2009-10-16，4:38， Alexander Repenning 写道：
getting closer to WHAT is happening but not WHY. Keep in mind this
worked on Leopard but not Snow Leopard. I would assume this is has
something to do with the new version of Rosetta. Here are some
stunning listener interactions (this is in a Listerner 1 process
"initial" breaking after the error occurring for the first time
resulting in float /0 errors):
1 > 3
3
;; OK
1 > 3.0
1.06099791E-315
;; HUH!!!
1 > (setq *read-default-float-format* 'short-float)
SHORT-FLOAT
1 > 3
3
1 > 3.3
0.0
1 > (float 3)
0.0
1 > (+ 4.5 5.5)
0.0
Looks as if ANY kind of float returned is a 0.0
Meanwhile, in the regular listerner things are still working as
expected.
I am stumped at the moment and would appreciate any pointer or even
wild guesses on how RMCL could possibly enter this state.
So far I have only seen the problem in process initial but I am not
sure if this is relevant.
all the best, Alex
On Oct 14, 2009, at 2:57 PM, Terje Norderhaug wrote:
On Oct 14, 2009, at 9:15 AM, Alexander Repenning wrote:
What kinds of issues do people have out there with RMCL 5.2 and
Snow Leopard (OS X, 10.6.1)?
Things almost work here but there are some strange floating point
issues (with shorts).
At least we get further, ironically, with RCML 5.2 than CCL 1.3
which immediately quits. What is the version of CCL one should use
to work under OS X 10.6.1?
Are these the same as the problems discussed in issue 8 at
mcl.googlecode.com?
http://code.google.com/p/mcl/issues/detail?id=8
Gary made some changes to the floating point functionality, but come
to think about it, these changes may not have been propagated into
the distribution yet:
http://code.google.com/p/mcl/source/detail?
r=ff3f7eb878e5d61e1a8e83f6d19b3a3ea86de346
-- Terje
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University of Colorado
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Prof. Alexander Repenning
University of Colorado
Computer Science Department
Boulder, CO 80309-430
vCard: http://www.cs.colorado.edu/~ralex/AlexanderRepenning.vcf
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