[Gsll-devel] SVD problem

[Viktor Leis]

I'm using SBCL 1.0.25 on AMD64 and SBCL 1.0.17 on a 32-bit box.
By nonsense results I mean wrong results: the second return value
contains only zeros.
When SBCL crashes I either get a SB-SYS:MEMORY-FAULT-ERROR or "fatal
error encountered in SBCL pid 31660(tid 140110828128592): no scavenge
function for object 0x79109fe4 (widetag 0xe4)". This definitely looks
like an SBCL bug.

Viktor

On Mon, Mar 9, 2009 at 12:27 AM, Liam Healy <lhealy at common-lisp.net> wrote:
> Viktor,
>
> What version of SBCL are you running, and what do you mean by
> "nonsense results"?
> When I run sbcl 1.0.18.debian, I get an error from (test 1000) which
> looks like it's in
> the printing routine as it tries to return the answer matrix:
> debugger invoked on a SB-SYS:MEMORY-FAULT-ERROR in thread #<THREAD
> "initial thread" RUNNING {10039ADBF1}>:
>  Unhandled memory fault at #x0.
> Type HELP for debugger help, or (SB-EXT:QUIT) to exit from SBCL.
> restarts (invokable by number or by possibly-abbreviated name):
>  0: [ABORT] Exit debugger, returning to top level.
> (SB-SYS:MEMORY-FAULT-ERROR)
> 0]
> WARNING: Starting a select without a timeout while interrupts are disabled.
> :ba
> 0: (SB-SYS:MEMORY-FAULT-ERROR)
> 1: (SB-SYS:MEMORY-FAULT-ERROR)[:EXTERNAL]
> 2: ("foreign function: #x41EAA2")
> 3: ("foreign function: #x41EB70")
> 4: ("foreign function: #x40D53D")
> 5: ("foreign function: #x41CA5C")
> 6: (SB-KERNEL::COLLECT-GARBAGE 0)
> 7: ((FLET SB-THREAD::WITH-MUTEX-THUNK))
> 8: ((FLET #:WITHOUT-INTERRUPTS-BODY-[CALL-WITH-MUTEX]477))
> 9: ((FLET #:WITHOUT-INTERRUPTS-BODY-[SUB-GC]60))
> 10: (SB-KERNEL:SUB-GC)[:EXTERNAL]
> 11: ("foreign function: #x41EAA2")
> 12: ("foreign function: #x40D435")
> 13: ("foreign function: #x4116C3")
> 14: (SB-BIGNUM:MULTIPLY-BIGNUM-AND-FIXNUM
>     #<unavailable argument>
>     #<unavailable argument>)
> 15: (SB-IMPL::FLONUM-TO-DIGITS
>     0.006426902231453881d0
>     #<unavailable argument>
>     NIL)
> 16: (SB-IMPL::OUTPUT-FLOAT-AUX
>     0.006426902231453881d0
>     #<SB-PRETTY:PRETTY-STREAM {100631AE51}>
>     -3
>     8)
> 17: (SB-PRETTY:OUTPUT-PRETTY-OBJECT
>     0.006426902231453881d0
>     #<SB-PRETTY:PRETTY-STREAM {100631AE51}>)
> 18: ((FLET #:WITH-PRETTY-STREAM-2825) #<SB-PRETTY:PRETTY-STREAM {100631AE51}>)
> 19: ((LABELS SB-PRETTY::OUTPUT-GUTS)
>     #<SB-PRETTY:PRETTY-STREAM {100631AE51}>
>     0
>     (1000))
> 20: ((FLET #:WITH-PRETTY-STREAM-2825) #<SB-PRETTY:PRETTY-STREAM {100631AE51}>)
> 21: ((LABELS SB-PRETTY::OUTPUT-GUTS)
>     #<SB-PRETTY:PRETTY-STREAM {100631AE51}>
>     0
>     (1000 1000))
> 22: (SB-PRETTY:OUTPUT-PRETTY-OBJECT
>     #2A((-0.03152179146033235d0 -0.0064356015982750805d0
>          0.031318650821186636d0 0.021215786371980315d0 0.003314355400406193d0
>          0.0033404976598180773d0 -0.024914202255263d0 0.022145320720119623d0
>          -0.023703547290539858d0 0.010257175021330184d0
>    ...
> 23: (PRINC
>     #2A((-0.03152179146033235d0 -0.0064356015982750805d0
>          0.031318650821186636d0 0.021215786371980315d0 0.003314355400406193d0
>   ...
>
> I didn't try (test 3000).
> By the way, I tried Clozure  CL 1.2 on the same platform (Debian
> amd64) with both
> (test 1000) and (test 3000), and both run to completion and look
> reasonable, so I
> think at least what I'm seeing is a problem with SBCL.
>
> Liam
>
> On Sun, Mar 8, 2009 at 8:11 AM, Viktor Leis <viktor.leis at googlemail.com> wrote:
>> Hi,
>>
>> I've got a problem with singular value decomposition: Big matrices
>> (e.g. 3000x3000) crash SBCL. With a matrix of 1000x1000 it doesn't
>> crash but instead I usually get nonsense results. With a small matrix
>> (e.g. 500x500) it works perfectly fine. I get the same behavior on 32
>> and 64 bit Linux.
>>
>> (defun test (n)
>>  (let ((a (make-marray 'double-float :dimensions (list n n)))
>>        (s (make-marray 'double-float :dimensions n))
>>        (v (make-marray 'double-float :dimensions (list n n))))
>>    (dotimes (i n)
>>      (dotimes (j n)
>>        (setf (maref a i j) (random 1.0d0))))
>>    (multiple-value-list (sv-decomposition a s v))))
>>
>> Viktor Leis
>