Yuck! Sorry for the sucky tables. I am resending with some columns
removed, in the hopes that it will be easier to read (the removed
columns don't contribute to the discussion).
On May 12, 2007, at 11:04 , Michel wrote:
>
> I found the problem I think. Consider:
>
> time RR(0).exact_rational()
>
> CPU times: user 0.81 s, sys: 0.39 s, total: 1.21 s
> Wall time: 1.23
>
> 0.81s for such a trivial command is not normal. Also memory
> consumption
> goes up a lot, presumably causing an out of memory error on systems
> with little memory.
>
> I suspect there is a bug in mpfr_get_z_exp(value1,value2)
> when value2 is zero.
Yow! I ran 'top' while SAGE worked on this. SAGE tells me (Mac OS
X, on a 2x2.7GHz G5 with 2.5 GB of memory)
==========================================
sage: time RR(0).exact_rational()
CPU times: user 0.80 s, sys: 0.77 s, total: 1.57 s
Wall time: 1.89
0
==========================================
'top' shows (with roughly a 1-second interval):
==========================================
PID COMMAND %CPU TIME RPRVT RSHRD RSIZE VSIZE
1671 python 0.0% 0:03.48 30.0M 13.2M 41.0M 231M
1671 python 0.0% 0:03.48 30.0M 13.2M 41.0M 231M
1671 python 20.8% 0:03.75 143M+ 13.3M+ 154M+ 359M+
1671 python 84.3% 0:04.93 286M+ 13.3M+ 375M+ 615M+
1671 python 8.8% 0:05.06 158M- 13.3M 169M- 359M-
1671 python 0.0% 0:05.06 158M 13.3M 169M 359M
1671 python 0.0% 0:05.06 158M 13.3M 169M 359M
==========================================
The 'VSIZE' is the total memory used by the process. 'RSIZE' is
resident (in-memory) usage. It seems that in this case, we could
have a leak (or there is a huge data structure to hold '0' :-}).
Note that the increase is all in "private" memory. I believe this
means that the memory is "malloc()"d and is not shared library code.
I can try to nail this down if it's of interest.
A second run of the same command (10 minutes later) shows
==========================================
sage: time RR(0).exact_rational()
CPU times: user 0.81 s, sys: 0.78 s, total: 1.59 s
Wall time: 2.91
0
==========================================
and
==========================================
PID COMMAND %CPU TIME RPRVT RSHRD RSIZE VSIZE
1671 python 0.0% 0:05.06 158M 13.3M 169M 359M
1671 python 0.0% 0:05.06 158M 13.3M 169M 359M
1671 python 0.0% 0:05.06 158M 13.3M 169M 359M
1671 python 78.1% 0:06.07 420M+ 13.3M 431M+ 743M+
1671 python 21.5% 0:06.37 521M+ 13.3M 532M+ 743M
1671 python 18.6% 0:06.65 286M- 13.3M 297M- 487M-
1671 python 0.0% 0:06.65 286M 13.3M 297M 487M
1671 python 0.0% 0:06.65 286M 13.3M 297M 487M
1671 python 0.0% 0:06.65 286M 13.3M 297M 487M
==========================================
Justin
--
Justin C. Walker, Curmudgeon-At-Large
Institute for the Absorption of Federal Funds
--------
Some people have a mental horizon of radius zero, and
call it their point of view.
-- David Hilbert
--------
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