[PPL-devel] [Fink-devel] ppl-0.10.2 check thorough test fail

[David Fang]

> Il 29/03/2011 02:39, David Fang ha scritto:
>> Hello,
>>     With ppl-0.10.2, several Mac OS X fink users (including myself) have
>> observed the following single test failure on 10.5 and 10.6, using
>> Apple's gcc-4.2, arch i686-apple-darwin{9,10}, with thorough tests enabled:
>>
>> /usr/bin/grep -E "^Optimum value: " ../../../demos/ppl_lpsol/expected_mpz
>>> expected_optima && /usr/bin/grep -E "^Optimum value: " obtained
>>> obtained_optima && diff -u expected_optima obtained_optima
>> --- expected_optima     2011-03-22 21:05:58.000000000 -0400
>> +++ obtained_optima     2011-03-22 21:05:58.000000000 -0400
>> @@ -1,9 +1,10 @@
>> -Optimum value: -3
>> -Optimum value: 2
>> +Optimum value: -2
>> +Optimum value: 1
>
> I agree with Roberto that all of the symptoms suggest that Apple gcc-4.2
> is miscompiling something (and we would really appreciate if someone can
> try out using a newer gcc).
>
> The first differences above are related to a very simple MIP problem
> test. Can you please provide us with the output of the following command:
>
> $ cd <PATH_TO_PPL_BUILD>/demos/ppl_lpsol
> $ ./ppl_lpsol -s -p1 -v 4 -c -M
> <PATH_TO_PPL_SRC>/demos/ppl_lpsol/examples/ex1.mps
>
> This will also show the problem as read from the input, which should be
> something like:
> =============
> Integer variables:
> x1 x2
> Constraints:
> -2*x1 - x2 >= -5
> 4*x1 - 4*x2 >= -5
> x1 >= 0
> x2 >= 0
> Objective function:
> x1 - 2*x2
> Maximizing.
> =============

Hi,
 	On 10.6/i686, apple-gcc-4.2, gmp-5.0.1, I get:

fang at fangbook 4> ./ppl_lpsol -s -p1 -v 4 -c -M ../../../demos/ppl_lpsol/examples/ex1.mps
Integer variables:
x1 x2
Constraints:
-2*x1 - x2 >= -5
4*x1 - 4*x2 >= -5
x1 >= 0
-x1 >= -1
x2 >= 0
-x2 >= -1
Objective function:
x1 - 2*x2
Maximizing.
Optimum value: 1
Optimum location:
x1 = 1
x2 = 0

Different indeed!  Does this indicate an earlier parse error?

Fang

> We would like to be sure that we are not stumbling on (a miscompilation
> causing) an input-parsing bug well before entering the optimization code.
>
> Also note that the same command above can be used (in this specific case
> only!) as a quick replacement for the lengthy 'make check' for those
> building the ppl with a newer gcc. If the bug is still there, you will
> obtain something different wrt the following:
> =============
> Optimum value: 2
> Optimum location:
> x1 = 2
> x2 = 0
> =============
>
> Thanks,
> Enea.
>
>
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David Fang
http://www.csl.cornell.edu/~fang/
http://www.achronix.com/