Dear Sylvain,

this is a known issue, cf.
https://lists.gnu.org/archive/html/bug-glpk/2009-05/msg00009.html

http://glpk-java.sourceforge.net/usage.html#Locales describes that you
can call method GLPK.glp_java_set_numeric_locale("C"); to set the locale
for numbers to match the expectations of GLPK.

Please, inform me if this solves your problem.

Best regards

Heinrich

On 8/6/20 11:41 PM, Andrew Makhorin wrote:
> -------- Forwarded Message --------
>
> *Date*: Thu, 6 Aug 2020 17:12:26 -0300
> *Subject*: Exportation/importation problem that seems to be related to
> decimal numbers
> *To*: [email protected] <mailto:[email protected]>
> *From*: Sylvain Fournier <[email protected]
> <mailto:sylvain%20fournier%20%[email protected]%3e>>
>> Hi,
>>
>> I'd like to be able to export a model into a (text) file in order to
>> be able to run it again later. I noticed there are three couples of
>> procedures for this:
>>
>>   * glp_write_lp / glp_read_lp
>>   * glp_write_prob / glp_read_prob
>>   * glp_write_mps / glp_read_mps
>>
>> I tried with each of them, and failed to import the model for specific
>> reasons:
>>
>>   * glp_*_lp: the exported file shows decimal numbers using a comma
>>     instead of a dot (it must be because it is the way to write
>>     decimals in Brazil). As a result, when trying to import back, I
>>     get the following message: "(line) *4: constraints section
>>     missing*". Note that if I manually replace the comma by a dot, I
>>     get another error: "*4: numeric constant '93.2807074368' out of
>>     range*".
>>   * glp_*_prob: when trying to import the file back, the program stops
>>     at the first line describing the objective coefficients (starting
>>     with 'a') with the following message: "*error: objective
>>     coefficient missing or invalid*". If I replace the ',' by a dot, I
>>     get the same message.
>>   * glp_*_mps: here it is even more strange. It seems that the
>>     exported file describes a cost function very different from the
>>     original model one (coincidentally - or not -, the only decimal
>>     numbers in this model are the variables cost coefficients). In
>>     fact, it looks like it mistook one of the constraints with the
>>     cost coefficients. I could send the original (lp) file and the
>>     generated (mps) file for a better understanding of the issue, if
>>     needed. Besides, the generated file doesn't export the rows and
>>     columns names, but instead uses names like C0000143 or R0000143,
>>     which makes the model far more difficult to understand.
>>
>> Note that I am running GLPK through the Java wrapper libglpk-java-1.12.0.
>> Am I doing something wrong? Is there some workaround to this issue?
>>  
>> *Sylvain Fournier*
>> Operations Research Manager
>> *48 3239-2428*
>> WPLEX Software Ltda.
>> Rod SC 401 no. 8600 Corporate Park bloco 5 sala 101
>> 88050-000 Santo Antônio de Lisboa, Florianópolis SC +55 48 3239-2400
>> wplex.com.br <http://wplex.com.br/>
>> WPLEX
>>
>>
>>


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