Re: [Help-glpk] csv_driver:unable to create ....csv - Permission denied

[Heinrich Schuchardt]

Hello Martin,

please, check that the CSV file is not opened by an other program.

Excel locks opened files.

Same happens if Java opens a file for writing. The lock is kept until the file 
is closed.

Best regards

Heinrich Schuchardt

http://www.xypron.de

Am 06.01.15 um 11:53 schrieb Martin Albrecht

> Dear all,
> 
> 
> 
> I am running a GLPK model that is sequentially started from a frame 
> 
> program in Java.
> 
> The frame program does the following:
> 
> -It creates data files (.csv) that are read in by the GLPK model thereafter
> 
> -The call of the GLPK model is according to the help documentation:
> 
> 
> 
> /public void start() {
> 
> 
> 
>              glp_prob lp = null;
> 
>              glp_tran tran;
> 
>              glp_iocp iocp;
> 
> 
> 
>              int skip = 0;
> 
>              int ret;
> 
> 
> 
>             // GlpkCallback.addListener(this);
> 
> 
> 
>              lp = GLPK.glp_create_prob();
> 
>              System.out.println("Problem created");
> 
> 
> 
>              tran = GLPK.glp_mpl_alloc_wksp();
> 
>              ret = GLPK.glp_mpl_read_model(tran, fname, skip);
> 
>              if (ret != 0) {
> 
>                  GLPK.glp_mpl_free_wksp(tran);
> 
>                  GLPK.glp_delete_prob(lp);
> 
>                  throw new RuntimeException("Model file not found: " + 
> 
> fname);
> 
>              }
> 
> 
> 
>              // generate model
> 
>              GLPK.glp_mpl_generate(tran, null);
> 
>              // build model
> 
>              GLPK.glp_mpl_build_prob(tran, lp);
> 
>              // set solver parameters
> 
>              iocp = new glp_iocp();
> 
>              GLPK.glp_init_iocp(iocp);
> 
>              iocp.setPresolve(GLPKConstants.GLP_ON);
> 
>              // solve model
> 
>              ret = GLPK.glp_intopt(lp, iocp);
> 
>              // postsolve model
> 
>              if (ret == 0) {
> 
>                  GLPK.glp_mpl_postsolve(tran, lp, GLPKConstants.GLP_MIP);
> 
>              }
> 
>              // free memory
> 
>              GLPK.glp_mpl_free_wksp(tran);
> 
>              GLPK.glp_delete_prob(lp);
> 
> 
> 
>       }
> 
> }/
> 
> 
> 
> The GKLP model writes some output tables (csv.), and the results are 
> 
> read in again by Java after terminating the optimization run, and so on.
> 
> 
> 
> Unfortunately,  I get sometime error when opening the .csv files.
> 
> Here is an example:
> 
> /
> 
> csv_driver: unable to open BOM.csv - Permission denied
> 
> allocation.mod:113: error on opening table tab_BOM
> 
> glp_mpl_build_prob: invalid call sequence
> 
> Error detected in file ..\src\glpapi14.c at line 93/
> 
> 
> 
> I do not get this error at each call of the Java model (one error after 
> 
> approx. 50 calls). Moreover, these errors do not occur in a 
> 
> deterministic manner, they cannot be reproduced. I each run of the Java 
> 
> program they occur at another place.
> 
> 
> 
> Do you have any advice what I could do about that?
> 
> 
> 
> Many thanks for your effort.
> 
> 
> 
> Best regards
> 
> Martin
> 
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> 
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> 
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