fopen and fprintf do not work within parfor or smpd running on grid
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Hello everyone,
I met a problem to use fopen and fprintf within parfor or smpd when I run my codes on grid. Here are my codes:
spmd
fid = fopen(sprintf( 'worker_%d.csv', labindex ),'w');
fprintf(fid,'%s\r\n',vector1);
fclose(fid);
...
end
OR
parfor i=1:100
t = getCurrentTask();
fid = fopen(sprintf( 'worker_%d.csv', t.ID ),'w');
fprintf(fid,'%s\r\n',vector1);
fclose(fid);
...
end
Neither one would work, and both of them will generated the similar error messages:
spmd:
??? Error using ==> spmd_feval at 8
Error detected on lab(s) 2 15 16
Error in ==> BruteForce2>(spmd) at 103
spmd
Error in ==> BruteForce2 at 103
spmd
Caused by:
Invalid file identifier. Use fopen to generate a valid file identifier.
Error stack:
BruteForce2>(spmd body) at 105
Invalid file identifier. Use fopen to generate a valid file identifier.
Error stack:
BruteForce2>(spmd body) at 105
Invalid file identifier. Use fopen to generate a valid file identifier.
Error stack:
BruteForce2>(spmd body) at 105
PARFOR:
??? Error using ==> parallel_function at 598
Error in ==> BruteForce2>(parfor body) at 146
Invalid file identifier. Use fopen to generate a valid file identifier.
Error in ==> BruteForce2 at 105
parfor i = 1:g
The problem is my fopen, fid returns -1. The codes are running ok with local workers. So would it be some writing permission issues? I would like to know what the problem is, and where our admin should change on his side. Could anyone give me any suggestion? Thanks a lot!
Rui
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采纳的回答
Walter Roberson
2013-5-3
fname = sprintf( 'worker_%d.csv', t.ID );
[fid, message] = fopen(fname, 'w');
if fid < 0;
fprintf(2, 'failed to open "%s" because "%s"\n', fname, message);
%and here, get out gracefully
end
9 个评论
Walter Roberson
2013-5-6
Are all the fopen() failing, or only some of them? Try something like,
fname = sprintf( 'worker_%d.csv', t.ID );
fprintf(2, 'About to open "%s"\n', fname);
[fid, message] = fopen(fname, 'w');
if fid < 0;
fprintf(2, 'failed to open "%s" because "%s"\n', fname, message);
%and here, get out gracefully
else
fprintf(2, 'Success opening "%s"\n', fname);
fprintf(fid,'%s\r\n',vector1);
fclose(fid);
fprintf(2,, 'Closed file "%s"\n', fname);
end
更多回答(2 个)
Jason Ross
2013-5-6
It's possible that the workers are running under a different user name than yours. You haven't provided the specifics of the operating systems and what schedulers you are using, but you can get this information using
spmd
system('whoami')
end
And then make sure that username also has access to the directories where you want to open the files.
Jan
2013-5-4
- Do you have write permissions to the current directory?
- Is the file open already from a former crashing call? See fopen all.
- Is the file opened from another application?
Using absolute filenames is an important strategy especially for parallel processing and multi-threading. Checking the success of FOPEN is a good programming practize also.
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