"Mike" <SulfateIon@gmail.com> wrote in message news:firstname.lastname@example.org... > Hi, dpb > > thank you for your info. > To be more clear, I simply my question with follows: > 1) I create a fortran file with following: > > program main > integer:: i > open(10,file='inputpar.dat',status='old') > read(10,*) i > write(30,*) i > write(*,*) 'fortran main :', i > end > > I compile it within the project and have Console2.exe in > 'D:\temp\Console2\Console2\Debug'. > > 2) in matlab, I have following: > fid2=fopen('test.dat','a'); % this file should be run parallel' > matlabpool open local 3 > parfor i=1:100
The workers have no idea that fid2 is a file identifier; they didn't open the file so they don't have access to it.
> fid1=fopen('inputpar.dat','w'); % be read by Console2.exe > fprintf(fid1,'%2d\n',i); > fclose(fid1); > dos('Console2.exe<inputpar.dat'); > out=importdata('fort.30') > fprintf(fid2,'%2d\n',out); > end > matlabpool close > s=load('test.dat') > > Then I run this cell (step 2), I have the results: > Starting matlabpool using the 'local' configuration ... connected to 3 > labs. > fortran main : 64 > fortran main : 64 > fortran main : 64 > ??? Error using ==> parallel_function at 598 > Error in ==> parallel_function>make_general_channel/channel_general at 894 > Invalid file identifier. Use fopen to generate a valid file identifier.
Note that the iterations of a PARFOR loop are NOT repeat NOT guaranteed to be executed in any particular order. Therefore if you were to do this, at best your output would be in arbitrary order in the file; at worst each worker may "scribble" over the results another worker wrote to the file at the same time.
I would either assemble all your data in a _variable_ rather than a file inside the PARFOR loop [different workers can write to different elements of a variable simultaneously without a problem] or have each worker write its output to a separate file and combine them all together _after_ the PARFOR loop is finished.