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error with changing directory in for loop

Asked by Vincent Davis on 16 Jul 2019
Latest activity Edited by Walter Roberson
on 16 Jul 2019
I'm having a problem with "cd" when looping through folders using an SSH (Putty). Here is the relevant part of my function:
for ii = 1:10
parfor i=1:size(xmat,1)
file = sprintf('res_%d',i);
x0 = xmat(i,:);
[t,Y] = hackathon_ode(x0);
myFolder = cd(['output/mat_npaths_1000/np_10000_binsz_0.01/' int2str(ii) '/']);
dlmwrite(file, [t Y], ' ')
x1 = xmat1(i,:);
[t,Y] = hackathon_ode(x1);
myFolder = cd(['output/mat_npaths_1000/np_10000_binsz_0.1/' int2str(ii) '/']);
dlmwrite(file, [t Y], ' ')
And I get this as an output:
cannot CD to
/output/mat_npaths_1000/np_10000_binsz_0.1/1/output/mat_npaths_1000/np_10000_binsz_0.1/1
(Name is nonexistent or not a directory).
This is what it should look like:
/output/mat_npaths_1000/np_10000_binsz_0.1/1
When I run this from my computer it works fine. Can anyone see what I'm missing and why it repeats the directory on Putty?

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1 Answer

Answer by Adam Danz
on 16 Jul 2019
 Accepted Answer

Do not use cd(); use fullfile() instead and then feed in the full path of the file to dlmwrite().

  1 Comment

I agree with Adam Danz's suggestion. As an explanation for what's happening: you cd into a directory but then never return to the directory you were in before the cd call. Therefore when you cd a second time, you're changing to a directory relative to where you were after your first cd.
Or to use a whimsical example: you're doing the Hokey Pokey by putting your right foot in then trying to put your right foot in again. You skipped the "put your right foot out" step inbetween.

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