How do you add parameter values to filename?

Hello,

I am running a program in which an analysis is done using a set of 3 parameter values. How can save the output so that it will incorporate the values of the parameters in the filename?

For example, rep=250 num=1000 dx=20

are the initial values of the parameters.

I would like the filename to be 'rep=250-num=1000-dx=20'. And then when I go into the program next and change the parameter values at the beginning, I would like the filename to automatically change to reflect that new set of parameter values. How do I automate this?

I am using dlmwrite to save the output. Thank you so much!

Answer 1

[Star Strider]

Use sprintf to create the file name, then write to it:

file_name = sprintf('rep=%.0f-num=%.0f-dx=%.0f.txt', rep, num,dx);
fido = fopen(file_name,'wt');
    ... CODE ...
fclose(fido);

Note: This is UNTESTED CODE. It should work if your operating system allows such characters in file names.

[Guillaume]

If the numbers are integer, %d is a better format than %.0f

Answer 2

[Guillaume]

Use sprintf to build strings:

param1 = 250; param2 = 1000; param3 = 20;
filename = sprintf('rep=%d-num=%d-dx=%d.txt', param1, param2, param3);
dlmwrite(fullfile(folder, filename), somematrix);

[Duffie]

Thank you, Guillaume. That code worked perfectly!

I do have another question. If I want to have the program run 40 times, so I would have 40 versions of output from the same set of initial parameters, how could I add that version number to the filename as well?

So in the beginning, I would have for k=1:40 and then the program would run.

I would like that value of k to be in the filename also?

Thank you very much!

[Guillaume]

Do read the documentation of sprintf.

Simply add the parameter as an extra argument to sprintf and adjust the format string accordingly:

filename = sprintf('rep=%d-num=%d-dx=%d-k=%d.txt', param1, param2, param3, k);

[Duffie]

Thank you again! I really appreciate it and will explore sprintf more.