compiled matlab script where incorrect variables are passing

Hello,

I compiled a matlab script and am submitting it as a job in bash:

#!/bin/bash
# Generates and submits one SLURM job per slice, using the compiled
# TSE_multispinecho_EPG executable + MATLAB Runtime.

# ------------- USER‑ADJUSTABLE PARAMETERS --------------------------
PROJECT_DIR="/path/to/dir"
PROJECT_NAME="project"
SLICE=1

SUBJECT_CODE='subj1'


EXEC="$PROJECT_NAME/bin/TSE_multispinecho_EPG"   # compiled executable
# -------------------------------------------------------------------

    cat > "$JOB" <<EOF
#!/bin/bash

echo "  slice       : ${SLICE}"

"${EXEC}" "${PROJECT_DIR}" "${PROJECT_NAME}" "${SUBJECT_CODE}" "${SLICE}"
EOF
    # ---- submit -----
    sbatch "$JOB"
  done
  

and then the beginning of the matlab functions looks like:

  function TSE_multispinecho_EPG(project_directory, project_name, subject_code, slice);

%% TSE multi spin echo EPG

fprintf('slice within function: %d\n', slice);

and the slice number should be 1. When I run the bash command, I get '1', but when it gets the matlab part of the script I am getting '49'.

I cleared the cache, I made sure there weren't any extra slice variables causing renaming issues.

I can run the non-compiled command just fine, and then slice 1 will be printed correctly:

matlab -nodisplay -nosplash -r "TSE_multispinecho_EPG("/projectdir", "projectname", "subj01", "1")"

Any help would be much appreciated,

Thanks.

Answer 1

[Star Strider]

The '49' is the ASCII code for '1' --

Q = double('1')

Q = 49

Mystery solved!

You may need to change parts of your code, or perhaps use the str2double function --

N = str2double('1')

N = 1

It all depends on what you want to do, and the result you want.

EDIT -- (8 Jul 2025 at 19:26)

The problem may be here:

slice = '1';
fprintf('slice within function: %d\n', slice)

slice within function: 49

so one option could be --

fprintf('slice within function: %s\n', slice);

slice within function: 1

.

[Steven Lord]

Alternately, you could specify that you want all numeric inputs to the application to be numeric doubles, as stated in the second bullet point in the Handle Input Arguments in MATLAB section on this documentation page.

[nines]

thank you so much! you're the best!!

[Star Strider]

As always, my pleasure!

I very much appreciate your compliment!

Answer 2

[Walter Roberson]

Note that

double('1')

ans = 49

so somehow you are getting a quoted 1 instead of a numeric 1.

I would suggest trying

matlab -nodisplay -nosplash -r "TSE_multispinecho_EPG("/projectdir", "projectname", "subj01", 1)"

[Walter Roberson]

Ah, I did not notice that the executable was compiled. Compiled executables always receive their parameters as strings, never as actual numeric values.