ifft(fft(x) returns very small imaginary parts when x is real?

[address@hidden]

I have a problem with Octave:

x = dlmread('fin');
y = transpose(x);
z = fft(y);
w = ifft(z);
dlmwrite('fout',w,' ');

fin is real, but fout is complex with all data have very small imaginary
parts.  This seems to be a known bug:
https://savannah.gnu.org/bugs/?45932

Matlab does not have this problem with this same code.  However, while I can
create a script to run fine as a batch job in Octave, I cannot do this in
Matlab?  For example, the first line in an Octave script is
#!/opt/octave/bin/octave -qf
but I have not been able to find the Matlab counterpart.  For example,
#!/opt/matlab/2018a/bin/matlab
just puts me into Matlab instead of running the script.  I have tried
various flags that might be like Octave's "-qf" without success?




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