[MacPorts] #69108: gfortran-mp-13: gfortran-compiled binary randomly gives right or wrong outcome

[MacPorts]

#69108: gfortran-mp-13: gfortran-compiled binary randomly gives right or wrong
outcome
-----------------------+--------------------
 Reporter:  tpcklaver  |      Owner:  (none)
     Type:  defect     |     Status:  new
 Priority:  Normal     |  Milestone:
Component:  ports      |    Version:  2.8.1
 Keywords:             |       Port:  gcc13
-----------------------+--------------------
 I have a piece of f90 research code that I've compiled on an M2 Pro Apple
 Silicon Macbook, running macOS Sonoma 14.2.1, Xcode 15.2. I've compiled it
 with gfortran-mp-13, part of gcc-13, which was installed with MacPorts
 2.8.1.
 About half the time the binary produces the right outcome (checked against
 the same code compiled with gfortran on an Intel Macbook), about half the
 time it produces a wrong outcome (but always the same wrong outcome, it's
 wrong but not random noise). This random alternating happens when running
 the same calculation with the same input in the same working directory
 with the same binary like 10 times in a row.
 As it works fine with a gfortran-compiled binary on an Intel Macbook, I
 wonder if the gfortran portion of gcc-13 on Apple Silicon has a problem.
 Then again, I also tried with gfortran from Homebrew on my Apple Silicon
 Macbook, and there I had the exact same problem, sometimes the binary
 gives the right outcome, sometimes the wrong outcome. I guess this may
 indicate a more generral problem in gfortran on Apple Silicon, not
 necessarily the MacPort port of it?
 I attach an archive to this ticket that contains the f90 source code
 (Aneto, a code to determine elastic interaction energy between periodic
 defect images), two input files (OUTCAR, input_elast) for a test case, and
 the binary I compiled. The calculation is run by simply running the binary
 from a directory containing the two input files. If the calculation goes
 right, the outcome contains a line
 Delta E  =  1.65765823     eV
 If it goes wrong, the outcome contains a line
 Delta E  = 0.137904249     eV
 If anyone can make sence of this, please let me know.

-- 
Ticket URL: <https://trac.macports.org/ticket/69108>
MacPorts <https://www.macports.org/>
Ports system for macOS