Problems using Fortran Binary Files as inputs

[ingwag]

Hi,

I was trying to use aronnax for some eddy simulations and wanted to use fortran binary files similar to how you do it in mitgcm.
However, I can't get it to work.
I am generating the fields in python and then save them as binary files.
When I try to save the files with the numpy .astype('>f8').tofile('fname') the aronnax driver returns with the error:

FortranFormattingError: End of file in the middle of a record

I also tried to write my own write function that adheres to the fortran binary format.

def write_binary(fname,array):
    ''' writes an unformatted binary fortran file one row at a time'''
    with open(fname,'wb') as f:
        for j in range(array.shape[1]):
            row_data = array[:,j].tobytes()
            record_size = len(row_data)
            f.write(struct.pack("i", record_size))
            f.write(row_data)  # Write the actual data
            f.write(struct.pack("i", record_size))

With this aronnax.driver doesn't complain anymore. But now the fortran routines crash.

At line 226 of file src/io.f90 (unit = 10, file = 'input/init_h_file.bin')
Fortran runtime error: I/O past end of record on unformatted file


Error termination. Backtrace:
#0  0x7f10eafabe59 in ???

[aronnax_minimal.zip](https://github.com/user-attachments/files/18942139/aronnax_minimal.zip)

#1  0x7f10eafaca71 in ???
#2  0x7f10eafad6dc in ???
#3  0x7f10eb248149 in ???
#4  0x7f10eb24308b in ???
#5  0x55abc304f6ec in __io_MOD_read_input_fileh
        at src/io.f90:226
#6  0x55abc3062169 in aronnax
        at src/aronnax.f90:241
#7  0x55abc303b29e in main
        at src/aronnax.f90:35

I am assuming something about how I write the fortran files is wrong. But then again this method .astype('>f8').tofile('fname') has worked for me in mitgcm.

I have attached a python script to generate the data (gendata_minimal.py), my aronnax.conf and the script to run the model (run_minimal.py).
aronnax_minimal.zip

Best regards,
Ingo

PS: I am running the latest aronnax master on ubuntu 24.04 with an intel i7-1365U CPU. Drivers and libraries should all be up to date.