playing with MITgcm input files

read+write_input_mitgcm.py

#!/usr/bin/env python

import numpy as np
import sys

# playing with input files from tutorial_global_oce_latlon
filein = 'lev_t.bin'

# MITgcm likes its binary in big endian, float ('>f') or double ('>d')
raw = np.fromfile(filein, dtype='>f')
# Temp has 12 time records, 15 vertical levels, 40 in lat, 90 in lon
temp = np.reshape(raw, (12,15,40,90))

# for lev_sst.bin and bathymetry.bin, I would do :

#sst = np.reshape(raw, (12,40,90))
#bathy = np.reshape(data, (40,90))

# the numpy.tofile don't let you have control on the
# precision (float/double) so I don't recommend.
# intstead use:

def write_to_binary(data, fileout, precision='single'):
    ''' write variable from np.array to fileout with precision '''
    # write data to binary files
    fid   = open(fileout, "wb")
    flatdata = data.flatten()
    if precision == 'single':
        if sys.byteorder == 'little':
            tmp = flatdata.astype(np.dtype('f')).byteswap(True).tobytes()
        else:
            tmp = flatdata.astype(np.dtype('f')).tobytes()
    elif precision == 'double':
        if sys.byteorder == 'little':
            tmp = flatdata.astype(np.dtype('d')).byteswap(True).tobytes()
        else:
            tmp = flatdata.astype(np.dtype('d')).tobytes()
    fid.write(tmp)
    fid.close()
    return None