MS_SAVE - Write a set of elastic constants from a file.

MS_save( fname, C, rho, ... )

Usage:
    MS_save(fname, C, rho)
         Write the elastic constants, C, and density, rho, to file
         'fname'. C must be provided in GPa and rho must be provided in
         kg/m3. See file format below.

MS_save(fname, C, rho, ..., 'format',fmt)
    Specify format for file. See below for descriptions. Available
    options are:
       'simple' : Formatted text file (default)
       'ematrix' : Format read by EMATRIX (D. Mainprice).

MS_save(fname, C, rho, ..., 'eunit',unit)
    Specify elasticity unit; this is used to convert from GPa (msat's
    default operating unit)
       'GPa' - elastic constants are written in GPa (default)
       'Mbar' - elastic constants are written in Mbar
       'Pa' - elastic constants are written in Pascals
       'bar' - elastic constants are written in bar
    Note: when using a density normalised tensor, specify the unit
    *before* normalisation (i.e., a unit of pressure).

MS_save(fname, C, rho, ..., 'dunit',unit)
    Specify density unit; this is used to convert from kg/m3 (msat's
    default operating unit)
       'kgm3' - density is written in kg/m3 (default)
       'gcc' - density is written g/cc

MS_save(fname, C, rho, ..., 'Aij')
    Elasticities are written in density normalised form. This option
    requires a density to be specified. The provided elastic
    constants are first converted to the unit specified by the
    'eunit' argument (if provided) and the density converted to the
    unit specified in the by the 'dunit' argument (if provided) then
    the elastic constants are divided by the density before being
    written to the file.

Supported file formats:
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