[Numpy-discussion] example reading binary Fortran file

[David Froger]

>
> You're half wrong.  FortranFile can read arrays written as above, but it
> sees them as a single real array.  So, with the attached Fortran program::
>
> In [1]: from fortranfile import FortranFile
>
> In [2]: f = FortranFile('uxuyp.bin', endian='<') # Original bug was
> incorrect byte order
>
> In [3]: u = f.readReals()
>
> In [4]: u.shape
> Out[4]: (20,)
>
> In [5]: u
> Out[5]:
> array([ 101.,  111.,  102.,  112.,  103.,  113.,  104.,  114.,  105.,
>        115.,  201.,  211.,  202.,  212.,  203.,  213.,  204.,  214.,
>        205.,  215.], dtype=float32)
>
> In [6]: ux = u[:10].reshape(2,5); uy = u[10:].reshape(2,5)
>
> In [7]: p = f.readReals().reshape(2,5)
>
> In [8]: ux, uy, p
> Out[8]:
> (array([[ 101.,  111.,  102.,  112.,  103.],
>       [ 113.,  104.,  114.,  105.,  115.]], dtype=float32),
>  array([[ 201.,  211.,  202.,  212.,  203.],
>       [ 213.,  204.,  214.,  205.,  215.]], dtype=float32),
>  array([[ 301.,  311.,  302.,  312.,  303.],
>       [ 313.,  304.,  314.,  305.,  315.]], dtype=float32))


ok! That's exactlly what I was looking for, thank you.

Awesome!  The thoughts banging around in my head right now are that some
> sort of mini-language that encapsulates the content of the declarations and
> the write statements should allow one to tease out exactly which struct call
> will unpack the right information.  f2py has some fortran parsing
> capabilities, so you might be able to use the fortran itself as the
> mini-language.  Something like
>
> spec = fortranfile.OutputSpecification(\
> """real(4),dimension(2,5):: ux,uy
> write(11) ux,uy""")
> ux, uy = fortranfile.FortranFile('uxuyp.bin').readSpec(spec)
>

whouhou, I'm really enthusiastic, I love this solution!!! I begin to code
it... I'll give news around 1 june, (somethings to finish before).

One more time, thanks for this help!

best,

David
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