[SciPy-User] writing data to binary for fortran

[Neil Martinsen-Burrell]

On 2010-05-12 14:58, Gideon wrote:
> Tried both, but I got the same error in both cases.

If you want doubles in your file, you have to request them:

F.writeReals(x, prec='d')

makes everything work for me (Ubuntu 10.04, python 2.6.5, gfortran 
4.4.3).  Note that looking at the size of the file that you would expect 
to have for the data you are expecting to read would have demonstrated 
this: 10 doubles at eight bytes per double plus two 4-byte integers 
would have given you 88 bytes for the file, rather than the 48 that were 
being produced.

I use fortranfile most heavily for reading files, rather than writing 
them, so I may have missed this opportunity, but do you think that the 
precision used in writeReals should be auto-detected from the data type 
that it is passed.  That is, would

def writeReals(self, reals, prec=None):
     if prec is None:
         prec = reals.dtype.char
     ...

be better for your use?  That would have made your original code work as 
written.

-Neil