Thanks for the reply. On 11/17/10 7:00 PM, Pauli Virtanen wrote:

Wed, 17 Nov 2010 08:40:50 +0100, Laurent Gautier wrote: [clip]

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__main__:1: RuntimeWarning: Item size computed from the PEP 3118 buffer format string does not match the actual item size. [clip] I tried tracing a bit further but I am a little confused by what is the intent (a lot of nested calls). Numpy is warning you that the view that you passed to it is inconsistent, and it indicates that it refuses to consider it as a PEP 3118 buffer. If you use it on Python 2.x, it probably falls back to using the legacy buffer interface which does not care about the format string.

That would be the __array_struct__ attribute, I suppose.

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my buffer format is 'f', and the view has itemsize set as: view->itemsize = sizeof(double);

Any pointer regarding what might be going on ? Seehttp://docs.python.org/library/struct.html#format-strings

The format 'f' means 32-bit float, so the view itemsize should be sizeof(float) and not sizeof(double). If your view really contains floats in sizeof(double) bytes, the buffer format string probably should indicate the padding.

It seems that I have been mislead by some documentation (which I cannot find again). I had something that 'f' indicated a "Python float", which I understand to be represented by a double at C-level. Laurent

-- Pauli Virtanen