[Pyrex] Numeric and Pyrex

[len-l at telus.net]

On 19 Sep 2005 at 15:45, Nitin Madnani wrote:

> Thanks so much Lenard !! That was dumb of me.
> 
> However, I still can't figure out how to do the actual-fill in of the  
> Numeric array. The example included with Pyrex shows how to read from  
> a given array and now how to fill in one. I just figured that it's  
> probably done in a similar way but it doesn't seem to be working.  
> Probably another dumb error:
> 
> import Numeric
> 
> cdef extern from "/nfshomes/nmadnani/local/include/python2.4/Numeric/ 
> arrayobject.h":
> 
>      struct PyArray_Descr:
>          int type_num, elsize
>          char type
> 
>      ctypedef class Numeric.ArrayType [object PyArrayObject]:
>          cdef char *data
>          cdef int nd
>          cdef int *dimensions, *strides
>          cdef object base
>          cdef PyArray_Descr *descr
>          cdef int flags
> 
> def test():
>      cdef int i,j, index
>      cdef float *elems
>      cdef ArrayType m
> 
>      m = Numeric.ones((3, 3), Numeric.Float)
>      elems = <float *>m.data
>      elems[1] = 3.0
> 
>      return m
> 
> After compilation and usage in a test python file, this returns the  
> following array:
> [[ 32.   1.   1.]
> [  1.   1.   1.]
> [  1.   1.   1.]]
> 
> Therefore, I guess this is not the way to fill in the array.
> Thanks in advance !

The Numeric.Float is a C double, like the Python float.

>>> import Numeric
>>> Numeric.Float
'd'

Lenard Lindstrom
<len-l at telus.net>