On 1/27/2009 12:37 PM, Sturla Molden wrote:
> import ctypes
> import numpy
>
> fftw_malloc = ctypes.cdll.fftw.fftw_malloc
> fftw_malloc.argtypes = [ctypes.c_ulong,]
> fftw_malloc.restype = ctypes.c_ulong
>
> def aligned_array(N, dtype):
> d = dtype()
> address = fftw_malloc(N * d.nbytes) # restype = ctypes.c_ulong
> if (address = 0): raise MemoryError, 'fftw_malloc returned NULL'
> class Dummy(object): pass
> d = Dummy()
> d.__array_interface__ = {
> 'data' = (address, False),
> 'typestr' : dtype.str,
> 'descr' : dtype.descr,
> 'shape' : shape,
> 'strides' : strides,
> 'version' : 3
> }
> return numpy.asarray(d)
Or if you just want to use numpy, aligning to a 16 byte boundary
can be done like this:
def aligned_array(N, dtype):
d = dtype()
tmp = numpy.array(N * d.nbytes + 16, dtype=numpy.uint8)
address = tmp.__array_interface__['data'][0]
offset = (16 - address % 16) % 16
return tmp[offset:offset+N].view(dtype=dtype)
S.M.
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