On Mon, Aug 8, 2011 at 10:54 AM, Olivier Delalleau <shish@keba.be> wrote:

Hi,

This is with numpy 1.6.1 under Linux x86_64, testing the upcast mechanism of "scalar + array":

>>> import numpy; print (numpy.array(3, dtype=numpy.complex128) + numpy.ones(3, dtype=numpy.float32)).dtype
complex64

Since it has to upcast my array (float32 is not "compatible enough" with complex128), why does it upcast it to complex64 instead of complex128?
As far as I can tell 1.4.x and 1.5.x versions of numpy are indeed upcasting to complex128.

The 0 dimensional array is being treated as a scalar, hence is cast to the type of the 1d array. This seems more consistent with the idea that 0 dimensional arrays act like scalars, but I suppose that is open to discussion.

Chuck