[Numpy-discussion] meshgrid dtype casting

[j***@gmail.com]

I'm trying to build a meshgrid with small nonnegative integers

default is int32

np.meshgrid([0,1,2], [0,1])[0].dtype

dtype('int32')

If I use uint, then the arrays are upcast to int64 - Why?

np.meshgrid(np.array([0,1,2], np.uint), np.array([0,1],

np.uint))[0].dtype
dtype('int64')


broadcast_arrays preserves dtype

np.broadcast_arrays(np.array([0,1,2], np.uint)[:,None], np.array([0,1],

np.uint)[None, :])
[array([[0, 0],
[1, 1],
[2, 2]], dtype=uint32), array([[0, 1],
[0, 1],
[0, 1]], dtype=uint32)]



with uint8

np.broadcast_arrays(np.array([0,1,2], np.uint8)[:,None],

np.array([0,1], np.uint8)[None, :])
[array([[0, 0],
[1, 1],
[2, 2]], dtype=uint8), array([[0, 1],
[0, 1],
[0, 1]], dtype=uint8)]

np.meshgrid(np.array([0,1,2], np.uint8), np.array([0,1],

np.uint8))[0].dtype
dtype('int32')
Winpython 64 bit

np.__version__

'1.9.2rc1'

Josef