Division between int-gpuarray and int scalar does not work

[untom]

Consider:

import pycuda.autoinit
from pycuda import gpuarray
x = gpuarray.to_gpu(np.arange(4))
x / 4

This will give the following exception:

error                                     Traceback (most recent call last)
<ipython-input-1-c5776fbf102a> in <module>()
      3 
      4 x = gpuarray.to_gpu(np.arange(4))
----> 5 x / 4

/usr/local/lib/python3.4/dist-packages/pycuda-2015.1.2-py3.4-linux-x86_64.egg/pycuda/gpuarray.py in __div__(self, other)
    476                 # create a new array for the result
    477                 result = self._new_like_me(_get_common_dtype(self, other))
--> 478                 return self._axpbz(1/other, 0, result)
    479 
    480     __truediv__ = __div__

/usr/local/lib/python3.4/dist-packages/pycuda-2015.1.2-py3.4-linux-x86_64.egg/pycuda/gpuarray.py in _axpbz(self, selffac, other, out, stream)
    319         func.prepared_async_call(self._grid, self._block, stream,
    320                 selffac, self.gpudata,
--> 321                 other, out.gpudata, self.mem_size)
    322 
    323         return out

/usr/local/lib/python3.4/dist-packages/pycuda-2015.1.2-py3.4-linux-x86_64.egg/pycuda/driver.py in function_prepared_async_call(func, grid, block, stream, *args, **kwargs)
    506 
    507         from pycuda._pvt_struct import pack
--> 508         arg_buf = pack(func.arg_format, *args)
    509 
    510         for texref in func.texrefs:

error: required argument is not an integer

As far as I understand, the problem is the following: within __div__, it is assumed that the output has the same dtype as the input, but this is not the case when dividing an integer array by a scalar. This could be fixed easily by making sure that division always returns a floating point type.

As a sidenote, a related problem is that // (the 'integer division' from Py3) is not yet implemented in gpuarray. As far as I can see, the "turn the division into a multiplication" does not work for that operator, so maybe the division-mechanism should be entirely switched to something other than axpbz.

[inducer]

I'd be happy to take a (tested) patch of either issue, but I don't have the time to work on this myself.