[Numpy-discussion] Do ufuncs returned by frompyfunc() have the out arg?
Ken Basye
kbasye1 at jhu.edu
Tue Apr 6 15:42:41 EDT 2010
Folks,
I hope this is a simple question. When I created a ufunc with
np.frompyfunc(), I got an error when I called the result with an 'out'
argument:
>>> def foo(x): return x * x + 1
>>> ufoo = np.frompyfunc(foo, 1, 1)
>>> arr = np.arange(9).reshape(3,3)
>>> ufoo(arr, out=arr)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: 'out' is an invalid keyword to foo (vectorized)
But I notice that if I just put the array there as a second argument, it
seems to work:
>>> ufoo(arr, arr)
array([[2, 5, 26],
[101, 290, 677],
[1370, 2501, 4226]], dtype=object)
# and now arr is the same as the return value
Is it reasonable to conclude that there is an out-arg in the resulting
ufunc and I just don't know the right name for it? I also tried putting
some other right-shaped array as a second argument and it did indeed get
filled in.
Thanks as always,
Ken
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