Yes. This is the behavior. It was part of the original Numeric implementation. In the code generator file: numpy/core/code_generators/generate_umath.py ufuncs with a registered type of 'P' have this behavior. There is a long list of them. -Travis On Feb 2, 2012, at 12:04 AM, Warren Weckesser wrote:
Bump...
On Mon, Jan 30, 2012 at 1:17 AM, Warren Weckesser <warren.weckesser@enthought.com> wrote: In the following code, numpy.sin() calls the object's sin() function:
In [2]: class Foo(object): ...: def sin(self): ...: return "spam" ...:
In [3]: f = Foo()
In [4]: np.sin(f) Out[4]: 'spam'
Is this, in fact, guaranteed behavior for a ufunc? It does not appear to be documented.
This question came up in the discussion of SciPy pull request 138 (https://github.com/scipy/scipy/pull/138), where the idea is to add numpy unary ufunc support to SciPy's sparse arrays.
(Sorry if this email shows up twice. I sent it the first time while the Enthought servers were down, and eventually got an email back saying it had not been sent.)
Warren
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