[Numpy-discussion] Vectorizing a class method

Wojciech Śmigaj puddleglum@o2...
Wed Feb 14 12:27:31 CST 2007


Timothy Hochberg wrote:
> On 2/14/07, *Wojciech Śmigaj* <puddleglum@o2.pl 
> <mailto:puddleglum@o2.pl>> wrote:
>>     I have a question about the vectorize function. I'd like to use it to
>>     create a vectorized version of a class method. I've tried the following
>>     code:
>> 
>>        from numpy import *
>> 
>>        class X:
>>            def func(self, n):
>>                return 2 * n  # example
>>            func = vectorize(func)
>> 
>> [...]

> I think you want staticmethod. Something like:
> 
> class X:
>    def f(x):
>        return 2*x
>    f = staticmethod(vectorize(x))
> 
> However, I don't have a Python distribution available here to check 
> that. If that doesn't work, as search on staticmethod should get you to 
> the correct syntax.
> 
> I'll just note in passing that if your function is composed of 
> completely of things that will operate on arrays as is (as your example 
> is), then vectorizing the function is counter productive. However, your 
> real code may well need vectorize to work.

Thank you for your answer. I see now that my example was oversimplified. 
In reality, the method func() accesses internal data of the object, so 
it cannot be made a staticmethod. In addition, it does not operate on 
the array as a whole: basically, it does calculations according to some 
formula if n != 0, and to another one otherwise. Perhaps both parts 
could be merged in some intelligent way, but right now I want to make 
the program work, and optimization will be done later. And vectorize is 
a very nice and quick way of making functions accept arrays, even if it 
is not super-efficient.

Best regards,
Wojciech Smigaj



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