[Numpy-discussion] python numpy code many times slower than c++

[Neal Becker]

Robert Kern wrote:

> 2009/1/20 Neal Becker <ndbecker2 at gmail.com>:
>> I tried a little experiment, implementing some code in numpy (usually I
>> build modules in c++ to interface to python).  Since these operations are
>> all large vectors, I hoped it would be reasonably efficient.
>>
>> The code in question is simple.  It is a model of an amplifier, modeled
>> by it's AM/AM and AM/PM characteristics.
>>
>> The function in question is the __call__ operator.  The test program
>> plots a spectrum, calling this operator 1024 times each time with a
>> vector of 4096.
> 
> If you want to find out what lines in that function are taking the
> most time, you can try my line_profiler module:
> 
> http://www.enthought.com/~rkern/cgi-bin/hgwebdir.cgi/line_profiler/
> 
> That might give us a better idea in the absence of a self-contained
> example.
> 
Sounds interesting, I'll give that a try.  But, not sure how to use it.

If my main script is plot_spectrum.py, and I want to profile the 
ampl.__call__ function (defined in ampl.py), what do I need to do?  I tried 
running kernprof.py plot_spectrum.py having added @profile decorators in 
ampl.py, but that didn't work:
  File "../mod/ampl.py", line 43, in ampl
    @profile
NameError: name 'profile' is not defined