why scipy cause my program slow?

[HYRY]

Thanks, by your hint, I change type(data) to type(data[0]), and I get
<type 'float'>
<type 'numpy.float64'>
So, calculate with float is about 5x faster numpy.float64.

Robert Kern wrote:
> HYRY wrote:
> > Why the exec time of test(readdata()) and test(randomdata()) of
> > following program is different?
> > my test file 150Hz10dB.wav has 2586024 samples, so I set randomdata
> > function
> > to return a list with 2586024 samples.
> > the exec result is:
> > 2586024
> > <type 'list'>
> > 10.8603842736
> > 2586024
> > <type 'list'>
> > 2.16525233979
> > test(randomdata()) is 5x faster than test(readdata())
> > if I remove "from scipy import *" then I get the following result:
> > 2586024
> > <type 'list'>
> > 2.21851601473
> > 2586024
> > <type 'list'>
> > 2.13885042216
> >
> > So, what the problem with scipy?
>
> You're importing (through scipy) numpy's sum() function. The result type of that
> function is a numpy scalar type. The set of scalar types was introduced for a
> number of reasons, mostly having to do with being able to represent the full
> range of numerical datatypes that Python does not have builtin types for.
> Unfortunately, the code paths that get executed when arithmetic is performed
> sith such scalars are still suboptimal; I believe they are still going through
> the full ufunc machinery.
>
> --
> Robert Kern
>
> "I have come to believe that the whole world is an enigma, a harmless enigma
>  that is made terrible by our own mad attempt to interpret it as though it had
>  an underlying truth."
>   -- Umberto Eco