Newbie : innerproduct function from Numarray

[Ohkyu Yoon]

Wow! Thank you all.
My program runs super fast now.
The biggest problem was changing lists into arrays.
By starting with arrays, the program runs almost infinitely faster.

Ohkyu


"Ohkyu Yoon" <okyoon at stanford.edu> wrote in message
news:bv40rm$ra$1 at news.Stanford.EDU...
> I have two vectors that have about 2000 elements.
> I need to calculate the innerproducts of those vectors 2000 times where
> one of them cycles left(ie 1234, then 2341, then 3412, etc)
> Basically, I want to calculate A*x, where A is a left-circulant cyclic
> matrix,
> and x is a vector.
>
> I tried it two ways.
> vector1 & vector2 are lists.
>
> 1)
> from Numarray import innerproduct
> output = []
> temp = vector1 + vector1    # temp is twice the length of vector1
> for i in range(2000):
>      output.append(innerproduct(temp[i:(i+2000)],vector2)
> 2)
> output = []
> temp = vector1 + vector1
> for i in range(2000):
>     sum = 0
>     for j in range(2000):
>         sum += temp[i+j] * vector2[j]
>     output.append(sum)
>
> I thought the first method using Numarray should be faster.
> But it looks like the second method is faster.
> Am I doing anything wrong?
> Do you guys know any faster way to do this?
>
> Thank you.
>
>