numarray speed question

[Christopher T King]

On Wed, 4 Aug 2004, grv wrote:

> So it is supposed to be very fast to have an array of say 5 million 
> integers stored in a binary file and do
> 
> a = numarray.fromfile('filename', (2, 2, 2))
> numarray.add(a, 9, a)
> 
> but how is that faster than reading the entire file into memory and then 
> having a for loop in C:
>    (loop over range) {
>       *p++ += 9      }
> 
> or is that essentially what's going on?

That's essentially what's going on ;) The point of numarray isn't to be 
hyper-fast, but to be as fast as the equivalent C (or Fortran, or 
what-have-you) implementation.  In many cases, it's faster, because 
numarray is designed with several speed hacks in mind, but it's nothing 
you can't do (without a little work) in C.