Re: Speed up 'unique'

[Daniel J Sebald]

Jaroslav Hajek wrote:

> > Always
> > program as efficiently as possible.  Basically, Octave/Matlab isn't too much
> > of a loss over C if done efficiently, but extaneous string tests really take
> > a hit.
>
>
> Here, I think the main problem is that the strmatch function used to
> parse the options is an m-function. Although Octave's library
> m-functions bypass (by default) timestamp checks, calling an
> m-function is significantly slower than calling a built-in or dld
> function.

Yes.  One recent bottle neck I ran across is using "diff" to check for equal 
contiguous array elements.  Unique uses array indexing to achieve the same effect much 
faster.  I now use the latter approach.

Dan