Re: Particle Swarm Optimization

anton@[EMAIL PROTECTED]
 (Anton Ertl) writes Re: Particle Swarm
Optimization
> mhx@[EMAIL PROTECTED]
 (Marcel Hendrix) writes:
>> Triggered by a (German) C't article, last week I experimented a bit 
>> with Particle Swarm Optimization.
> ...
>> Unfortunately, I found the results quite unconvincing. 
[..]
> Yes.  Maybe I missed something, but the particle swarm stuff seems to
> be similar to ant algorithms to me; and that fails to convince me, too
> (but maybe I miss the point of that, too): We know the best path yet
> after the first ant walks it, no need to simulate multiple ants
> walking the same path.  Such algorithms may have a place if you have
> massive parallelism, and very limited communication bandwidth compared
> to computation, but not in settings that most of us use.

Well, ant algorithms can solve 'discrete' problems (without 
derivatives) which is useful. AFAIK, particle swarms can't 
handle such discrete problems, and are very bad at accurately 
finding derivatives. Apparently the algorithm is so deeply 
buried in C++ that even C't editors can't find it. Or maybe
they were only looking at the graphics :-)

>> STRUCT
>>   dfloat% FIELD .myBestResult
[..]
>> END-STRUCT node%        

> Nice to see that you picked up my STRUCT syntax (although it's too
> late for Forth200x).

I'd rather keep on using it. Would the following be close enough 
for Forth 200x? I think the word +FIELD can be combined with 
Gforth's structures? (An obvious problem would be that a Gforth
structure has an aligned size and would produce wrong results 
when creating structures of structures.)

( @[EMAIL PROTECTED]
 HEAD> @[EMAIL PROTECTED]
 >BODY  finds the body address of the last word 
  defined ).

-- ANS 200x 
: +FIELD ( align1 offset1 size "name" -- align2 offset2 ) 1 SWAP FIELD ;
: BEGIN-STRUCTURE ( "name" -- addr 1 0 ) 0 VALUE  @[EMAIL PROTECTED]
 HEAD> @[EMAIL PROTECTED]
 >BODY 1
0 ;
: END-STRUCTURE   ( addr align size -- ) NIP SWAP ! ;
: CFIELD:  char%   FIELD ; 
: FIELD:   cell%   FIELD ; 
: FFIELD:  float%  FIELD ;
: SFFIELD: dfloat% FIELD ;
: DFFIELD: sfloat% FIELD ;

-marcel