[Freeciv-Dev] Re: directional system: more magic code cleanups

[Raimar Falke <hawk@xxxxxxxxxxxxxxxxxxxxxxx>]

On Fri, Sep 21, 2001 at 10:56:52PM -0400, Ross W. Wetmore wrote:
> At 09:11 AM 01/09/21 +0200, Raimar Falke wrote:
> >On Thu, Sep 20, 2001 at 08:29:12PM -0400, Ross W. Wetmore wrote:
> >> But at least this is an O(0) solution instead of the fully fledged
> >> O(n) one you started with.
> >> 
> >> We are getting there! even if by process of elimination :-)
> >
> >If you make a benchmark of Jason's scalar product method (float and
> >sqrt), my scalar product method (int), my int tan(pi/8) method and
> >your bit method AND check that each method returns the same value I
> >will consider this. If you (or somebody) else will do this I will
> >apply my int scalar product method tomorrow.
> 
> So your default choice is to go with the obviously worst implementation
> over fairly minor modifications to the previous CVS code if someone else
> doesn't prove that your method and a lot of other unrelated noise are
> better?

I found the time to run the proposed algorithms.

Here is a profile:
Flat profile:

Each sample counts as 0.01 seconds.
  %   cumulative   self              self     total           
 time   seconds   seconds    calls  us/call  us/call  name    
 26.83      5.98     5.98  3260000     1.83     1.83  
jason_straightest_direction
 11.44      8.53     2.55  3260000     0.78     0.78  
raimar_straightest_direction
  9.24     10.59     2.06                             normalize_map_pos
  4.62     11.62     1.03                             is_real_tile
  3.99     12.51     0.89  3260000     0.27     0.27  
raimar2_straightest_direction
  3.81     13.36     0.85     1643   517.35   656.31  really_generate_warmap
  2.69     13.96     0.60  3260000     0.18     3.25  straightest_direction
  2.65     14.55     0.59                             tech_exists
  1.97     14.99     0.44                             map_get_tile
  1.66     15.36     0.37                             map_get_terrain
  1.44     15.68     0.32                             get_invention
  1.35     15.98     0.30  3260000     0.09     0.09  ross_straightest_direction
  1.21     16.25     0.27  3260000     0.08     0.08  orig_straightest_direction

The attached patch was used. 

Ross your version is buggy. Remove the comment in

+  if ( /*jason != orig || */ /*jason != ross || */jason != raimar
+      || jason != raimar2) {

to show the problem cases.

The current version of Ross is buggy and unreadable. Jason, Ross do
you find raimar2_straightest_direction acceptable?

Does anybody else want to comment?

        Raimar

-- 
 email: rf13@xxxxxxxxxxxxxxxxx
  +#if defined(__alpha__) && defined(CONFIG_PCI)
  +       /*
  +        * The meaning of life, the universe, and everything. Plus
  +        * this makes the year come out right.
  +        */
  +       year -= 42;
  +#endif
    -- Patch for 1.3.2 (kernel/time.c) from Marcus Meissner

straightest_direction.diff
Description: Text document