[gnugo-devel] questions regarding cosmic option in gnugo 3.4

[Harry Wang]

I didn't find much explanation on the cosmic option in the documentation.
So I have some questions.

gnugo 3.4 do not use cosmic as default, in order to enable it, I need to
set --enable-cosmic-gnugo at ./configure, correct?

I noticed cosmic was a default in previous version of gnugo, why is it not
a default in 3.4?

most importantly, I am puzzled by the variable cosmic_importance in
engine/influence.c file.

#if COSMIC_GNUGO

  float t;

  /* Initialisation of some global positional values, based on
   * game stage.
   */
    if ((board_size != 19) || (movenum <= 2) || ((movenum / 2) % 2)   )
      cosmic_importance = 0.0;
    else {
      cosmic_importance = 1.0 - (movenum / 120.0)*(movenum / 120.0);
      cosmic_importance = gg_max(0.0, cosmic_importance);
    }

the part about conjunction of
((movenum / 2) % 2)

this part assigns zero to cosmic_importance intermittently. This is very
strange to me. Is there a reason why cosmic_importance gets used in such
strange manner?

#0:cosmic_importance = 0
#1:cosmic_importance = 0
#2:cosmic_importance = 0
#3:cosmic_importance = 0
#4:cosmic_importance = parabolic
#5:cosmic_importance = parabolic
#6:cosmic_importance = 0
#7:cosmic_importance = 0
#8:cosmic_importance = parabolic
#9:cosmic_importance = parabolic
#10:cosmic_importance = 0
#11:cosmic_importance = 0
#12:cosmic_importance = parabolic
#13:cosmic_importance = parabolic
#14:cosmic_importance = 0
#15:cosmic_importance = 0
#16:cosmic_importance = parabolic
#17:cosmic_importance = parabolic
#18:cosmic_importance = 0
#19:cosmic_importance = 0
#20:cosmic_importance = parabolic
#21:cosmic_importance = parabolic
#22:cosmic_importance = 0
#23:cosmic_importance = 0
#24:cosmic_importance = parabolic
#25:cosmic_importance = parabolic
#26:cosmic_importance = 0
#27:cosmic_importance = 0


Harry Wang
-----------------------------------
Department of Computer Science
University of California Santa Cruz
Email: address@hidden
-----------------------------------
"Unix is user-friendly. It's just very selective about who its friends are."
-source unknown.