From 3b2f42dbf37413391af5f448f6cef7d43642d232 Mon Sep 17 00:00:00 2001
From: Petr Baudis <pasky@ucw.cz>
Date: Sat, 2 Jan 2010 02:18:52 +0100
Subject: [PATCH] probdist_add(), probdist_mul(): Phase out in favor of
 probdist_set()

---
 playout/elo.c |  8 +++++---
 probdist.h    | 22 +++++++---------------
 2 files changed, 12 insertions(+), 18 deletions(-)

diff --git a/playout/elo.c b/playout/elo.c
index 59908ff..f8bdc31 100644
--- a/playout/elo.c
+++ b/playout/elo.c
@@ -84,14 +84,14 @@ elo_get_probdist(struct playout_policy *p, struct patternset *ps, struct board *
 
 		moves++;
 		/* Each valid move starts with gamma 1. */
-		probdist_add(pd, f, 1.f);
+		float g = 1.f;
 
 		/* Some easy features: */
 		/* XXX: We just disable them for now since we call the
 		 * pattern matcher; you need the gammas file. */
 #if 0
 		if (is_bad_selfatari(b, to_play, m.coord))
-			probdist_mul(pd, f, pp->selfatari);
+			g *= pp->selfatari;
 #endif
 
 		/* Match pattern features: */
@@ -102,8 +102,10 @@ elo_get_probdist(struct playout_policy *p, struct patternset *ps, struct board *
 			float gamma = feature_gamma(ps->fg, &p.f[i], NULL);
 			//char buf[256] = ""; feature2str(buf, &p.f[i]);
 			//fprintf(stderr, "<%d> %s feat %s gamma %f\n", f, coord2sstr(m.coord, b), buf, gamma);
-			probdist_mul(pd, f, gamma);
+			g *= gamma;
 		}
+
+		probdist_set(pd, f, g);
 		//fprintf(stderr, "<%d> %s %f\n", f, coord2sstr(m.coord, b), pd->items[m.coord]);
 	}
 
diff --git a/probdist.h b/probdist.h
index d28459c..91b6af7 100644
--- a/probdist.h
+++ b/probdist.h
@@ -3,6 +3,10 @@
 
 /* Tools for picking an item according to a probability distribution. */
 
+/* The probability distribution structure is designed to be once
+ * initialized, then each item sequentially assigned a value one,
+ * then multiple times an item picked randomly. */
+
 #include "move.h"
 
 struct probdist {
@@ -12,8 +16,7 @@ struct probdist {
 };
 
 struct probdist *probdist_init(struct probdist *pd, int n);
-static void probdist_add(struct probdist *pd, int i, float val);
-static void probdist_mul(struct probdist *pd, int i, float val);
+static void probdist_set(struct probdist *pd, int i, float val);
 int probdist_pick(struct probdist *pd);
 void probdist_done(struct probdist *pd); // Doesn't free pd itself
 
@@ -23,25 +26,14 @@ void probdist_done(struct probdist *pd); // Doesn't free pd itself
  * functions otherwise. */
 
 static inline void
-probdist_add(struct probdist *pd, int i, float val)
+probdist_set(struct probdist *pd, int i, float val)
 {
 #if 0
 	assert(i >= 0 && i < pd->n);
 	assert(val >= 0);
 #endif
-	pd->items[i] += val;
+	pd->items[i] = val;
 	pd->total += val;
 }
 
-static inline void
-probdist_mul(struct probdist *pd, int i, float val)
-{
-#if 0
-	assert(i >= 0 && i < pd->n);
-	assert(val >= 0);
-#endif
-	pd->total += (val - 1) * pd->items[i];
-	pd->items[i] *= val;
-}
-
 #endif
-- 
2.11.4.GIT