Rearrange interpolation formula

Put the division at the end to reduce
rounding errors. This alters the bench
due to different rounding errors, but
should not alter ELO in any way.

bench: 7615217

diff --git a/src/evaluate.cpp b/src/evaluate.cpp
index ccc3d9154d62612daea3c68ab972e42d6afb2553..ede94ec0d7beaaeaf5d34b2d035a961fc7dde37c 100644 (file)
--- a/src/evaluate.cpp
+++ b/src/evaluate.cpp
@@ -779,9 +779,9 @@ namespace {
              sf = ScaleFactor(50 * sf / SCALE_FACTOR_NORMAL);
     }
 
-    // Interpolate between a middlegame and an endgame score, scaling by 'sf'
+    // Interpolate between a middlegame and a (scaled by 'sf') endgame score
     Value v =  mg_value(score) * int(ei.mi->game_phase())
-             + eg_value(score) * int(sf) / SCALE_FACTOR_NORMAL * int(PHASE_MIDGAME - ei.mi->game_phase());
+             + eg_value(score) * int(PHASE_MIDGAME - ei.mi->game_phase()) * sf / SCALE_FACTOR_NORMAL;
 
     v /= PHASE_MIDGAME;