Use lowply-history also on low depths

pb00067 · vondele · commit 15e190e9428b · 2020-06-06T16:18:42.000+02:00
STC: https://tests.stockfishchess.org/tests/view/5ed75078f29b40b0fc95a8b9 LLR: 2.93 (-2.94,2.94) {-0.50,1.50} Total: 73928 W: 14301 L: 14005 D: 45622 Ptnml(0-2): 1243, 8572, 17096, 8752, 1301 LTC: https://tests.stockfishchess.org/tests/view/5ed895e0f29b40b0fc95a976 LLR: 2.93 (-2.94,2.94) {0.25,1.75} Total: 154848 W: 19684 L: 19074 D: 116090 Ptnml(0-2): 1048, 14108, 46627, 14468, 1173 closes #2718 bench: 4582693
diff --git a/src/movepick.cpp b/src/movepick.cpp
@@ -110,7 +110,7 @@ void MovePicker::score() {
                    + 2 * (*continuationHistory[1])[pos.moved_piece(m)][to_sq(m)]
                    + 2 * (*continuationHistory[3])[pos.moved_piece(m)][to_sq(m)]
                    +     (*continuationHistory[5])[pos.moved_piece(m)][to_sq(m)]
-                   + (ply < MAX_LPH ?  4 * (*lowPlyHistory)[ply][from_to(m)] : 0);
+                   + (ply < MAX_LPH ? std::min(4, depth / 3) * (*lowPlyHistory)[ply][from_to(m)] : 0);
 
       else // Type == EVASIONS
       {
diff --git a/src/search.cpp b/src/search.cpp
@@ -971,7 +971,7 @@ namespace {
                                       contHist,
                                       countermove,
                                       ss->killers,
-                                      depth > 12 ? ss->ply : MAX_PLY);
+                                      ss->ply);
 
     value = bestValue;
     singularQuietLMR = moveCountPruning = false;

Original file line number	Diff line number	Diff line change
`@@ -110,7 +110,7 @@ void MovePicker::score() {`
`110`	`110`	`+ 2 * (*continuationHistory[1])[pos.moved_piece(m)][to_sq(m)]`
`111`	`111`	`+ 2 * (*continuationHistory[3])[pos.moved_piece(m)][to_sq(m)]`
`112`	`112`	`+ (*continuationHistory[5])[pos.moved_piece(m)][to_sq(m)]`
`113`		`- + (ply < MAX_LPH ? 4 * (*lowPlyHistory)[ply][from_to(m)] : 0);`
	`113`	`+ + (ply < MAX_LPH ? std::min(4, depth / 3) * (*lowPlyHistory)[ply][from_to(m)] : 0);`
`114`	`114`
`115`	`115`	`else // Type == EVASIONS`
`116`	`116`	`{`