Use minimumSplitDepth = 5

Using minimumSplitDepth = 5 seems to be the best compromise in the
current SMP implementation

STC, 11 threads:

ELO: 14.87 +-4.1 (95%) LOS: 100.0%
Total: 8509 W: 1497 L: 1133 D: 5879

STC, 4 threads:

ELO: 0.30 +-2.8 (95%) LOS: 58.2%
Total: 20000 W: 3365 L: 3348 D: 13287

STC, 2 threads:

ELO: -1.02 +-2.0 (95%) LOS: 16.4%
Total: 40000 W: 7087 L: 7204 D: 25709

Resolves #324

diff --git a/src/thread.cpp b/src/thread.cpp
index 2fd3c7aa9e37fbfc24b579ddd2f89d33dbb6d983..c73f55660330545d300857b2874287fd54b21563 100644 (file)
--- a/src/thread.cpp
+++ b/src/thread.cpp
@@ -323,7 +323,7 @@ void ThreadPool::read_uci_options() {
 
   // If zero (default) then set best minimum split depth automatically
   if (!minimumSplitDepth)
 
   // If zero (default) then set best minimum split depth automatically
   if (!minimumSplitDepth)

-      minimumSplitDepth = requested < 8 ? 4 * ONE_PLY : 7 * ONE_PLY;
+      minimumSplitDepth =  5 * ONE_PLY ;

 
   while (size() < requested)
       push_back(new_thread<Thread>());
 
   while (size() < requested)
       push_back(new_thread<Thread>());