Small tweak to block size

Author: noelchalmers

include/ogs/ogsOperator.hpp

@@ -120,7 +120,7 @@ class ogsOperator_t {
 
   //NC: Hard code these for now. Should be sufficient for GPU devices, but needs attention for CPU
   static constexpr int blockSize = 256;
-  static constexpr int gatherNodesPerBlock = 1024; //should be a multiple of blockSize for good unrolling
+  static constexpr int gatherNodesPerBlock = 512; //should be a multiple of blockSize for good unrolling
 
   //4 types - Float, Double, Int32, Int64
   //4 ops - Add, Mul, Max, Min