not not use -DUSE_POW_LOOKUP, actually faster to just use pow()

Author: stivalaa

src/common.mk

@@ -39,6 +39,9 @@ CFLAGS     = $(OPTFLAGS) $(WARNFLAGS)
 # Use the Random123 library
 CPPFLAGS =  -DUSE_RANDOM123 -IRandom123-1.09/include
 
+## Use lookup table for pow()
+#CPPFLAGS += -DUSE_POW_LOOKUP
+
 # Using the uthash hash table 
 # See https://troydhanson.github.io/uthash/userguide.html
 # and https://github.com/troydhanson/uthash

src/utils.h

@@ -94,7 +94,7 @@ extern "C" {
 /* Integer power y of double x, may be faster than pow(x, y). x set in
    init_powtable(). Note CANNOT compile with -ffast-math on gcc as we
    depend on IEEE handling of NaN in changeStatisticsDirected.c */
-#define POWTABLE_SIZE 1000 /* number of entries in POW_TABLE */
+#define POWTABLE_SIZE 10000 /* number of entries in POW_TABLE */
 #define POW_LOOKUP(x, y) ((y) < POWTABLE_SIZE ? POWTABLE[(y)] : pow((x), (y)))
 #else
 #define POW_LOOKUP(x, y) (pow((x), (y)))