Added sum reduction. NOTE: Scalar sum does not pass the automated test but vector sum does. I couldn't see anything wrong with the code itself and I strongly suspect that the failures are caused by loss of precision due to summing a huge amount of numbers of different magnitudes. However I'm not yet completely sure. Something like the Kahan summation algorithm might be useful if the errors are really caused by fp arithmetic.

include/astaroth_defines.h

@@ -77,7 +77,14 @@ typedef struct {
 
 typedef enum { AC_SUCCESS = 0, AC_FAILURE = 1 } AcResult;
 
-typedef enum { RTYPE_MAX, RTYPE_MIN, RTYPE_RMS, RTYPE_RMS_EXP, NUM_REDUCTION_TYPES } ReductionType;
+typedef enum {
+    RTYPE_MAX,
+    RTYPE_MIN,
+    RTYPE_RMS,
+    RTYPE_RMS_EXP,
+    RTYPE_SUM,
+    NUM_REDUCTION_TYPES
+} ReductionType;
 
 typedef enum {
     STREAM_DEFAULT,