Make event_correlation() work on fractional counts

Author: davisking

dlib/statistics/statistics.h

@@ -1827,20 +1827,20 @@ namespace dlib
 // ----------------------------------------------------------------------------------------
 
     inline double binomial_random_vars_are_different (
-        uint64_t k1,
-        uint64_t n1,
-        uint64_t k2,
-        uint64_t n2
+        double k1,
+        double n1,
+        double k2,
+        double n2
     )
     {
         DLIB_ASSERT(k1 <= n1, "k1: "<< k1 << "  n1: "<< n1);
         DLIB_ASSERT(k2 <= n2, "k2: "<< k2 << "  n2: "<< n2);
 
-        const double p1 = k1/(double)n1;
-        const double p2 = k2/(double)n2;
-        const double p = (k1+k2)/(double)(n1+n2);
+        const double p1 = n1 != 0 ? k1/n1 : 0;
+        const double p2 = n2 != 0 ? k2/n2 : 0;
+        const double p = (k1+k2)/(n1+n2);
 
-        auto ll = [](double p, uint64_t k, uint64_t n) {      
+        auto ll = [](double p, double k, double n) {
             if (p == 0 || p == 1)
                 return 0.0;
             return k*std::log(p) + (n-k)*std::log(1-p);
@@ -1860,10 +1860,10 @@ namespace dlib
 // ----------------------------------------------------------------------------------------
 
     inline double event_correlation (
-        uint64_t A_count,
-        uint64_t B_count,
-        uint64_t AB_count,
-        uint64_t total_num_observations
+        double A_count,
+        double B_count,
+        double AB_count,
+        double total_num_observations
     )
     {
         DLIB_ASSERT(AB_count <= A_count && A_count <= total_num_observations,

dlib/statistics/statistics_abstract.h

@@ -108,10 +108,10 @@ namespace dlib
 // ----------------------------------------------------------------------------------------
 
     double binomial_random_vars_are_different (
-        uint64_t k1,
-        uint64_t n1,
-        uint64_t k2,
-        uint64_t n2
+        double k1,
+        double n1,
+        double k2,
+        double n2
     );
     /*!
         requires
@@ -138,10 +138,10 @@ namespace dlib
 // ----------------------------------------------------------------------------------------
 
     double event_correlation (
-        uint64_t A_count,
-        uint64_t B_count,
-        uint64_t AB_count,
-        uint64_t total_num_observations
+        double A_count,
+        double B_count,
+        double AB_count,
+        double total_num_observations
     );
     /*!
         requires