Combined function changed to geometric mean as the more indicative one

README.md

@@ -38,9 +38,9 @@ Execution Options:
 $ ../xmeasures -h
 xmeasures 3.1
 
-Extrinsic measures evaluation: F1 (prob, harm and score) for overlapping
-multi-resolution clusterings with possible unequal node base and standard NMI
-for non-overlapping clustering on a single resolution.
+Extrinsic measures evaluation: F1 (probabilistic, harmonic and standard score) 
+for overlapping multi-resolution clusterings with possible unequal node base and
+standard NMI for non-overlapping clustering on a single resolution.
 
 Usage:  xmeasures [OPTIONS] clustering1 clustering2
 
@@ -113,7 +113,7 @@ F1 Options:
   -k, --kind[=ENUM]       kind of the matching policy:
                              - w  - weighted (default)
                              - u  - unweighed
-                             - c  - combined: F1(w, u)
+                             - c  - combined(w, u) using geometric mean
                                (possible values="weighted", "unweighed",
                             "combined" default=`weighted')
 

args.ggo

@@ -70,7 +70,7 @@ NOTE: F1p <= F1h <= F1s, where:
 option  "kind" k  "kind of the matching policy:
  - w  - weighted (default)
  - u  - unweighed
- - c  - combined: F1(w, u)
+ - c  - combined(w, u) using geometric mean
  "
   values ="weighted","unweighed","combined"  enum default="weighted" argoptional
   dependon="f1"

autogen/cmdline.c

@@ -42,7 +42,7 @@ const char *gengetopt_args_info_help[] = {
   "  -d, --detailed          detailed (verbose) results output  (default=off)",
   "\nF1 Options:",
   "  -f, --f1[=ENUM]         evaluate F1 of the [weighted] average of the greatest\n                            (maximal) match by F1 or partial probability.\n                            NOTE: F1p <= F1h <= F1s, where:\n                             - p (F1p)  - Harmonic mean of the [weighted]\n                            average of Partial Probabilities, the most\n                            discriminative and satisfies the largest number of\n                            the Formal Constraints (homogeneity, completeness,\n                            rag bag,  size/quantity, balance);\n                             - h (F1h)  - Harmonic mean of the [weighted]\n                            average of F1s;\n                             - s (F1s)  - Arithmetic mean (average) of the\n                            [weighted] average of F1s, Standard F1-Score, the\n                            least discriminative and satisfies the lowest\n                            number of the Formal Constraints.\n                              (possible values=\"partprob\", \"harmonic\",\n                            \"standard\" default=`partprob')",
-  "  -k, --kind[=ENUM]       kind of the matching policy:\n                             - w  - weighted (default)\n                             - u  - unweighed\n                             - c  - combined: F1(w, u)\n                               (possible values=\"weighted\", \"unweighed\",\n                            \"combined\" default=`weighted')",
+  "  -k, --kind[=ENUM]       kind of the matching policy:\n                             - w  - weighted (default)\n                             - u  - unweighed\n                             - c  - combined(w, u) using geometric mean\n                               (possible values=\"weighted\", \"unweighed\",\n                            \"combined\" default=`weighted')",
   "\nNMI Options:",
   "  -n, --nmi               evaluate NMI (Normalized Mutual Information)\n                            (default=off)",
   "  -a, --all               evaluate all NMIs using sqrt, avg and min\n                            denominators besides the max one  (default=off)",
@@ -716,7 +716,7 @@ cmdline_parser_internal (
         case 'k':	/* kind of the matching policy:
          - w  - weighted (default)
          - u  - unweighed
-         - c  - combined: F1(w, u)
+         - c  - combined(w, u) using geometric mean
          .  */
 
 

autogen/cmdline.h

@@ -76,17 +76,17 @@ struct gengetopt_args_info
   enum enum_kind kind_arg;	/**< @brief kind of the matching policy:
    - w  - weighted (default)
    - u  - unweighed
-   - c  - combined: F1(w, u)
+   - c  - combined(w, u) using geometric mean
     (default='weighted').  */
   char * kind_orig;	/**< @brief kind of the matching policy:
    - w  - weighted (default)
    - u  - unweighed
-   - c  - combined: F1(w, u)
+   - c  - combined(w, u) using geometric mean
     original value given at command line.  */
   const char *kind_help; /**< @brief kind of the matching policy:
    - w  - weighted (default)
    - u  - unweighed
-   - c  - combined: F1(w, u)
+   - c  - combined(w, u) using geometric mean
     help description.  */
   int nmi_flag;	/**< @brief evaluate NMI (Normalized Mutual Information) (default=off).  */
   const char *nmi_help; /**< @brief evaluate NMI (Normalized Mutual Information) help description.  */

include/interface.h

@@ -479,7 +479,7 @@ enum struct Match: MatchBase {
 	NONE = 0,  //!< Note initialized
 	WEIGHTED,  //!< Weighted matching by the number of members in each cluster (macro weighting)
 	UNWEIGHTED,  //!< Unweighted matching of each cluster (micro weighting)
-	COMBINED  //!< Combined weighting of macro and micro: F1(macro_weighting, micro_weighting)
+	COMBINED  //!< Combined of macro and micro weightings using geometric mean
 };
 
 //! \brief String representation of the Match
@@ -653,6 +653,13 @@ class Collection: public NodeBaseI {
 //! \return AccProb  - resulting mean
 AccProb hmean(AccProb a, AccProb b) noexcept;
 
+//! \brief Geometric mean
+//!
+//! \param a AccProb  - first item
+//! \param b AccProb  - second item
+//! \return AccProb  - resulting mean
+AccProb gmean(AccProb a, AccProb b) noexcept;
+
 //! \brief Arithmetic mean (average)
 //!
 //! \param a AccProb  - first item

include/interface.hpp

@@ -339,7 +339,9 @@ Prob Collection<Count>::f1(const CollectionT& cn1, const CollectionT& cn2, F1 ki
 		const AccProb  resw = kind != F1::STANDARD
 			? hmean(f1ga1w, f1ga2w)
 			: (f1ga1w + f1ga2w) / 2;
-		return hmean(res, resw);
+		// Note: geometric mean >= harmonic mean for [0, 1] and yields more indicative values,
+		// dropping the value not so much when (usually) the weighted match is larger
+		return gmean(res, resw);
 	}
 	return res;
 }