extended API: separate method for normalization

corehunter-base/src/main/java/org/corehunter/API.java

@@ -379,6 +379,54 @@ public static CoreHunterArguments createArguments(CoreHunterData data, int size,
     /* Execution */
     /* --------- */
 
+    /**
+     * Get normalization ranges of all objectives in a multi-objective configuration.
+     * Executes a preliminary random descent search per objective (in parallel) to approximate the
+     * best solution in terms of each included objective. For an objective that is being maximized,
+     * the upper bound is set to the value of the best solution for that objective, while the lower
+     * bound is set to the Pareto minimum, i.e. the minimum value obtained when evaluating all optimal
+     * solutions with the considered objective. For an objective that is being minimized, the roles
+     * of minimum and maximum are interchanged.
+     * 
+     * @param args Core Hunter arguments including data, objectives and subset size.
+     * @param mode Execution mode, one of "default" or "fast". Only affects the default
+     *             stop conditions, not the used algorithm (always random descent).
+     * @param timeLimit Absolute runtime limit in seconds.
+     *                  If set to a negative value no time limit is used.
+     * @param maxTimeWithoutImprovement Maximum time without finding an improvement, in seconds.
+     *                                  If set to a negative value, the default improvement time of
+     *                                  the chosen execution mode is used: 10 seconds in default mode,
+     *                                  2 seconds in fast mode.
+     * @return Matrix containing normalization ranges.
+     *         One row per objective, and two columns with lower and upper bound, respectively.
+     */
+    public static double[][] getNormalizationRanges(CoreHunterArguments args, String mode,
+                                                    int timeLimit, int maxTimeWithoutImprovement){
+        // interpret arguments
+        CoreHunterExecutionMode exMode = CoreHunterExecutionMode.DEFAULT;
+        if (mode.equals("fast")) {
+            exMode = CoreHunterExecutionMode.FAST;
+        }
+        // create Core Hunter executor
+        CoreHunter ch = new CoreHunter(exMode);
+        if (timeLimit > 0) {
+            ch.setTimeLimit(1000 * timeLimit); // convert to milliseconds
+        }
+        if (maxTimeWithoutImprovement > 0) {
+            ch.setMaxTimeWithoutImprovement(1000 * maxTimeWithoutImprovement); // convert to milliseconds
+        }
+        // determine ranges
+        List<Range<Double>> rangeList = ch.normalize(args);
+        // convert result
+        double[][] ranges = new double[rangeList.size()][2];
+        for(int o = 0; o < rangeList.size(); o++){
+            Range<Double> range = rangeList.get(o);
+            ranges[o][0] = range.getLower();
+            ranges[o][1] = range.getUpper();
+        }
+        return ranges;
+    }
+
     /**
      * Sample a core collection.
      * 
@@ -388,8 +436,8 @@ public static CoreHunterArguments createArguments(CoreHunterData data, int size,
      *                  If set to a negative value no time limit is used.
      * @param maxTimeWithoutImprovement Maximum time without finding an improvement, in seconds.
      *                                  If set to a negative value, the default improvement time of
-     *                                  the chosen execution mode is used: 5 seconds in default mode,
-     *                                  1 second in fast mode.
+     *                                  the chosen execution mode is used: 10 seconds in default mode,
+     *                                  2 seconds in fast mode.
      * @param silent If <code>true</code> no output is written to the console.
      * @return Indices of selected items (zero-based).
      */

corehunter-base/src/main/java/org/corehunter/listener/SimpleCoreHunterListener.java

@@ -72,7 +72,7 @@ public void newBestSolution(Search<? extends SubsetSolution> search,
                                 SubsetSolution newBestSolution,
                                 Evaluation newBestSolutionEvaluation,
                                 Validation newBestSolutionValidation) {
-        printStream.format("%sValue: %f%n", prefix, newBestSolutionEvaluation.getValue());
+        printStream.format("%sCurrent value: %f%n", prefix, newBestSolutionEvaluation.getValue());
     }
 
     @Override