From: Arnaud Giersch <arnaud.giersch@iut-bm.univ-fcomte.fr>
Date: Mon, 24 Jan 2011 17:04:05 +0000 (+0100)
Subject: Define class statistics for computing sum, mean, and standard deviation.
X-Git-Tag: v0.1~188^2~18
X-Git-Url: https://bilbo.iut-bm.univ-fcomte.fr/and/gitweb/loba.git/commitdiff_plain/825abbb3bde6c35ab1d1cdfba25fba4be5dcea2f?ds=inline;hp=-c

Define class statistics for computing sum, mean, and standard deviation.
---

825abbb3bde6c35ab1d1cdfba25fba4be5dcea2f
diff --git a/Makefile b/Makefile
index 2760531..2b0df87 100644
--- a/Makefile
+++ b/Makefile
@@ -38,6 +38,7 @@ SRC.loba := main.cpp		\
 	neighbor.cpp		\
 	options.cpp		\
 	process.cpp		\
+	statistics.cpp		\
 	version.cpp
 
 SRC.simple_async := simple_async.cpp
diff --git a/main.cpp b/main.cpp
index 5da797a..3a47b92 100644
--- a/main.cpp
+++ b/main.cpp
@@ -1,11 +1,6 @@
-#include <algorithm>
-#include <cmath>
 #include <cstring>
-#include <tr1/functional>
 #include <iostream>
-#include <numeric>
 #include <stdexcept>
-#include <vector>
 #include <msg/msg.h>
 #include <xbt/log.h>
 
@@ -24,6 +19,7 @@ XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(main);
 #include "misc.h"
 #include "options.h"
 #include "process.h"
+#include "statistics.h"
 #include "timer.h"
 #include "tracing.h"
 #include "version.h"
@@ -38,14 +34,9 @@ namespace {
         EXIT_FAILURE_CLEAN = 0x08,  // error at cleanup
     };
 
-    std::vector<double> comps;
-    double comp_total;
-    double comp_avg;
-    double comp_stddev;
+    struct statistics comps;
+    struct statistics loads;
 
-    std::vector<double> loads;
-    double load_avg;
-    double load_stddev;
 }
 
 static int simulation_main(int argc, char* argv[])
@@ -55,8 +46,8 @@ static int simulation_main(int argc, char* argv[])
     try {
         proc = opt::loba_algorithms.new_instance(opt::loba_algo, argc, argv);
         result = proc->run();
-        comps.push_back(proc->get_comp());
-        loads.push_back(proc->get_load());
+        comps.push(proc->get_comp());
+        loads.push(proc->get_load());
         delete proc;
     }
     catch (std::invalid_argument& e) {
@@ -94,38 +85,10 @@ static void check_for_lost_load()
                total_running, running_ratio);
 }
 
-static void statistics(const std::vector<double>& vec,
-                       double* sum, double* avg, double* stddev)
-{
-    using std::tr1::bind;
-    using std::tr1::placeholders::_1;
-
-    unsigned n = vec.size();
-    double vec_sum = std::accumulate(vec.begin(), vec.end(), 0.0);
-    double vec_avg = vec_sum / n;
-
-    if (sum)
-        *sum = vec_sum;
-    if (avg)
-        *avg = vec_avg;
-
-    if (stddev) {
-        std::vector<double> diff(vec);
-        std::transform(diff.begin(), diff.end(), diff.begin(),
-                       bind(std::minus<double>(), _1, vec_avg));
-        double epsilon = std::accumulate(diff.begin(), diff.end(), 0.0);
-        double square_sum = std::inner_product(diff.begin(), diff.end(),
-                                               diff.begin(), 0.0);
-        double variance = (square_sum - (epsilon * epsilon) / n) / n;
-        *stddev = sqrt(variance);
-    }
-}
-
-static void compute_metrics()
-{
-    statistics(comps, &comp_total, &comp_avg, &comp_stddev);
-    statistics(loads, NULL, &load_avg, &load_stddev);
-}
+#define PR_STATS(descr, st)                                             \
+    INFO5("| %.*s: %g / %g / %g", 39,                                   \
+          descr " total/avg./stddev. at exit.........................", \
+          st.get_sum(), st.get_avg(), st.get_stddev())
 
 int main(int argc, char* argv[])
 {
@@ -235,12 +198,9 @@ int main(int argc, char* argv[])
     if (simulated_time >= 0.0) {
         simulation_time.stop();
         check_for_lost_load();
-        compute_metrics();
         INFO0(",----[ Results ]");
-        INFO2("| Load avg./stddev. at exit..............: %g / %g",
-              load_avg, load_stddev);
-        INFO3("| Computation total/avg./stddev. at exit.: %g / %g / %g",
-              comp_total, comp_avg, comp_stddev);
+        PR_STATS("Load", loads);
+        PR_STATS("Computation", comps);
         INFO1("| Total simulated time...................: %g", simulated_time);
         INFO1("| Total simulation time..................: %g",
               simulation_time.duration());
diff --git a/statistics.cpp b/statistics.cpp
new file mode 100644
index 0000000..77f415f
--- /dev/null
+++ b/statistics.cpp
@@ -0,0 +1,75 @@
+#include <algorithm>
+#include <cmath>
+#include <tr1/functional>
+#include <numeric>
+
+#include "statistics.h"
+
+statistics::statistics()
+    : up2date(false)
+{
+}
+
+void statistics::reset()
+{
+    values.clear();
+    up2date = false;
+}
+
+void statistics::push(double val)
+{
+    values.push_back(val);
+    up2date = false;
+}
+
+size_t statistics::get_count()
+{
+    return values.size();
+}
+
+double statistics::get_sum()
+{
+    update();
+    return sum;
+}
+
+double statistics::get_avg()
+{
+    update();
+    return avg;
+}
+
+double statistics::get_stddev()
+{
+    update();
+    return stddev;
+}
+
+void statistics::update()
+{
+    if (up2date)
+        return;
+
+    if (values.empty()) {
+        sum = 0.0;
+        avg = stddev = 0.0 / 0.0;
+    }
+
+    using std::tr1::bind;
+    using std::tr1::placeholders::_1;
+
+    unsigned n = values.size();
+    sum = std::accumulate(values.begin(), values.end(), 0.0);
+    avg = sum / n;
+
+    std::vector<double> diff(values);
+    std::transform(diff.begin(), diff.end(), diff.begin(),
+                   bind(std::minus<double>(), _1, avg));
+    double epsilon = std::accumulate(diff.begin(), diff.end(), 0.0);
+    double square_sum = std::inner_product(diff.begin(), diff.end(),
+                                           diff.begin(), 0.0);
+    double variance = (square_sum - (epsilon * epsilon) / n) / n;
+    stddev = sqrt(variance);
+
+    up2date = true;
+}
diff --git a/statistics.h b/statistics.h
new file mode 100644
index 0000000..2978747
--- /dev/null
+++ b/statistics.h
@@ -0,0 +1,33 @@
+#ifndef STATISTICS_H
+#define STATISTICS_H
+
+#include <vector>
+
+class statistics {
+public:
+    statistics();
+
+    void reset();
+    void push(double value);
+
+    size_t get_count();
+    double get_sum();
+    double get_avg();
+    double get_stddev();
+
+private:
+    bool up2date;
+
+    std::vector<double> values;
+    double sum;
+    double avg;
+    double stddev;
+
+    void update();
+};
+
+#endif // !STATISTICS_H
+
+// Local variables:
+// mode: c++
+// End: