Changeset eac29c7

Timestamp:

11/15/18 17:01:27 (2 years ago)

Author:

Jacob Van Walraven <jcv9@…>

Branches:

develop

Children:

f611921

Parents:

96ec511

Message:

Improve skewness calculation by using median instead of mode

File:

• examples/tutorial/ipdist-parallel.c (modified) (6 diffs)

examples/tutorial/ipdist-parallel.c

@@ -33 +33 @@
         double mean_src[4];
         double mean_dst[4];
+        double median_src[4];
+        double median_dst[4];
         double stddev_src[4];
         double stddev_dst[4];
@@ -64 +66 @@
 uint64_t tickrate;
 
-char *stats_outputdir = "/home/jcv9/output-spectre/";
+char *stats_outputdir = "";
 /* Calculate and plot the percentage change from the previous plot */
 int stats_percentage_change = 0;
@@ -159 +161 @@
                         }
                 }
+
                 tally->stats->mean_src[k] = (k + (ex / n));
                 tally->stats->variance_src[k] = ((ex2 - (ex*ex)/n) / n);
@@ -180 +183 @@
                 tally->stats->variance_dst[k] = ((ex2 - (ex*ex)/n) / n);
                 tally->stats->stddev_dst[k] = sqrt(tally->stats->variance_dst[k]);
-
+                /* Get the median */
+                int c = (n/2) - tally->src[k][0];
+                int c2 = 0;
+                while(c > 0) {
+                        c2 += 1;
+                        c -= tally->src[k][c2];
+                }
+                tally->stats->median_src[k] = c2;
+                c = (n/2) - tally->dst[k][0];
+                c2 = 0;
+                while(c > 0) {
+                        c2 += 1;
+                        c -= tally->dst[k][c2];
+                }
+                tally->stats->median_dst[k] = c2;
+                /* Get the mode which is the first item in the priority queue */
                 tally->stats->mode_src[k] = peak(&tally->stats->rank_src[k]);
                 tally->stats->mode_dst[k] = peak(&tally->stats->rank_src[k]);
-                /* Calculate skewness using pearsons mode method. This is accurate with large amounts of data */
-                tally->stats->skewness_src[k] = (tally->stats->mean_src[k] - tally->stats->mode_src[k]) / tally->stats->stddev_src[k];
-                tally->stats->skewness_dst[k] = (tally->stats->mean_dst[k] - tally->stats->mode_dst[k]) / tally->stats->stddev_dst[k];
-        }
-
-        printf("skewnesss: %f\n", tally->stats->skewness_dst[1]);
+                /* Calculate skewness */
+                tally->stats->skewness_src[k] = (tally->stats->mean_src[k] - tally->stats->median_src[k]) / tally->stats->stddev_src[k];
+                tally->stats->skewness_dst[k] = (tally->stats->mean_dst[k] - tally->stats->median_dst[k]) / tally->stats->stddev_dst[k];
+        }
 
 }
@@ -392 +408 @@
                 tally->stats->mean_src[i] = 0;
                 tally->stats->mean_dst[i] = 0;
+                tally->stats->median_src[i] = 0;
+                tally->stats->median_dst[i] = 0;
                 tally->stats->stddev_src[i] = 0;
                 tally->stats->stddev_dst[i] = 0;
@@ -452 +470 @@
         tmp = fopen(outputfile_stats, "w");
         /* append stats data to end of file */
-        fprintf(tmp, "#\tmean\tstddev\tvariance\tmode\tskewness\n");
+        fprintf(tmp, "#\tmean\tstddev\tvariance\tmedian\tmode\tskewness\n");
         for(i=0;i<4;i++) {
-                fprintf(tmp, "src%d\t%0.f\t%0.f\t%0.f\t\t%0.f\t%f\n", i+1, tally->stats->mean_src[i], tally->stats->stddev_src[i], tally->stats->variance_src[i], tally->stats->mode_src[i], tally->stats->skewness_src[i]);
-                fprintf(tmp, "dst%d\t%0.f\t%0.f\t%0.f\t\t%0.f\t%f\n", i+1, tally->stats->mean_dst[i], tally->stats->stddev_dst[i], tally->stats->variance_dst[i], tally->stats->mode_dst[i], tally->stats->skewness_dst[i]);
+                fprintf(tmp, "src%d\t%0.f\t%0.f\t%0.f\t\t%0.f\t%0.f\t%f\n", i+1, tally->stats->mean_src[i], tally->stats->stddev_src[i], tally->stats->variance_src[i], tally->stats->median_src[i], tally->stats->mode_src[i], tally->stats->skewness_src[i]);
+                fprintf(tmp, "dst%d\t%0.f\t%0.f\t%0.f\t\t%0.f\t%0.f\t%f\n", i+1, tally->stats->mean_dst[i], tally->stats->stddev_dst[i], tally->stats->variance_dst[i], tally->stats->median_src[i], tally->stats->mode_dst[i], tally->stats->skewness_dst[i]);
                 fprintf(tmp, "\n\n");
         }