Merge pull request #368 from JohT/fix/skip-p-values-when-not-enough-samples

Fix missing pairwise changed dependencies

Author: JohT

Diff for: cypher/GitLog/List_pairwise_changed_files_with_dependencies.cypher

@@ -2,7 +2,8 @@
 
 MATCH (firstCodeFile:File)-[dependency:DEPENDS_ON]->(secondCodeFile:File)
 MATCH (firstCodeFile)-[pairwiseChange:CHANGED_TOGETHER_WITH]-(secondCodeFile)
-WHERE elementId(firstCodeFile) < elementId(secondCodeFile)
+//De-duplicating the pairs of files isn't necessary, because the dependency relation is directed.
+//WHERE elementId(firstCodeFile) < elementId(secondCodeFile)
  WITH  firstCodeFile.fileName      AS firstFileName
       ,secondCodeFile.fileName     AS secondFileName
       ,coalesce(dependency.weight, dependency.cardinality)    AS dependencyWeight

Diff for: jupyter/GitHistoryGeneral.ipynb

@@ -1338,15 +1338,26 @@
     "display(pairwise_changed_git_files_with_dependencies.corr(method='pearson'))\n",
     "\n",
     "display(\"Pairwise changed git files compared to dependency weights - Spearman Correlation\")\n",
-    "display(pairwise_changed_git_files_with_dependencies.corr(method='spearman'))\n",
-    "\n",
-    "from scipy.stats import pearsonr, spearmanr\n",
+    "display(pairwise_changed_git_files_with_dependencies.corr(method='spearman'))"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "5a4ae651",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "if pairwise_changed_git_files_with_dependencies.shape[0] < 5:\n",
+    "    print(\"Less than 5 samples are not enough to calculate p-values\")\n",
+    "else:\n",
+    "    from scipy.stats import pearsonr, spearmanr\n",
     "\n",
-    "display(\"Pearson Correlation with p-value for commitCount and dependencyWeight\")\n",
-    "display(pearsonr(pairwise_changed_git_files_with_dependencies['commitCount'], pairwise_changed_git_files_with_dependencies['dependencyWeight']))\n",
+    "    display(\"Pearson Correlation with p-value for commitCount and dependencyWeight\")\n",
+    "    display(pearsonr(pairwise_changed_git_files_with_dependencies['commitCount'], pairwise_changed_git_files_with_dependencies['dependencyWeight']))\n",
     "\n",
-    "display(\"Spearman Correlation with p-value for commitCount and dependencyWeight\")\n",
-    "display(spearmanr(pairwise_changed_git_files_with_dependencies['commitCount'], pairwise_changed_git_files_with_dependencies['dependencyWeight']))"
+    "    display(\"Spearman Correlation with p-value for commitCount and dependencyWeight\")\n",
+    "    display(spearmanr(pairwise_changed_git_files_with_dependencies['commitCount'], pairwise_changed_git_files_with_dependencies['dependencyWeight']))"
    ]
   },
   {