First fix for angeloskath#64

Author: slava-vishnyakov

src/NlpTools/Models/Lda.php

@@ -239,8 +239,15 @@ public function getDocumentsPerTopicsProbabilities($limit_docs=-1)
          $denom = $doccnt + $this->ntopics*$this->a;
          $count_topics_docs = array();
          foreach ($this->count_docs_topics as $doc=>$topics) {
-             foreach ($topics as $t=>$c)
-                $count_topics_docs[$doc][$t]++;
+             foreach ($topics as $t=>$c) {
+                 if (!isset($count_topics_docs[$doc])) {
+                     $count_topics_docs[$doc] = array();
+                 }
+                 if (!isset($count_topics_docs[$doc][$t])) {
+                     $count_topics_docs[$doc][$t] = 0;
+                 }
+                 $count_topics_docs[$doc][$t]++;
+             }
          }
 
          foreach ($p_t_d as $topic=>&$p) {