From a4f65bd13fe6889cd73b5d06ad7ced1bc86144ed Mon Sep 17 00:00:00 2001
From: Arkadiusz Kondas <arkadiusz.kondas@gmail.com>
Date: Mon, 12 Dec 2016 18:34:20 +0100
Subject: [PATCH] Short syntax for applied operations

---
 src/Phpml/FeatureExtraction/TfIdfTransformer.php     | 4 +---
 src/Phpml/FeatureExtraction/TokenCountVectorizer.php | 2 --
 src/Phpml/Math/Statistic/Correlation.php             | 6 +++---
 src/Phpml/Metric/Accuracy.php                        | 2 +-
 src/Phpml/Preprocessing/Normalizer.php               | 4 ++--
 5 files changed, 7 insertions(+), 11 deletions(-)

diff --git a/src/Phpml/FeatureExtraction/TfIdfTransformer.php b/src/Phpml/FeatureExtraction/TfIdfTransformer.php
index da1f25f..9335775 100644
--- a/src/Phpml/FeatureExtraction/TfIdfTransformer.php
+++ b/src/Phpml/FeatureExtraction/TfIdfTransformer.php
@@ -43,15 +43,13 @@ class TfIdfTransformer implements Transformer
     {
         foreach ($samples as &$sample) {
             foreach ($sample as $index => &$feature) {
-                $feature = $feature * $this->idf[$index];
+                $feature *= $this->idf[$index];
             }
         }
     }
 
     /**
      * @param array $samples
-     *
-     * @return array
      */
     private function countTokensFrequency(array $samples)
     {
diff --git a/src/Phpml/FeatureExtraction/TokenCountVectorizer.php b/src/Phpml/FeatureExtraction/TokenCountVectorizer.php
index 226cb55..f5fab21 100644
--- a/src/Phpml/FeatureExtraction/TokenCountVectorizer.php
+++ b/src/Phpml/FeatureExtraction/TokenCountVectorizer.php
@@ -173,8 +173,6 @@ class TokenCountVectorizer implements Transformer
 
     /**
      * @param array $samples
-     *
-     * @return array
      */
     private function checkDocumentFrequency(array &$samples)
     {
diff --git a/src/Phpml/Math/Statistic/Correlation.php b/src/Phpml/Math/Statistic/Correlation.php
index cc1767c..0f60223 100644
--- a/src/Phpml/Math/Statistic/Correlation.php
+++ b/src/Phpml/Math/Statistic/Correlation.php
@@ -33,9 +33,9 @@ class Correlation
         for ($i = 0; $i < $count; ++$i) {
             $a = $x[$i] - $meanX;
             $b = $y[$i] - $meanY;
-            $axb = $axb + ($a * $b);
-            $a2 = $a2 + pow($a, 2);
-            $b2 = $b2 + pow($b, 2);
+            $axb += ($a * $b);
+            $a2 += pow($a, 2);
+            $b2 += pow($b, 2);
         }
 
         $corr = $axb / sqrt((float) ($a2 * $b2));
diff --git a/src/Phpml/Metric/Accuracy.php b/src/Phpml/Metric/Accuracy.php
index 0e9dc03..3dfcb34 100644
--- a/src/Phpml/Metric/Accuracy.php
+++ b/src/Phpml/Metric/Accuracy.php
@@ -31,7 +31,7 @@ class Accuracy
         }
 
         if ($normalize) {
-            $score = $score / count($actualLabels);
+            $score /= count($actualLabels);
         }
 
         return $score;
diff --git a/src/Phpml/Preprocessing/Normalizer.php b/src/Phpml/Preprocessing/Normalizer.php
index 22ba555..5cff6e8 100644
--- a/src/Phpml/Preprocessing/Normalizer.php
+++ b/src/Phpml/Preprocessing/Normalizer.php
@@ -64,7 +64,7 @@ class Normalizer implements Preprocessor
             $sample = array_fill(0, $count, 1.0 / $count);
         } else {
             foreach ($sample as &$feature) {
-                $feature = $feature / $norm1;
+                $feature /= $norm1;
             }
         }
     }
@@ -84,7 +84,7 @@ class Normalizer implements Preprocessor
             $sample = array_fill(0, count($sample), 1);
         } else {
             foreach ($sample as &$feature) {
-                $feature = $feature / $norm2;
+                $feature /= $norm2;
             }
         }
     }