random split implementation and tests

src/Phpml/CrossValidation/RandomSplit.php

@@ -29,13 +29,34 @@ class RandomSplit
      */
     private $testLabels = [];
 
-    public function __construct(Dataset $dataset, float $testSize = 0.3)
+    /**
+     * @param Dataset $dataset
+     * @param float $testSize
+     * @param int $seed
+     *
+     * @throws InvalidArgumentException
+     */
+    public function __construct(Dataset $dataset, float $testSize = 0.3, int $seed = null)
     {
-        if (0 > $testSize || 1 < $testSize) {
+        if (0 >= $testSize || 1 <= $testSize) {
             throw InvalidArgumentException::percentNotInRange('testSize');
         }
+        $this->seedGenerator($seed);
 
-        // TODO: implement this !
+        $samples = $dataset->getSamples();
+        $labels = $dataset->getLabels();
+        $datasetSize = count($samples);
+
+        for($i=$datasetSize; $i>0; $i--) {
+            $key = mt_rand(0, $datasetSize-1);
+            $setName = count($this->testSamples) / $datasetSize >= $testSize ? 'train' : 'test';
+
+            $this->{$setName.'Samples'}[] = $samples[$key];
+            $this->{$setName.'Labels'}[] = $labels[$key];
+
+            $samples = array_values($samples);
+            $labels = array_values($labels);
+        }
     }
 
     /**
@@ -69,4 +90,16 @@ class RandomSplit
     {
         return $this->testLabels;
     }
+
+    /**
+     * @param int|null $seed
+     */
+    private function seedGenerator(int $seed = null)
+    {
+        if (null === $seed) {
+            mt_srand();
+        } else {
+            mt_srand($seed);
+        }
+    }
 }

src/Phpml/Dataset/ArrayDataset.php

@@ -0,0 +1,46 @@
+<?php
+declare(strict_types = 1);
+
+namespace Phpml\Dataset;
+
+class ArrayDataset implements Dataset
+{
+
+    /**
+     * @var array
+     */
+    private $samples = [];
+
+    /**
+     * @var array
+     */
+    private $labels = [];
+
+    /**
+     * @param array $samples
+     * @param array $labels
+     */
+    public function __construct(array $samples, array $labels)
+    {
+        $this->samples = $samples;
+        $this->labels = $labels;
+    }
+
+
+    /**
+     * @return array
+     */
+    public function getSamples(): array
+    {
+        return $this->samples;
+    }
+
+    /**
+     * @return array
+     */
+    public function getLabels(): array
+    {
+        return $this->labels;
+    }
+    
+}

src/Phpml/Dataset/CsvDataset.php

@@ -21,7 +21,7 @@ abstract class CsvDataset implements Dataset
     /**
      * @var array
      */
-    private $lables = [];
+    private $labels = [];
 
     public function __construct()
     {
@@ -39,7 +39,7 @@ abstract class CsvDataset implements Dataset
                     continue;
                 }
                 $this->samples[] = array_slice($data, 0, 4);
-                $this->lables[] = $data[4];
+                $this->labels[] = $data[4];
             }
             fclose($handle);
         } else {
@@ -60,6 +60,6 @@ abstract class CsvDataset implements Dataset
      */
     public function getLabels(): array
     {
-        return $this->lables;
+        return $this->labels;
     }
 }

src/Phpml/Dataset/Demo/Iris.php

@@ -2,7 +2,9 @@
 
 declare (strict_types = 1);
 
-namespace Phpml\Dataset;
+namespace Phpml\Dataset\Demo;
+
+use Phpml\Dataset\CsvDataset;
 
 /**
  * Classes: 3

tests/Phpml/CrossValidation/RandomSplitTest.php

@@ -0,0 +1,95 @@
+<?php
+declare(strict_types = 1);
+
+namespace tests\Phpml\CrossValidation;
+
+use Phpml\CrossValidation\RandomSplit;
+use Phpml\Dataset\ArrayDataset;
+
+class RandomSplitTest extends \PHPUnit_Framework_TestCase
+{
+
+    /**
+     * @expectedException \Phpml\Exception\InvalidArgumentException
+     */
+    public function testThrowExceptionOnToSmallTestSize()
+    {
+        new RandomSplit(new ArrayDataset([], []), 0);
+    }
+
+    /**
+     * @expectedException \Phpml\Exception\InvalidArgumentException
+     */
+    public function testThrowExceptionOnToBigTestSize()
+    {
+        new RandomSplit(new ArrayDataset([], []), 1);
+    }
+
+    public function testDatasetRandomSplitWithoutSeed()
+    {
+        $dataset = new ArrayDataset(
+            $samples = [[1], [2], [3], [4]],
+            $labels = ['a', 'a', 'b', 'b']
+        );
+
+        $randomSplit1 = new RandomSplit($dataset, 0.5);
+
+        $this->assertEquals(2, count($randomSplit1->getTestSamples()));
+        $this->assertEquals(2, count($randomSplit1->getTrainSamples()));
+
+        $randomSplit2 = new RandomSplit($dataset, 0.25);
+
+        $this->assertEquals(1, count($randomSplit2->getTestSamples()));
+        $this->assertEquals(3, count($randomSplit2->getTrainSamples()));
+    }
+
+    public function testDatasetRandomSplitWithSameSeed()
+    {
+        $dataset = new ArrayDataset(
+            $samples = [[1], [2], [3], [4], [5], [6], [7], [8]],
+            $labels = ['a', 'a', 'a', 'a', 'b', 'b', 'b', 'b']
+        );
+
+        $seed = 123;
+
+        $randomSplit1 = new RandomSplit($dataset, 0.5, $seed);
+        $randomSplit2 = new RandomSplit($dataset, 0.5, $seed);
+
+        $this->assertEquals($randomSplit1->getTestLabels(), $randomSplit2->getTestLabels());
+        $this->assertEquals($randomSplit1->getTestSamples(), $randomSplit2->getTestSamples());
+        $this->assertEquals($randomSplit1->getTrainLabels(), $randomSplit2->getTrainLabels());
+        $this->assertEquals($randomSplit1->getTrainSamples(), $randomSplit2->getTrainSamples());
+    }
+
+    public function testDatasetRandomSplitWithDifferentSeed()
+    {
+        $dataset = new ArrayDataset(
+            $samples = [[1], [2], [3], [4], [5], [6], [7], [8]],
+            $labels = ['a', 'a', 'a', 'a', 'b', 'b', 'b', 'b']
+        );
+
+        $randomSplit1 = new RandomSplit($dataset, 0.5, 4321);
+        $randomSplit2 = new RandomSplit($dataset, 0.5, 1234);
+
+        $this->assertNotEquals($randomSplit1->getTestLabels(), $randomSplit2->getTestLabels());
+        $this->assertNotEquals($randomSplit1->getTestSamples(), $randomSplit2->getTestSamples());
+        $this->assertNotEquals($randomSplit1->getTrainLabels(), $randomSplit2->getTrainLabels());
+        $this->assertNotEquals($randomSplit1->getTrainSamples(), $randomSplit2->getTrainSamples());
+    }
+
+    public function testRandomSplitCorrectSampleAndLabelPosition()
+    {
+        $dataset = new ArrayDataset(
+            $samples = [[1], [2], [3], [4]],
+            $labels = [1, 2, 3, 4]
+        );
+
+        $randomSplit = new RandomSplit($dataset, 0.5);
+
+        $this->assertEquals($randomSplit->getTestSamples()[0][0], $randomSplit->getTestLabels()[0]);
+        $this->assertEquals($randomSplit->getTestSamples()[1][0], $randomSplit->getTestLabels()[1]);
+        $this->assertEquals($randomSplit->getTrainSamples()[0][0], $randomSplit->getTrainLabels()[0]);
+        $this->assertEquals($randomSplit->getTrainSamples()[1][0], $randomSplit->getTrainLabels()[1]);
+    }
+    
+}

tests/Phpml/Dataset/Demo/IrisTest.php

@@ -2,9 +2,9 @@
 
 declare (strict_types = 1);
 
-namespace tests\Phpml\Dataset;
+namespace tests\Phpml\Dataset\Demo;
 
-use Phpml\Dataset\Iris;
+use Phpml\Dataset\Demo\Iris;
 
 class IrisTest extends \PHPUnit_Framework_TestCase
 {