Correct SVM Use (#346)

* Correct SVM Use

* Update OneClassSVM.php

* Update OneClassSVM.php

Author: LouisAUTHIE

src/AnomalyDetectors/OneClassSVM.php

@@ -79,6 +79,7 @@ public function __construct(
             new ExtensionIsLoaded('svm'),
             new ExtensionMinimumVersion('svm', '0.2.0'),
         ])->check();
+        
 
         if ($nu < 0.0 or $nu > 1.0) {
             throw new InvalidArgumentException('Nu must be between'
@@ -182,7 +183,14 @@ public function train(Dataset $dataset) : void
             new SamplesAreCompatibleWithEstimator($dataset, $this),
         ])->check();
 
-        $this->model = $this->svm->train($dataset->samples());
+        $data = [];
+
+        foreach ($dataset->samples() as $sample) {
+            array_unshift($sample, 1);
+            $data[] = $sample;
+        }
+
+        $this->model = $this->svm->train($data);
     }
 
     /**
@@ -211,7 +219,13 @@ public function predictSample(array $sample) : int
             throw new RuntimeException('Estimator has not been trained.');
         }
 
-        return $this->model->predict($sample) !== 1.0 ? 0 : 1;
+        $sampleWithOffset = [];
+
+        foreach ($sample as $key => $value) {
+            $sampleWithOffset[$key + 1] = $value;
+        }
+
+        return $this->model->predict($sampleWithOffset) == 1 ? 0 : 1;
     }
 
     /**