Switch to using a single array (not nested) for the constructor, since a vector should never have more than one row. Add helper factory method to cast from a matrix to a vector.

Author: mcordingley

src/Vector.php

@@ -6,9 +6,22 @@
 
 final class Vector extends Matrix
 {
+    /**
+     * @param array $literal
+     */
     public function __construct(array $literal)
     {
-        parent::__construct($literal);
+        parent::__construct([$literal]);
+    }
+
+    /**
+     * @param Matrix $matrix
+     * @param int $row
+     * @return Vector
+     */
+    public static function fromMatrix(Matrix $matrix, int $row = 0): self
+    {
+        return new self($matrix->toArray()[$row]);
     }
 
     /**************************************************************************
@@ -156,7 +169,7 @@ public function crossProduct(Vector $other): self
         $y = -(($this->toArray()[0] * $other->toArray()[2]) - ($this->toArray()[2] * $other->toArray()[0]));
         $z =   ($this->toArray()[0] * $other->toArray()[1]) - ($this->toArray()[1] * $other->toArray()[0]);
 
-        return new Vector([[$x, $y, $z]]);
+        return new self([$x, $y, $z]);
     }
 
     /**
@@ -176,7 +189,7 @@ public function normalize(): self
     {
         $norm = $this->l2norm();
 
-        return $this->divideScalar($norm);
+        return self::fromMatrix($this->divideScalar($norm));
     }
 
     /**
@@ -193,7 +206,7 @@ public function normalize(): self
      */
     public function projection(self $other): self
     {
-        return $other->multiplyScalar($this->dotProduct($other) / (($other->l2norm())**2));
+        return self::fromMatrix($other->multiplyScalar($this->dotProduct($other) / ($other->l2norm() ** 2)));
     }
 
     /**************************************************************************

tests/VectorTest.php

@@ -9,9 +9,7 @@ class VectorTest extends \PHPUnit_Framework_TestCase
 {
     private function buildVector()
     {
-        return new Vector([
-            [1, 2, 3, 4],
-        ]);
+        return new Vector([1, 2, 3, 4]);
     }
 
     public function testEmptyCount()
@@ -42,66 +40,46 @@ public function testSum()
 
     public function testLength()
     {
-        $vector = new Vector([
-            [3, 4]
-        ]);
+        $vector = new Vector([3, 4]);
 
         $this->assertEquals(5, $vector->length());
     }
 
     public function testDotProduct()
     {
-        $vector1 = new Vector([
-            [1,2,3,4]
-        ]);
-        $vector2 = new Vector([
-            [-1,3,5,2]
-        ]);
+        $vector1 = new Vector([1, 2, 3, 4]);
+        $vector2 = new Vector([-1, 3, 5, 2]);
 
         $this->assertEquals((1 * -1) + (2 * 3) + (3 * 5) + (4 * 2), $vector1->dotProduct($vector2));
     }
 
     public function testOuterProduct()
     {
-        $vector1 = new Vector([
-            [1,2]
-        ]);
-        $vector2 = new Vector([
-            [3,4,5]
-        ]);
+        $vector1 = new Vector([1, 2]);
+        $vector2 = new Vector([3, 4, 5]);
 
-        $this->assertEquals(new Matrix([[3,4,5],[6,8,10]]), $vector1->outerProduct($vector2));
+        $this->assertEquals(new Matrix([[3, 4, 5], [6, 8, 10]]), $vector1->outerProduct($vector2));
 
         //this test case appear  A ⨂ B != B ⨂ A
-        $vector1 = new Vector([
-            [3,4,5]
-        ]);
-        $vector2 = new Vector([
-            [1,2]
-        ]);
-
-        $this->assertEquals(new Matrix([[3,6],[4,8],[5,10]]), $vector1->outerProduct($vector2));
+        $vector1 = new Vector([3, 4, 5]);
+        $vector2 = new Vector([1, 2]);
+
+        $this->assertEquals(new Matrix([[3, 6], [4, 8], [5, 10]]), $vector1->outerProduct($vector2));
     }
 
     public function testCrossProduct()
     {
-        $vector1 = new Vector([
-            [2,3,4]
-        ]);
-        $vector2 = new Vector([
-            [5,6,7]
-        ]);
-
-        $this->assertEquals(new Vector([[-3,6,-3]]), $vector1->crossProduct($vector2));
+        $vector1 = new Vector([2, 3, 4]);
+        $vector2 = new Vector([5, 6, 7]);
+
+        $this->assertEquals(new Vector([-3, 6, -3]), $vector1->crossProduct($vector2));
     }
 
     public function testNormalize()
     {
-        $vector = new Vector([
-            [3,4]
-        ]);
+        $vector = new Vector([3, 4]);
 
-        $this->assertEquals(new Vector([[3/5, 4/5]]), $vector->normalize());
+        $this->assertEquals(new Vector([3 / 5, 4 / 5]), $vector->normalize());
     }
 
     public function testL1Norm()
@@ -111,22 +89,16 @@ public function testL1Norm()
 
     public function testL2Norm()
     {
-        $vector = new Vector([
-            [3, 4]
-        ]);
+        $vector = new Vector([3, 4]);
 
         $this->assertEquals(5, $vector->l2Norm());
     }
 
     public function testProjection()
     {
-        $vector1 = new Vector([
-            [1,1]
-        ]);
-        $vector2 = new Vector([
-            [3,1]
-        ]);
-
-        $this->assertEquals(new Vector([[12/10, 4/10]]), $vector1->projection($vector2));
+        $vector1 = new Vector([1, 1]);
+        $vector2 = new Vector([3, 1]);
+
+        $this->assertEquals(new Vector([12 / 10, 4 / 10]), $vector1->projection($vector2));
     }
 }