Time for an 2014 update…

Task/Vector-products/PHP/vector-products.php

@@ -0,0 +1,104 @@
+<?php
+
+class Vector
+{
+	private $values;
+
+	public function setValues(array $values)
+	{
+		if (count($values) != 3)
+			throw new Exception('Values must contain exactly 3 values');
+		foreach ($values as $value)
+			if (!is_int($value) && !is_float($value))
+				throw new Exception('Value "' . $value . '" has an invalid type');
+		$this->values = $values;
+	}
+
+	public function getValues()
+	{
+		if ($this->values == null)
+			$this->setValues(array (
+					0,
+					0,
+					0
+			));
+		return $this->values;
+	}
+
+	public function Vector(array $values)
+	{
+		$this->setValues($values);
+	}
+
+	public static function dotProduct(Vector $va, Vector $vb)
+	{
+		$a = $va->getValues();
+		$b = $vb->getValues();
+		return ($a[0] * $b[0]) + ($a[1] * $b[1]) + ($a[2] * $b[2]);
+	}
+
+	public static function crossProduct(Vector $va, Vector $vb)
+	{
+		$a = $va->getValues();
+		$b = $vb->getValues();
+		return new Vector(array (
+				($a[1] * $b[2]) - ($a[2] * $b[1]),
+				($a[2] * $b[0]) - ($a[0] * $b[2]),
+				($a[0] * $b[1]) - ($a[1] * $b[0])
+		));
+	}
+
+	public static function scalarTripleProduct(Vector $va, Vector $vb, Vector $vc)
+	{
+		return self::dotProduct($va, self::crossProduct($vb, $vc));
+	}
+
+	public static function vectorTrippleProduct(Vector $va, Vector $vb, Vector $vc)
+	{
+		return self::crossProduct($va, self::crossProduct($vb, $vc));
+	}
+}
+
+class Program
+{
+
+	public function Program()
+	{
+		$a = array (
+				3,
+				4,
+				5
+		);
+		$b = array (
+				4,
+				3,
+				5
+		);
+		$c = array (
+				-5,
+				-12,
+				-13
+		);
+		$va = new Vector($a);
+		$vb = new Vector($b);
+		$vc = new Vector($c);
+
+		$result1 = Vector::dotProduct($va, $vb);
+		$result2 = Vector::crossProduct($va, $vb)->getValues();
+		$result3 = Vector::scalarTripleProduct($va, $vb, $vc);
+		$result4 = Vector::vectorTrippleProduct($va, $vb, $vc)->getValues();
+
+		printf("\n");
+		printf("A = (%0.2f, %0.2f, %0.2f)\n", $a[0], $a[1], $a[2]);
+		printf("B = (%0.2f, %0.2f, %0.2f)\n", $b[0], $b[1], $b[2]);
+		printf("C = (%0.2f, %0.2f, %0.2f)\n", $c[0], $c[1], $c[2]);
+		printf("\n");
+		printf("A · B = %0.2f\n", $result1);
+		printf("A × B = (%0.2f, %0.2f, %0.2f)\n", $result2[0], $result2[1], $result2[2]);
+		printf("A · (B × C) = %0.2f\n", $result3);
+		printf("A × (B × C) =(%0.2f, %0.2f, %0.2f)\n", $result4[0], $result4[1], $result4[2]);
+	}
+}
+
+new Program();
+?>