From d5fef266f5f8d8dd067eda2c6aa07225cb3b7e51 Mon Sep 17 00:00:00 2001
From: Dennis Eichhorn <spl1nes.com@googlemail.com>
Date: Sat, 29 Jan 2022 20:51:25 +0100
Subject: [PATCH] add matrix cross3 and dot product

---
 Math/Matrix/Vector.php | 20 ++++++++++
 Utils/ArrayUtils.php   | 85 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 105 insertions(+)

diff --git a/Math/Matrix/Vector.php b/Math/Matrix/Vector.php
index 0f8830b9a..c6aa69079 100644
--- a/Math/Matrix/Vector.php
+++ b/Math/Matrix/Vector.php
@@ -87,4 +87,24 @@ final class Vector extends Matrix
 
         return $this;
     }
+
+    /**
+     * Calculate the cross product
+     *
+     * @param self $vector 3 Vector
+     *
+     * @return Vector
+     *
+     * @since 1.0.0
+     */
+    public function cross3(self $vector) : self
+    {
+        $crossArray = [
+            $this->getV(1) * $vector->getV(2) - $this->getV(2) * $vector->getV(1),
+            $this->getV(2) * $vector->getV(0) - $this->getV(0) * $vector->getV(2),
+            $this->getV(0) * $vector->getV(1) - $this->getV(1) * $vector->getV(0),
+        ];
+
+        return self::fromArray($crossArray);
+    }
 }
diff --git a/Utils/ArrayUtils.php b/Utils/ArrayUtils.php
index 888270108..7560a22c0 100644
--- a/Utils/ArrayUtils.php
+++ b/Utils/ArrayUtils.php
@@ -14,6 +14,8 @@ declare(strict_types=1);
 
 namespace phpOMS\Utils;
 
+use phpOMS\Math\Matrix\Exception\InvalidDimensionException;
+
 /**
  * Array utils.
  *
@@ -452,4 +454,87 @@ final class ArrayUtils
 
         return $diff;
     }
+
+    /**
+     * Get the dot product of two arrays
+     *
+     * @param array $value1 Value 1 is a matrix or a vector
+     * @param array $value2 Value 2 is a matrix or vector (cannot be a matrix if value1 is a vector)
+     *
+     * @return array
+     *
+     * @since 1.0.0
+     */
+    public static function dot(array $value1, array $value2) : int|float|array
+    {
+        $m1 = \count($value1);
+        $n1 = ($isMatrix1 = \is_array($value1[0])) ? \count($value1[0]) : 1;
+
+        $m2 = \count($value2);
+        $n2 = ($isMatrix2 = \is_array($value2[0])) ? \count($value2[0]) : 1;
+
+        $result = null;
+
+        if ($isMatrix1 && $isMatrix2) {
+            if ($m2 !== $n1) {
+                throw new InvalidDimensionException($m2 . 'x' . $n2 . ' not compatible with ' . $m1 . 'x' . $n1);
+            }
+
+            $result = [[]];
+            for ($i = 0; $i < $m1; ++$i) { // Row of 1
+                for ($c = 0; $c < $n2; ++$c) { // Column of 2
+                    $temp = 0;
+
+                    for ($j = 0; $j < $m2; ++$j) { // Row of 2
+                        $temp += $value1[$i][$j] * $value2[$j][$c];
+                    }
+
+                    $result[$i][$c] = $temp;
+                }
+            }
+        } elseif (!$isMatrix1 && !$isMatrix2) {
+            if ($m1 !== $m2) {
+                throw new InvalidDimensionException($m1 . ' vs. ' . $m2);
+            }
+
+            $result = 0;
+            for ($i = 0; $i < $m1; ++$i) {
+                $result += $value1[$i] * $value2[$i];
+            }
+        } elseif ($isMatrix1 && !$isMatrix2) {
+            $result = [];
+            for ($i = 0; $i < $m1; ++$i) { // Row of 1
+                $temp = 0;
+
+                for ($c = 0; $c < $m2; ++$c) { // Row of 2
+                    $temp += $value1[$i][$c] * $value2[$c];
+                }
+
+                $result[$i] = $temp;
+            }
+        } else {
+            throw new \InvalidArgumentException();
+        }
+
+        return $result;
+    }
+
+    /**
+     * Calculate the vector corss product
+     *
+     * @param array $vector1 First 3 vector
+     * @param array $vector2 Second 3 vector
+     *
+     * @return array<int, int|float>
+     *
+     * @since 1.0.0
+     */
+    public function cross3(array $vector1, array $vector2) : array
+    {
+        return [
+            $vector1[1] * $vector2[2] - $vector1[2] * $vector2[1],
+            $vector1[2] * $vector2[0] - $vector1[0] * $vector2[2],
+            $vector1[0] * $vector2[1] - $vector1[1] * $vector2[0],
+        ];
+    }
 }