From 34281e40eec2c71cf6a242c5b1f4c708179ee4a4 Mon Sep 17 00:00:00 2001
From: Arkadiusz Kondas <arkadiusz.kondas@gmail.com>
Date: Thu, 21 Apr 2016 00:23:03 +0200
Subject: [PATCH] add scalar product function

---
 src/Phpml/Math/Product.php       | 25 +++++++++++++++++++++++++
 tests/Phpml/Math/ProductTest.php | 20 ++++++++++++++++++++
 2 files changed, 45 insertions(+)
 create mode 100644 src/Phpml/Math/Product.php
 create mode 100644 tests/Phpml/Math/ProductTest.php

diff --git a/src/Phpml/Math/Product.php b/src/Phpml/Math/Product.php
new file mode 100644
index 0000000..992eeaa
--- /dev/null
+++ b/src/Phpml/Math/Product.php
@@ -0,0 +1,25 @@
+<?php
+declare(strict_types = 1);
+
+namespace Phpml\Math;
+
+class Product
+{
+
+    /**
+     * @param array $a
+     * @param array $b
+     *
+     * @return mixed
+     */
+    public function scalar(array $a, array $b)
+    {
+        $product = 0;
+        foreach ($a as $index => $value) {
+            $product += $value * $b[$index];
+        }
+
+        return $product;
+    }
+
+}
diff --git a/tests/Phpml/Math/ProductTest.php b/tests/Phpml/Math/ProductTest.php
new file mode 100644
index 0000000..d7aa015
--- /dev/null
+++ b/tests/Phpml/Math/ProductTest.php
@@ -0,0 +1,20 @@
+<?php
+declare(strict_types = 1);
+
+namespace tests\Phpml\Math;
+
+use Phpml\Math\Product;
+
+class ProductTest extends \PHPUnit_Framework_TestCase
+{
+
+    public function testScalarProduct()
+    {
+        $product = new Product();
+
+        $this->assertEquals(10, $product->scalar([2, 3], [-1, 4]));
+        $this->assertEquals(-0.1, $product->scalar([1, 4, 1], [-2, 0.5, -0.1]));
+        $this->assertEquals(8, $product->scalar([2], [4]));
+    }
+
+}
\ No newline at end of file