trueskill/tests/Numerics/MatrixTest.php

<?php

declare(strict_types=1);

namespace DNW\Skills\Tests\Numerics;

use DNW\Skills\Numerics\IdentityMatrix;
use DNW\Skills\Numerics\Matrix;
use DNW\Skills\Numerics\SquareMatrix;
use PHPUnit\Framework\TestCase;
use Exception;

// phpcs:disable PSR2.Methods.FunctionCallSignature,Generic.Functions.FunctionCallArgumentSpacing.TooMuchSpaceAfterComma
class MatrixTest extends TestCase
{
    public function testTwoByTwoDeterminant(): void
    {
        $a = new SquareMatrix(1, 2,
                              3, 4);

        $this->assertEquals(-2, $a->getDeterminant());

        $b = new SquareMatrix(3, 4,
                              5, 6);

        $this->assertEquals(-2, $b->getDeterminant());

        $c = new SquareMatrix(1, 1,
                              1, 1);

        $this->assertEquals(0, $c->getDeterminant());

        $d = new SquareMatrix(12, 15,
                              17, 21);

        $this->assertEquals(12 * 21 - 15 * 17, $d->getDeterminant());
    }

    public function testThreeByThreeDeterminant(): void
    {
        $a = new SquareMatrix(1, 2, 3,
                              4, 5, 6,
                              7, 8, 9);

        $this->assertEquals(0, $a->getDeterminant());

        $pi = new SquareMatrix(3, 1, 4,
                               1, 5, 9,
                               2, 6, 5);

        // Verified against http://www.wolframalpha.com/input/?i=determinant+%7B%7B3%2C1%2C4%7D%2C%7B1%2C5%2C9%7D%2C%7B2%2C6%2C5%7D%7D
        $this->assertEquals(-90, $pi->getDeterminant());
    }

    public function testFourByFourDeterminant(): void
    {
        $a = new SquareMatrix(1,  2,  3,  4,
                               5,  6,  7,  8,
                               9, 10, 11, 12,
                              13, 14, 15, 16);

        $this->assertEquals(0, $a->getDeterminant());

        $pi = new SquareMatrix(3, 1, 4, 1,
                               5, 9, 2, 6,
                               5, 3, 5, 8,
                               9, 7, 9, 3);

        // Verified against http://www.wolframalpha.com/input/?i=determinant+%7B+%7B3%2C1%2C4%2C1%7D%2C+%7B5%2C9%2C2%2C6%7D%2C+%7B5%2C3%2C5%2C8%7D%2C+%7B9%2C7%2C9%2C3%7D%7D
        $this->assertEquals(98, $pi->getDeterminant());
    }

    public function testEightByEightDeterminant(): void
    {
        $a = new SquareMatrix(1,  2,  3,  4,  5,  6,  7,  8,
                               9, 10, 11, 12, 13, 14, 15, 16,
                              17, 18, 19, 20, 21, 22, 23, 24,
                              25, 26, 27, 28, 29, 30, 31, 32,
                              33, 34, 35, 36, 37, 38, 39, 40,
                              41, 42, 32, 44, 45, 46, 47, 48,
                              49, 50, 51, 52, 53, 54, 55, 56,
                              57, 58, 59, 60, 61, 62, 63, 64);

        $this->assertEquals(0, $a->getDeterminant());

        $pi = new SquareMatrix(3, 1, 4, 1, 5, 9, 2, 6,
                               5, 3, 5, 8, 9, 7, 9, 3,
                               2, 3, 8, 4, 6, 2, 6, 4,
                               3, 3, 8, 3, 2, 7, 9, 5,
                               0, 2, 8, 8, 4, 1, 9, 7,
                               1, 6, 9, 3, 9, 9, 3, 7,
                               5, 1, 0, 5, 8, 2, 0, 9,
                               7, 4, 9, 4, 4, 5, 9, 2);

        // Verified against http://www.wolframalpha.com/input/?i=det+%7B%7B3%2C1%2C4%2C1%2C5%2C9%2C2%2C6%7D%2C%7B5%2C3%2C5%2C8%2C9%2C7%2C9%2C3%7D%2C%7B2%2C3%2C8%2C4%2C6%2C2%2C6%2C4%7D%2C%7B3%2C3%2C8%2C3%2C2%2C7%2C9%2C5%7D%2C%7B0%2C2%2C8%2C8%2C4%2C1%2C9%2C7%7D%2C%7B1%2C6%2C9%2C3%2C9%2C9%2C3%2C7%7D%2C%7B5%2C1%2C0%2C5%2C8%2C2%2C0%2C9%7D%2C%7B7%2C4%2C9%2C4%2C4%2C5%2C9%2C2%7D%7D
        $this->assertEquals(1378143, $pi->getDeterminant());
    }

    public function testEquals(): void
    {
        $a = new SquareMatrix(1, 2,
                              3, 4);

        $b = new SquareMatrix(1, 2,
                              3, 4);

        $this->assertTrue($a->equals($b));

        $c = Matrix::fromRowsColumns(2, 3,
                                     1, 2, 3,
                                     4, 5, 6);

        $d = Matrix::fromRowsColumns(2, 3,
                                     1, 2, 3,
                                     4, 5, 6);

        $this->assertTrue($c->equals($d));

        $e = Matrix::fromRowsColumns(3, 2,
                                     1, 4,
                                     2, 5,
                                     3, 6);

        $f = $e->getTranspose();
        $this->assertTrue($d->equals($f));

        // Test rounding (thanks to nsp on GitHub for finding this case)
        $g = new SquareMatrix(1, 2.00000000000001,
                              3, 4);

        $h = new SquareMatrix(1, 2,
                              3, 4);

        $this->assertTrue($g->equals($h));

        $i = new Matrix(1, 2, [[1,2]]);
        $j = new Matrix(2, 1, [[1],[2]]);

        $this->assertFalse($i->equals($j));

        $k = new Matrix(2, 2, [[1,2],[3,4]]);
        $l = new Matrix(2, 2, [[4,3],[2,1]]);

        $this->assertFalse($k->equals($l));
    }

    public function testAdjugate(): void
    {
        // From Wikipedia: http://en.wikipedia.org/wiki/Adjugate_matrix
        $a = new SquareMatrix(1, 2,
                              3, 4);

        $b = new SquareMatrix(4, -2,
                              -3, 1);

        $this->assertTrue($b->equals($a->getAdjugate()));

        $c = new SquareMatrix(-3, 2, -5,
                              -1, 0, -2,
                               3, -4, 1);

        $d = new SquareMatrix(-8, 18, -4,
                              -5, 12, -1,
                               4, -6, 2);

        $this->assertTrue($d->equals($c->getAdjugate()));
    }

    public function testInverse(): void
    {
        // see http://www.mathwords.com/i/inverse_of_a_matrix.htm
        $a = new SquareMatrix(4, 3,
                              3, 2);

        $b = new SquareMatrix(-2,  3,
                               3, -4);

        $aInverse = $a->getInverse();
        $this->assertTrue($b->equals($aInverse));

        $identity2x2 = new IdentityMatrix(2);

        $aaInverse = Matrix::multiply($a, $aInverse);
        $this->assertTrue($identity2x2->equals($aaInverse));

        $c = new SquareMatrix(1, 2, 3,
                              0, 4, 5,
                              1, 0, 6);

        $cInverse = $c->getInverse();
        $d = Matrix::scalarMultiply((1.0 / 22), new SquareMatrix(24, -12, -2,
                                                                  5,   3, -5,
                                                                 -4, 2, 4));

        $this->assertTrue($d->equals($cInverse));
        $identity3x3 = new IdentityMatrix(3);

        $ccInverse = Matrix::multiply($c, $cInverse);
        $this->assertTrue($identity3x3->equals($ccInverse));
    }

    public function testErrorDeterminant(): void
    {
        $this->expectException(Exception::class);
        $matrix = new Matrix(2, 3, [[1,2,3],[1,2,3]]);
        $matrix->getDeterminant();
    }

    public function testErrorAdjugate(): void
    {
        $this->expectException(Exception::class);
        $matrix = new Matrix(2, 3, [[1,2,3],[1,2,3]]);
        $matrix->getAdjugate();
    }

    public function testErrorAdd(): void
    {
        $this->expectException(Exception::class);
        $m1 = new Matrix(2, 3, [[1,2,3],[1,2,3]]);
        $m2 = new Matrix(1, 1, [[1,1]]);
        Matrix::add($m1, $m2);
    }

    public function testErrorMultiply(): void
    {
        $this->expectException(Exception::class);
        $m1 = new Matrix(2, 3, [[1,2,3],[1,2,3]]);
        $m2 = new Matrix(1, 1, [[1,1]]);
        Matrix::multiply($m1, $m2);
    }
}
// phpcs:enable