Matrix::isSingular() - Code Metrics - Inspection of "Check if matrix is singular doing inverse (#49)" - php-ai/php-ml - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Push — master ( a33d5f...f0a798 )

by Arkadiusz

created 2017-02-15 09:09 UTC

Matrix::isSingular() A

↳ Parent: Matrix

Complexity

Conditions	1
Paths	1

Size

Total Lines	4
Code Lines	2

Duplication

Lines	0
Ratio	0 %

Importance

Changes

Metric	Value
dl	0
loc	4
rs	10
c	0
b	0
f	0
cc	1
eloc	2
nc	1
nop	0

<?php

declare(strict_types=1);

namespace Phpml\Math;

use Phpml\Exception\InvalidArgumentException;
use Phpml\Exception\MatrixException;

class Matrix
{
    /**
     * @var array
     */
    private $matrix;

    /**
     * @var int
     */
    private $rows;

    /**
     * @var int
     */
    private $columns;

    /**
     * @var float
     */
    private $determinant;

    /**
     * @param array $matrix
     * @param bool  $validate
     *
     * @throws InvalidArgumentException
     */
    public function __construct(array $matrix, bool $validate = true)
    {
        $this->rows = count($matrix);
        $this->columns = count($matrix[0]);

        if ($validate) {
            for ($i = 0; $i < $this->rows; ++$i) {
                if (count($matrix[$i]) !== $this->columns) {
                    throw InvalidArgumentException::matrixDimensionsDidNotMatch();
                }
            }
        }

        $this->matrix = $matrix;
    }

    /**
     * @param array $array
     *
     * @return Matrix
     */
    public static function fromFlatArray(array $array)
    {
        $matrix = [];
        foreach ($array as $value) {
            $matrix[] = [$value];
        }

        return new self($matrix);
    }

    /**
     * @return array
     */
    public function toArray()
    {
        return $this->matrix;
    }

    /**
     * @return int
     */
    public function getRows()
    {
        return $this->rows;
    }

    /**
     * @return int
     */
    public function getColumns()
    {
        return $this->columns;
    }

    /**
     * @param $column
     *
     * @return array
     *
     * @throws MatrixException
     */
    public function getColumnValues($column)
    {
        if ($column >= $this->columns) {
            throw MatrixException::columnOutOfRange();
        }

        $values = [];
        for ($i = 0; $i < $this->rows; ++$i) {
            $values[] = $this->matrix[$i][$column];
        }

        return $values;
    }

    /**
     * @return float|int
     *
     * @throws MatrixException
     */
    public function getDeterminant()
    {
        if ($this->determinant) {
            return $this->determinant;
        }

        if (!$this->isSquare()) {
            throw MatrixException::notSquareMatrix();
        }

        return $this->determinant = $this->calculateDeterminant();
class Id
{
    public $id;

    public function __construct($id)
    {
        $this->id = $id;
    }

}

class Account
{
    /** @var  Id $id */
    public $id;
}

$account_id = false;

if (starsAreRight()) {
    $account_id = new Id(42);
}

$account = new Account();
if ($account instanceof Id)
{
    $account->id = $account_id;
}
    }

    /**
     * @return float|int
     *
     * @throws MatrixException
     */
    private function calculateDeterminant()
    {
        $determinant = 0;
        if ($this->rows == 1 && $this->columns == 1) {
            $determinant = $this->matrix[0][0];
        } elseif ($this->rows == 2 && $this->columns == 2) {
            $determinant =
                $this->matrix[0][0] * $this->matrix[1][1] -
                $this->matrix[0][1] * $this->matrix[1][0];
        } else {
            for ($j = 0; $j < $this->columns; ++$j) {
                $subMatrix = $this->crossOut(0, $j);
                $minor = $this->matrix[0][$j] * $subMatrix->getDeterminant();
                $determinant += fmod((float) $j, 2.0) == 0 ? $minor : -$minor;
            }
        }

        return $determinant;
    }

    /**
     * @return bool
     */
    public function isSquare()
    {
        return $this->columns === $this->rows;
    }

    /**
     * @return Matrix
     */
    public function transpose()

    {
        $newMatrix = [];
        for ($i = 0; $i < $this->rows; ++$i) {
            for ($j = 0; $j < $this->columns; ++$j) {
                $newMatrix[$j][$i] = $this->matrix[$i][$j];
            }
        }

        return new self($newMatrix, false);
    }

    /**
     * @param Matrix $matrix
     *
     * @return Matrix
     *
     * @throws InvalidArgumentException
     */
    public function multiply(Matrix $matrix)
    {
        if ($this->columns != $matrix->getRows()) {
            throw InvalidArgumentException::inconsistentMatrixSupplied();
        }

        $product = [];
        $multiplier = $matrix->toArray();
        for ($i = 0; $i < $this->rows; ++$i) {
            $columns = $matrix->getColumns();
            for ($j = 0; $j < $columns; ++$j) {
                $product[$i][$j] = 0;
                for ($k = 0; $k < $this->columns; ++$k) {
                    $product[$i][$j] += $this->matrix[$i][$k] * $multiplier[$k][$j];
                }
            }
        }

        return new self($product, false);
    }

    /**
     * @param $value
     *
     * @return Matrix
     */
    public function divideByScalar($value)

    {
        $newMatrix = [];
        for ($i = 0; $i < $this->rows; ++$i) {
            for ($j = 0; $j < $this->columns; ++$j) {
                $newMatrix[$i][$j] = $this->matrix[$i][$j] / $value;
            }
        }

        return new self($newMatrix, false);
    }

    /**
     * @return Matrix
     *
     * @throws MatrixException
     */
    public function inverse()
    {
        if (!$this->isSquare()) {
            throw MatrixException::notSquareMatrix();
        }

        if ($this->isSingular()) {
            throw MatrixException::singularMatrix();
        }

        $newMatrix = [];
        for ($i = 0; $i < $this->rows; ++$i) {
            for ($j = 0; $j < $this->columns; ++$j) {
                $minor = $this->crossOut($i, $j)->getDeterminant();
                $newMatrix[$i][$j] = fmod((float) ($i + $j), 2.0) == 0 ? $minor : -$minor;
            }
        }

        $cofactorMatrix = new self($newMatrix, false);

        return $cofactorMatrix->transpose()->divideByScalar($this->getDeterminant());
    }

    /**
     * @param int $row
     * @param int $column
     *
     * @return Matrix
     */
    public function crossOut(int $row, int $column)
    {
        $newMatrix = [];
        $r = 0;
        for ($i = 0; $i < $this->rows; ++$i) {
            $c = 0;
            if ($row != $i) {
                for ($j = 0; $j < $this->columns; ++$j) {
                    if ($column != $j) {
                        $newMatrix[$r][$c] = $this->matrix[$i][$j];
                        ++$c;
                    }
                }
                ++$r;
            }
        }

        return new self($newMatrix, false);
    }

    /**
     * @return bool
     */
    public function isSingular() : bool
    {
        return 0 == $this->getDeterminant();
    }
}


1			<?php
2
3			declare(strict_types=1);
4
5			namespace Phpml\Math;
6
7			use Phpml\Exception\InvalidArgumentException;
8			use Phpml\Exception\MatrixException;
9
10			class Matrix
11			{
12			/**
13			* @var array
14			*/
15			private $matrix;
16
17			/**
18			* @var int
19			*/
20			private $rows;
21
22			/**
23			* @var int
24			*/
25			private $columns;
26
27			/**
28			* @var float
29			*/
30			private $determinant;
31
32			/**
33			* @param array $matrix
34			* @param bool $validate
35			*
36			* @throws InvalidArgumentException
37			*/
38			public function __construct(array $matrix, bool $validate = true)
39			{
40			$this->rows = count($matrix);
41			$this->columns = count($matrix[0]);
42
43			if ($validate) {
44			for ($i = 0; $i < $this->rows; ++$i) {
45			if (count($matrix[$i]) !== $this->columns) {
46			throw InvalidArgumentException::matrixDimensionsDidNotMatch();
47			}
48			}
49			}
50
51			$this->matrix = $matrix;
52			}
53
54			/**
55			* @param array $array
56			*
57			* @return Matrix
58			*/
59			public static function fromFlatArray(array $array)
60			{
61			$matrix = [];
62			foreach ($array as $value) {
63			$matrix[] = [$value];
64			}
65
66			return new self($matrix);
67			}
68
69			/**
70			* @return array
71			*/
72			public function toArray()
73			{
74			return $this->matrix;
75			}
76
77			/**
78			* @return int
79			*/
80			public function getRows()
81			{
82			return $this->rows;
83			}
84
85			/**
86			* @return int
87			*/
88			public function getColumns()
89			{
90			return $this->columns;
91			}
92
93			/**
94			* @param $column
95			*
96			* @return array
97			*
98			* @throws MatrixException
99			*/
100			public function getColumnValues($column)
101			{
102			if ($column >= $this->columns) {
103			throw MatrixException::columnOutOfRange();
104			}
105
106			$values = [];
107			for ($i = 0; $i < $this->rows; ++$i) {
108			$values[] = $this->matrix[$i][$column];
109			}
110
111			return $values;
112			}
113
114			/**
115			* @return float\|int
116			*
117			* @throws MatrixException
118			*/
119			public function getDeterminant()
120			{
121			if ($this->determinant) {
122			return $this->determinant;
123			}
124
125			if (!$this->isSquare()) {
126			throw MatrixException::notSquareMatrix();
127			}
128
129			return $this->determinant = $this->calculateDeterminant();
			0 ignored issues – show Documentation Bug introduced 2016-04-30 22:59 UTC by Report Bug Copy Issue Report It seems like `$this->calculateDeterminant()` can also be of type `integer`. However, the property `$determinant` is declared as type `double`. Maybe add an additional type check? Our type inference engine has found a suspicous assignment of a value to a property. This check raises an issue when a value that can be of a mixed type is assigned to a property that is type hinted more strictly. For example, imagine you have a variable `$accountId` that can either hold an Id object or false (if there is no account id yet). Your code now assigns that value to the `id` property of an instance of the `Account` class. This class holds a proper account, so the id value must no longer be false. Either this assignment is in error or a type check should be added for that assignment. class Id { public $id; public function __construct($id) { $this->id = $id; } } class Account { /** @var Id $id */ public $id; } $account_id = false; if (starsAreRight()) { $account_id = new Id(42); } $account = new Account(); if ($account instanceof Id) { $account->id = $account_id; } Loading history...
130			}
131
132			/**
133			* @return float\|int
134			*
135			* @throws MatrixException
136			*/
137			private function calculateDeterminant()
138			{
139			$determinant = 0;
140			if ($this->rows == 1 && $this->columns == 1) {
141			$determinant = $this->matrix[0][0];
142			} elseif ($this->rows == 2 && $this->columns == 2) {
143			$determinant =
144			$this->matrix[0][0] * $this->matrix[1][1] -
145			$this->matrix[0][1] * $this->matrix[1][0];
146			} else {
147			for ($j = 0; $j < $this->columns; ++$j) {
148			$subMatrix = $this->crossOut(0, $j);
149			$minor = $this->matrix[0][$j] * $subMatrix->getDeterminant();
150			$determinant += fmod((float) $j, 2.0) == 0 ? $minor : -$minor;
151			}
152			}
153
154			return $determinant;
155			}
156
157			/**
158			* @return bool
159			*/
160			public function isSquare()
161			{
162			return $this->columns === $this->rows;
163			}
164
165			/**
166			* @return Matrix
167			*/
168			public function transpose()
			0 ignored issues – show Duplication introduced 2016-04-29 23:01 UTC by Report Bug Copy Issue Report This method seems to be duplicated in your project. Duplicated code is one of the most pungent code smells. If you need to duplicate the same code in three or more different places, we strongly encourage you to look into extracting the code into a single class or operation. You can also find more detailed suggestions in the “Code” section of your repository. Loading history...
169			{
170			$newMatrix = [];
171			for ($i = 0; $i < $this->rows; ++$i) {
172			for ($j = 0; $j < $this->columns; ++$j) {
173			$newMatrix[$j][$i] = $this->matrix[$i][$j];
174			}
175			}
176
177			return new self($newMatrix, false);
178			}
179
180			/**
181			* @param Matrix $matrix
182			*
183			* @return Matrix
184			*
185			* @throws InvalidArgumentException
186			*/
187			public function multiply(Matrix $matrix)
188			{
189			if ($this->columns != $matrix->getRows()) {
190			throw InvalidArgumentException::inconsistentMatrixSupplied();
191			}
192
193			$product = [];
194			$multiplier = $matrix->toArray();
195			for ($i = 0; $i < $this->rows; ++$i) {
196			$columns = $matrix->getColumns();
197			for ($j = 0; $j < $columns; ++$j) {
198			$product[$i][$j] = 0;
199			for ($k = 0; $k < $this->columns; ++$k) {
200			$product[$i][$j] += $this->matrix[$i][$k] * $multiplier[$k][$j];
201			}
202			}
203			}
204
205			return new self($product, false);
206			}
207
208			/**
209			* @param $value
210			*
211			* @return Matrix
212			*/
213			public function divideByScalar($value)
			0 ignored issues – show Duplication introduced 2016-04-29 23:01 UTC by Report Bug Copy Issue Report This method seems to be duplicated in your project. Duplicated code is one of the most pungent code smells. If you need to duplicate the same code in three or more different places, we strongly encourage you to look into extracting the code into a single class or operation. You can also find more detailed suggestions in the “Code” section of your repository. Loading history...
214			{
215			$newMatrix = [];
216			for ($i = 0; $i < $this->rows; ++$i) {
217			for ($j = 0; $j < $this->columns; ++$j) {
218			$newMatrix[$i][$j] = $this->matrix[$i][$j] / $value;
219			}
220			}
221
222			return new self($newMatrix, false);
223			}
224
225			/**
226			* @return Matrix
227			*
228			* @throws MatrixException
229			*/
230			public function inverse()
231			{
232			if (!$this->isSquare()) {
233			throw MatrixException::notSquareMatrix();
234			}
235
236			if ($this->isSingular()) {
237			throw MatrixException::singularMatrix();
238			}
239
240			$newMatrix = [];
241			for ($i = 0; $i < $this->rows; ++$i) {
242			for ($j = 0; $j < $this->columns; ++$j) {
243			$minor = $this->crossOut($i, $j)->getDeterminant();
244			$newMatrix[$i][$j] = fmod((float) ($i + $j), 2.0) == 0 ? $minor : -$minor;
245			}
246			}
247
248			$cofactorMatrix = new self($newMatrix, false);
249
250			return $cofactorMatrix->transpose()->divideByScalar($this->getDeterminant());
251			}
252
253			/**
254			* @param int $row
255			* @param int $column
256			*
257			* @return Matrix
258			*/
259			public function crossOut(int $row, int $column)
260			{
261			$newMatrix = [];
262			$r = 0;
263			for ($i = 0; $i < $this->rows; ++$i) {
264			$c = 0;
265			if ($row != $i) {
266			for ($j = 0; $j < $this->columns; ++$j) {
267			if ($column != $j) {
268			$newMatrix[$r][$c] = $this->matrix[$i][$j];
269			++$c;
270			}
271			}
272			++$r;
273			}
274			}
275
276			return new self($newMatrix, false);
277			}
278
279			/**
280			* @return bool
281			*/
282			public function isSingular() : bool
283			{
284			return 0 == $this->getDeterminant();
285			}
286			}
287

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Matrix::isSingular() A

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