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<?php
/**
*
* Class for the management of Matrices
*
* @copyright Copyright (c) 2018 Mark Baker (https://github.com/MarkBaker/PHPMatrix)
* @license https://opensource.org/licenses/MIT MIT
*/
namespace Matrix;
use Generator;
use Matrix\Decomposition\LU;
use Matrix\Decomposition\QR;
/**
* Matrix object.
*
* @package Matrix
*
* @property-read int $rows The number of rows in the matrix
* @property-read int $columns The number of columns in the matrix
* @method Matrix antidiagonal()
* @method Matrix adjoint()
* @method Matrix cofactors()
* @method float determinant()
* @method Matrix diagonal()
* @method Matrix identity()
* @method Matrix inverse()
* @method Matrix minors()
* @method float trace()
* @method Matrix transpose()
* @method Matrix add(...$matrices)
* @method Matrix subtract(...$matrices)
* @method Matrix multiply(...$matrices)
* @method Matrix divideby(...$matrices)
* @method Matrix divideinto(...$matrices)
* @method Matrix directsum(...$matrices)
*/
class Matrix
{
protected $rows;
protected $columns;
protected $grid = [];
/*
* Create a new Matrix object from an array of values
*
* @param array $grid
*/
final public function __construct(array $grid)
{
$this->buildFromArray(array_values($grid));
}
/*
* Create a new Matrix object from an array of values
*
* @param array $grid
*/
protected function buildFromArray(array $grid): void
{
$this->rows = count($grid);
$columns = array_reduce(
$grid,
function ($carry, $value) {
return max($carry, is_array($value) ? count($value) : 1);
}
);
$this->columns = $columns;
array_walk(
$grid,
function (&$value) use ($columns) {
if (!is_array($value)) {
$value = [$value];
}
$value = array_pad(array_values($value), $columns, null);
}
);
$this->grid = $grid;
}
/**
* Validate that a row number is a positive integer
*
* @param int $row
* @return int
* @throws Exception
*/
public static function validateRow(int $row): int
{
if ((!is_numeric($row)) || (intval($row) < 1)) {
throw new Exception('Invalid Row');
}
return (int)$row;
}
/**
* Validate that a column number is a positive integer
*
* @param int $column
* @return int
* @throws Exception
*/
public static function validateColumn(int $column): int
{
if ((!is_numeric($column)) || (intval($column) < 1)) {
throw new Exception('Invalid Column');
}
return (int)$column;
}
/**
* Validate that a row number falls within the set of rows for this matrix
*
* @param int $row
* @return int
* @throws Exception
*/
protected function validateRowInRange(int $row): int
{
$row = static::validateRow($row);
if ($row > $this->rows) {
throw new Exception('Requested Row exceeds matrix size');
}
return $row;
}
/**
* Validate that a column number falls within the set of columns for this matrix
*
* @param int $column
* @return int
* @throws Exception
*/
protected function validateColumnInRange(int $column): int
{
$column = static::validateColumn($column);
if ($column > $this->columns) {
throw new Exception('Requested Column exceeds matrix size');
}
return $column;
}
/**
* Return a new matrix as a subset of rows from this matrix, starting at row number $row, and $rowCount rows
* A $rowCount value of 0 will return all rows of the matrix from $row
* A negative $rowCount value will return rows until that many rows from the end of the matrix
*
* Note that row numbers start from 1, not from 0
*
* @param int $row
* @param int $rowCount
* @return static
* @throws Exception
*/
public function getRows(int $row, int $rowCount = 1): Matrix
{
$row = $this->validateRowInRange($row);
if ($rowCount === 0) {
$rowCount = $this->rows - $row + 1;
}
return new static(array_slice($this->grid, $row - 1, (int)$rowCount));
}
/**
* Return a new matrix as a subset of columns from this matrix, starting at column number $column, and $columnCount columns
* A $columnCount value of 0 will return all columns of the matrix from $column
* A negative $columnCount value will return columns until that many columns from the end of the matrix
*
* Note that column numbers start from 1, not from 0
*
* @param int $column
* @param int $columnCount
* @return Matrix
* @throws Exception
*/
public function getColumns(int $column, int $columnCount = 1): Matrix
{
$column = $this->validateColumnInRange($column);
if ($columnCount < 1) {
$columnCount = $this->columns + $columnCount - $column + 1;
}
$grid = [];
for ($i = $column - 1; $i < $column + $columnCount - 1; ++$i) {
$grid[] = array_column($this->grid, $i);
}
return (new static($grid))->transpose();
}
/**
* Return a new matrix as a subset of rows from this matrix, dropping rows starting at row number $row,
* and $rowCount rows
* A negative $rowCount value will drop rows until that many rows from the end of the matrix
* A $rowCount value of 0 will remove all rows of the matrix from $row
*
* Note that row numbers start from 1, not from 0
*
* @param int $row
* @param int $rowCount
* @return static
* @throws Exception
*/
public function dropRows(int $row, int $rowCount = 1): Matrix
{
$this->validateRowInRange($row);
if ($rowCount === 0) {
$rowCount = $this->rows - $row + 1;
}
$grid = $this->grid;
array_splice($grid, $row - 1, (int)$rowCount);
return new static($grid);
}
/**
* Return a new matrix as a subset of columns from this matrix, dropping columns starting at column number $column,
* and $columnCount columns
* A negative $columnCount value will drop columns until that many columns from the end of the matrix
* A $columnCount value of 0 will remove all columns of the matrix from $column
*
* Note that column numbers start from 1, not from 0
*
* @param int $column
* @param int $columnCount
* @return static
* @throws Exception
*/
public function dropColumns(int $column, int $columnCount = 1): Matrix
{
$this->validateColumnInRange($column);
if ($columnCount < 1) {
$columnCount = $this->columns + $columnCount - $column + 1;
}
$grid = $this->grid;
array_walk(
$grid,
function (&$row) use ($column, $columnCount) {
array_splice($row, $column - 1, (int)$columnCount);
}
);
return new static($grid);
}
/**
* Return a value from this matrix, from the "cell" identified by the row and column numbers
* Note that row and column numbers start from 1, not from 0
*
* @param int $row
* @param int $column
* @return mixed
* @throws Exception
*/
public function getValue(int $row, int $column)
{
$row = $this->validateRowInRange($row);
$column = $this->validateColumnInRange($column);
return $this->grid[$row - 1][$column - 1];
}
/**
* Returns a Generator that will yield each row of the matrix in turn as a vector matrix
* or the value of each cell if the matrix is a column vector
*
* @return Generator|Matrix[]|mixed[]
*/
public function rows(): Generator
{
foreach ($this->grid as $i => $row) {
yield $i + 1 => ($this->columns == 1)
? $row[0]
: new static([$row]);
}
}
/**
* Returns a Generator that will yield each column of the matrix in turn as a vector matrix
* or the value of each cell if the matrix is a row vector
*
* @return Generator|Matrix[]|mixed[]
*/
public function columns(): Generator
{
for ($i = 0; $i < $this->columns; ++$i) {
yield $i + 1 => ($this->rows == 1)
? $this->grid[0][$i]
: new static(array_column($this->grid, $i));
}
}
/**
* Identify if the row and column dimensions of this matrix are equal,
* i.e. if it is a "square" matrix
*
* @return bool
*/
public function isSquare(): bool
{
return $this->rows === $this->columns;
}
/**
* Identify if this matrix is a vector
* i.e. if it comprises only a single row or a single column
*
* @return bool
*/
public function isVector(): bool
{
return $this->rows === 1 || $this->columns === 1;
}
/**
* Return the matrix as a 2-dimensional array
*
* @return array
*/
public function toArray(): array
{
return $this->grid;
}
/**
* Solve A*X = B.
*
* @param Matrix $B Right hand side
*
* @throws Exception
*
* @return Matrix ... Solution if A is square, least squares solution otherwise
*/
public function solve(Matrix $B): Matrix
{
if ($this->columns === $this->rows) {
return (new LU($this))->solve($B);
}
return (new QR($this))->solve($B);
}
protected static $getters = [
'rows',
'columns',
];
/**
* Access specific properties as read-only (no setters)
*
* @param string $propertyName
* @return mixed
* @throws Exception
*/
public function __get(string $propertyName)
{
$propertyName = strtolower($propertyName);
// Test for function calls
if (in_array($propertyName, self::$getters)) {
return $this->$propertyName;
}
throw new Exception('Property does not exist');
}
protected static $functions = [
'adjoint',
'antidiagonal',
'cofactors',
'determinant',
'diagonal',
'identity',
'inverse',
'minors',
'trace',
'transpose',
];
protected static $operations = [
'add',
'subtract',
'multiply',
'divideby',
'divideinto',
'directsum',
];
/**
* Returns the result of the function call or operation
*
* @param string $functionName
* @param mixed[] $arguments
* @return Matrix|float
* @throws Exception
*/
public function __call(string $functionName, $arguments)
{
$functionName = strtolower(str_replace('_', '', $functionName));
// Test for function calls
if (in_array($functionName, self::$functions, true)) {
return Functions::$functionName($this, ...$arguments);
}
// Test for operation calls
if (in_array($functionName, self::$operations, true)) {
return Operations::$functionName($this, ...$arguments);
}
throw new Exception('Function or Operation does not exist');
}
}
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