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Diffstat (limited to 'src/math/matrix.php')
| -rw-r--r-- | src/math/matrix.php | 266 |
1 files changed, 266 insertions, 0 deletions
diff --git a/src/math/matrix.php b/src/math/matrix.php new file mode 100644 index 0000000..dae2f64 --- /dev/null +++ b/src/math/matrix.php @@ -0,0 +1,266 @@ +<?php +/** + * File containing the abstract ezcGraphMatrix class + * + * @package Graph + * @version //autogentag// + * @copyright Copyright (C) 2005, 2006 eZ systems as. All rights reserved. + * @license http://ez.no/licenses/new_bsd New BSD License + */ +/** + * Provides a genereic matrix class with basic math operations + * + * @package Graph + */ +class ezcGraphMatrix +{ + + protected $columns; + + protected $rows; + + protected $matrix; + + /** + * Constructor + * + * Creates a matrix with given dimensions. Optionally accepts an array to + * define the initial matrix values. If no array is given an identity + * matrix is created. + * + * @param int $columns Number of columns + * @param int $rows Number of rows + * @param array $values Array with values + * @return void + */ + public function __construct( $columns = 3, $rows = 3, array $values = null ) + { + $this->columns = max( 2, (int) $columns ); + $this->rows = max( 2, (int) $rows ); + + if ( $values !== null ) + { + $this->fromArray( $values ); + } + else + { + $this->init(); + } + } + + /** + * Create matrix from array + * + * Use the array values to set matrix values + * + * @param array $values Array with values + * @return ezcGraphMatrix Modified matrix + */ + public function fromArray( array $values ) + { + for ( $i = 0; $i < $this->columns; ++$i ) + { + for ( $j = 0; $j < $this->rows; ++$j ) + { + $this->matrix[$i][$j] = + ( isset( $values[$i][$j] ) + ? (float) $values[$i][$j] + : 0 ); + } + } + + return $this; + } + + /** + * Init matrix + * + * Sets matrix to identity matrix + * + * @return ezcGraphMatrix Modified matrix + */ + public function init() + { + for ( $i = 0; $i < $this->columns; ++$i ) + { + for ( $j = 0; $j < $this->rows; ++$j ) + { + $this->matrix[$i][$j] = ( $i === $j ? 1 : 0 ); + } + } + + return $this; + } + + /** + * Returns number of columns + * + * @return int Number of columns + */ + public function columns() + { + return $this->columns; + } + + /** + * Returns number of rows + * + * @return int Number of rows + */ + public function rows() + { + return $this->rows; + } + + /** + * Get a single matrix value + * + * Returns the value of the matrix at the given position + * + * @param int $i Row + * @param int $j Column + * @return float Matrix value + */ + public function get( $i, $j ) + { + if ( !isset( $this->matrix[$i][$j] ) ) + { + throw new ezcGraphMatrixOutOfBoundingsException( $this->columns, $this->rows, $i, $j ); + } + + return $this->matrix[$i][$j]; + } + + /** + * Set a single matrix value + * + * Sets the value of the matrix at the given position + * + * @param int $i Row + * @param int $j Column + * @param float $value Value + * @return ezcGraphMatrix Updated matrix + */ + public function set( $i, $j, $value ) + { + if ( !isset( $this->matrix[$i][$j] ) ) + { + throw new ezcGraphMatrixOutOfBoundingsException( $this->columns, $this->rows, $i, $j ); + } + + $this->matrix[$i][$j] = $value; + + return $this; + } + + /** + * Adds one matrix to the current one + * + * Calculate the sum of two matrices and returns the resulting matrix. + * + * @param ezcGraphMatrix $matrix Matrix to sum with + * @return ezcGraphMatrix Result matrix + */ + public function add( ezcGraphMatrix $matrix ) + { + if ( ( $this->columns !== $matrix->columns() ) || + ( $this->rows !== $matrix->rows() ) ) + { + throw new ezcGraphMatrixInvalidDimensionsException( $this->columns, $this->rows, $matrix->columns(), $matrix->rows() ); + } + + for ( $i = 0; $i < $this->columns; ++$i ) + { + for ( $j = 0; $j < $this->rows; ++$j ) + { + $this->matrix[$i][$j] += $matrix->get( $i, $j ); + } + } + + return $this; + } + + /** + * Subtracts matrix from current one + * + * Calculate the diffenrence of two matices and returns the result matrix. + * + * @param ezcGraphMatrix $matrix subtrahend + * @return ezcGraphMatrix Result matrix + */ + public function diff( ezcGraphMatrix $matrix ) + { + if ( ( $this->columns !== $matrix->columns() ) || + ( $this->rows !== $matrix->rows() ) ) + { + throw new ezcGraphMatrixInvalidDimensionsException( $this->columns, $this->rows, $matrix->columns(), $matrix->rows() ); + } + + for ( $i = 0; $i < $this->columns; ++$i ) + { + for ( $j = 0; $j < $this->rows; ++$j ) + { + $this->matrix[$i][$j] -= $matrix->get( $i, $j ); + } + } + + return $this; + } + + /** + * Scalar multiplication + * + * Multiplies matrix with the given scalar and returns the result matrix + * + * @param float $scalar Scalar + * @return ezcGraphMatrix Result matrix + */ + public function scalar( $scalar ) + { + $scalar = (float) $scalar; + + for ( $i = 0; $i < $this->columns; ++$i ) + { + for ( $j = 0; $j < $this->rows; ++$j ) + { + $this->matrix[$i][$j] *= $scalar; + } + } + } + + /** + * Multiplies two matrices + * + * Multiply current matrix with another matrix and returns the result + * matrix. + * + * @param ezcGraphMatrix $matrix Second factor + * @returns ezcGraphMatrix Result matrix + */ + public function multiply( ezcGraphMatrix $matrix ) + { + $mColumns = $matrix->columns(); + if ( $this->columns !== ( $mRows = $matrix->rows() ) ) + { + throw new ezcGraphMatrixInvalidDimensionsException( $this->columns, $this->rows, $mColumns, $mRows ); + } + + $result = new ezcGraphMatrix( $mRows, $mRows ); + + for ( $i = 0; $i < $this->columns; ++$i ) + { + for ( $j = 0; $j < $mRows; ++$j ) + { + $sum = 0; + for ( $k = 0; $k < $mColumns; ++$k ) { + $sum += $this->matrix[$i][$k] * $matrix->get( $k, $j ); + } + + $result->set( $i, $j, $sum ); + } + } + + return $result; + } +} +?> |
