PHPExcel_Polynomial_Best_Fit Class Reference

Inheritance diagram for PHPExcel_Polynomial_Best_Fit:

Collaboration diagram for PHPExcel_Polynomial_Best_Fit:

Public Member Functions
	getOrder ()
	Return the order of this polynomial. More...
	getValueOfYForX ($xValue)
	Return the Y-Value for a specified value of X. More...
	getValueOfXForY ($yValue)
	Return the X-Value for a specified value of Y. More...
	getEquation ($dp=0)
	Return the Equation of the best-fit line. More...
	getSlope ($dp=0)
	Return the Slope of the line. More...
	getCoefficients ($dp=0)
	__construct ($order, $yValues, $xValues=array(), $const=True)
	Define the regression and calculate the goodness of fit for a set of X and Y data values. More...
Public Member Functions inherited from PHPExcel_Best_Fit
	getError ()
	getBestFitType ()
	getValueOfYForX ($xValue)
	Return the Y-Value for a specified value of X. More...
	getValueOfXForY ($yValue)
	Return the X-Value for a specified value of Y. More...
	getXValues ()
	Return the original set of X-Values. More...
	getEquation ($dp=0)
	Return the Equation of the best-fit line. More...
	getSlope ($dp=0)
	Return the Slope of the line. More...
	getSlopeSE ($dp=0)
	Return the standard error of the Slope. More...
	getIntersect ($dp=0)
	Return the Value of X where it intersects Y = 0. More...
	getIntersectSE ($dp=0)
	Return the standard error of the Intersect. More...
	getGoodnessOfFit ($dp=0)
	Return the goodness of fit for this regression. More...
	getGoodnessOfFitPercent ($dp=0)
	getStdevOfResiduals ($dp=0)
	Return the standard deviation of the residuals for this regression. More...
	getSSRegression ($dp=0)
	getSSResiduals ($dp=0)
	getDFResiduals ($dp=0)
	getF ($dp=0)
	getCovariance ($dp=0)
	getCorrelation ($dp=0)
	getYBestFitValues ()
	__construct ($yValues, $xValues=array(), $const=True)
	Define the regression. More...

Protected Attributes
	$_bestFitType = 'polynomial'
	$_order = 0
Protected Attributes inherited from PHPExcel_Best_Fit
	$_error = False
	$_bestFitType = 'undetermined'
	$_valueCount = 0
	$_xValues = array()
	$_yValues = array()
	$_adjustToZero = False
	$_yBestFitValues = array()
	$_goodnessOfFit = 1
	$_stdevOfResiduals = 0
	$_covariance = 0
	$_correlation = 0
	$_SSRegression = 0
	$_SSResiduals = 0
	$_DFResiduals = 0
	$_F = 0
	$_slope = 0
	$_slopeSE = 0
	$_intersect = 0
	$_intersectSE = 0
	$_Xoffset = 0
	$_Yoffset = 0

Private Member Functions
	_polynomial_regression ($order, $yValues, $xValues, $const)
	Execute the regression and calculate the goodness of fit for a set of X and Y data values. More...

Additional Inherited Members
Protected Member Functions inherited from PHPExcel_Best_Fit
	_calculateGoodnessOfFit ($sumX, $sumY, $sumX2, $sumY2, $sumXY, $meanX, $meanY, $const)
	_leastSquareFit ($yValues, $xValues, $const)

Detailed Description

Definition at line 40 of file polynomialBestFitClass.php.

Constructor & Destructor Documentation

__construct()

PHPExcel_Polynomial_Best_Fit::__construct	(		$order,
			$yValues,
			$xValues = array(),
			$const = True
	)

Define the regression and calculate the goodness of fit for a set of X and Y data values.

Parameters

int	$order	Order of Polynomial for this regression
	float[]	$yValues The set of Y-values for this regression
	float[]	$xValues The set of X-values for this regression
boolean	$const

Definition at line 209 of file polynomialBestFitClass.php.

References _polynomial_regression(), and PHPExcel_Best_Fit\getGoodnessOfFit().

                                                                              {
                if (parent::__construct($yValues, $xValues) !== False) {
                        if ($order < $this->_valueCount) {
                                $this->_bestFitType .= '_'.$order;
                                $this->_order = $order;
                                $this->_polynomial_regression($order, $yValues, $xValues, $const);
                                if (($this->getGoodnessOfFit() < 0.0) || ($this->getGoodnessOfFit() > 1.0)) {
                                        $this->_error = True;
                                }
                        } else {
                                $this->_error = True;
                        }
                }
        }       //      function __construct()

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Member Function Documentation

_polynomial_regression()

PHPExcel_Polynomial_Best_Fit::_polynomial_regression (   $order,   $yValues,   $xValues,   $const  )

private

Execute the regression and calculate the goodness of fit for a set of X and Y data values.

Parameters

int	$order	Order of Polynomial for this regression
	float[]	$yValues The set of Y-values for this regression
	float[]	$xValues The set of X-values for this regression
boolean	$const

Definition at line 152 of file polynomialBestFitClass.php.

References PHPExcel_Best_Fit\$_valueCount, $i, $r, PHPExcel_Best_Fit\_calculateGoodnessOfFit(), array, and getValueOfYForX().

Referenced by __construct().

                                                                                    {
                // calculate sums
                $x_sum = array_sum($xValues);
                $y_sum = array_sum($yValues);
                $xx_sum = $xy_sum = 0;
                for($i = 0; $i < $this->_valueCount; ++$i) {
                        $xy_sum += $xValues[$i] * $yValues[$i];
                        $xx_sum += $xValues[$i] * $xValues[$i];
                        $yy_sum += $yValues[$i] * $yValues[$i];
                }
                /*
                 *      This routine uses logic from the PHP port of polyfit version 0.1
                 *      written by Michael Bommarito and Paul Meagher
                 *
                 *      The function fits a polynomial function of order $order through
                 *      a series of x-y data points using least squares.
                 *
                 */
                for ($i = 0; $i < $this->_valueCount; ++$i) {
                        for ($j = 0; $j <= $order; ++$j) {
                                $A[$i][$j] = pow($xValues[$i], $j);
                        }
                }
                for ($i=0; $i < $this->_valueCount; ++$i) {
                        $B[$i] = array($yValues[$i]);
                }
                $matrixA = new Matrix($A);
                $matrixB = new Matrix($B);
                $C = $matrixA->solve($matrixB);

                $coefficients = array();
                for($i = 0; $i < $C->m; ++$i) {
                        $r = $C->get($i, 0);
                        if (abs($r) <= pow(10, -9)) {
                                $r = 0;
                        }
                        $coefficients[] = $r;
                }

                $this->_intersect = array_shift($coefficients);
                $this->_slope = $coefficients;

                $this->_calculateGoodnessOfFit($x_sum,$y_sum,$xx_sum,$yy_sum,$xy_sum);
                foreach($this->_xValues as $xKey => $xValue) {
                        $this->_yBestFitValues[$xKey] = $this->getValueOfYForX($xValue);
                }
        }       //      function _polynomial_regression()

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getCoefficients()

PHPExcel_Polynomial_Best_Fit::getCoefficients

(

$dp = 0

)

Definition at line 139 of file polynomialBestFitClass.php.

References array, PHPExcel_Best_Fit\getIntersect(), and getSlope().

                                               {
                return array_merge(array($this->getIntersect($dp)),$this->getSlope($dp));
        }       //      function getCoefficients()

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getEquation()

PHPExcel_Polynomial_Best_Fit::getEquation

(

$dp = 0

)

Return the Equation of the best-fit line.

Parameters

int

$dp

Number of places of decimal precision to display

Returns

string

Definition at line 104 of file polynomialBestFitClass.php.

References $key, PHPExcel_Best_Fit\getIntersect(), and getSlope().

                                           {
                $slope = $this->getSlope($dp);
                $intersect = $this->getIntersect($dp);

                $equation = 'Y = '.$intersect;
                foreach($slope as $key => $value) {
                        if ($value != 0.0) {
                                $equation .= ' + '.$value.' * X';
                                if ($key > 0) {
                                        $equation .= '^'.($key + 1);
                                }
                        }
                }
                return $equation;
        }       //      function getEquation()

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getOrder()

PHPExcel_Polynomial_Best_Fit::getOrder

(

)

Return the order of this polynomial.

Returns

int

Definition at line 64 of file polynomialBestFitClass.php.

References $_order.

                                   {
                return $this->_order;
        }       //      function getOrder()

getSlope()

PHPExcel_Polynomial_Best_Fit::getSlope

(

$dp = 0

)

Return the Slope of the line.

Parameters

int

$dp

Number of places of decimal precision to display

Returns

string

Definition at line 127 of file polynomialBestFitClass.php.

References PHPExcel_Best_Fit\$_slope, and array.

Referenced by getCoefficients(), getEquation(), getValueOfXForY(), and getValueOfYForX().

                                        {
                if ($dp != 0) {
                        $coefficients = array();
                        foreach($this->_slope as $coefficient) {
                                $coefficients[] = round($coefficient,$dp);
                        }
                        return $coefficients;
                }
                return $this->_slope;
        }       //      function getSlope()

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getValueOfXForY()

PHPExcel_Polynomial_Best_Fit::getValueOfXForY

(

$yValue

)

Return the X-Value for a specified value of Y.

Parameters

float

$yValue

Y-Value

Returns

float X-Value

Definition at line 93 of file polynomialBestFitClass.php.

References PHPExcel_Best_Fit\getIntersect(), and getSlope().

                                                 {
                return ($yValue - $this->getIntersect()) / $this->getSlope();
        }       //      function getValueOfXForY()

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getValueOfYForX()

PHPExcel_Polynomial_Best_Fit::getValueOfYForX

(

$xValue

)

Return the Y-Value for a specified value of X.

Parameters

float

$xValue

X-Value

Returns

float Y-Value

Definition at line 75 of file polynomialBestFitClass.php.

References $key, PHPExcel_Best_Fit\getIntersect(), and getSlope().

Referenced by _polynomial_regression().

                                                 {
                $retVal = $this->getIntersect();
                $slope = $this->getSlope();
                foreach($slope as $key => $value) {
                        if ($value != 0.0) {
                                $retVal += $value * pow($xValue, $key + 1);
                        }
                }
                return $retVal;
        }       //      function getValueOfYForX()

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Field Documentation

$_bestFitType

PHPExcel_Polynomial_Best_Fit::$_bestFitType = 'polynomial'

protected

Definition at line 48 of file polynomialBestFitClass.php.

$_order

PHPExcel_Polynomial_Best_Fit::$_order = 0

protected

Definition at line 56 of file polynomialBestFitClass.php.

Referenced by getOrder().

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The documentation for this class was generated from the following file:

• libs/composer/vendor/phpoffice/phpexcel/Classes/PHPExcel/Shared/trend/polynomialBestFitClass.php