bestFitClass.php

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<?php
class PHPExcel_Best_Fit
{
        protected $_error                               = False;

        protected $_bestFitType                 = 'undetermined';

        protected $_valueCount                  = 0;

        protected $_xValues                             = array();

        protected $_yValues                             = array();

        protected $_adjustToZero                = False;

        protected $_yBestFitValues              = array();

        protected $_goodnessOfFit               = 1;

        protected $_stdevOfResiduals    = 0;

        protected $_covariance                  = 0;

        protected $_correlation                 = 0;

        protected $_SSRegression                = 0;

        protected $_SSResiduals                 = 0;

        protected $_DFResiduals                 = 0;

        protected $_F                                   = 0;

        protected $_slope                               = 0;

        protected $_slopeSE                             = 0;

        protected $_intersect                   = 0;

        protected $_intersectSE                 = 0;

        protected $_Xoffset                             = 0;

        protected $_Yoffset                             = 0;


        public function getError() {
                return $this->_error;
        }       //      function getBestFitType()


        public function getBestFitType() {
                return $this->_bestFitType;
        }       //      function getBestFitType()


        public function getValueOfYForX($xValue) {
                return False;
        }       //      function getValueOfYForX()


        public function getValueOfXForY($yValue) {
                return False;
        }       //      function getValueOfXForY()


        public function getXValues() {
                return $this->_xValues;
        }       //      function getValueOfXForY()


        public function getEquation($dp=0) {
                return False;
        }       //      function getEquation()


        public function getSlope($dp=0) {
                if ($dp != 0) {
                        return round($this->_slope,$dp);
                }
                return $this->_slope;
        }       //      function getSlope()


        public function getSlopeSE($dp=0) {
                if ($dp != 0) {
                        return round($this->_slopeSE,$dp);
                }
                return $this->_slopeSE;
        }       //      function getSlopeSE()


        public function getIntersect($dp=0) {
                if ($dp != 0) {
                        return round($this->_intersect,$dp);
                }
                return $this->_intersect;
        }       //      function getIntersect()


        public function getIntersectSE($dp=0) {
                if ($dp != 0) {
                        return round($this->_intersectSE,$dp);
                }
                return $this->_intersectSE;
        }       //      function getIntersectSE()


        public function getGoodnessOfFit($dp=0) {
                if ($dp != 0) {
                        return round($this->_goodnessOfFit,$dp);
                }
                return $this->_goodnessOfFit;
        }       //      function getGoodnessOfFit()


        public function getGoodnessOfFitPercent($dp=0) {
                if ($dp != 0) {
                        return round($this->_goodnessOfFit * 100,$dp);
                }
                return $this->_goodnessOfFit * 100;
        }       //      function getGoodnessOfFitPercent()


        public function getStdevOfResiduals($dp=0) {
                if ($dp != 0) {
                        return round($this->_stdevOfResiduals,$dp);
                }
                return $this->_stdevOfResiduals;
        }       //      function getStdevOfResiduals()


        public function getSSRegression($dp=0) {
                if ($dp != 0) {
                        return round($this->_SSRegression,$dp);
                }
                return $this->_SSRegression;
        }       //      function getSSRegression()


        public function getSSResiduals($dp=0) {
                if ($dp != 0) {
                        return round($this->_SSResiduals,$dp);
                }
                return $this->_SSResiduals;
        }       //      function getSSResiduals()


        public function getDFResiduals($dp=0) {
                if ($dp != 0) {
                        return round($this->_DFResiduals,$dp);
                }
                return $this->_DFResiduals;
        }       //      function getDFResiduals()


        public function getF($dp=0) {
                if ($dp != 0) {
                        return round($this->_F,$dp);
                }
                return $this->_F;
        }       //      function getF()


        public function getCovariance($dp=0) {
                if ($dp != 0) {
                        return round($this->_covariance,$dp);
                }
                return $this->_covariance;
        }       //      function getCovariance()


        public function getCorrelation($dp=0) {
                if ($dp != 0) {
                        return round($this->_correlation,$dp);
                }
                return $this->_correlation;
        }       //      function getCorrelation()


        public function getYBestFitValues() {
                return $this->_yBestFitValues;
        }       //      function getYBestFitValues()


        protected function _calculateGoodnessOfFit($sumX,$sumY,$sumX2,$sumY2,$sumXY,$meanX,$meanY, $const) {
                $SSres = $SScov = $SScor = $SStot = $SSsex = 0.0;
                foreach($this->_xValues as $xKey => $xValue) {
                        $bestFitY = $this->_yBestFitValues[$xKey] = $this->getValueOfYForX($xValue);

                        $SSres += ($this->_yValues[$xKey] - $bestFitY) * ($this->_yValues[$xKey] - $bestFitY);
                        if ($const) {
                                $SStot += ($this->_yValues[$xKey] - $meanY) * ($this->_yValues[$xKey] - $meanY);
                        } else {
                                $SStot += $this->_yValues[$xKey] * $this->_yValues[$xKey];
                        }
                        $SScov += ($this->_xValues[$xKey] - $meanX) * ($this->_yValues[$xKey] - $meanY);
                        if ($const) {
                                $SSsex += ($this->_xValues[$xKey] - $meanX) * ($this->_xValues[$xKey] - $meanX);
                        } else {
                                $SSsex += $this->_xValues[$xKey] * $this->_xValues[$xKey];
                        }
                }

                $this->_SSResiduals = $SSres;
                $this->_DFResiduals = $this->_valueCount - 1 - $const;

                if ($this->_DFResiduals == 0.0) {
                        $this->_stdevOfResiduals = 0.0;
                } else {
                        $this->_stdevOfResiduals = sqrt($SSres / $this->_DFResiduals);
                }
                if (($SStot == 0.0) || ($SSres == $SStot)) {
                        $this->_goodnessOfFit = 1;
                } else {
                        $this->_goodnessOfFit = 1 - ($SSres / $SStot);
                }

                $this->_SSRegression = $this->_goodnessOfFit * $SStot;
                $this->_covariance = $SScov / $this->_valueCount;
                $this->_correlation = ($this->_valueCount * $sumXY - $sumX * $sumY) / sqrt(($this->_valueCount * $sumX2 - pow($sumX,2)) * ($this->_valueCount * $sumY2 - pow($sumY,2)));
                $this->_slopeSE = $this->_stdevOfResiduals / sqrt($SSsex);
                $this->_intersectSE = $this->_stdevOfResiduals * sqrt(1 / ($this->_valueCount - ($sumX * $sumX) / $sumX2));
                if ($this->_SSResiduals != 0.0) {
                        if ($this->_DFResiduals == 0.0) {
                                $this->_F = 0.0;
                        } else {
                                $this->_F = $this->_SSRegression / ($this->_SSResiduals / $this->_DFResiduals);
                        }
                } else {
                        if ($this->_DFResiduals == 0.0) {
                                $this->_F = 0.0;
                        } else {
                                $this->_F = $this->_SSRegression / $this->_DFResiduals;
                        }
                }
        }       //      function _calculateGoodnessOfFit()


        protected function _leastSquareFit($yValues, $xValues, $const) {
                // calculate sums
                $x_sum = array_sum($xValues);
                $y_sum = array_sum($yValues);
                $meanX = $x_sum / $this->_valueCount;
                $meanY = $y_sum / $this->_valueCount;
                $mBase = $mDivisor = $xx_sum = $xy_sum = $yy_sum = 0.0;
                for($i = 0; $i < $this->_valueCount; ++$i) {
                        $xy_sum += $xValues[$i] * $yValues[$i];
                        $xx_sum += $xValues[$i] * $xValues[$i];
                        $yy_sum += $yValues[$i] * $yValues[$i];

                        if ($const) {
                                $mBase += ($xValues[$i] - $meanX) * ($yValues[$i] - $meanY);
                                $mDivisor += ($xValues[$i] - $meanX) * ($xValues[$i] - $meanX);
                        } else {
                                $mBase += $xValues[$i] * $yValues[$i];
                                $mDivisor += $xValues[$i] * $xValues[$i];
                        }
                }

                // calculate slope
//              $this->_slope = (($this->_valueCount * $xy_sum) - ($x_sum * $y_sum)) / (($this->_valueCount * $xx_sum) - ($x_sum * $x_sum));
                $this->_slope = $mBase / $mDivisor;

                // calculate intersect
//              $this->_intersect = ($y_sum - ($this->_slope * $x_sum)) / $this->_valueCount;
                if ($const) {
                        $this->_intersect = $meanY - ($this->_slope * $meanX);
                } else {
                        $this->_intersect = 0;
                }

                $this->_calculateGoodnessOfFit($x_sum,$y_sum,$xx_sum,$yy_sum,$xy_sum,$meanX,$meanY,$const);
        }       //      function _leastSquareFit()


        function __construct($yValues, $xValues=array(), $const=True) {
                //      Calculate number of points
                $nY = count($yValues);
                $nX = count($xValues);

                //      Define X Values if necessary
                if ($nX == 0) {
                        $xValues = range(1,$nY);
                        $nX = $nY;
                } elseif ($nY != $nX) {
                        //      Ensure both arrays of points are the same size
                        $this->_error = True;
                        return False;
                }

                $this->_valueCount = $nY;
                $this->_xValues = $xValues;
                $this->_yValues = $yValues;
        }       //      function __construct()

}       //      class bestFit