protected function PHPExcel_Best_Fit::_leastSquareFit in Loft Data Grids 7.2

Same name and namespace in other branches

1. 6.2 vendor/phpoffice/phpexcel/Classes/PHPExcel/Shared/trend/bestFitClass.php \PHPExcel_Best_Fit::_leastSquareFit()

4 calls to PHPExcel_Best_Fit::_leastSquareFit()

PHPExcel_Exponential_Best_Fit::_exponential_regression in vendor/phpoffice/phpexcel/Classes/PHPExcel/Shared/trend/exponentialBestFitClass.php

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

PHPExcel_Linear_Best_Fit::_linear_regression in vendor/phpoffice/phpexcel/Classes/PHPExcel/Shared/trend/linearBestFitClass.php

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

PHPExcel_Logarithmic_Best_Fit::_logarithmic_regression in vendor/phpoffice/phpexcel/Classes/PHPExcel/Shared/trend/logarithmicBestFitClass.php

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

PHPExcel_Power_Best_Fit::_power_regression in vendor/phpoffice/phpexcel/Classes/PHPExcel/Shared/trend/powerBestFitClass.php

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

File

vendor/phpoffice/phpexcel/Classes/PHPExcel/Shared/trend/bestFitClass.php, line 368

Class

PHPExcel_Best_Fit

PHPExcel_Best_Fit

Code

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);
}