File Source for trendClass.php

PHPExcel

# Source for file trendClass.php

Documentation is available at trendClass.php

1. <?php
3. require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/linearBestFitClass.php';
4. require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/logarithmicBestFitClass.php';
5. require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/exponentialBestFitClass.php';
6. require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/powerBestFitClass.php';
7. require_once PHPEXCEL_ROOT . 'PHPExcel/Shared/trend/polynomialBestFitClass.php';
10. class trendClass
11. {
12. const TREND_LINEAR = 'Linear';
13. const TREND_LOGARITHMIC = 'Logarithmic';
14. const TREND_EXPONENTIAL = 'Exponential';
15. const TREND_POWER = 'Power';
16. const TREND_POLYNOMIAL_2 = 'Polynomial_2';
17. const TREND_POLYNOMIAL_3 = 'Polynomial_3';
18. const TREND_POLYNOMIAL_4 = 'Polynomial_4';
19. const TREND_POLYNOMIAL_5 = 'Polynomial_5';
20. const TREND_POLYNOMIAL_6 = 'Polynomial_6';
21. const TREND_BEST_FIT = 'Bestfit';
22. const TREND_BEST_FIT_NO_POLY = 'Bestfit_no_Polynomials';
24. private static $_trendTypes = array( self:: TREND_LINEAR,
25. self:: TREND_LOGARITHMIC,
26. self:: TREND_EXPONENTIAL,
27. self:: TREND_POWER
28. );
29. private static $_trendTypePolyOrders = array( self:: TREND_POLYNOMIAL_2,
30. self:: TREND_POLYNOMIAL_3,
31. self:: TREND_POLYNOMIAL_4,
32. self:: TREND_POLYNOMIAL_5,
33. self:: TREND_POLYNOMIAL_6
34. );
36. private static $_trendCache = array();
39. public static function calculate($trendType=self:: TREND_BEST_FIT, $yValues, $xValues=array(), $const=True) {
40. // Calculate number of points in each dataset
41. $nY = count($yValues);
42. $nX = count($xValues);
44. // Define X Values if necessary
45. if ($nX == 0) {
46. $xValues = range(1,$nY);
47. $nX = $nY;
48. } elseif ($nY != $nX) {
49. // Ensure both arrays of points are the same size
50. trigger_error("trend(): Number of elements in coordinate arrays do not match.", E_USER_ERROR);
51. }
53. $key = md5($trendType.$const.serialize($yValues).serialize($xValues));
54. // Determine which trend method has been requested
55. switch ($trendType) {
56. // Instantiate and return the class for the requested trend method
57. case self:: TREND_LINEAR :
58. case self:: TREND_LOGARITHMIC :
59. case self:: TREND_EXPONENTIAL :
60. case self:: TREND_POWER :
61. if (!isset(self::$_trendCache[$key])) {
62. $className = 'PHPExcel_'.$trendType.'_Best_Fit';
63. self::$_trendCache[$key] = new $className($yValues,$xValues,$const);
64. }
65. return self::$_trendCache[$key];
66. break;
67. case self:: TREND_POLYNOMIAL_2 :
68. case self:: TREND_POLYNOMIAL_3 :
69. case self:: TREND_POLYNOMIAL_4 :
70. case self:: TREND_POLYNOMIAL_5 :
71. case self:: TREND_POLYNOMIAL_6 :
72. if (!isset(self::$_trendCache[$key])) {
73. $order = substr($trendType,-1);
74. self::$_trendCache[$key] = new PHPExcel_Polynomial_Best_Fit($order,$yValues,$xValues,$const);
75. }
76. return self::$_trendCache[$key];
77. break;
78. case self:: TREND_BEST_FIT :
79. case self:: TREND_BEST_FIT_NO_POLY :
80. // If the request is to determine the best fit regression, then we test each trend line in turn
81. // Start by generating an instance of each available trend method
82. foreach(self::$_trendTypes as $trendMethod) {
83. $className = 'PHPExcel_'.$trendMethod.'BestFit';
84. $bestFit[$trendMethod] = new $className($yValues,$xValues,$const);
85. $bestFitValue[$trendMethod] = $bestFit[$trendMethod]->getGoodnessOfFit();
86. }
87. if ($trendType != self:: TREND_BEST_FIT_NO_POLY) {
88. foreach(self::$_trendTypePolyOrders as $trendMethod) {
89. $order = substr($trendMethod,-1);
90. $bestFit[$trendMethod] = new PHPExcel_Polynomial_Best_Fit($order,$yValues,$xValues,$const);
91. if ($bestFit[$trendMethod]->getError()) {
92. unset($bestFit[$trendMethod]);
93. } else {
94. $bestFitValue[$trendMethod] = $bestFit[$trendMethod]->getGoodnessOfFit();
95. }
96. }
97. }
98. // Determine which of our trend lines is the best fit, and then we return the instance of that trend class
99. arsort($bestFitValue);
100. $bestFitType = key($bestFitValue);
101. return $bestFit[$bestFitType];
102. break;
103. default :
104. return false;
105. }
106. } // function calculate()
108. } // class trendClass

Documentation generated on Sun, 27 Feb 2011 16:35:44 -0800 by phpDocumentor 1.4.3