/** * Returns the regularized gamma function P(a, x). */ public static function regularizedGammaP($a, $x, $epsilon, $maxIterations) { $ret; if (is_nan($a) || is_nan($x) || $a <= 0.0 || $x < 0.0) { $ret = NAN; } else { if ($x == 0.0) { $ret = 0.0; } else { if ($x >= $a + 1) { // use regularizedGammaQ because it should converge faster in this // case. $ret = 1.0 - Statistics::regularizedGammaQ($a, $x, $epsilon, $maxIterations); } else { // calculate series $n = 0.0; // current element index $an = 1.0 / $a; // n-th element in the series $sum = $an; // partial sum while (abs($an / $sum) > $epsilon && $n < $maxIterations && $sum < INF) { // compute next element in the series $n = $n + 1.0; $an = $an * ($x / ($a + $n)); // update partial sum $sum = $sum + $an; } if ($n >= $maxIterations) { throw new Exception("Statistics::reqularizedGammaP: " . "max # iterations reached: " . $maxIterations); } else { if (is_infinite($sum)) { $ret = 1.0; } else { $ret = exp(-$x + $a * log($x) - Statistics::logGamma($a)) * $sum; } } } } } return $ret; }
try { Statistics::invGamma1pm1(-2.5); notify('InvGamma1pm1 too small', "Exception thrown", "Ok"); } catch (Exception $ex1) { notify('InvGamma1pm1 too small', $ex1, $ex1); } try { Statistics::invGamma1pm1(2.5); notify('InvGamma1pm1 too large', "Exception thrown", "Ok"); } catch (Exception $ex1) { notify('InvGamma1pm1 too large', $ex1, $ex1); } notify('Lanczos', 19.194552097849, Statistics::lanczos(0.5)); notify('LogGamma', 0.5723649429247, Statistics::logGamma(0.5)); notify('RegularizedGammaP', 0.77932863808015, Statistics::regularizedGammaP(0.5, 0.75, 1.0E-15, 10000)); notify('RegularizedGammaQ', 0.061368829139402, Statistics::regularizedGammaQ(0.5, 1.75, 1.0E-15, 10000)); // Global test $rtgm->calculate(); notify('Get risk coefficient', $riskCoeff, $rtgm->riskCoeff); notify('Get rtgm iter', $rtgmIters, $rtgm->rtgmIters); notify('Get risk iter', $riskIters, $rtgm->riskIters); printf("\nriskCoeff: %s\n", $rtgm->riskCoeff); printf("rtgmIters: [%s]\n", implode(', ', $rtgm->rtgmIters)); printf("riskIters: [%s]\n", implode(', ', $rtgm->riskIters)); } catch (Exception $e) { print $e->getMessage() . "\n"; } exit($exit_code); ?>