Calculates the upper and lower incomplete gamma functions as well as their normalised versions. More...
Go to the source code of this file.
Namespaces | |
Foam | |
Namespace for OpenFOAM. | |
Functions | |
static scalar | calcQE11 (const scalar a, const scalar x, const int e=30) |
static scalar | calcPE15 (const scalar a, const scalar x, const int nmax=20) |
static scalar | calcQE16 (const scalar a, const scalar x, const int N=20) |
static scalar | calcTE18 (const scalar a, const scalar e0, const scalar x, const scalar lambda, const scalar sigma, const scalar phi) |
Calculates the upper and lower incomplete gamma functions as well as their normalised versions.
Original source file incGamma.C
The algorithm is described in detail in DiDonato et al. (1986).
DiDonato, A. R., & Morris Jr, A. H. (1986). Computation of the incomplete gamma function ratios and their inverse. ACM Transactions on Mathematical Software (TOMS), 12(4), 377-393.
All equation numbers in the following code refer to the above paper. The algorithm in function 'incGammaRatio_Q' is described in section 3. The accuracy parameter IND is set to a value of 1.
Definition in file incGamma.C.