Advanced Analysis Library Only
double Gamma (double x, double *a);
Evaluates the gamma function or the incomplete gamma function, depending on the value of a. The gamma function is defined as follows:
The incomplete gamma function is defined as follows:
The following formula relates the gamma function to the factorial function:
| Input | ||
| Name | Type | Description |
| x | double-precision | The point at which the gamma function is evaluated. |
| a | double-precision pointer | The upper limit of the incomplete gamma function. The gamma function is evaluated if a is NULL. Otherwise, the incomplete gamma function is evaluated. |
| Name | Type | Description |
| result | double-precision | The value of the evaluated gamma or incomplete gamma function. |