log_gamma
Evaluates the logarithm of the absolute value of the gamma function log |Γ(x)|.
Synopsis
#include <imsls.h>
float imsls_f_log_gamma (float x)
The type double procedure is imsls_d_log_gamma.
Required Arguments
float x (Input)
Point at which the logarithm of the absolute value of the gamma function is to be evaluated.
Point at which the logarithm of the absolute value of the gamma function is to be evaluated.
Return Value
The value of the logarithm of gamma function log |Γ(x)|.
Description
The logarithm of the absolute value of the gamma function log |Γ(x)| is computed.
Figure 43, Plot of log|Γ(x)|
Example
In this example, log |Γ(3.5)| is computed and printed.
#include <stdio.h>
#include <imsls.h>
int main()
{
float x = 3.5;
float ans;
ans = imsls_f_log_gamma(x);
printf("log gamma(%f) = %f\n", x, ans);
}
Output
log gamma(3.500000) = 1.200974
Warning Errors
IMSLS_NEAR_NEG_INT_WARN | The result is accurate to less than one-half precision because x is too close to a negative integer. |
Fatal Errors
IMSLS_NEGATIVE_INTEGER | The argument for the function cannot be a negative integer. |
IMSLS_NEAR_NEG_INT_FATAL | The argument for the function is too close to a negative integer. |
IMSLS_LARGE_ABS_ARG_OVERFLOW | |x| must not be so large that the result overflows. |
