beta

Evaluates the real beta function β(x, y).

Synopsis

#include <imsl.h>

float imsl_f_beta (float x, float y)

The type double function is imsl_d_beta.

Required Arguments

float x (Input)
Point at which the beta function is to be evaluated. It must be positive.

float y (Input)
Point at which the beta function is to be evaluated. It must be positive.

Return Value

The value of the beta function β (x, y). If no result can be computed, NaN is returned.

Description

The beta function, β (x, y), is defined to be

 

The beta function requires that x > 0 and y > 0. It underflows for large arguments.

 

Figure 1,  Plot of β(x,y)

Example

Evaluate the beta function β (0.5, 0.2).

 

#include <imsl.h>

#include <stdio.h>

 

int main()

{

float x = 0.5;

float y = 0.2;

float ans;

 

ans = imsl_f_beta(x, y);

printf("beta(%f,%f) = %f\n", x, y, ans);

}

Output

 

beta(0.500000,0.200000) = 6.268653

Alert Errors

IMSL_BETA_UNDERFLOW

The arguments must not be so large that the result underflows.

Fatal Errors

IMSL_ZERO_ARG_OVERFLOW

One of the arguments is so close to zero that the result overflows.