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bessel(3)  —  Subroutines

NAME

bessel, j0, j1, jn, y0, y1, yn − Compute Bessel functions

LIBRARY

Math Library (libm.a)

SYNOPSIS

#include <math.h>

double j0  (double x);
float  j0f (float  x);
double j1  (double x);
float  j1f (float  x);
double jn  (int n, double x);
float  jnf (int n, float  x);
double y0  (double x);
float  y0f (float  x);
double y1  (double x);
float  y1f (float  x);
double yn  (int n, double x);
float  ynf (int n, float  x);

STANDARDS

Interfaces documented on this reference page conform to industry standards as follows:

j0():  XPG4

j1():  XPG4

jn():  XPG4

y0():  XPG4

y1():  XPG4

yn():  XPG4

Refer to the standards(5) reference page for more information about industry standards and associated tags. 

DESCRIPTION

The j0(), j0f(), j1(), and j1f() functions return the value of the Bessel function of the first kind of orders 0 (zero) and 1, respectively. 

The jn() and jnf() functions return the value of the Bessel function of the first kind of order n. 

The y0(), y0f(), y1(), and y1f() functions return the value of the Bessel functions of the second kind of orders 0 (zero) and 1, respectively. 

The yn() and ynf()  functions return the value of the Bessel function of the second kind of order n. 

The following table describes function behavior in response to exceptional arguments:

Function Exceptional Argument Routine Behavior
j0(), j1(), jn() None N/A
j0f(), j1f(), jnf() None N/A
y0(), y1(), yn() x < 0 Invalid argument
y0f(), y1f(), ynf() x < 0 Invalid argument
y0(), y1(), yn() x = 0 Overflow
y0f(), y1f(), ynf() x = 0 Overflow

The j1() and jn() functions can result in an underflow as x gets small.  The largest value of x for which this occurs is a function of n. 

The y1() and yn() functions can result in an overflow as x gets small.  The largest value of x for which this occurs is a function of n. 
 
 
 
 
 

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