j1(3) - Linux man page

Name

j0, j0f, j0l, j1, j1f, j1l, jn, jnf, jnl, y0, y0f, y0l, y1, y1f, y1l, yn, ynf, ynl - Bessel functions

Synopsis

#define _GNU_SOURCE#include <math.h>
double j0(double x);
double j1(double x);
double jn(int n, double x);
double y0(double x);
double y1(double x);
double yn(int n, double x);
float j0f(float x);
float j1f(float x);
float jnf(int n, float x);
float y0f(float x);
float y1f(float x);
float ynf(int n, float x);
long double j0l(long double x);
long double j1l(long double x);
long double jnl(int n, long double x);
long double y0l(long double x);
long double y1l(long double x);
long double ynl(int n, long double x);

Link with -lm.

Description

The j0() and j1() functions return Bessel functions of x of the first kind of orders 0 and 1, respectively. The jn() function returns the Bessel function of x of the first kind of order n.

The y0() and y1() functions return Bessel functions of x of the second kind of orders 0 and 1, respectively. The yn() function returns the Bessel function of x of the second kind of order n.

For the functions y0(), y1() and yn(), the value of x must be positive. For negative values of x, these functions return -HUGE_VAL.

The j0f() etc. and j0l() etc. functions are versions that take and return float and long double values, respectively.

Conforming to

The functions returning double conform to SVr4, 4.3BSD, POSIX.1-2001.

Bugs

There are errors of up to 2e-16 in the values returned by j0(), j1() and jn() for values of x between -8 and 8.