J0(3) BSD Programmer's Manual J0(3)NAME
j0, j0f, j1, j1f, jn, jnf, y0, y0f, y1, y1f, yn, ynf - Bessel functions
of first and second kind
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);
DESCRIPTION
The functions j0(), j0f(), j1() and j1f() compute the Bessel function of
the first kind of the order 0 and the order 1, respectively, for the real
value x; the functions jn() and jnf() compute the Bessel function of the
first kind of the integer order n for the real value x.
The functions y0(), y0f(), y1(), and y1f() compute the linearly indepen-
dent Bessel function of the second kind of the order 0 and the order 1,
respectively, for the positive real value x; the functions yn() and ynf()
compute the Bessel function of the second kind for the integer order n
for the positive real value x.
ERRORS
For y0(), y0f(), y1(), y1f(), yn(), or ynf(), if x <= 0 then:
_IEEE_ The return value is -Inf if x = 0, or NaN if x < 0.
_POSIX_ The return value is -Inf, and errno is set to EDOM.
_XOPEN_ Same as _POSIX_, but errno is only set if matherr(3) returns 0.
The exception type is DOMAIN.
_SVID_ Same as _XOPEN_, but the return value is -MAXFLOAT, and a mes-
sage is printed to stderr if errno is set.
If the magnitude of x would lead to a result with a total loss of signif-
icance, then:
_IEEE_ The return value is 0.
_POSIX_ Same as _IEEE_, but errno is also set to ERANGE.
_XOPEN_ Same as _POSIX_, but errno is only set if matherr(3) returns 0.
The exception type is TLOSS.
_SVID_ Same as _XOPEN_, and a message is printed to stderr if errno is
set.
SEE ALSOmath(3)HISTORY
This set of functions appeared in Version 7 AT&T UNIX.
4th Berkeley Distribution February 17, 1998 2
