HP-UX Reference (11i v2 04/09) - 3 Library Functions N-Z (vol 7)

y0(3M) y0(3M)

NAME

y0( ), y0f( ), y1( ), y1f( ), yn( ), ynf( ) - Bessel functions of the second kind

SYNOPSIS

#include <math.h>

double y0(double x);

double y1(double x);

double yn(int n, double x);

Itanium(R)-based System Only

float y0f(float x);

float y1f(float x);

float ynf(int n, float x);

DESCRIPTION

y0() and y1() return Bessel functions of x of the second kind of orders 0 and 1 respectively.

yn()

returns the Bessel function of x of the second kind of order n.

y0f(), y1f(), and ynf() are float versions of y0(), y1(), snd yn(); each takes a

float argu-

ment x and returns a

float result.

USAGE

To use these functions, compile either with the default

-Ae option or with the

-Aa and

-D_HPUX_SOURCE options. Make sure your program includes

<math.h>. Link in the math library by

specifying

-lm on the compiler or linker command line.

RETURN VALUE

If x is negative or zero,

y0(), y1(), and yn() return −HUGE_VAL (equal to −INFINITY)

If x is NaN,

y0(), y1(), and yn() return NaN.

If the correct result would overﬂow,

y0(), y1(), and yn() return −HUGE_VAL

ERRORS

No errors are deﬁned.