NAME    [Toc]    [Back]

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

SYNOPSIS    [Toc]    [Back]

       #include <math.h>

       double j0(
               double x ); float j0f(
               float x ); long double j0l(
               long double x ); double j1(
               double x ); float j1f(
               float x ); long double j1l(
               long double x ); double jn(
               int n,
               double x ); float jnf(
               int n,
               float x ); long double jnl(
               int n,
               long double x ); double y0(
               double x ); float y0f(
               float x ); long double y0l(
               long double x ); double y1(
               double x ); float y1f(
               float x ); long double y1l(
               long double x ); double yn(
               int n,
               double x ); float ynf(
               int n,
               float x ); long double ynl(
               int n,
               long double x );

LIBRARY    [Toc]    [Back]

       Math Library (libm)

STANDARDS    [Toc]    [Back]

       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    [Toc]    [Back]

       The  j0(),  j0f(), j0l(), j1(), j1f(), and j1l() functions
       return the value of the Bessel function of the first  kind
       of orders 0 (zero) and 1, respectively.

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

       The y0(), y0f(), y0l(), y1(), y1f(), and  y1l()  functions
       return  the  value  of  the Bessel functions of the second
       kind of orders 0 (zero) and 1, respectively.

       The yn(), ynf(), and ynl() 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
       j0l(),j1l(), jnl()        None                   N/A
       y0(), y1(), yn()          x < 0                  Invalid argument
       y0f(), y1f(), ynf()       x < 0                  Invalid argument
       y0l(), y1l(), ynl()       x < 0                  Invalid argument
       y0(), y1(), yn()          x = 0                  Overflow
       y0f(), y1f(), ynf()       x = 0                  Overflow
       y0l(), y1l(), ynl()       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.



                                                        bessel(3)