J0(3)                               Linux Programmer's Manual                               J0(3)



NAME
       j0, j0f, j0l, j1, j1f, j1l, jn, jnf, jnl - Bessel functions of the first kind

SYNOPSIS
       #include <math.h>

       double j0(double x);
       double j1(double x);
       double jn(int n, double x);

       float j0f(float x);
       float j1f(float x);
       float jnf(int n, float x);

       long double j0l(long double x);
       long double j1l(long double x);
       long double jnl(int n, long double x);

       Link with -lm.

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       j0(), j1(), jn():
           _SVID_SOURCE || _BSD_SOURCE || _XOPEN_SOURCE
       j0f(), j0l(), j1f(), j1l(), jnf(), jnl():
           _SVID_SOURCE || _BSD_SOURCE || _XOPEN_SOURCE >= 600

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  j0f(),  j1f(),  and  jnf(), functions are versions that take and return float values.
       The j0l(), j1l(), and jnl() functions are versions that take and return long  double  val‐
       ues.

RETURN VALUE
       On success, these functions return the appropriate Bessel value of the first kind for x.

       If x is a NaN, a NaN is returned.

       If  x  is  too large in magnitude, or the result underflows, a range error occurs, and the
       return value is 0.

ERRORS
       See math_error(7) for information on how to determine whether an error has  occurred  when
       calling these functions.

       The following errors can occur:

       Range error: result underflow, or x is too large in magnitude
              errno is set to ERANGE.

       These functions do not raise exceptions for fetestexcept(3).

CONFORMING TO
       The functions returning double conform to SVr4, 4.3BSD, POSIX.1-2001.  The others are non‐
       standard functions that also exist on the BSDs.

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.

SEE ALSO
       y0(3)

COLOPHON
       This  page  is  part of release 3.74 of the Linux man-pages project.  A description of the
       project, information about reporting bugs, and the latest version of  this  page,  can  be
       found at http://www.kernel.org/doc/man-pages/.



                                            2014-01-18                                      J0(3)