jn

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():
           _XOPEN_SOURCE
               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
               || /* Glibc versions <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE
       j0f(), j0l(), j1f(), j1l(), jnf(), jnl():
           _XOPEN_SOURCE  >= 600
               || (_ISOC99_SOURCE && _XOPEN_SOURCE)
               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
               || /* Glibc versions <= 2.19: */ _SVID_SOURCE || _BSD_SOURCE

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  re-
       turn  float values.  The j0l(), j1l(), and jnl() functions are versions
       that take and return long double values.

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).

ATTRIBUTES
       For  an  explanation  of  the  terms  used  in  this  section,  see at-
       tributes(7).

       +-------------------+---------------+---------+
       |Interface          | Attribute     | Value   |
       +-------------------+---------------+---------+
       |j0(), j0f(), j0l() | Thread safety | MT-Safe |
       +-------------------+---------------+---------+
       |j1(), j1f(), j1l() | Thread safety | MT-Safe |
       +-------------------+---------------+---------+
       |jn(), jnf(), jnl() | Thread safety | MT-Safe |
       +-------------------+---------------+---------+
CONFORMING TO
       The functions returning double conform to SVr4,  4.3BSD,  POSIX.1-2001,
       and POSIX.1-2008.  The others are nonstandard 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 5.05 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
       https://www.kernel.org/doc/man-pages/.

                                  2017-09-15                             J0(3)