man3/j0.3

   1 .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
   2 .\" and Copyright 2008, Linux Foundation, written by Michael Kerrisk
   3 .\"     <mtk.manpages@gmail.com>
   4 .\"
   5 .\" Permission is granted to make and distribute verbatim copies of this
   6 .\" manual provided the copyright notice and this permission notice are
   7 .\" preserved on all copies.
   8 .\"
   9 .\" Permission is granted to copy and distribute modified versions of this
  10 .\" manual under the conditions for verbatim copying, provided that the
  11 .\" entire resulting derived work is distributed under the terms of a
  12 .\" permission notice identical to this one.
  13 .\"
  14 .\" Since the Linux kernel and libraries are constantly changing, this
  15 .\" manual page may be incorrect or out-of-date.  The author(s) assume no
  16 .\" responsibility for errors or omissions, or for damages resulting from
  17 .\" the use of the information contained herein.  The author(s) may not
  18 .\" have taken the same level of care in the production of this manual,
  19 .\" which is licensed free of charge, as they might when working
  20 .\" professionally.
  21 .\"
  22 .\" Formatted or processed versions of this manual, if unaccompanied by
  23 .\" the source, must acknowledge the copyright and authors of this work.
  24 .\"
  25 .\" References consulted:
  26 .\"     Linux libc source code
  27 .\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
  28 .\"     386BSD man pages
  29 .\" Modified Sat Jul 24 19:08:17 1993 by Rik Faith (faith@cs.unc.edu)
  30 .\" Modified 2002-08-25, aeb
  31 .\" Modified 2004-11-12 as per suggestion by Fabian Kreutz/AEB
  32 .\" 2008-07-24, mtk, moved yxx() material into separate y0.3 page
  33 .\"
  34 .TH J0 3  2008-08-05 "" "Linux Programmer's Manual"
  35 .SH NAME
  36 j0, j0f, j0l, j1, j1f, j1l, jn, jnf, jnl \-
  37 Bessel functions of the first kind
  38 .SH SYNOPSIS
  39 .nf
  40 .B #include <math.h>
  41 .sp
  42 .fi
  43 .BI "double j0(double " x );
  44 .br
  45 .BI "double j1(double " x );
  46 .br
  47 .BI "double jn(int " n ", double " x );
  48 .sp
  49 .BI "float j0f(float " x );
  50 .br
  51 .BI "float j1f(float " x );
  52 .br
  53 .BI "float jnf(int " n ", float " x );
  54 .sp
  55 .BI "long double j0l(long double " x );
  56 .br
  57 .BI "long double j1l(long double " x );
  58 .br
  59 .BI "long double jnl(int " n ", long double " x );
  60 .sp
  61 Link with \fI\-lm\fP.
  62 .sp
  63 .in -4n
  64 Feature Test Macro Requirements for glibc (see
  65 .BR feature_test_macros (7)):
  66 .in
  67 .sp
  68 .ad l
  69 .BR j0 (),
  70 .BR j1 (),
  71 .BR jn ():
  72 _SVID_SOURCE || _BSD_SOURCE || _XOPEN_SOURCE
  73 .br
  74 .BR j0f (),
  75 .BR j0l (),
  76 .BR j1f (),
  77 .BR j1l (),
  78 .BR jnf (),
  79 .BR jnl ():
  80 _SVID_SOURCE || _BSD_SOURCE || _XOPEN_SOURCE\ >=\ 600
  81 .\" Also seems to work: -std=c99 -D_XOPEN_SOURCE
  82 .ad b
  83 .SH DESCRIPTION
  84 The
  85 .BR j0 ()
  86 and
  87 .BR j1 ()
  88 functions return Bessel functions of \fIx\fP
  89 of the first kind of orders 0 and 1, respectively.
  90 The
  91 .BR jn ()
  92 function
  93 returns the Bessel function of \fIx\fP of the first kind of order \fIn\fP.
  94 .PP
  95 The
  96 .BR j0f ()
  97 etc. and
  98 .BR j0l ()
  99 etc. functions are versions that take and return
 100 .I float
 101 and
 102 .I "long double"
 103 values, respectively.
 104 .SH RETURN VALUE
 105 On success, these functions return the appropriate
 106 Bessel value of the first kind for
 107 .IR x .
 108
 109 If
 110 .I x
 111 is a NaN, a NaN is returned.
 112
 113 If
 114 .I x
 115 is too large in magnitude,
 116 or the result underflows,
 117 a range error occurs,
 118 and the return value is 0.
 119 .SH ERRORS
 120 See
 121 .BR math_error (7)
 122 for information on how to determine whether an error has occurred
 123 when calling these functions.
 124 .PP
 125 The following errors can occur:
 126 .TP
 127 Range error: result underflow, or \fIx\fP is too large in magnitude
 128 .I errno
 129 is set to
 130 .BR ERANGE .
 131 .\" An underflow floating-point exception
 132 .\" .RB ( FE_UNDERFLOW )
 133 .\" is raised.
 134 .PP
 135 These functions do not raise exceptions for
 136 .BR fetestexcept (3).
 137 .\" FIXME . Is it intentional that these functions do not raise exceptions?
 138 .\" e.g., j0(1.5e16)
 139 .\" Bug raised: http://sources.redhat.com/bugzilla/show_bug.cgi?id=6805
 140 .SH "CONFORMING TO"
 141 The functions returning
 142 .I double
 143 conform to SVr4, 4.3BSD,
 144 POSIX.1-2001.
 145 The others are nonstandard functions that also exist on the BSDs.
 146 .SH BUGS
 147 There are errors of up to 2e\-16 in the values returned by
 148 .BR j0 (),
 149 .BR j1 ()
 150 and
 151 .BR jn ()
 152 for values of \fIx\fP between \-8 and 8.
 153 .SH SEE ALSO
 154 .BR y0 (3)