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git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@3693 d0543943-73ff-0310-b7d9-9358b9ac24b2
129 lines
4.1 KiB
C
129 lines
4.1 KiB
C
/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
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*
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* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is Mozilla Communicator client code, released
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* March 31, 1998.
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*
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* The Initial Developer of the Original Code is
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* Sun Microsystems, Inc.
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* Portions created by the Initial Developer are Copyright (C) 1998
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either of the GNU General Public License Version 2 or later (the "GPL"),
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* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK ***** */
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/* @(#)w_jn.c 1.3 95/01/18 */
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/*
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* ====================================================
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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* Developed at SunSoft, a Sun Microsystems, Inc. business.
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* Permission to use, copy, modify, and distribute this
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* software is freely granted, provided that this notice
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* is preserved.
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* ====================================================
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*/
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/*
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* wrapper jn(int n, double x), yn(int n, double x)
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* floating point Bessel's function of the 1st and 2nd kind
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* of order n
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*
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* Special cases:
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* y0(0)=y1(0)=yn(n,0) = -inf with division by zero signal;
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* y0(-ve)=y1(-ve)=yn(n,-ve) are NaN with invalid signal.
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* Note 2. About jn(n,x), yn(n,x)
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* For n=0, j0(x) is called,
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* for n=1, j1(x) is called,
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* for n<x, forward recursion us used starting
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* from values of j0(x) and j1(x).
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* for n>x, a continued fraction approximation to
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* j(n,x)/j(n-1,x) is evaluated and then backward
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* recursion is used starting from a supposed value
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* for j(n,x). The resulting value of j(0,x) is
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* compared with the actual value to correct the
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* supposed value of j(n,x).
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*
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* yn(n,x) is similar in all respects, except
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* that forward recursion is used for all
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* values of n>1.
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*
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*/
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#include "fdlibm.h"
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#ifdef __STDC__
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double fd_jn(int n, double x) /* wrapper jn */
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#else
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double fd_jn(n,x) /* wrapper jn */
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double x; int n;
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#endif
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{
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#ifdef _IEEE_LIBM
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return __ieee754_jn(n,x);
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#else
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double z;
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z = __ieee754_jn(n,x);
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if(_LIB_VERSION == _IEEE_ || fd_isnan(x) ) return z;
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if(fd_fabs(x)>X_TLOSS) {
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int err;
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return __kernel_standard((double)n,x,38,&err); /* jn(|x|>X_TLOSS,n) */
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} else
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return z;
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#endif
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}
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#ifdef __STDC__
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double yn(int n, double x) /* wrapper yn */
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#else
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double yn(n,x) /* wrapper yn */
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double x; int n;
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#endif
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{
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#ifdef _IEEE_LIBM
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return __ieee754_yn(n,x);
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#else
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double z;
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int err;
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z = __ieee754_yn(n,x);
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if(_LIB_VERSION == _IEEE_ || fd_isnan(x) ) return z;
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if(x <= 0.0){
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if(x==0.0)
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/* d= -one/(x-x); */
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return __kernel_standard((double)n,x,12,&err);
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else
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/* d = zero/(x-x); */
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return __kernel_standard((double)n,x,13,&err);
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}
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if(x>X_TLOSS) {
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return __kernel_standard((double)n,x,39,&err); /* yn(x>X_TLOSS,n) */
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} else
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return z;
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#endif
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}
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