| |
| /* |
| * IBM Accurate Mathematical Library |
| * written by International Business Machines Corp. |
| * Copyright (C) 2001 Free Software Foundation |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU Lesser General Public License as published by |
| * the Free Software Foundation; either version 2.1 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| */ |
| /******************************************************************/ |
| /* MODULE_NAME: mpatan2.c */ |
| /* */ |
| /* FUNCTIONS:mpatan2 */ |
| /* */ |
| /* FILES NEEDED: mpa.h */ |
| /* mpa.c mpatan.c mpsqrt.c */ |
| /* */ |
| /* Multi-Precision Atan2(y,x) function subroutine, */ |
| /* for precision p >= 4. */ |
| /* y=0 is not permitted if x<=0. No error messages are given. */ |
| /* The relative error of the result is bounded by 44.84*r**(1-p) */ |
| /* if x <= 0, y != 0 and by 37.33*r**(1-p) if x>0. here r=2**24. */ |
| /* */ |
| /******************************************************************/ |
| |
| |
| |
| #include "mpa.h" |
| |
| void __mpsqrt(mp_no *, mp_no *, int); |
| void __mpatan(mp_no *, mp_no *, int); |
| |
| /* Multi-Precision Atan2(y,x) function subroutine, for p >= 4. */ |
| /* y=0 is not permitted if x<=0. No error messages are given. */ |
| void __mpatan2(mp_no *y, mp_no *x, mp_no *z, int p) { |
| |
| static const double ZERO = 0.0, ONE = 1.0; |
| |
| mp_no mpone = {0,{0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0, |
| 0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0, |
| 0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0,0.0}}; |
| mp_no mpt1,mpt2,mpt3; |
| |
| |
| if (X[0] <= ZERO) { |
| mpone.e = 1; mpone.d[0] = mpone.d[1] = ONE; |
| __dvd(x,y,&mpt1,p); __mul(&mpt1,&mpt1,&mpt2,p); |
| if (mpt1.d[0] != ZERO) mpt1.d[0] = ONE; |
| __add(&mpt2,&mpone,&mpt3,p); __mpsqrt(&mpt3,&mpt2,p); |
| __add(&mpt1,&mpt2,&mpt3,p); mpt3.d[0]=Y[0]; |
| __mpatan(&mpt3,&mpt1,p); __add(&mpt1,&mpt1,z,p); |
| } |
| else |
| { __dvd(y,x,&mpt1,p); |
| __mpatan(&mpt1,z,p); |
| } |
| |
| return; |
| } |