46 lines
1.3 KiB
C
Executable File
46 lines
1.3 KiB
C
Executable File
/* atan2f.c: Computes atan2(x) where x is a 32-bit float.
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Copyright (C) 2001, 2002 Jesus Calvino-Fraga, jesusc@ieee.org
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with this library; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
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/* Version 1.0 - Initial release */
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#include "math.h"
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#include "errno.h"
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float atan2f(const float x, const float y)
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{
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float r;
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if ((x==0.0) && (y==0.0))
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{
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errno=EDOM;
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return 0.0;
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}
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if(fabsf(y)>=fabsf(x))
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{
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r=atanf(x/y);
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if(y<0.0) r+=(x>=0?PI:-PI);
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}
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else
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{
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r=-atanf(y/x);
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r+=(x<0.0?-HALF_PI:HALF_PI);
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}
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return r;
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}
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