gr_math.h

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00001 /* -*- c++ -*- */
00002 /*
00003  * Copyright 2003,2005 Free Software Foundation, Inc.
00004  * 
00005  * This file is part of GNU Radio
00006  * 
00007  * GNU Radio is free software; you can redistribute it and/or modify
00008  * it under the terms of the GNU General Public License as published by
00009  * the Free Software Foundation; either version 3, or (at your option)
00010  * any later version.
00011  * 
00012  * GNU Radio is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00015  * GNU General Public License for more details.
00016  * 
00017  * You should have received a copy of the GNU General Public License
00018  * along with GNU Radio; see the file COPYING.  If not, write to
00019  * the Free Software Foundation, Inc., 51 Franklin Street,
00020  * Boston, MA 02110-1301, USA.
00021  */
00022 
00023 /*
00024  * mathematical odds and ends.
00025  */
00026 
00027 #ifndef _GR_MATH_H_
00028 #define _GR_MATH_H_
00029 
00030 #include <gr_complex.h>
00031 
00032 long gr_gcd (long m, long n);
00033 
00034 // returns a non-zero value if value is "not-a-number" (NaN), and 0 otherwise
00035 int gr_isnan (double value);
00036 
00037 // returns a non-zero value if the value of x has its sign bit set.
00038 //
00039 // This  is  not  the  same  as `x < 0.0', because IEEE 754 floating point
00040 // allows zero to be signed.  The comparison `-0.0 < 0.0'  is  false,  but
00041 // `gr_signbit (-0.0)' will return a nonzero value.
00042 
00043 int gr_signbit (double x);
00044   
00061 float gr_fast_atan2f(float y, float x);
00062 
00063 static inline float gr_fast_atan2f(gr_complex z) 
00064 { 
00065   return gr_fast_atan2f(z.imag(), z.real()); 
00066 }
00067 
00068 
00069 /* This bounds x by +/- clip without a branch */
00070 
00071 static inline float gr_branchless_clip(float x, float clip)
00072 {
00073   float x1 = fabsf(x+clip);
00074   float x2 = fabsf(x-clip);
00075   x1 -= x2;
00076   return 0.5*x1;
00077 }
00078 
00079 
00080 
00081 #endif /* _GR_MATH_H_ */

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