gr_math.h

Go to the documentation of this file.
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 static inline bool
00033 gr_is_power_of_2(long x)
00034 {
00035   return x != 0 && (x & (x-1)) == 0;
00036 }
00037 
00038 long gr_gcd (long m, long n);
00039 
00040 // returns a non-zero value if value is "not-a-number" (NaN), and 0 otherwise
00041 int gr_isnan (double value);
00042 
00043 // returns a non-zero value if the value of x has its sign bit set.
00044 //
00045 // This  is  not  the  same  as `x < 0.0', because IEEE 754 floating point
00046 // allows zero to be signed.  The comparison `-0.0 < 0.0'  is  false,  but
00047 // `gr_signbit (-0.0)' will return a nonzero value.
00048 
00049 int gr_signbit (double x);
00050   
00067 float gr_fast_atan2f(float y, float x);
00068 
00069 static inline float gr_fast_atan2f(gr_complex z) 
00070 { 
00071   return gr_fast_atan2f(z.imag(), z.real()); 
00072 }
00073 
00074 
00075 /* This bounds x by +/- clip without a branch */
00076 
00077 static inline float gr_branchless_clip(float x, float clip)
00078 {
00079   float x1 = fabsf(x+clip);
00080   float x2 = fabsf(x-clip);
00081   x1 -= x2;
00082   return 0.5*x1;
00083 }
00084 
00085 static inline float gr_clip(float x, float clip)
00086 {
00087   float y;
00088   if(x > clip)
00089     y = clip;
00090   else if(x < -clip)
00091     y = -clip;
00092   return y;
00093 }
00094 
00095 #endif /* _GR_MATH_H_ */

Generated on Thu Mar 5 09:01:11 2009 for GNU Radio 3.1.3 by  doxygen 1.5.8