rand.h

00001 /*
00002  * Orca-Robotics Project: Components for robotics 
00003  *               http://orca-robotics.sf.net/
00004  * Copyright (c) 2004-2009 Alex Brooks, Alexei Makarenko, Tobias Kaupp
00005  *
00006  * This distribution is licensed to you under the terms described in
00007  * the LICENSE file included in this distribution.
00008  *
00009  */
00010 #ifndef HYDROUTIL_NRAND__H
00011 #define HYDROUTIL_NRAND__H
00012 
00013 #include <cmath>
00014 
00015 //
00016 // General-purpose random number utilities
00017 //
00018 // Author: Alex Brooks
00019 //
00020 
00021 namespace hydroutil {
00022 
00023     // Fuck you, windows.
00024     // const double INV_SQRT_TWO_PI = 1/sqrt(2*M_PI);
00025     const double INV_SQRT_TWO_PI = (double)(1.0/std::sqrt(2*3.14159265358979));
00026 
00028     inline double G( double dist, double sd )
00029     { return (double)( (INV_SQRT_TWO_PI/sd) * std::exp( -(dist*dist)/(2.0*sd*sd) ) ); }
00030 
00032     inline double GCov( double dist, double cov )
00033     { return (double)( (INV_SQRT_TWO_PI/std::sqrt(cov)) * std::exp( -(dist*dist)/(2.0*cov) ) ); }
00034 
00037     inline double multiG( double xDiff, double yDiff, double xx, double yy )
00038     { return G(xDiff,std::sqrt(xx)) * G(yDiff,std::sqrt(yy)); }
00039 
00041     double normalRand( double mean, double std );
00042 
00044     double randNum( double minVal, double maxVal );
00045 
00047     double randNumInclusive( double minVal, double maxVal );
00048 }
00049 
00050 #endif