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# localdef.h

    00001 //
    00002 // localdef.h
    00003 //
    00004 // Copyright (C) 1996 Limit Point Systems, Inc.
    00005 //
    00006 // Author: Edward Seidl <seidl@janed.com>
    00007 // Maintainer: LPS
    00008 //
    00009 // This file is part of the SC Toolkit.
    00010 //
    00011 // The SC Toolkit is free software; you can redistribute it and/or modify
    00012 // it under the terms of the GNU Library General Public License as published by
    00013 // the Free Software Foundation; either version 2, or (at your option)
    00014 // any later version.
    00015 //
    00016 // The SC Toolkit is distributed in the hope that it will be useful,
    00017 // but WITHOUT ANY WARRANTY; without even the implied warranty of
    00018 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    00019 // GNU Library General Public License for more details.
    00020 //
    00021 // You should have received a copy of the GNU Library General Public License
    00022 // along with the SC Toolkit; see the file COPYING.LIB.  If not, write to
    00023 // the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
    00024 //
    00025 // The U.S. Government is granted a limited license as per AL 91-7.
    00026 //
    00027
    00028 // some inline functions for dealing with 3 dimensional vectors
    00029
    00030 #ifndef _localdef_h
    00031 #define _localdef_h
    00032
    00033 #include <math.h>
    00034
    00035 namespace sc {
    00036
    00037 static const double pi=M_PI;
    00038 static const double pih=M_PI_2;
    00039 static const double tpi=2.0*pi;
    00040
    00041 static const double bohr = 0.52917706;
    00042
    00043 // /////////////////////////////////////////////////////////
    00044
    00045 static inline void
    00046 delta(double u[], const double a[], const double b[])
    00047 {
    00048   u[0]=a[0]-b[0];
    00049   u[1]=a[1]-b[1];
    00050   u[2]=a[2]-b[2];
    00051 }
    00052
    00053 // /////////////////////////////////////////////////////////
    00054
    00055 // returns the distance between two points
    00056 static inline double
    00057 dist(const double a[], const double b[])
    00058 {
    00059   double x,y,z;
    00060   return (sqrt((x=a[0]-b[0])*x + (y=a[1]-b[1])*y + (z=a[2]-b[2])*z));
    00061 }
    00062
    00063 // /////////////////////////////////////////////////////////
    00064
    00065 // given sin(x) returns cos(x)
    00066 static inline double
    00067 s2(double x)
    00068 {
    00069   double tmp = 1.0 - x*x;
    00070   if (tmp < 0.0) tmp = 0.0;
    00071   return sqrt(tmp);
    00072 }
    00073
    00074 // /////////////////////////////////////////////////////////
    00075
    00076 // returns the dot product for two vectors
    00077 static inline double
    00078 scalar(const double a[], const double b[])
    00079 {
    00080   double x = a[0]*b[0];
    00081   double x1 = a[1]*b[1];
    00082   x += a[2]*b[2];
    00083   return x+x1;
    00084 }
    00085
    00086 // /////////////////////////////////////////////////////////
    00087
    00088 // given vectors a and b, returns a unit vector directed along the difference
    00089 // of the two vectors
    00090 static inline void
    00091 norm(double u[], const double a[], const double b[])
    00092 {
    00093   delta(u,a,b);
    00094   double x = 1.0/sqrt(scalar(u,u));
    00095   u[0] *= x; u[1] *= x; u[2] *= x;
    00096 }
    00097
    00098 // /////////////////////////////////////////////////////////
    00099
    00100 // given two vectors, returns the normalized cross product of those vectors
    00101 static inline void
    00102 normal(const double a[], const double b[], double w[])
    00103 {
    00104   w[0] = a[1]*b[2]-a[2]*b[1];
    00105   w[1] = a[2]*b[0]-a[0]*b[2];
    00106   w[2] = a[0]*b[1]-a[1]*b[0];
    00107   double x = 1.0/sqrt(scalar(w,w));
    00108   w[0] *= x; w[1] *= x; w[2] *= x;
    00109 }
    00110
    00111 }
    00112
    00113 #endif
    00114
    00115 // Local Variables:
    00116 // mode: c++
    00117 // c-file-style: "ETS"
    00118 // End: