00001
00012 #ifdef _MSC_VER
00013 #include "msdevstudio/MSconfig.h"
00014 #endif
00015
00016 #include "BrokenPowerLaw.h"
00017
00018 #include "FunctionHelper.h"
00019
00020 #include <cmath>
00021 #include <cassert>
00022
00023 #ifdef ITERATOR_MEMBER_DEFECT
00024 using namespace std;
00025 #else
00026 using std::max;
00027 using std::vector;
00028 #endif
00029
00030 namespace hippodraw {
00031
00032 BrokenPowerLaw::BrokenPowerLaw ( )
00033 {
00034 initialize ();
00035 }
00036
00037 BrokenPowerLaw::BrokenPowerLaw ( double prefactor, double index1,
00038 double index2, double x_break)
00039 {
00040 initialize ();
00041
00042 m_parms[0] = prefactor;
00043 m_parms[1] = index1;
00044 m_parms[2] = index2;
00045 m_parms[3] = x_break;
00046 }
00047
00048 void BrokenPowerLaw::initialize ()
00049 {
00050 m_name = "BrokenPowerLaw";
00051 m_parm_names.push_back ( "Prefactor" );
00052 m_parm_names.push_back ( "Index1" );
00053 m_parm_names.push_back ( "Index2" );
00054 m_parm_names.push_back ( "Break" );
00055
00056 resize ();
00057 }
00058
00059 FunctionBase * BrokenPowerLaw::clone () const
00060 {
00061 return new BrokenPowerLaw ( *this );
00062 }
00063
00064 double BrokenPowerLaw::operator () ( double x ) const
00065 {
00066 if (x < m_parms[3]) {
00067 return m_parms[0]*pow(x/m_parms[3], m_parms[1]);
00068 } else {
00069 return m_parms[0]*pow(x/m_parms[3], m_parms[2]);
00070 }
00071 }
00072
00073
00074 void
00075 BrokenPowerLaw::
00076 initialParameters ( const FunctionHelper * helper )
00077 {
00078 double min_x = helper->minCoord ();
00079 double max_x = helper->maxCoord ();
00080 max_x = (min_x + max_x)/2.;
00081
00082 double min_y, max_y;
00083 try {
00084 min_y = helper->valueAt(min_x);
00085 max_y = helper->valueAt(max_x);
00086 if (min_y != 0 && max_y != 0) {
00087 m_parms[1] = log( max_y/min_y ) / log( max_x/min_x );
00088 m_parms[2] = m_parms[1];
00089 m_parms[3] = helper->meanCoord();
00090 m_parms[0] = max_y/pow(max_x/m_parms[3], m_parms[1]);
00091 return;
00092 }
00093 } catch (...) {
00094
00095 }
00096
00097
00098 min_y = max(helper->minValue(), 1.);
00099 max_y = helper->maxValue();
00100 m_parms[1] = log( max_y/min_y ) / log( max_x/min_x );
00101 m_parms[2] = m_parms[1];
00102 m_parms[3] = helper->meanCoord();
00103 m_parms[0] = max_y/pow(max_x/m_parms[3], m_parms[1]);
00104 }
00105
00106 double BrokenPowerLaw::derivByParm ( int i, double x ) const
00107 {
00108 switch ( i ) {
00109 case 0 :
00110 return operator()(x)/m_parms[0];
00111 break;
00112
00113 case 1 :
00114 if (x < m_parms[3]) {
00115 return operator()(x)*log(x/m_parms[3]);
00116 } else {
00117 return 0;
00118 }
00119 break;
00120
00121 case 2 :
00122 if (x < m_parms[3]) {
00123 return 0;
00124 } else {
00125 return operator()(x)*log(x/m_parms[3]);
00126 }
00127 break;
00128
00129 case 3 :
00130 if (x < m_parms[3]) {
00131 return -m_parms[1]*operator()(x)/m_parms[3];
00132 } else {
00133 return -m_parms[2]*operator()(x)/m_parms[3];
00134 }
00135 break;
00136
00137 default:
00138 assert ( false );
00139 break;
00140 }
00141 return 0.0;
00142 }
00143
00144 }