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25 //
26 /*
27 * G4DNARevertFunction.hh
28 *
29 * Created on: Aug 25, 2015
30 * Author: mkaramit
31 */
32
33 #ifndef SOURCE_PROCESSES_ELECTROMAGNETIC_DNA_UTILS_INCLUDE_G4DNAREVERTPROBABILITY_HH_
34 #define SOURCE_PROCESSES_ELECTROMAGNETIC_DNA_UTILS_INCLUDE_G4DNAREVERTPROBABILITY_HH_
35
36 #include <functional>
37
38 //------------------------------------------------------------------------------
39 // *****************************************************
40 // Revert a probability by binary search
41 // *****************************************************
42
43 class G4DNARevertProbability
44 {
45 public:
46 double fXmax;
47 double fXmin;
48 double fXmaxDef;
49 double fXminDef;
50 double fToleranceProba;
51 double fIncreasingCumulativeFunction;
52
53 G4DNARevertProbability(double toleranceY) :
54 fToleranceProba(toleranceY)
55 {
56 fXmax = 0.;
57 fXmin = 0.;
58 fXminDef = 0.;
59 fXmaxDef = 0.;
60 fIncreasingCumulativeFunction = 0.;
61 }
62
63 G4DNARevertProbability(double xmin, double xmax, double toleranceY) :
64 fXmax(xmax), fXmin(xmin), fToleranceProba(toleranceY)
65 {
66 if(fXmax < fXmin)
67 {
68 double tmp = fXmin;
69 fXmin = fXmax;
70 fXmax = tmp;
71 }
72
73 fXminDef = fXmin;
74 fXmaxDef = fXmax;
75 fIncreasingCumulativeFunction = 0;
76 }
77
78 void Reset()
79 {
80 fXmin = fXminDef;
81 fXmax = fXmaxDef;
82 }
83
84 void SetBoundaries(double xmin, double xmax)
85 {
86 fXmax = xmax;
87 fXmin = xmin;
88 if(fXmax < fXmin)
89 {
90 double tmp = fXmin;
91 fXmin = fXmax;
92 fXmax = tmp;
93 }
94
95 fXminDef = fXmin;
96 fXmaxDef = fXmax;
97 }
98
99 void SetTolerance(double toleranceY)
100 {
101 fToleranceProba = toleranceY;
102 }
103
104 bool Propose(double proposedXValue,
105 double proposedProba,
106 double nextProba,
107 double& returnedValue)
108 {
109 bool returnFlag = false;
110
111 if(proposedProba < nextProba - fToleranceProba) // proba trop petite ==> augmente
112 {
113 if(fIncreasingCumulativeFunction > 0) // croissant
114 {
115 if(proposedXValue > fXmin) fXmin = proposedXValue;
116 }
117 else if(fIncreasingCumulativeFunction < 0) // decroissant
118 {
119 if(proposedXValue < fXmax) fXmax = proposedXValue;
120 }
121
122 returnedValue = (fXmax + fXmin) / 2.;
123 returnFlag = false;
124 }
125 else if(proposedProba > nextProba + fToleranceProba) // proba trop grande
126 {
127 if(fIncreasingCumulativeFunction > 0)
128 {
129 if(proposedXValue < fXmax)
130 {
131 fXmax = proposedXValue;
132 }
133 }
134 else if(fIncreasingCumulativeFunction < 0)
135 {
136 if(proposedXValue > fXmin)
137 {
138 fXmin = proposedXValue;
139 }
140 }
141
142 returnedValue = (fXmax + fXmin) / 2.;
143 returnFlag = false;
144 }
145 else
146 {
147 // Assuming search for next proba is increasing
148 if(fIncreasingCumulativeFunction < 0)
149 {
150 fXmin = fXminDef;
151 fXmax = proposedXValue;
152 }
153 else if(fIncreasingCumulativeFunction > 0)
154 {
155 fXmin = proposedXValue;
156 fXmax = fXmaxDef;
157 }
158 returnFlag = true;
159 }
160
161 return returnFlag;
162 }
163
164 //**********************************
165 // *** REVERT THE FUNCTION "FUNCT"
166 // *********************************
167
168 double Revert(double probaForSearchedTime,
169 std::function<double(double)>& funct)
170 {
171 Reset();
172 bool notFound = true;
173 double proposedX;
174 double x = fXmax;
175
176 fIncreasingCumulativeFunction = (funct(fXmax) - funct(fXmin))
177 / (fXmax - fXmin);
178
179 while(notFound)
180 {
181 double newProba = funct(x);
182
183 if(Propose(x, newProba, probaForSearchedTime, proposedX))
184 {
185 notFound = false;
186 }
187 else
188 {
189 if(x == proposedX)
190 {
191 return x;
192 // G4cout << "BREAK : x= " << x << G4endl;
193 // G4cout << "nextProba= " << probaForSearchedTime << G4endl;
194 // G4cout << "newProba= " << newProba << G4endl;
195 // abort();
196 }
197 x = proposedX;
198 }
199 }
200 return x;
201 }
202 };
203 #endif /* SOURCE_PROCESSES_ELECTROMAGNETIC_DNA_UTILS_INCLUDE_G4DNAREVERTPROBABILITY_HH_ */
204