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1 | // Copyright (c) 1997-1999 Matra Datavision |
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2 | // Copyright (c) 1999-2014 OPEN CASCADE SAS |
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3 | // |
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4 | // This file is part of Open CASCADE Technology software library. |
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5 | // |
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6 | // This library is free software; you can redistribute it and/or modify it under |
7 | // the terms of the GNU Lesser General Public License version 2.1 as published |
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8 | // by the Free Software Foundation, with special exception defined in the file |
9 | // OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT |
10 | // distribution for complete text of the license and disclaimer of any warranty. |
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11 | // |
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12 | // Alternatively, this file may be used under the terms of Open CASCADE |
13 | // commercial license or contractual agreement. |
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14 | |
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15 | |
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16 | #include <math_FunctionWithDerivative.hxx> |
17 | #include <math_NewtonFunctionRoot.hxx> |
18 | #include <StdFail_NotDone.hxx> |
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19 | |
20 | math_NewtonFunctionRoot::math_NewtonFunctionRoot (math_FunctionWithDerivative& F, |
21 | const Standard_Real Guess, |
22 | const Standard_Real EpsX , |
23 | const Standard_Real EpsF , |
24 | const Standard_Real A, |
25 | const Standard_Real B, |
26 | const Standard_Integer NbIterations ){ |
27 | EpsilonX = EpsX; |
28 | EpsilonF = EpsF; |
29 | Binf = A; |
30 | Bsup = B; |
31 | Itermax = NbIterations; |
32 | Done = Standard_False; |
33 | X = RealLast(); |
34 | DFx = 0; |
35 | Fx = RealLast(); |
36 | It = 0; |
37 | Perform(F, Guess); |
38 | } |
39 | |
40 | |
41 | math_NewtonFunctionRoot::math_NewtonFunctionRoot (const Standard_Real A , |
42 | const Standard_Real B, |
43 | const Standard_Real EpsX , |
44 | const Standard_Real EpsF , |
45 | const Standard_Integer NbIterations ){ |
46 | |
47 | Binf = A; |
48 | Bsup = B; |
49 | EpsilonX = EpsX; |
50 | EpsilonF = EpsF; |
51 | Itermax = NbIterations; |
52 | Done = Standard_False; |
53 | X = RealLast(); |
54 | DFx = 0; |
55 | Fx = RealLast(); |
56 | It = 0; |
57 | } |
58 | |
59 | |
60 | math_NewtonFunctionRoot::math_NewtonFunctionRoot (math_FunctionWithDerivative& F, |
61 | const Standard_Real Guess, |
62 | const Standard_Real EpsX , |
63 | const Standard_Real EpsF , |
64 | const Standard_Integer NbIterations ){ |
65 | EpsilonX = EpsX; |
66 | EpsilonF = EpsF; |
67 | Itermax = NbIterations; |
68 | Binf = RealFirst(); |
69 | Bsup = RealLast(); |
70 | Done = Standard_False; |
71 | X = RealLast(); |
72 | DFx = 0; |
73 | Fx = RealLast(); |
74 | It = 0; |
75 | Perform(F, Guess); |
76 | } |
77 | |
78 | |
79 | void math_NewtonFunctionRoot::Perform(math_FunctionWithDerivative& F, |
80 | const Standard_Real Guess) { |
81 | |
82 | Standard_Real Dx; |
83 | Standard_Boolean Ok; |
84 | Standard_Real AA, BB; |
85 | |
86 | //-------------------------------------------------- |
87 | //-- lbr le 12 Nov 97 |
88 | //-- la meilleure estimation n est pas sauvee et on |
89 | //-- renvoie une solution plus fausse que Guess |
90 | Standard_Real BestX=X,BestFx=RealLast(); |
91 | //-- |
92 | |
93 | if ( Binf < Bsup) { |
94 | AA = Binf; |
95 | BB = Bsup; |
96 | } |
97 | else { |
98 | AA = Bsup; |
99 | BB = Binf; |
100 | } |
101 | |
102 | Dx = RealLast(); |
103 | Fx = RealLast(); |
104 | X = Guess; |
105 | It = 1; |
106 | while ( (It <= Itermax) && ( (Abs(Dx) > EpsilonX) || |
107 | (Abs(Fx) > EpsilonF) ) ) { |
108 | Ok = F.Values(X,Fx,DFx); |
109 | |
110 | Standard_Real AbsFx = Fx; if(AbsFx<0) AbsFx=-AbsFx; |
111 | if(AbsFx<BestFx) { |
112 | BestFx=AbsFx; |
113 | BestX =X; |
114 | } |
115 | |
116 | if (Ok) { |
117 | if (DFx == 0.) { |
118 | Done = Standard_False; |
119 | It = Itermax + 1; |
120 | } |
121 | else { |
122 | Dx = Fx/DFx; |
123 | X -= Dx; |
124 | // Limitation des variations de X: |
125 | if (X <= AA) X = AA; |
126 | if (X >= BB) X = BB; |
127 | It++; |
128 | } |
129 | } |
130 | else { |
131 | Done = Standard_False; |
132 | It = Itermax + 1; |
133 | } |
134 | } |
135 | X = BestX; |
136 | |
137 | if (It <= Itermax) { |
138 | Done = Standard_True; |
139 | } |
140 | else |
141 | { |
142 | Done = Standard_False; |
143 | } |
144 | } |
145 | |
146 | |
147 | void math_NewtonFunctionRoot::Dump(Standard_OStream& o) const { |
148 | |
149 | o <<"math_NewtonFunctionRoot "; |
150 | if (Done) { |
151 | o << " Status = Done \n"; |
152 | o << " Location found = " << X <<"\n"; |
153 | o << " function value at this minimum = " << Fx <<"\n"; |
154 | o << " Number of iterations = " << It <<"\n"; |
155 | } |
156 | else { |
157 | o << "Status = not Done \n"; |
158 | } |
159 | } |
160 | |
161 | |
162 | |