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d5f74e42d6
License statement text corrected; compiler warnings caused by Bison 2.41 disabled for MSVC; a few other compiler warnings on 54-bit Windows eliminated by appropriate type cast Wrong license statements corrected in several files. Copyright and license statements added in XSD and GLSL files. Copyright year updated in some files. Obsolete documentation files removed from DrawResources.
117 lines
3.9 KiB
C++
117 lines
3.9 KiB
C++
// Copyright (c) 1997-1999 Matra Datavision
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// Copyright (c) 1999-2014 OPEN CASCADE SAS
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//
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// This file is part of Open CASCADE Technology software library.
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//
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// This library is free software; you can redistribute it and/or modify it under
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// the terms of the GNU Lesser General Public License version 2.1 as published
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// by the Free Software Foundation, with special exception defined in the file
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// OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT
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// distribution for complete text of the license and disclaimer of any warranty.
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//
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// Alternatively, this file may be used under the terms of Open CASCADE
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// commercial license or contractual agreement.
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#include <math_BracketedRoot.ixx>
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#include <math_Function.hxx>
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// reference algorithme:
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// Brent method
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// numerical recipes in C p 269
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math_BracketedRoot::math_BracketedRoot (math_Function& F,
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const Standard_Real Bound1,
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const Standard_Real Bound2,
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const Standard_Real Tolerance,
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const Standard_Integer NbIterations,
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const Standard_Real ZEPS ) {
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Standard_Real Fa,Fc,a,c=0,d=0,e=0;
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Standard_Real min1,min2,p,q,r,s,tol1,xm;
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a = Bound1;
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TheRoot = Bound2;
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F.Value(a,Fa);
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F.Value(TheRoot,TheError);
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if (Fa*TheError > 0.) { Done = Standard_False;}
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else {
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Fc = TheError ;
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for (NbIter = 1; NbIter <= NbIterations; NbIter++) {
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if (TheError*Fc > 0.) {
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c = a; // rename a TheRoot c and adjust bounding interval d
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Fc = Fa;
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d = TheRoot - a;
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e = d;
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}
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if ( Abs(Fc) < Abs(Fa) ) {
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a = TheRoot;
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TheRoot = c;
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c = a;
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Fa = TheError;
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TheError = Fc;
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Fc = Fa;
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}
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tol1 = 2.*ZEPS * Abs(TheRoot) + 0.5 * Tolerance; // convergence check
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xm = 0.5 * ( c - TheRoot );
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if (Abs(xm) <= tol1 || TheError == 0. ) {
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Done = Standard_True;
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return;
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}
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if (Abs(e) >= tol1 && Abs(Fa) > Abs(TheError) ) {
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s = TheError / Fa; // attempt inverse quadratic interpolation
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if (a == c) {
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p = 2.*xm*s;
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q = 1. - s;
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}
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else {
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q = Fa / Fc;
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r = TheError / Fc;
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p = s * (2.*xm *q * (q - r) - (TheRoot - a)*(r - 1.));
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q = (q -1.) * (r - 1.) * (s - 1.);
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}
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if ( p > 0. ) { q = -q;} // check whether in bounds
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p = Abs(p);
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min1 = 3.* xm* q - Abs(tol1 *q);
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min2 = Abs(e * q);
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if (2.* p < (min1 < min2 ? min1 : min2) ) {
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e = d ; // accept interpolation
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d = p / q;
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}
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else {
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d = xm; // interpolation failed,use bissection
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e = d;
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}
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}
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else { // bounds decreasing too slowly ,use bissection
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d = xm;
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e =d;
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}
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a = TheRoot ; // move last best guess to a
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Fa = TheError;
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if (Abs(d) > tol1) { // evaluate new trial root
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TheRoot += d;
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}
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else {
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TheRoot += (xm > 0. ? Abs(tol1) : -Abs(tol1));
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}
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F.Value(TheRoot,TheError);
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}
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Done = Standard_False;
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}
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}
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void math_BracketedRoot::Dump(Standard_OStream& o) const {
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o << "math_BracketedRoot ";
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if(Done) {
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o << " Status = Done \n";
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o << " Number of iterations = " << NbIter << endl;
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o << " The Root is: " << TheRoot << endl;
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o << " The value at the root is: " << TheError << endl;
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}
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else {
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o << " Status = not Done \n";
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}
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}
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