MOAB: Mesh Oriented datABase  (version 5.4.0)
EdgeSizeSimpleImplicit.hpp
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00001 /*
00002  * MOAB, a Mesh-Oriented datABase, is a software component for creating,
00003  * storing and accessing finite element mesh data.
00004  *
00005  * Copyright 2004 Sandia Corporation.  Under the terms of Contract
00006  * DE-AC04-94AL85000 with Sandia Corporation, the U.S. Government
00007  * retains certain rights in this software.
00008  *
00009  * This library is free software; you can redistribute it and/or
00010  * modify it under the terms of the GNU Lesser General Public
00011  * License as published by the Free Software Foundation; either
00012  * version 2.1 of the License, or (at your option) any later version.
00013  *
00014  */
00015 
00016 /**\class moab::EdgeSizeSimpleImplicit
00017  *
00018  * This is an simple example edge evaluator tha subdivides edges based
00019  * on their midpoint's distance to a simple, fixed-form implicit surface
00020  * written as \f$ x^T A x + B x + C \f$ where \f$x\f$ is a column vector of
00021  * holding the edge midpoint coordinates, \f$A\f$ is a symmetric 3x3 matrix,
00022  * \f$B\f$ is a 1x3 row vector, and \f$C\f$ is a scalar.
00023  * Whenever the implicit function divided by half of the edge length is smaller than
00024  * some minimum ratio (which defaults to 1), the edge is marked for subdivision.
00025  *
00026  * \author David Thompson
00027  *
00028  * \date 19 November 2007
00029  */
00030 #ifndef MOAB_EDGE_SIZE_SIMPLE_IMPLICIT_HPP
00031 #define MOAB_EDGE_SIZE_SIMPLE_IMPLICIT_HPP
00032 
00033 #include "EdgeSizeEvaluator.hpp"
00034 
00035 namespace moab
00036 {
00037 
00038 class EdgeSizeSimpleImplicit : public EdgeSizeEvaluator
00039 {
00040   public:
00041     /// Construct an evaluator.
00042     EdgeSizeSimpleImplicit();
00043     /// Destruction is virtual so subclasses may clean up after refinement.
00044     virtual ~EdgeSizeSimpleImplicit();
00045 
00046     /** \brief Given an edge of length L, true when edge midpoint is within $\alpha^2$ of
00047      * $\left(\frac{2f(x,y,z)}{L}\right)^2$.
00048      */
00049     virtual bool evaluate_edge( const double* p0,
00050                                 const void* t0,
00051                                 double* p1,
00052                                 void* t1,
00053                                 const double* p2,
00054                                 const void* t2 );
00055 
00056     /// Set the 10 coefficients of the implicit function. The vector contains the entries of A,
00057     /// followed by B, followed by C.
00058     virtual void set_implicit_function( double* coeffs );
00059     /// Get the 10 coefficients of the implicit function. The vector contains the entries of A,
00060     /// followed by B, followed by C.
00061     void get_implicit_function( double*& coeffs );
00062 
00063     /// Set the threshold ratio of function value to half-edge length that triggers subdivision.
00064     virtual void set_ratio( double r )
00065     {
00066         this->ratio = r;
00067     }
00068     /// Get the threshold ratio of function value to half-edge length that triggers subdivision.
00069     double get_ratio()
00070     {
00071         return this->ratio;
00072     }
00073 
00074   protected:
00075     double coeffA[6];
00076     double coeffB[3];
00077     double coeffC;
00078     double ratio;
00079 };
00080 
00081 }  // namespace moab
00082 
00083 #endif  // MOAB_EDGE_SIZE_SIMPLE_IMPLICIT_HPP
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