1 // The libMesh Finite Element Library. 2 // Copyright (C) 2002-2020 Benjamin S. Kirk, John W. Peterson, Roy H. Stogner 3 4 // This library is free software; you can redistribute it and/or 5 // modify it under the terms of the GNU Lesser General Public 6 // License as published by the Free Software Foundation; either 7 // version 2.1 of the License, or (at your option) any later version. 8 9 // This library is distributed in the hope that it will be useful, 10 // but WITHOUT ANY WARRANTY; without even the implied warranty of 11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 12 // Lesser General Public License for more details. 13 14 // You should have received a copy of the GNU Lesser General Public 15 // License along with this library; if not, write to the Free Software 16 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 17 18 19 20 #ifndef LIBMESH_ERROR_VECTOR_H 21 #define LIBMESH_ERROR_VECTOR_H 22 23 // Local Includes 24 #include "libmesh/statistics.h" 25 26 // C++ includes 27 #include <cstddef> 28 29 namespace libMesh 30 { 31 32 // Forward Declarations 33 class MeshBase; 34 class Mesh; 35 36 /** 37 * The \p ErrorVector is a specialization of the 38 * \p StatisticsVector for error data computed on a finite element 39 * mesh. In general, when computing the error on a mesh only the 40 * active elements are considered, but the \p ErrorVector is sized 41 * according to the total number of elements in the mesh. The 42 * \p ErrorVector is thus padded with zeros for all the inactive 43 * elements, and this must be taken into account when calculating 44 * the statistics. Since the error is a positive quantity this class 45 * assumes it contains positive data (i.e. min_val >= 0.). 46 * 47 * \author Benjamin S. Kirk 48 * \date 2003 49 */ 50 class ErrorVector : public StatisticsVector<ErrorVectorReal> 51 { 52 public: 53 54 /** 55 * ErrorVector constructor; sets initial length to \p i. 56 * 57 * If mesh is not null, MeshBase::elem() and Elem::is_active() will 58 * be used to distinguish active and inactive elements. If mesh is null, 59 * ErrorVector will assume that all 0.0 error values correspond to inactive 60 * elements and all non-zero error values correspond to active elements. 61 */ 62 ErrorVector(dof_id_type i=0, MeshBase * mesh = nullptr) : 63 StatisticsVector<ErrorVectorReal> (i), 64 _mesh(mesh) 65 {} 66 67 /** 68 * ErrorVector constructor; sets initial length to \p i and initial values to \p val. 69 * 70 * If mesh is not null, MeshBase::elem() and Elem::is_active() will 71 * be used to distinguish active and inactive elements. If mesh is null, 72 * ErrorVector will assume that all 0.0 error values correspond to inactive 73 * elements and all non-zero error values correspond to active elements. 74 */ ErrorVector(dof_id_type i,ErrorVectorReal val)75 ErrorVector(dof_id_type i, ErrorVectorReal val) : 76 StatisticsVector<ErrorVectorReal> (i,val) {} 77 78 /** 79 * \returns The minimum nonzero value in the data set. 80 */ 81 virtual ErrorVectorReal minimum() const override; 82 83 /** 84 * \returns The mean value of the data set. Ignores 85 * zero values. 86 */ 87 virtual Real mean() const override; 88 89 /** 90 * \returns The median (e.g. the middle) value of the data set, 91 * ignoring inactive elements. 92 * 93 * This function modifies the original data by sorting, so it can't 94 * be called on const objects. Source: GNU Scientific Library 95 */ 96 virtual Real median() override; 97 98 /** 99 * A const version of the median function. 100 * Requires twice the memory of original 101 * data set but does not change the original. 102 */ 103 virtual Real median() const override; 104 105 /** 106 * \returns The variance of the data set ignoring inactive elements. 107 * 108 * Uses a recurrence relation to prevent data overflow for large 109 * sums. 110 * 111 * \note The variance is equal to the standard deviation squared. 112 * The variance is normalized by N in this case. Source: GNU 113 * Scientific Library. 114 */ variance()115 virtual Real variance() const override 116 { return this->variance(this->mean()); } 117 118 /** 119 * \returns The variance of the data set ignoring inactive elements 120 * and given the \p mean. 121 * 122 * This is useful for efficiency when you have already calculated 123 * the mean. Uses a recurrence relation to prevent data overflow for 124 * large sums. 125 * 126 * \note The variance is equal to the standard deviation squared. 127 * Source: GNU Scientific Library. 128 */ 129 virtual Real variance(const Real mean) const override; 130 131 /** 132 * \returns A vector of dof_id_types which correspond 133 * to the indices of every member of the data set 134 * below the cutoff value cut ignoring inactive elements. 135 */ 136 virtual std::vector<dof_id_type> cut_below(Real cut) const override; 137 138 /** 139 * \returns A vector of dof_id_types which correspond 140 * to the indices of every member of the data set 141 * above the cutoff value cut ignoring inactive elements. 142 */ 143 virtual std::vector<dof_id_type> cut_above(Real cut) const override; 144 145 /** 146 * Plots a data file, of a type determined by looking at 147 * the file extension in \p filename, of the error values on 148 * the active elements of \p mesh. 149 */ 150 void plot_error(const std::string & filename, 151 const MeshBase & mesh) const; 152 153 protected: 154 /** 155 * Utility function to decide whether element i is active 156 */ 157 bool is_active_elem (dof_id_type i) const; 158 159 /** 160 * Pointer to the mesh, which may be used to decide which 161 * elements are active 162 */ 163 MeshBase * _mesh; 164 }; 165 166 } // namespace libMesh 167 168 #endif // LIBMESH_ERROR_VECTOR_H 169