/usr/include/deal.II/fe/component_mask.h is in libdeal.ii-dev 8.4.2-2+b1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 | // ---------------------------------------------------------------------
//
// Copyright (C) 2009 - 2015 by the deal.II authors
//
// This file is part of the deal.II library.
//
// The deal.II library is free software; you can use it, redistribute
// it, and/or modify it under the terms of the GNU Lesser General
// Public License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
// The full text of the license can be found in the file LICENSE at
// the top level of the deal.II distribution.
//
// ---------------------------------------------------------------------
#ifndef dealii__fe_component_mask_h
#define dealii__fe_component_mask_h
#include <deal.II/base/config.h>
#include <deal.II/base/exceptions.h>
#include <deal.II/base/memory_consumption.h>
#include <vector>
#include <iosfwd>
DEAL_II_NAMESPACE_OPEN
/**
* This class represents a mask that can be used to select individual vector
* components of a finite element (see also
* @ref GlossComponentMask "this glossary entry").
* It will typically have as many elements as the finite element has vector
* components, and one can use <code>operator[]</code> to query whether a
* particular component has been selected.
*
* Objects of this kind are used in many places where one wants to restrict
* operations to a certain subset of components, e.g. in
* DoFTools::make_zero_boundary_values or
* VectorTools::interpolate_boundary_values. These objects can either be
* created by hand, or, simpler, by asking the finite element to generate a
* component mask from certain selected components using code such as this
* where we create a mask that only denotes the velocity components of a
* Stokes element (see
* @ref vector_valued):
* @code
* FESystem<dim> stokes_fe (FE_Q<dim>(2), dim, // Q2 element for the velocities
* FE_Q<dim>(1), 1); // Q1 element for the pressure
* FEValuesExtractors::Scalar pressure(dim);
* ComponentMask pressure_mask = stokes_fe.component_mask (pressure);
* @endcode
* The result is a component mask that, in 2d, would have values <code>[false,
* false, true]</code>. Similarly, using
* @code
* FEValuesExtractors::Vector velocities(0);
* ComponentMask velocity_mask = stokes_fe.component_mask (velocities);
* @endcode
* would result in a mask <code>[true, true, false]</code> in 2d. Of course,
* in 3d, the result would be <code>[true, true, true, false]</code>.
*
* @ingroup fe
* @author Wolfgang Bangerth
* @date 2012
* @ingroup vector_valued
*/
class ComponentMask
{
public:
/**
* Initialize a component mask. The default is that a component mask
* represents a set of components that are <i>all</i> selected, i.e.,
* calling this constructor results in a component mask that always returns
* <code>true</code> whenever asked whether a component is selected.
*/
ComponentMask ();
/**
* Initialize an object of this type with a set of selected components
* specified by the argument.
*
* @param component_mask A vector of <code>true/false</code> entries that
* determine which components of a finite element are selected. If the
* length of the given vector is zero, then this interpreted as the case
* where <i>every</i> component is selected.
*/
ComponentMask (const std::vector<bool> &component_mask);
/**
* Initialize the component mask with a number of elements that are either
* all true or false.
*
* @param n_components The number of elements of this mask
* @param initializer The value each of these elements is supposed to have:
* either true or false.
*/
ComponentMask (const unsigned int n_components,
const bool initializer);
/**
* Set a particular entry in the mask to a value.
*/
void set (const unsigned int index, const bool value);
/**
* If this component mask has been initialized with a mask of size greater
* than zero, then return the size of the mask represented by this object.
* On the other hand, if this mask has been initialized as an empty object
* that represents a mask that is true for every element (i.e., if this
* object would return true when calling represents_the_all_selected_mask())
* then return zero since no definite size is known.
*/
unsigned int size () const;
/**
* Return whether a particular component is selected by this mask. If this
* mask represents the case of an object that selects <i>all components</i>
* (e.g. if it is created using the default constructor or is converted from
* an empty vector of type bool) then this function returns true regardless
* of the given argument.
*
* @param component_index The index for which the function should return
* whether the component is selected. If this object represents a mask in
* which all components are always selected then any index is allowed here.
* Otherwise, the given index needs to be between zero and the number of
* components that this mask represents.
*/
bool operator[] (const unsigned int component_index) const;
/**
* Return whether this component mask represents a mask with exactly
* <code>n</code> components. This is true if either it was initialized with
* a vector with exactly <code>n</code> entries of type <code>bool</code>
* (in this case, @p n must equal the result of size()) or if it was
* initialized with an empty vector (or using the default constructor) in
* which case it can represent a mask with an arbitrary number of components
* and will always say that a component is selected.
*/
bool
represents_n_components (const unsigned int n) const;
/**
* Return the number of components that are selected by this mask.
*
* Since empty component masks represent a component mask that would return
* <code>true</code> for every component, this function may not know the
* true size of the component mask and it therefore requires an argument
* that denotes the overall number of components.
*
* If the object has been initialized with a non-empty mask (i.e., if the
* size() function returns something greater than zero, or equivalently if
* represents_the_all_selected_mask() returns false) then the argument can
* be omitted and the result of size() is taken.
*/
unsigned int
n_selected_components (const unsigned int overall_number_of_components = numbers::invalid_unsigned_int) const;
/**
* Return the index of the first selected component. The argument is there
* for the same reason it exists with the n_selected_components() function.
*
* The function throws an exception if no component is selected at all.
*/
unsigned int
first_selected_component (const unsigned int overall_number_of_components = numbers::invalid_unsigned_int) const;
/**
* Return true if this mask represents a default constructed mask that
* corresponds to one in which all components are selected. If true, then
* the size() function will return zero.
*/
bool
represents_the_all_selected_mask () const;
/**
* Return a component mask that contains the union of the components
* selected by the current object and the one passed as an argument.
*/
ComponentMask operator | (const ComponentMask &mask) const;
/**
* Return a component mask that has only those elements set that are set
* both in the current object as well as the one passed as an argument.
*/
ComponentMask operator & (const ComponentMask &mask) const;
/**
* Return whether this object and the argument are identical.
*/
bool operator== (const ComponentMask &mask) const;
/**
* Return whether this object and the argument are not identical.
*/
bool operator!= (const ComponentMask &mask) const;
/**
* Determine an estimate for the memory consumption (in bytes) of this
* object.
*/
std::size_t
memory_consumption () const;
/**
* Exception
*/
DeclExceptionMsg (ExcNoComponentSelected,
"The number of selected components in a mask "
"must be greater than zero.");
private:
/**
* The actual component mask.
*/
std::vector<bool> component_mask;
// make the output operator a friend so it can access
// the component_mask array
friend
std::ostream &operator << (std::ostream &out,
const ComponentMask &mask);
};
/**
* Write a component mask to an output stream. If the component mask
* represents one where all components are selected without specifying a
* particular size of the mask, then it writes the string <code>[all
* components selected]</code> to the stream. Otherwise, it prints the
* component mask in a form like <code>[true,true,true,false]</code>.
*
* @param out The stream to write to.
* @param mask The mask to write. @return A reference to the first argument.
*/
std::ostream &operator << (std::ostream &out,
const ComponentMask &mask);
// -------------------- inline functions ---------------------
inline
ComponentMask::ComponentMask()
{}
inline
ComponentMask::ComponentMask(const std::vector<bool> &component_mask)
:
component_mask (component_mask)
{}
inline
ComponentMask::ComponentMask(const unsigned int n_components,
const bool initializer)
:
component_mask (n_components, initializer)
{}
inline
unsigned int
ComponentMask::size () const
{
return component_mask.size();
}
inline
void
ComponentMask::set(const unsigned int index, const bool value)
{
AssertIndexRange(index, component_mask.size());
component_mask[index] = value;
}
inline
bool
ComponentMask::operator [](const unsigned int component_index) const
{
// if the mask represents the all-component mask
// then always return true
if (component_mask.size() == 0)
return true;
else
{
// otherwise check the validity of the index and
// return whatever is appropriate
AssertIndexRange (component_index, component_mask.size());
return component_mask[component_index];
}
}
inline
bool
ComponentMask::represents_n_components(const unsigned int n) const
{
return ((component_mask.size() == 0)
||
(component_mask.size() == n));
}
inline
unsigned int
ComponentMask::n_selected_components(const unsigned int n) const
{
if ((n != numbers::invalid_unsigned_int) && (size() > 0))
AssertDimension (n, size());
const unsigned int real_n = (n != numbers::invalid_unsigned_int
?
n
:
size());
if (component_mask.size() == 0)
return real_n;
else
{
AssertDimension (real_n, component_mask.size());
unsigned int c = 0;
for (unsigned int i=0; i<component_mask.size(); ++i)
if (component_mask[i] == true)
++c;
return c;
}
}
inline
unsigned int
ComponentMask::first_selected_component(const unsigned int n) const
{
if ((n != numbers::invalid_unsigned_int) && (size() > 0))
AssertDimension (n, size());
if (component_mask.size() == 0)
return 0;
else
{
for (unsigned int c=0; c<component_mask.size(); ++c)
if (component_mask[c] == true)
return c;
Assert (false, ExcMessage ("No component is selected at all!"));
return numbers::invalid_unsigned_int;
}
}
inline
bool
ComponentMask::represents_the_all_selected_mask () const
{
return (component_mask.size() == 0);
}
inline
ComponentMask
ComponentMask::operator | (const ComponentMask &mask) const
{
// if one of the two masks denotes the all-component mask,
// then return the other one
if (component_mask.size() == 0)
return mask;
else if (mask.component_mask.size() == 0)
return *this;
else
{
// if both masks have individual entries set, form
// the combination of the two
AssertDimension(component_mask.size(), mask.component_mask.size());
std::vector<bool> new_mask (component_mask.size());
for (unsigned int i=0; i<component_mask.size(); ++i)
new_mask[i] = (component_mask[i] || mask.component_mask[i]);
return new_mask;
}
}
inline
ComponentMask
ComponentMask::operator & (const ComponentMask &mask) const
{
// if one of the two masks denotes the all-component mask,
// then return the other one
if (component_mask.size() == 0)
return mask;
else if (mask.component_mask.size() == 0)
return *this;
else
{
// if both masks have individual entries set, form
// the combination of the two
AssertDimension(component_mask.size(), mask.component_mask.size());
std::vector<bool> new_mask (component_mask.size());
for (unsigned int i=0; i<component_mask.size(); ++i)
new_mask[i] = (component_mask[i] && mask.component_mask[i]);
return new_mask;
}
}
inline
bool
ComponentMask::operator== (const ComponentMask &mask) const
{
return component_mask == mask.component_mask;
}
inline
bool
ComponentMask::operator!= (const ComponentMask &mask) const
{
return component_mask != mask.component_mask;
}
DEAL_II_NAMESPACE_CLOSE
#endif
|