Reference documentation for deal.II version 9.3.0
\(\newcommand{\dealvcentcolon}{\mathrel{\mathop{:}}}\) \(\newcommand{\dealcoloneq}{\dealvcentcolon\mathrel{\mkern-1.2mu}=}\) \(\newcommand{\jump}[1]{\left[\!\left[ #1 \right]\!\right]}\) \(\newcommand{\average}[1]{\left\{\!\left\{ #1 \right\}\!\right\}}\)
Public Types | Public Member Functions | Static Public Member Functions | Protected Member Functions | Protected Attributes | List of all members
Table< 3, T > Class Template Reference

#include <deal.II/base/table.h>

Inheritance diagram for Table< 3, T >:
[legend]

Public Types

using size_type = typename TableBase< 3, T >::size_type
 
using value_type = T
 

Public Member Functions

 Table ()=default
 
 Table (const size_type size1, const size_type size2, const size_type size3)
 
template<typename InputIterator >
 Table (const size_type size1, const size_type size2, const size_type size3, InputIterator entries, const bool C_style_indexing=true)
 
::internal::TableBaseAccessors::Accessor< 3, T, true, 2 > operator[] (const size_type i) const
 
::internal::TableBaseAccessors::Accessor< 3, T, false, 2 > operator[] (const size_type i)
 
AlignedVector< T >::const_reference operator() (const size_type i, const size_type j, const size_type k) const
 
AlignedVector< T >::reference operator() (const size_type i, const size_type j, const size_type k)
 
bool operator== (const TableBase< N, T > &T2) const
 
void reset_values ()
 
void reinit (const TableIndices< N > &new_size, const bool omit_default_initialization=false)
 
size_type size (const unsigned int i) const
 
const TableIndices< N > & size () const
 
size_type n_elements () const
 
bool empty () const
 
void fill (InputIterator entries, const bool C_style_indexing=true)
 
void fill (const T &value)
 
AlignedVector< T >::reference operator() (const TableIndices< N > &indices)
 
AlignedVector< T >::const_reference operator() (const TableIndices< N > &indices) const
 
void replicate_across_communicator (const MPI_Comm &communicator, const unsigned int root_process)
 
void swap (TableBase< N, T > &v)
 
std::size_t memory_consumption () const
 
void serialize (Archive &ar, const unsigned int version)
 
Subscriptor functionality

Classes derived from Subscriptor provide a facility to subscribe to this object. This is mostly used by the SmartPointer class.

void subscribe (std::atomic< bool > *const validity, const std::string &identifier="") const
 
void unsubscribe (std::atomic< bool > *const validity, const std::string &identifier="") const
 
unsigned int n_subscriptions () const
 
template<typename StreamType >
void list_subscribers (StreamType &stream) const
 
void list_subscribers () const
 

Static Public Member Functions

static ::ExceptionBaseExcInUse (int arg1, std::string arg2, std::string arg3)
 
static ::ExceptionBaseExcNoSubscriber (std::string arg1, std::string arg2)
 

Protected Member Functions

size_type position (const TableIndices< N > &indices) const
 
AlignedVector< T >::reference el (const TableIndices< N > &indices)
 
AlignedVector< T >::const_reference el (const TableIndices< N > &indices) const
 

Protected Attributes

AlignedVector< T > values
 
TableIndices< N > table_size
 

Detailed Description

template<typename T>
class Table< 3, T >

A class representing a three-dimensional table of objects (not necessarily only numbers). The majority of the interface of this class is implemented in the TableBase base class.See there for an outline of the rationale for and interface of this class.

Definition at line 1478 of file table.h.

Member Typedef Documentation

◆ size_type

template<typename T >
using Table< 3, T >::size_type = typename TableBase<3, T>::size_type

Integer type used to count the number of elements in this container.

Definition at line 1484 of file table.h.

◆ value_type

using TableBase< N, T >::value_type = T
inherited

Definition at line 441 of file table.h.

Constructor & Destructor Documentation

◆ Table() [1/3]

template<typename T >
Table< 3, T >::Table ( )
default

Default constructor. Set all dimensions to zero.

◆ Table() [2/3]

template<typename T >
Table< 3, T >::Table ( const size_type  size1,
const size_type  size2,
const size_type  size3 
)

Constructor. Pass down the given dimensions to the base class.

◆ Table() [3/3]

template<typename T >
template<typename InputIterator >
Table< 3, T >::Table ( const size_type  size1,
const size_type  size2,
const size_type  size3,
InputIterator  entries,
const bool  C_style_indexing = true 
)

Constructor. Create a table with a given size and initialize it from a set of iterators.

This function is entirely equivalent to creating a table t of the given size and then calling

t.fill (entries, C_style_indexing);

on it, using the TableBase::fill() function where the arguments are explained in more detail. The point, however, is that that is only possible if the table can be changed after running the constructor, whereas calling the current constructor allows sizing and initializing an object right away so that it can be marked const.

Using this constructor, you can do things like this (shown here for a two-dimensional table, but the same works for the current class):

const double values[] = { 1, 2, 3, 4, 5, 6 };
const Table<2,double> t(2, 3, entries, true);

You can also initialize a table right from a file, using input iterators:

std::ifstream input ("myfile");
const Table<2,double> t(2, 3,
std::istream_iterator<double>(input),
true);
Parameters
size1The size of this table in the first dimension.
size2The size of this table in the second dimension.
size3The size of this table in the third dimension.
entriesAn iterator to a set of elements from which to initialize this table. It is assumed that iterator can be incremented and dereferenced a sufficient number of times to fill this table.
C_style_indexingIf true, run over elements of the table with the last index changing fastest as we dereference subsequent elements of the input range. If false, change the first index fastest.

Member Function Documentation

◆ operator[]() [1/2]

template<typename T >
::internal::TableBaseAccessors::Accessor<3, T, true, 2> Table< 3, T >::operator[] ( const size_type  i) const

Access operator. Generate an object that accesses the requested two- dimensional subobject of this three-dimensional table. Range checks are performed.

This version of the function only allows read access.

◆ operator[]() [2/2]

template<typename T >
::internal::TableBaseAccessors::Accessor<3, T, false, 2> Table< 3, T >::operator[] ( const size_type  i)

Access operator. Generate an object that accesses the requested two- dimensional subobject of this three-dimensional table. Range checks are performed.

This version of the function allows read-write access.

◆ operator()() [1/4]

template<typename T >
AlignedVector<T>::const_reference Table< 3, T >::operator() ( const size_type  i,
const size_type  j,
const size_type  k 
) const

Direct access to one element of the table by specifying all indices at the same time. Range checks are performed.

This version of the function only allows read access.

◆ operator()() [2/4]

template<typename T >
AlignedVector<T>::reference Table< 3, T >::operator() ( const size_type  i,
const size_type  j,
const size_type  k 
)

Direct access to one element of the table by specifying all indices at the same time. Range checks are performed.

This version of the function allows read-write access.

◆ operator==()

bool TableBase< N, T >::operator== ( const TableBase< N, T > &  T2) const
inherited

Test for equality of two tables.

◆ reset_values()

void TableBase< N, T >::reset_values ( )
inherited

Set all entries to their default value (i.e. copy them over with default constructed objects). Do not change the size of the table, though.

◆ reinit()

void TableBase< N, T >::reinit ( const TableIndices< N > &  new_size,
const bool  omit_default_initialization = false 
)
inherited

Set the dimensions of this object to the sizes given in the first argument, and allocate the required memory for table entries to accommodate these sizes. If omit_default_initialization is set to false, all elements of the table are set to a default constructed object for the element type. Otherwise the memory is left in an uninitialized or otherwise undefined state.

◆ size() [1/2]

size_type TableBase< N, T >::size ( const unsigned int  i) const
inherited

Size of the table in direction i.

◆ size() [2/2]

const TableIndices<N>& TableBase< N, T >::size ( ) const
inherited

Return the sizes of this object in each direction.

◆ n_elements()

size_type TableBase< N, T >::n_elements ( ) const
inherited

Return the number of elements stored in this object, which is the product of the extensions in each dimension.

◆ empty()

bool TableBase< N, T >::empty ( ) const
inherited

Return whether the object is empty, i.e. one of the directions is zero. This is equivalent to n_elements()==0.

◆ fill() [1/2]

void TableBase< N, T >::fill ( InputIterator  entries,
const bool  C_style_indexing = true 
)
inherited

Fill this table (which is assumed to already have the correct size) from a source given by dereferencing the given forward iterator (which could, for example, be a pointer to the first element of an array, or an inserting std::istream_iterator). The second argument denotes whether the elements pointed to are arranged in a way that corresponds to the last index running fastest or slowest. The default is to use C-style indexing where the last index runs fastest (as opposed to Fortran-style where the first index runs fastest when traversing multidimensional arrays. For example, if you try to fill an object of type Table<2,T>, then calling this function with the default value for the second argument will result in the equivalent of doing

for (unsigned int i=0; i<t.size(0); ++i)
for (unsigned int j=0; j<t.size(1); ++j)
t[i][j] = *entries++;

On the other hand, if the second argument to this function is false, then this would result in code of the following form:

for (unsigned int j=0; j<t.size(1); ++j)
for (unsigned int i=0; i<t.size(0); ++i)
t[i][j] = *entries++;

Note the switched order in which we fill the table elements by traversing the given set of iterators.

Parameters
entriesAn iterator to a set of elements from which to initialize this table. It is assumed that iterator can be incremented and dereferenced a sufficient number of times to fill this table.
C_style_indexingIf true, run over elements of the table with the last index changing fastest as we dereference subsequent elements of the input range. If false, change the first index fastest.

◆ fill() [2/2]

void TableBase< N, T >::fill ( const T &  value)
inherited

Fill all table entries with the same value.

◆ operator()() [3/4]

AlignedVector<T>::reference TableBase< N, T >::operator() ( const TableIndices< N > &  indices)
inherited

Return a read-write reference to the indicated element.

◆ operator()() [4/4]

AlignedVector<T>::const_reference TableBase< N, T >::operator() ( const TableIndices< N > &  indices) const
inherited

Return the value of the indicated element as a read-only reference.

We return the requested value as a constant reference rather than by value since this object may hold data types that may be large, and we don't know here whether copying is expensive or not.

◆ replicate_across_communicator()

void TableBase< N, T >::replicate_across_communicator ( const MPI_Comm communicator,
const unsigned int  root_process 
)
inherited

This function replicates the state found on the process indicated by root_process across all processes of the MPI communicator. The current state found on any of the processes other than root_process is lost in this process. One can imagine this operation to act like a call to Utilities::MPI::broadcast() from the root process to all other processes, though in practice the function may try to move the data into shared memory regions on each of the machines that host MPI processes and let all MPI processes on this machine then access this shared memory region instead of keeping their own copy. See the general documentation of this class for a code example.

The intent of this function is to quickly exchange large arrays from one process to others, rather than having to compute or create it on all processes. This is specifically the case for data loaded from disk – say, large data tables – that are more easily dealt with by reading once and then distributing across all processes in an MPI universe, than letting each process read the data from disk itself. Specifically, the use of shared memory regions allows for replicating the data only once per multicore machine in the MPI universe, rather than replicating data once for each MPI process. This results in large memory savings if the data is large on today's machines that can easily house several dozen MPI processes per shared memory space.

This function does not imply a model of keeping data on different processes in sync, as parallel::distributed::Vector and other vector classes do where there exists a notion of certain elements of the vector owned by each process and possibly ghost elements that are mirrored from its owning process to other processes. Rather, the elements of the current object are simply copied to the other processes, and it is useful to think of this operation as creating a set of const AlignedVector objects on all processes that should not be changed any more after the replication operation, as this is the only way to ensure that the vectors remain the same on all processes. This is particularly true because of the use of shared memory regions where any modification of a vector element on one MPI process may also result in a modification of elements visible on other processes, assuming they are located within one shared memory node.

Note
The use of shared memory between MPI processes requires that the detected MPI installation supports the necessary operations. This is the case for MPI 3.0 and higher.
This function is not cheap. It needs to create sub-communicators of the provided communicator object, which is generally an expensive operation. Likewise, the generation of shared memory spaces is not a cheap operation. As a consequence, this function primarily makes sense when the goal is to share large read-only data tables among processes; examples are data tables that are loaded at start-up time and then used over the course of the run time of the program. In such cases, the start-up cost of running this function can be amortized over time, and the potential memory savings from not having to store the table on each process may be substantial on machines with large core counts on which many MPI processes run on the same machine.
This function only makes sense if the data type T is "self-contained", i.e., all of its information is stored in its member variables, and if none of the member variables are pointers to other parts of the memory. This is because if a type T does have pointers to other parts of memory, then moving T into a shared memory space does not result in the other processes having access to data that the object points to with its member variable pointers: These continue to live only on one process, and are typically in memory areas not accessible to the other processes. As a consequence, the usual use case for this function is to share arrays of simple objects such as doubles or ints.
After calling this function, objects on different MPI processes share a common state. That means that certain operations become "collective", i.e., they must be called on all participating processors at the same time. In particular, you can no longer call resize(), reserve(), or clear() on one MPI process – you have to do so on all processes at the same time, because they have to communicate for these operations. If you do not do so, you will likely get a deadlock that may be difficult to debug. By extension, this rule of only collectively resizing extends to this function itself: You can not call it twice in a row because that implies that first all but the root_process throw away their data, which is not a collective operation. Generally, these restrictions on what can and can not be done hint at the correctness of the comments above: You should treat an AlignedVector on which the current function has been called as const, on which no further operations can be performed until the destructor is called.

◆ swap()

void TableBase< N, T >::swap ( TableBase< N, T > &  v)
inherited

Swap the contents of this table and the other table v. One could do this operation with a temporary variable and copying over the data elements, but this function is significantly more efficient since it only swaps the pointers to the data of the two vectors and therefore does not need to allocate temporary storage and move data around.

This function is analogous to the swap function of all C++ standard containers. Also, there is a global function swap(u,v) that simply calls u.swap(v), again in analogy to standard functions.

◆ memory_consumption()

std::size_t TableBase< N, T >::memory_consumption ( ) const
inherited

Determine an estimate for the memory consumption (in bytes) of this object.

◆ serialize()

void TableBase< N, T >::serialize ( Archive &  ar,
const unsigned int  version 
)
inherited

Write or read the data of this object to or from a stream for the purpose of serialization using the BOOST serialization library.

◆ position()

size_type TableBase< N, T >::position ( const TableIndices< N > &  indices) const
protectedinherited

Return the position of the indicated element within the array of elements stored one after the other. This function does no index checking.

◆ el() [1/2]

AlignedVector<T>::reference TableBase< N, T >::el ( const TableIndices< N > &  indices)
protectedinherited

Return a read-write reference to the indicated element.

This function does no bounds checking and is only to be used internally and in functions already checked.

◆ el() [2/2]

AlignedVector<T>::const_reference TableBase< N, T >::el ( const TableIndices< N > &  indices) const
protectedinherited

Return the value of the indicated element as a read-only reference.

This function does no bounds checking and is only to be used internally and in functions already checked.

We return the requested value as a constant reference rather than by value since this object may hold data types that may be large, and we don't know here whether copying is expensive or not.

◆ subscribe()

void Subscriptor::subscribe ( std::atomic< bool > *const  validity,
const std::string &  identifier = "" 
) const
inherited

Subscribes a user of the object by storing the pointer validity. The subscriber may be identified by text supplied as identifier.

Definition at line 136 of file subscriptor.cc.

◆ unsubscribe()

void Subscriptor::unsubscribe ( std::atomic< bool > *const  validity,
const std::string &  identifier = "" 
) const
inherited

Unsubscribes a user from the object.

Note
The identifier and the validity pointer must be the same as the one supplied to subscribe().

Definition at line 156 of file subscriptor.cc.

◆ n_subscriptions()

unsigned int Subscriptor::n_subscriptions ( ) const
inlineinherited

Return the present number of subscriptions to this object. This allows to use this class for reference counted lifetime determination where the last one to unsubscribe also deletes the object.

Definition at line 301 of file subscriptor.h.

◆ list_subscribers() [1/2]

template<typename StreamType >
void Subscriptor::list_subscribers ( StreamType &  stream) const
inlineinherited

List the subscribers to the input stream.

Definition at line 318 of file subscriptor.h.

◆ list_subscribers() [2/2]

void Subscriptor::list_subscribers ( ) const
inherited

List the subscribers to deallog.

Definition at line 204 of file subscriptor.cc.

Member Data Documentation

◆ values

AlignedVector<T> TableBase< N, T >::values
protectedinherited

Component-array.

Definition at line 787 of file table.h.

◆ table_size

TableIndices<N> TableBase< N, T >::table_size
protectedinherited

Size in each direction of the table.

Definition at line 792 of file table.h.


The documentation for this class was generated from the following file: