Grids#

Global and local grids are two data structures included into MPL to facilitate the implementation of domain decomposition mathods on regular rectangular multidimensional grids. See sections Distributed grid, Distributed grid collective operations, Heat equation Jacobi solver and Heat equation successive over-relaxation for examples.

Distributed grids#

template<std::size_t dim, typename T, typename A = std::allocator<T>> class distributed_grid#

Local portion of a distributed data grid including local overlap data.

Param dim:

number of dimensions of the data grid, may be 1, 2, 3 or 4

Template Parameters:

T – data type that is hold at each grid point
A – memory allocator

Public Types

using vector_type = std::vector<T, A>#: the underlying one-dimensional vector type

using value_type = typename vector_type::value_type#: data type that is hold at each grid point

using allocator_type = typename vector_type::allocator_type#: memory allocator

using size_type = std::ptrdiff_t#: type used for indexing

Note

This is a signed integer type (unlike for STL containers).

using difference_type = typename vector_type::difference_type#: signed integer type for iterator differences

using reference = typename vector_type::reference#: reference to value_type

using const_reference = typename vector_type::const_reference#: const reference to value_type

using pointer = typename vector_type::pointer#: pointer to value_type

using const_pointer = typename vector_type::const_pointer#: const pointer to value_type

Public Functions

inline explicit distributed_grid(const cartesian_communicator &communicator, const dimensions &dims)#

Creates the local portion of a distributed data grid.

Note

The number of dimensions of the Cartesian communicator and the size of the dims parameter must be equal.

Parameters:

communicator – Cartesian communicator that wil be employed to update overlap data between adjacent processes.
dims – size and overlap data of the global grid

inline size_type gsize(size_type d) const#

Determines the global size of the grid along a dimension.

Parameters:: d – dimension
Returns:: global size

inline size_type gbegin(size_type d) const#

Determines the smallest index into the global distributed grid to the local portion of the grid.

Parameters:: d – dimension
Returns:: grid index

inline size_type gend(size_type d) const#

Determines the smallest index into the global distributed grid that is beyond the local portion of the grid.

Parameters:: d – dimension
Returns:: grid index

inline size_type size(size_type d) const#

Determines the size of the local portion of the distributed data grid along a dimension.

Parameters:: d – dimension
Returns:: local grid size

inline size_type begin(size_type d) const#

Determines the lowest index to access the local portion of the distributed data grid along a dimension.

Parameters:: d – dimension
Returns:: grid index

inline size_type end(size_type d) const#

Determines the last index (plus one) to access the local portion of the distributed data grid along a dimension.

Parameters:: d – dimension
Returns:: grid index

inline size_type obegin(size_type d) const#

Determines the lowest index to access the local portion of the distributed grid including the overlap data along a dimension.

Parameters:: d – dimension
Returns:: grid index

inline size_type oend(size_type d) const#

Determines the last index (plus one) to access the local portion of the distributed grid including the overlap data along a dimension.

Parameters:: d – dimension
Returns:: grid index

inline size_type gindex(size_type d, size_type i) const#

Translates an index to access the local portion of the distributed data grid into an index into the global grid.

Parameters:

d – dimension
i – index with respect to local data

Returns:

grid index

template<std::size_t d = dim> inline std::enable_if_t<d == 1, reference> operator()(size_type i_0)#

Element access.

Parameters:: i_0 – 1st dimension index
Returns:: grid data element

template<std::size_t d = dim> inline std::enable_if_t<d == 1, const_reference> operator()(size_type i_0) const#

Element access.

Parameters:: i_0 – 1st dimension index
Returns:: grid data element

template<std::size_t d = dim> inline std::enable_if_t<d == 2, reference> operator()(size_type i_0, size_type i_1)#

Element access.

Parameters:

i_0 – 1st dimension index
i_1 – 2nd dimension index

Returns:

grid data element

template<std::size_t d = dim> inline std::enable_if_t<d == 2, const_reference> operator()(size_type i_0, size_type i_1) const#

Element access.

Parameters:

i_0 – 1st dimension index
i_1 – 2nd dimension index

Returns:

grid data element

template<std::size_t d = dim> inline std::enable_if_t<d == 3, reference> operator()(size_type i_0, size_type i_1, size_type i_2)#

Element access.

Parameters:

i_0 – 1st dimension index
i_1 – 2nd dimension index
i_2 – 3rd dimension index

Returns:

grid data element

template<std::size_t d = dim> inline std::enable_if_t<d == 3, const_reference> operator()(size_type i_0, size_type i_1, size_type i_2) const#

Element access.

Parameters:

i_0 – 1st dimension index
i_1 – 2nd dimension index
i_2 – 3rd dimension index

Returns:

grid data element

template<std::size_t d = dim> inline std::enable_if_t<d == 4, reference> operator()(size_type i_0, size_type i_1, size_type i_2, size_type i_3)#

Element access.

Parameters:

i_0 – 1st dimension index
i_1 – 2nd dimension index
i_2 – 3rd dimension index
i_3 – 4th dimension index

Returns:

grid data element

template<std::size_t d = dim> inline std::enable_if_t<d == 4, const_reference> operator()(size_type i_0, size_type i_1, size_type i_2, size_type i_3) const#

Element access.

Parameters:

i_0 – 1st dimension index
i_1 – 2nd dimension index
i_2 – 3rd dimension index
i_3 – 4th dimension index

Returns:

grid data element

inline pointer data()#

Grands access to the flattened grid data.

Returns:: pointer to grid data

inline const_pointer data() const#

Grands access to the flattened grid data.

Returns:: pointer to grid data

inline const subarray_layout<T> &left_mirror_layout(size_type d) const#

Get the memory layout for receiving data when updating data in overlap regions along a given dimension.

The returned memory layout represents data in the left overlap region.

Parameters:: d – dimension
Returns:: memory layout

inline const subarray_layout<T> &right_mirror_layout(size_type d) const#

Get the memory layout for receiving data when updating data in overlap regions along a given dimension.

The returned memory layout represents data in the right overlap region.

Parameters:: d – dimension
Returns:: memory layout

inline const subarray_layout<T> &left_border_layout(size_type d) const#

Get the memory layout for sending data when updating data in overlap regions along a given dimension.

The returned memory layout represents data next to the left overlap region.

Parameters:: d – dimension
Returns:: memory layout

inline const subarray_layout<T> &right_border_layout(size_type d) const#

Get the memory layout for sending data when updating data in overlap regions along a given dimension.

The returned memory layout represents data next to the right overlap region.

Parameters:: d – dimension
Returns:: memory layout

inline const subarray_layout<T> &interior_layout() const#

Get the memory layout for sending or receiving data without overlap data.

The returned memory layout represents inner grid data without the overlap regions.

Returns:: memory layout

inline void swap(distributed_grid<dim, T, A> &other)#

Swaps this distributed data grid with another.

Parameters:: other – other distributed data grid

class dimensions#

Characterizes the dimensionality, total size and overlap of a distributed data grid.

Public Types

using value_type = size_overlap_pair #

using reference = size_overlap_pair&#

using const_reference = const size_overlap_pair&#

using iterator = typename std::array<size_overlap_pair, dim>::iterator#

using const_iterator = typename std::array<size_overlap_pair, dim>::const_iterator#

Public Functions

inline dimensions(const size_overlap_pair &size_0)#

inline dimensions(const size_overlap_pair &size_0, const size_overlap_pair &size_1)#

inline dimensions(const size_overlap_pair &size_0, const size_overlap_pair &size_1, const size_overlap_pair &size_2)#

inline dimensions(const size_overlap_pair &size_0, const size_overlap_pair &size_1, const size_overlap_pair &size_2, const size_overlap_pair &size_3)#

inline size_type dimensionality() const#

Determines the dimensionality.

Returns:: dimensionality (number of dimensions)

inline size_type size(size_type dimension) const#

Determines the total size of a dimension.

Parameters:: dimension – the rank of the dimension
Returns:: the total size of the dimension

inline size_type overlap(size_type dimension) const#

Determines the overlap size of a dimension.

Parameters:: dimension – the rank of the dimension
Returns:: the overlap of the dimension

inline const_reference operator[](size_type dimension) const#

Determines then total size along a dimension and the overlap of a dimension.

Parameters:: dimension – the rank of the dimension
Returns:: the size and the overlap

inline reference operator[](size_type dimension)#

Determines then total size along a dimension and the overlap of a dimension.

Parameters:: dimension – the rank of the dimension
Returns:: the size and the overlap

inline iterator begin()#

inline const_iterator begin() const#

inline const_iterator cbegin() const#

inline iterator end()#

inline const_iterator end() const#

inline const_iterator cend() const#

Friends

friend class distributed_grid

class size_overlap_pair#

Pair of grid size and overlap size.

Public Functions

inline size_overlap_pair(size_type size, size_type overlap)#: Creates a size-overlap pair.

Public Members

size_type size = {0}#: indicates the total/global number data pints that the data grid holds along a dimension

size_type overlap = {0}#: indicates the number of overlap data points the each local process holds as a copy of data hold by adjacent processes

Local grids#

template<std::size_t dim, typename T, typename A = std::allocator<T>> class local_grid#

Data grid.

This data structure is suitable for gather and scatter operation in combination with distributed_grid.

Param dim:

number of dimensions of the data grid, may be 1, 2, 3 or 4

Template Parameters:

T – data type that is hold at each grid point
A – memory allocator

Public Types

using vector_type = std::vector<T, A>#: the underlying one-dimensional vector type

using value_type = typename vector_type::value_type#: data type that is hold at each grid point

using allocator_type = typename vector_type::allocator_type#: memory allocator

using size_type = std::ptrdiff_t#: type used for indexing

Note

This is a signed integer type (unlike for STL containers).

using difference_type = typename vector_type::difference_type#: signed integer type for iterator differences

using reference = typename vector_type::reference#: reference to value_type

using const_reference = typename vector_type::const_reference#: const reference to value_type

using pointer = typename vector_type::pointer#: pointer to value_type

using const_pointer = typename vector_type::const_pointer#: const pointer to value_type

Public Functions

inline local_grid(const cartesian_communicator &communicator, const dimensions &dims)#

Creates a local data grid.

Note

The number of dimensions of the Cartesian communicator and the size of the dims parameter must be equal.

Parameters:

communicator – Cartesian communicator that will be employed to scatter or gather data.
dims – size of the global grid

inline size_type size(size_type d) const#

Determines the size of the data grid along a dimension.

Parameters:: d – dimension
Returns:: local grid size

inline size_type begin(size_type d) const#

Determines the lowest index to access the data grid along a dimension.

Parameters:: d – dimension
Returns:: grid index

inline size_type end(size_type d) const#

Determines the last index (plus one) to access the data grid along a dimension.

Parameters:: d – dimension
Returns:: grid index

template<std::size_t d = dim> inline std::enable_if_t<d == 1, reference> operator()(size_type i_0)#

Element access.

Parameters:: i_0 – 1st dimension index
Returns:: grid data element

template<std::size_t d = dim> inline std::enable_if_t<d == 1, const_reference> operator()(size_type i_0) const#

Element access.

Parameters:: i_0 – 1st dimension index
Returns:: grid data element

template<std::size_t d = dim> inline std::enable_if_t<d == 2, reference> operator()(size_type i_0, size_type i_1)#

Element access.

Parameters:

i_0 – 1st dimension index
i_1 – 2nd dimension index

Returns:

grid data element

template<std::size_t d = dim> inline std::enable_if_t<d == 2, const_reference> operator()(size_type i_0, size_type i_1) const#

Element access.

Parameters:

i_0 – 1st dimension index
i_1 – 2nd dimension index

Returns:

grid data element

template<std::size_t d = dim> inline std::enable_if_t<d == 3, reference> operator()(size_type i_0, size_type i_1, size_type i_2)#

Element access.

Parameters:

i_0 – 1st dimension index
i_1 – 2nd dimension index
i_2 – 3rd dimension index

Returns:

grid data element

template<std::size_t d = dim> inline std::enable_if_t<d == 3, const_reference> operator()(size_type i_0, size_type i_1, size_type i_2) const#

Element access.

Parameters:

i_0 – 1st dimension index
i_1 – 2nd dimension index
i_2 – 3rd dimension index

Returns:

grid data element

template<std::size_t d = dim> inline std::enable_if_t<d == 4, reference> operator()(size_type i_0, size_type i_1, size_type i_2, size_type i_3)#

Element access.

Parameters:

i_0 – 1st dimension index
i_1 – 2nd dimension index
i_2 – 3rd dimension index
i_3 – 4th dimension index

Returns:

grid data element

template<std::size_t d = dim> inline std::enable_if_t<d == 4, const_reference> operator()(size_type i_0, size_type i_1, size_type i_2, size_type i_3) const#

Element access.

Parameters:

i_0 – 1st dimension index
i_1 – 2nd dimension index
i_2 – 3rd dimension index
i_3 – 4th dimension index

Returns:

grid data element

inline pointer data()#

Grands access to the flattened grid data.

Returns:: pointer to grid data

inline const_pointer data() const#

Grands access to the flattened grid data.

Returns:: pointer to grid data

inline const layouts<T> &sub_layouts() const#

Get layouts for scatting and gathering of the grid data.

If there is a local_grid and a distributed_grid that have been created with the same Cartesian communicator argument and if both grids have the same total size then the i-th returned layout is suitable to send a sub-set of data from the local_grid to the distributed grid at the process with rank i in the Cartesian communicator.

Returns:: set of layouts

inline void swap(local_grid<dim, T, A> &other)#

class dimensions#

Characterizes the dimensionality and the total size of a local data grid.

Public Types

using value_type = size_type #

using reference = size_type&#

using const_reference = const size_type&#

using iterator = typename std::array<size_type, dim>::iterator#

using const_iterator = typename std::array<std::size_t, dim>::const_iterator#

Public Functions

inline dimensions(const size_type &size_0)#

inline dimensions(const size_type &size_0, const size_type &size_1)#

inline dimensions(const size_type &size_0, const size_type &size_1, const size_type &size_2)#

inline dimensions(const size_type &size_0, const size_type &size_1, const size_type &size_2, const size_type &size_3)#

inline size_type dimensionality() const#

Determines the dimensionality.

Returns:: dimensionality (number of dimensions)

inline size_type size(size_type dimension) const#

Determines the total size of a dimension.

Parameters:: dimension – the rank of the dimension
Returns:: the total size of the dimension

inline const_reference operator[](size_type dimension) const#

Determines then total size along a dimension of a dimension.

Parameters:: dimension – the rank of the dimension
Returns:: the size and the overlap

inline reference operator[](size_type dimension)#

Determines then total size along a dimension.

Parameters:: dimension – the rank of the dimension
Returns:: the size and the overlap

inline iterator begin()#

inline const_iterator begin() const#

inline const_iterator cbegin() const#

inline iterator end()#

inline const_iterator end() const#

inline const_iterator cend() const#

Friends

friend class local_grid