Graphs¶

Programming interface¶

All types and functions in this section are declared in the oneapi::dal::preview namespace and are available via inclusion of the oneapi/dal/graph/common.hpp header file.

Graph¶

The graph concept is represented by the types with the _graph suffix and all of them are reference-counted:

The instance stores pointers to the graph topology and attributes of vertices and edges.
The reference count indicates how many graph objects refer to the same implementation.
The graph increments the reference count for it to be equal to the number of graph objects sharing the same implementation.
The graph decrements the reference count when the graph goes out of the scope. If the reference count is zero, the graph frees its implementation.

The graph types are defined as templated classes:

template <typename VertexValue,
          typename EdgeValue,
          typename GraphValue,
          typename IndexType,
          typename Allocator>
class [graph_name]_graph;

Type name	Description	Supported types
`VertexValue`	The type of the vertex attribute values	Empty value
`EdgeValue`	The type of the edge attribute values	`std::int32`, `double`, Empty value
`GraphValue`	The type of the graph attribute value	Empty value
`IndexType`	The type of the vertex indices	`std::int32`
`Allocator`	The type of a graph allocator	C++17 (ISO/IEC 14882:2017) compliant allocator

Empty value tag structure is used to define the absence of a specified attribute of a graph.

struct empty_value¶

Graph class contains the default and the move constructor as well as the move assignment operator. The graph is accessed using the service functions.

`graph_type` method	Description
Default constructor	Constructs an empty graph object
Move constructor	Creates a new graph instance and moves the implementation from another instance into this one
Move assignment	Swaps the implementation of this object and another one

Graph traits¶

Graph traits is a data type that defines the data model and a set of types associated with the graph. Graph traits are used by processing and service functionality.

Type graph_traits is specialized for each graph by following the pattern below.

template <typename G>
struct graph_traits {
   using graph_type = ...;
   using allocator_type = ...;
   ...
};

The full list of types defined in graph_traits<G> is in the table below:

Type, `graph_traits<G>::`	Description	Undirected Adjacency Vector Graph	Directed Adjacency Vector Graph
`graph_type`	The type of the graph `G`	`undirected_adjacency_vector_graph<VertexValue, EdgeValue, GraphValue, IndexType, Allocator>`	`directed_adjacency_vector_graph<VertexValue, EdgeValue, GraphValue, IndexType, Allocator>`
`allocator_type`	The type of the allocator of the graph `G`	`Allocator` [1]	`Allocator` [1]
`graph_user_value_type`	The type of the attribute of the graph `G`	`GraphValue` [1]	`GraphValue` [1]
`const_graph_user_value_type`	The constant type of the attribute of the graph `G`	`const GraphValue` [1]	`const GraphValue` [1]
`vertex_type`	The type of the vertices in the graph `G`	`IndexType` [1]	`IndexType` [1]
`vertex_iterator`	The type of the vertex iterator in the graph `G`	`vertex_type*`	`vertex_type*`
`const_vertex_iterator`	The constant type of the vertex iterator in the graph `G`	`const vertex_type*`	`const vertex_type*`
`vertex_size_type`	The type of the vertex indices in the graph `G`	`std::int64_t`	`std::int64_t`
`vertex_user_value_type`	The type of the vertex attribute of the graph `G`	`VertexValue` [1]	`VertexValue` [1]
`edge_type`	The type of edges in the graph `G`	`std::int64_t`	`std::int64_t`
`edge_iterator`	The type of the edge iterator in the graph `G`	Not available	Not available
`const_edge_iterator`	The constant type of the edge iterator in the graph `G`	Not available	Not available
`edge_size_type`	The type of the edge indices in the graph `G`	`std::int64_t`	`std::int64_t`
`edge_user_value_type`	The type of edge attribute	`EdgeValue` [1]	`EdgeValue` [1]
`vertex_edge_size_type`	The type of the vertex neighbors indices	`std::int64_t`	Not available
`vertex_outward_edge_size_type`	The type of the vertex outward neighbors indices	Not available	`std::int64_t`
`vertex_edge_iterator_type`	The type of the vertex neighbors iterator	`IndexType*` [1]	Not available
`const_vertex_edge_iterator_type`	The type of the vertex neighbors constant iterator	`const IndexType*` [1]	Not available
`vertex_outward_edge_iterator_type`	The type of the vertex outward neighbors iterator	Not available	`IndexType*` [1]
`const_vertex_outward_edge_iterator_type`	The type of the vertex outward neighbors constant iterator	Not available	`const IndexType*` [1]
`vertex_edge_range`	The type of the range of vertex neighbors	`std::pair<IndexType, IndexType>` [1]	Not available
`const_vertex_edge_range`	The type of the constant range of vertex neighbors	`std::pair<IndexType, IndexType>` [1]	Not available
`vertex_outward_edge_range`	The type of the range of vertex outward neighbors	Not available	`std::pair<IndexType, IndexType>` [1]
`const_vertex_outward_edge_range`	The type of the constant range of vertex outward neighbors	Not available	`std::pair<IndexType, IndexType>` [1]

[1] VertexValue, EdgeValue, GraphValue, IndexType, Allocator – template parameters of graph G.

This section describes API of the specified graph types.

CSV data source

Undirected adjacency vector graph

oneDAL documentation

Graphs¶

Programming interface¶

Graph¶

Graph traits¶