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Pack logtalk -- logtalk-3.98.0/docs/apis/_sources/graph_protocol_0.rst.txt

.. index:: single: graph_protocol .. _graph_protocol/0:

.. rst-class:: right

protocol

graph_protocol

Common protocol for all types of graphs. Graphs are represented using a dictionary where keys are vertices and values are sorted lists of neighbors (implicitly defining edges).

| Availability: | logtalk_load(graphs(loader))

| Author: Paulo Moura | Version: 1:0:0 | Date: 2026-02-25

| Compilation flags: | static

| Dependencies: | (none)

| Remarks: | (none)

| Inherited public predicates: | (none)

.. contents:: :local: :backlinks: top

Public predicates

.. index:: new/1 .. _graph_protocol/0::new/1:

new/1 ^^^^^^^^^

Creates a new empty graph.

| Compilation flags: | static

| Template: | new(Graph) | Mode and number of proofs: | new(-graph) - one


.. index:: new/2 .. _graph_protocol/0::new/2:

new/2 ^^^^^^^^^

Creates a new graph from a list of edges. Vertices are defined implicitly by edges.

| Compilation flags: | static

| Template: | new(Edges,Graph) | Mode and number of proofs: | new(+list(edge),-graph) - one


.. index:: new/3 .. _graph_protocol/0::new/3:

new/3 ^^^^^^^^^

Creates a new graph from a list of vertices and a list of edges. Vertices may also be defined implicitly by edges.

| Compilation flags: | static

| Template: | new(Vertices,Edges,Graph) | Mode and number of proofs: | new(+list(vertex),+list(edge),-graph) - one


.. index:: empty/1 .. _graph_protocol/0::empty/1:

empty/1 ^^^^^^^^^^^

True iff the given graph is empty.

| Compilation flags: | static

| Template: | empty(Graph) | Mode and number of proofs: | empty(@graph) - zero_or_one


.. index:: vertices/2 .. _graph_protocol/0::vertices/2:

vertices/2 ^^^^^^^^^^^^^^

Unifies Vertices with a sorted list of all vertices in the graph.

| Compilation flags: | static

| Template: | vertices(Graph,Vertices) | Mode and number of proofs: | vertices(+graph,-list(vertex)) - one


.. index:: edges/2 .. _graph_protocol/0::edges/2:

edges/2 ^^^^^^^^^^^

Unifies Edges with a list of all edges in the graph.

| Compilation flags: | static

| Template: | edges(Graph,Edges) | Mode and number of proofs: | edges(+graph,-list(edge)) - one


.. index:: add_vertex/3 .. _graph_protocol/0::add_vertex/3:

add_vertex/3 ^^^^^^^^^^^^^^^^

Adds a vertex to the graph. If the vertex already exists, the graph is unchanged.

| Compilation flags: | static

| Template: | add_vertex(Graph,Vertex,NewGraph) | Mode and number of proofs: | add_vertex(+graph,+vertex,-graph) - one


.. index:: add_vertices/3 .. _graph_protocol/0::add_vertices/3:

add_vertices/3 ^^^^^^^^^^^^^^^^^^

Adds a list of vertices to the graph.

| Compilation flags: | static

| Template: | add_vertices(Graph,Vertices,NewGraph) | Mode and number of proofs: | add_vertices(+graph,+list(vertex),-graph) - one


.. index:: delete_vertex/3 .. _graph_protocol/0::delete_vertex/3:

delete_vertex/3 ^^^^^^^^^^^^^^^^^^^

Deletes a vertex and all edges incident to it from the graph. If the vertex does not exist, the graph is unchanged.

| Compilation flags: | static

| Template: | delete_vertex(Graph,Vertex,NewGraph) | Mode and number of proofs: | delete_vertex(+graph,+vertex,-graph) - one


.. index:: delete_vertices/3 .. _graph_protocol/0::delete_vertices/3:

delete_vertices/3 ^^^^^^^^^^^^^^^^^^^^^

Deletes a list of vertices and all edges incident to them from the graph.

| Compilation flags: | static

| Template: | delete_vertices(Graph,Vertices,NewGraph) | Mode and number of proofs: | delete_vertices(+graph,+list(vertex),-graph) - one


.. index:: add_edges/3 .. _graph_protocol/0::add_edges/3:

add_edges/3 ^^^^^^^^^^^^^^^

Adds a list of edges to the graph. Vertices referenced by edges are added implicitly.

| Compilation flags: | static

| Template: | add_edges(Graph,Edges,NewGraph) | Mode and number of proofs: | add_edges(+graph,+list(edge),-graph) - one


.. index:: delete_edges/3 .. _graph_protocol/0::delete_edges/3:

delete_edges/3 ^^^^^^^^^^^^^^^^^^

Deletes a list of edges from the graph. Vertices are not deleted. Non-existing edges are silently ignored.

| Compilation flags: | static

| Template: | delete_edges(Graph,Edges,NewGraph) | Mode and number of proofs: | delete_edges(+graph,+list(edge),-graph) - one


.. index:: neighbors/3 .. _graph_protocol/0::neighbors/3:

neighbors/3 ^^^^^^^^^^^^^^^

Unifies Neighbors with a sorted list of the neighbors of Vertex in the graph. Fails if Vertex is not in the graph.

| Compilation flags: | static

| Template: | neighbors(Vertex,Graph,Neighbors) | Mode and number of proofs: | neighbors(+vertex,+graph,-list(vertex)) - zero_or_one


.. index:: reachable/3 .. _graph_protocol/0::reachable/3:

reachable/3 ^^^^^^^^^^^^^^^

Unifies Vertices with a sorted list of vertices reachable from Vertex (including Vertex itself). Fails if Vertex is not in the graph.

| Compilation flags: | static

| Template: | reachable(Vertex,Graph,Vertices) | Mode and number of proofs: | reachable(+vertex,+graph,-list(vertex)) - zero_or_one


.. index:: breadth_first_order/3 .. _graph_protocol/0::breadth_first_order/3:

breadth_first_order/3 ^^^^^^^^^^^^^^^^^^^^^^^^^

Unifies Vertices with the breadth-first traversal order rooted at Vertex. Fails if Vertex is not in the graph.

| Compilation flags: | static

| Template: | breadth_first_order(Vertex,Graph,Vertices) | Mode and number of proofs: | breadth_first_order(+vertex,+graph,-list(vertex)) - zero_or_one


.. index:: depth_first_order/3 .. _graph_protocol/0::depth_first_order/3:

depth_first_order/3 ^^^^^^^^^^^^^^^^^^^^^^^

Unifies Vertices with the depth-first traversal order rooted at Vertex. Fails if Vertex is not in the graph.

| Compilation flags: | static

| Template: | depth_first_order(Vertex,Graph,Vertices) | Mode and number of proofs: | depth_first_order(+vertex,+graph,-list(vertex)) - zero_or_one


.. index:: number_of_vertices/2 .. _graph_protocol/0::number_of_vertices/2:

number_of_vertices/2 ^^^^^^^^^^^^^^^^^^^^^^^^

Unifies N with the number of vertices in the graph.

| Compilation flags: | static

| Template: | number_of_vertices(Graph,N) | Mode and number of proofs: | number_of_vertices(+graph,-integer) - one


.. index:: number_of_edges/2 .. _graph_protocol/0::number_of_edges/2:

number_of_edges/2 ^^^^^^^^^^^^^^^^^^^^^

Unifies N with the number of edges in the graph.

| Compilation flags: | static

| Template: | number_of_edges(Graph,N) | Mode and number of proofs: | number_of_edges(+graph,-integer) - one


.. index:: path/3 .. _graph_protocol/0::path/3:

path/3 ^^^^^^^^^^

Returns a maximal path (list of vertices) rooted at Vertex, enumerating different paths on backtracking. Fails if Vertex is not in the graph.

| Compilation flags: | static

| Template: | path(Vertex,Graph,Path) | Mode and number of proofs: | path(+vertex,+graph,-list(vertex)) - zero_or_more


.. index:: has_path/3 .. _graph_protocol/0::has_path/3:

has_path/3 ^^^^^^^^^^^^^^

True iff there is a path from Vertex1 to Vertex2 in the graph.

| Compilation flags: | static

| Template: | has_path(Vertex1,Vertex2,Graph) | Mode and number of proofs: | has_path(+vertex,+vertex,+graph) - zero_or_one


.. index:: min_path/5 .. _graph_protocol/0::min_path/5:

min_path/5 ^^^^^^^^^^^^^^

Finds the minimum cost path from Vertex1 to Vertex2. For unweighted graphs, cost is the number of edges. Fails if no path exists.

| Compilation flags: | static

| Template: | min_path(Vertex1,Vertex2,Graph,Path,Cost) | Mode and number of proofs: | min_path(+vertex,+vertex,+graph,-list(vertex),-number) - zero_or_one


.. index:: max_path/5 .. _graph_protocol/0::max_path/5:

max_path/5 ^^^^^^^^^^^^^^

Finds the maximum cost acyclic path from Vertex1 to Vertex2. For unweighted graphs, cost is the number of edges. Fails if no path exists.

| Compilation flags: | static

| Template: | max_path(Vertex1,Vertex2,Graph,Path,Cost) | Mode and number of proofs: | max_path(+vertex,+vertex,+graph,-list(vertex),-number) - zero_or_one


.. index:: min_distances/3 .. _graph_protocol/0::min_distances/3:

min_distances/3 ^^^^^^^^^^^^^^^^^^^

Computes minimum path costs from Vertex to all reachable vertices. Returns a list of Target-Cost pairs including Vertex-0.

| Compilation flags: | static

| Template: | min_distances(Vertex,Graph,Distances) | Mode and number of proofs: | min_distances(+vertex,+graph,-list(pair)) - zero_or_one


.. index:: min_predecessors/3 .. _graph_protocol/0::min_predecessors/3:

min_predecessors/3 ^^^^^^^^^^^^^^^^^^^^^^

Computes predecessor links for minimum paths rooted at Vertex. Returns a list of Target-Predecessor pairs; the source predecessor is none.

| Compilation flags: | static

| Template: | min_predecessors(Vertex,Graph,Predecessors) | Mode and number of proofs: | min_predecessors(+vertex,+graph,-list(pair)) - zero_or_one


.. index:: all_pairs_min_paths/2 .. _graph_protocol/0::all_pairs_min_paths/2:

all_pairs_min_paths/2 ^^^^^^^^^^^^^^^^^^^^^^^^^

Computes minimum path costs for all ordered pairs of vertices with a path between them. Returns a list of (Vertex1-Vertex2)-Cost terms.

| Compilation flags: | static

| Template: | all_pairs_min_paths(Graph,Pairs) | Mode and number of proofs: | all_pairs_min_paths(+graph,-list(pair)) - one


.. index:: all_pairs_min_predecessors/2 .. _graph_protocol/0::all_pairs_min_predecessors/2:

all_pairs_min_predecessors/2 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Computes predecessor links for minimum paths for all ordered source-target pairs with a path. Returns a list of (Vertex1-Vertex2)-Predecessor terms.

| Compilation flags: | static

| Template: | all_pairs_min_predecessors(Graph,Pairs) | Mode and number of proofs: | all_pairs_min_predecessors(+graph,-list(pair)) - one


.. index:: is_complete/1 .. _graph_protocol/0::is_complete/1:

is_complete/1 ^^^^^^^^^^^^^^^^^

True iff every pair of distinct vertices in the graph is connected by an edge.

| Compilation flags: | static

| Template: | is_complete(Graph) | Mode and number of proofs: | is_complete(+graph) - zero_or_one


.. index:: is_bipartite/1 .. _graph_protocol/0::is_bipartite/1:

is_bipartite/1 ^^^^^^^^^^^^^^^^^^

True iff the graph is bipartite, i.e. its vertices can be partitioned into two sets such that every edge connects a vertex in one set to a vertex in the other.

| Compilation flags: | static

| Template: | is_bipartite(Graph) | Mode and number of proofs: | is_bipartite(+graph) - zero_or_one


.. index:: is_sparse/1 .. _graph_protocol/0::is_sparse/1:

is_sparse/1 ^^^^^^^^^^^^^^^

True iff the graph is sparse, i.e. the number of edges is at most |V| * log2(|V|). The cutoff |E| = |V| * log2(|V|) separates sparse graphs (where adjacency lists are efficient) from dense graphs (where adjacency matrix representations may be preferable).

| Compilation flags: | static

| Template: | is_sparse(Graph) | Mode and number of proofs: | is_sparse(+graph) - zero_or_one


Protected predicates

(none)

Private predicates

(none)

Operators

(none)