igraph Reference Manual

For using the igraph C library



add_edge, igraph_add_edge — Adds a single edge to a graph.
add_edges, igraph_add_edges — Adds edges to a graph object.
add_vertices, igraph_add_vertices — Adds vertices to a graph.
adhesion, igraph_adhesion — Graph adhesion, this is (almost) the same as edge connectivity.
adjacency, igraph_adjacency — Creates a graph object from an adjacency matrix.
adjacent, igraph_adjacent — Gives the incident edges of a vertex.
adjedgelist_destroy, igraph_adjedgelist_destroy — Frees all memory allocated for an incidence list.
adjedgelist_get, igraph_adjedgelist_get — Query a vector in an incidence list
adjedgelist_init, igraph_adjedgelist_init — Initialize an incidence list of edges
adjlist, igraph_adjlist — Create a graph from an adjacency list
adjlist_clear, igraph_adjlist_clear — Removes all edges from an adjacency list.
adjlist_destroy, igraph_adjlist_destroy — Deallocate memory
adjlist_get, igraph_adjlist_get — Query a vector in an adjlist
adjlist_init, igraph_adjlist_init — Initialize an adjacency list of vertices from a given graph
adjlist_init_complementer, igraph_adjlist_init_complementer — Adjacency lists for the complementer graph
adjlist_init_empty, igraph_adjlist_init_empty — Initialize an empty adjacency list
adjlist_simplify, igraph_adjlist_simplify — Simplify
adjlist_sort, igraph_adjlist_sort — Sort each vector in an adjacency list.
all_minimal_st_separators, igraph_all_minimal_st_separators — List all vertex sets that are minimal (s,t) separators for some s and t
all_st_cuts, igraph_all_st_cuts — List all edge-cuts between two vertices in a directed graph
all_st_mincuts, igraph_all_st_mincuts — All minimum s-t cuts of a directed graph
are_connected, igraph_are_connected — Decides whether two vertices are connected
arpack_function_t, igraph_arpack_function_t — Type of the ARPACK callback function
arpack_options_init, igraph_arpack_options_init — Initialize ARPACK options
arpack_options_t, igraph_arpack_options_t — Options for ARPACK
arpack_rnsolve, igraph_arpack_rnsolve — ARPACK solver for non-symmetric matrices
arpack_rssolve, igraph_arpack_rssolve — ARPACK solver for symmetric matrices
arpack_storage_destroy, igraph_arpack_storage_destroy — Deallocate ARPACK storage
arpack_storage_init, igraph_arpack_storage_init — Initialize ARPACK storage
arpack_storage_t, igraph_arpack_storage_t — Storage for ARPACK
arpack_unpack_complex, igraph_arpack_unpack_complex — Make the result of the non-symmetric ARPACK solver more readable
articulation_points, igraph_articulation_points — Find the articulation points in a graph.
assortativity, igraph_assortativity — Assortativity based on numeric properties of vertices
assortativity_degree, igraph_assortativity_degree — Assortativity of a graph based on vertex degree
assortativity_nominal, igraph_assortativity_nominal — Assortativity of a graph based on vertex categories
asymmetric_preference_game, igraph_asymmetric_preference_game — Generates a graph with asymmetric vertex types and connection preferences
atlas, igraph_atlas — Create a small graph from the “Graph Atlas”.
attribute_table_t, igraph_attribute_table_t — Table of functions to perform operations on attributes
attribute_type_t, igraph_attribute_type_t — The possible types of the attributes.
authority_score, igraph_authority_score — Kleinerg's authority scores
automorphisms, igraph_automorphisms — Number of automorphisms using BLISS
average_path_length, igraph_average_path_length — Calculates the average geodesic length in a graph.
avg_nearest_neighbor_degree, igraph_avg_nearest_neighbor_degree — Average nearest neighbor degree.


callaway_traits_game, igraph_callaway_traits_game — Simulate a growing network with vertex types.
canonical_permutation, igraph_canonical_permutation — Canonical permutation using BLISS
cattribute_EAB, igraph_cattribute_EAB — Query a boolean edge attribute.
cattribute_EABV, igraph_cattribute_EABV — Query a boolean edge attribute for many edges
cattribute_EAB_set, igraph_cattribute_EAB_set — Set a boolean edge attribute
cattribute_EAB_setv, igraph_cattribute_EAB_setv — Set a boolean edge attribute for all vertices.
cattribute_EAN, igraph_cattribute_EAN — Query a numeric edge attribute.
cattribute_EANV, igraph_cattribute_EANV — Query a numeric edge attribute for many edges
cattribute_EAN_set, igraph_cattribute_EAN_set — Set a numeric edge attribute
cattribute_EAN_setv, igraph_cattribute_EAN_setv — Set a numeric edge attribute for all vertices.
cattribute_EAS, igraph_cattribute_EAS — Query a string edge attribute.
cattribute_EASV, igraph_cattribute_EASV — Query a string edge attribute for many edges
cattribute_EAS_set, igraph_cattribute_EAS_set — Set a string edge attribute
cattribute_EAS_setv, igraph_cattribute_EAS_setv — Set a string edge attribute for all vertices.
cattribute_GAB, igraph_cattribute_GAB — Query a boolean graph attribute.
cattribute_GAB_set, igraph_cattribute_GAB_set — Set a boolean graph attribute
cattribute_GAN, igraph_cattribute_GAN — Query a numeric graph attribute.
cattribute_GAN_set, igraph_cattribute_GAN_set — Set a numeric graph attribute
cattribute_GAS, igraph_cattribute_GAS — Query a string graph attribute.
cattribute_GAS_set, igraph_cattribute_GAS_set — Set a string graph attribute.
cattribute_has_attr, igraph_cattribute_has_attr — Checks whether a (graph, vertex or edge) attribute exists
cattribute_list, igraph_cattribute_list — List all attributes
cattribute_remove_all, igraph_cattribute_remove_all — Remove all graph/vertex/edge attributes
cattribute_remove_e, igraph_cattribute_remove_e — Remove an edge attribute
cattribute_remove_g, igraph_cattribute_remove_g — Remove a graph attribute
cattribute_remove_v, igraph_cattribute_remove_v — Remove a vertex attribute
cattribute_VAB, igraph_cattribute_VAB — Query a boolean vertex attribute.
cattribute_VABV, igraph_cattribute_VABV — Query a boolean vertex attribute for many vertices
cattribute_VAB_set, igraph_cattribute_VAB_set — Set a boolean vertex attribute
cattribute_VAB_setv, igraph_cattribute_VAB_setv — Set a boolean vertex attribute for all vertices.
cattribute_VAN, igraph_cattribute_VAN — Query a numeric vertex attribute.
cattribute_VANV, igraph_cattribute_VANV — Query a numeric vertex attribute for many vertices
cattribute_VAN_set, igraph_cattribute_VAN_set — Set a numeric vertex attribute
cattribute_VAN_setv, igraph_cattribute_VAN_setv — Set a numeric vertex attribute for all vertices.
cattribute_VAS, igraph_cattribute_VAS — Query a string vertex attribute.
cattribute_VASV, igraph_cattribute_VASV — Query a string vertex attribute for many vertices
cattribute_VAS_set, igraph_cattribute_VAS_set — Set a string vertex attribute
cattribute_VAS_setv, igraph_cattribute_VAS_setv — Set a string vertex attribute for all vertices.
centralization, igraph_centralization — Calculate the centralization score from the node level scores
centralization_betweenness, igraph_centralization_betweenness — Calculate vertex betweenness and graph centralization
centralization_betweenness_tmax, igraph_centralization_betweenness_tmax — Theoretical maximum for graph centralization based on betweenness
centralization_closeness, igraph_centralization_closeness — Calculate vertex closeness and graph centralization
centralization_closeness_tmax, igraph_centralization_closeness_tmax — Theoretical maximum for graph centralization based on closeness
centralization_degree, igraph_centralization_degree — Calculate vertex degree and graph centralization
centralization_degree_tmax, igraph_centralization_degree_tmax — Theoretical maximum for graph centralization based on degree
centralization_eigenvector_centrality, igraph_centralization_eigenvector_centrality — Calculate eigenvector centrality scores and graph centralization
centralization_eigenvector_centrality_tmax, igraph_centralization_eigenvector_centrality_tmax — Theoretical maximum centralization for eigenvector centrality
CHECK, IGRAPH_CHECK — Check the return value of a function call.
cited_type_game, igraph_cited_type_game — Simulate a citation based on vertex types.
citing_cited_type_game, igraph_citing_cited_type_game — Simulate a citation network based on vertex types.
cliques, igraph_cliques — Find all or some cliques in a graph
clique_number, igraph_clique_number — Find the clique number of the graph
closeness, igraph_closeness — Closeness centrality calculations for some vertices.
closeness_estimate, igraph_closeness_estimate — Closeness centrality estimations for some vertices.
clusters, igraph_clusters — Calculates the (weakly or strongly) connected components in a graph.
cocitation, igraph_cocitation — Cocitation coupling.
cohesion, igraph_cohesion — Graph cohesion, this is the same as vertex connectivity.
cohesive_blocks, igraph_cohesive_blocks — Identifies the hierarchical cohesive block structure of a graph
community_eb_get_merges, igraph_community_eb_get_merges — Calculating the merges, ie. the dendrogram for an edge betweenness community structure
community_edge_betweenness, igraph_community_edge_betweenness — Community finding based on edge betweenness
community_fastgreedy, igraph_community_fastgreedy — Finding community structure by greedy optimization of modularity
community_infomap, igraph_community_infomap — Find community structure that minimizes the expected
community_label_propagation, igraph_community_label_propagation — Community detection based on label propagation
community_leading_eigenvector, igraph_community_leading_eigenvector — Leading eigenvector community finding (proper version).
community_leading_eigenvector_callback_t, igraph_community_leading_eigenvector_callback_t — Callback for the leading eigenvector community finding method.
community_multilevel, igraph_community_multilevel — Finding community structure by multi-level optimization of modularity
community_optimal_modularity, igraph_community_optimal_modularity — Calculate the community structure with the highest modularity value
community_spinglass, igraph_community_spinglass — Community detection based on statistical mechanics
community_spinglass_single, igraph_community_spinglass_single — Community of a single node based on statistical mechanics
community_to_membership, igraph_community_to_membership — Create membership vector from community structure dendrogram
community_walktrap, igraph_community_walktrap — This function is the implementation of the Walktrap community
compare_communities, igraph_compare_communities — Compares community structures using various metrics
complementer, igraph_complementer — Create the complementer of a graph
compose, igraph_compose — Calculates the composition of two graphs
connect_neighborhood, igraph_connect_neighborhood — Connects every vertex to its neighborhood
constraint, igraph_constraint — Burt's constraint scores.
contract_vertices, igraph_contract_vertices — Replace multiple vertices with a single one.
convex_hull, igraph_convex_hull — Determines the convex hull of a given set of points in the 2D plane
copy, igraph_copy — Creates an exact (deep) copy of a graph.
coreness, igraph_coreness — Finding the coreness of the vertices in a network.
count_isomorphisms_vf2, igraph_count_isomorphisms_vf2 — Number of isomorphisms via VF2
count_multiple, igraph_count_multiple — Count the number of appearances of the edges in a graph.
count_subisomorphisms_vf2, igraph_count_subisomorphisms_vf2 — Number of subgraph isomorphisms using VF2
create, igraph_create — Creates a graph with the specified edges.
create_bipartite, igraph_create_bipartite — Create a bipartite graph


decompose, igraph_decompose — Decompose a graph into connected components.
decompose_destroy, igraph_decompose_destroy — Free the memory allocated by igraph_decompose().
degree, igraph_degree — The degree of some vertices in a graph.
degree_sequence_game, igraph_degree_sequence_game — Generates a random graph with a given degree sequence
DELALL, DELALL — Remove all attributes.
DELEA, DELEA — Remove an edge attribute.
DELEAS, DELEAS — Remove all edge attributes.
delete_edges, igraph_delete_edges — Removes edges from a graph.
delete_vertices, igraph_delete_vertices — Removes vertices (with all their edges) from the graph.
DELGA, DELGA — Remove a graph attribute.
DELGAS, DELGAS — Remove all graph attributes.
DELVA, DELVA — Remove a vertex attribute.
DELVAS, DELVAS — Remove all vertex attributes.
density, igraph_density — Calculate the density of a graph.
destroy, igraph_destroy — Frees the memory allocated for a graph object.
deterministic_optimal_imitation, igraph_deterministic_optimal_imitation — Adopt a strategy via deterministic optimal imitation.
de_bruijn, igraph_de_bruijn — Generate a de Bruijn graph.
dfs, igraph_dfs — Depth-first search
dfshandler_t, igraph_dfshandler_t — Callback type for the DFS function
diameter, igraph_diameter — Calculates the diameter of a graph (longest geodesic).
diameter_dijkstra, igraph_diameter_dijkstra — Weighted diameter using Dijkstra's algorithm, non-negative weights only.
difference, igraph_difference — Calculate the difference of two graphs
disjoint_union, igraph_disjoint_union — Creates the union of two disjoint graphs
disjoint_union_many, igraph_disjoint_union_many — The disjint union of many graphs.
diversity, igraph_diversity — Structural diversity index of the vertices
dominator_tree, igraph_dominator_tree — Calculates the dominator tree of a flowgraph
dqueue_back, igraph_dqueue_back — Tail of the queue.
dqueue_clear, igraph_dqueue_clear — Remove all elements from the queue.
dqueue_destroy, igraph_dqueue_destroy — Destroy a double ended queue.
dqueue_empty, igraph_dqueue_empty — Decide whether the queue is empty.
dqueue_full, igraph_dqueue_full — Check whether the queue is full.
dqueue_head, igraph_dqueue_head — Head of the queue.
dqueue_init, igraph_dqueue_init — Initialize a double ended queue (deque).
dqueue_pop, igraph_dqueue_pop — Remove the head.
dqueue_pop_back, igraph_dqueue_pop_back — Remove the tail
dqueue_push, igraph_dqueue_push — Appends an element.
dqueue_size, igraph_dqueue_size — Number of elements in the queue.
dyad_census, igraph_dyad_census — Calculating the dyad census as defined by Holland and Leinhardt


EAB, EAB — Query a boolean edge attribute.
EABV, EABV — Query a boolean edge attribute for all edges.
EAN, EAN — Query a numeric edge attribute.
EANV, EANV — Query a numeric edge attribute for all edges.
EAS, EAS — Query a string edge attribute.
EASV, EASV — Query a string edge attribute for all edges.
eccentricity, igraph_eccentricity — Eccentricity of some vertices
ecount, igraph_ecount — The number of edges in a graph.
edge, igraph_edge — Gives the head and tail vertices of an edge.
edge_betweenness, igraph_edge_betweenness — Betweenness centrality of the edges.
edge_betweenness_estimate, igraph_edge_betweenness_estimate — Estimated betweenness centrality of the edges.
edge_connectivity, igraph_edge_connectivity — The minimum edge connectivity in a graph.
edge_disjoint_paths, igraph_edge_disjoint_paths — The maximum number of edge-disjoint paths between two vertices.
eigenvector_centrality, igraph_eigenvector_centrality — Eigenvector centrality of the vertices
eit_create, igraph_eit_create — Creates an edge iterator from an edge selector.
eit_destroy, igraph_eit_destroy — Destroys an edge iterator.
EIT_END, IGRAPH_EIT_END — Are we at the end?
EIT_GET, IGRAPH_EIT_GET — Query an edge iterator.
EIT_RESET, IGRAPH_EIT_RESET — Reset an edge iterator.
EIT_SIZE, IGRAPH_EIT_SIZE — Number of edges in the iterator.
empty, igraph_empty — Creates an empty graph with some vertices and no edges.
empty_attrs, igraph_empty_attrs — Creates an empty graph with some vertices, no edges and some graph attributes.
erdos_renyi_game, igraph_erdos_renyi_game — Generates a random (Erdos-Renyi) graph.
ERROR, IGRAPH_ERROR — Trigger an error.
error, igraph_error — Trigger an error.
errorf, igraph_errorf — Trigger an error, printf-like version.
error_handler_abort, igraph_error_handler_abort — Abort program in case of error.
error_handler_ignore, igraph_error_handler_ignore — Ignore errors.
error_handler_printignore, igraph_error_handler_printignore — Print and ignore errors.
error_handler_t, igraph_error_handler_t — Type of error handler functions.
error_type_t, igraph_error_type_t — Error code type.
ess_1, igraph_ess_1 — Immediate version of the single edge edge selector.
ess_all, igraph_ess_all — Edge set, all edges (immediate version)
ess_none, igraph_ess_none — Immediate empty edge selector.
ess_seq, igraph_ess_seq — Immediate version of the sequence edge selector.
ess_vector, igraph_ess_vector — Immediate vector view edge selector.
establishment_game, igraph_establishment_game — Generates a graph with a simple growing model with vertex types.
es_1, igraph_es_1 — Edge selector containing a single edge.
es_all, igraph_es_all — Edge set, all edges.
es_copy, igraph_es_copy — Creates a copy of an edge selector.
es_destroy, igraph_es_destroy — Destroys an edge selector object.
es_fromto, igraph_es_fromto — Edge selector, all edges between two vertex sets.
es_incident, igraph_es_incident — Edges incident on a given vertex.
es_is_all, igraph_es_is_all — Check whether an edge selector includes all edges.
es_none, igraph_es_none — Empty edge selector.
es_pairs, igraph_es_pairs — Edge selector, multiple edges defined by their endpoints in a vector.
es_pairs_small, igraph_es_pairs_small — Edge selector, multiple edges defined by their endpoints as arguments.
es_seq, igraph_es_seq — Edge selector, a sequence of edge ids.
es_size, igraph_es_size — Returns the size of the edge selector.
es_type, igraph_es_type — Returns the type of the edge selector.
es_vector, igraph_es_vector — Handle a vector as an edge selector.
es_vector_copy, igraph_es_vector_copy — Edge set, based on a vector, with copying.
extended_chordal_ring, igraph_extended_chordal_ring — Create an extended chordal ring


GAB, GAB — Query a boolean graph attribute.
GAN, GAN — Query a numeric graph attribute.
GAS, GAS — Query a string graph attribute.
get_adjacency, igraph_get_adjacency — Returns the adjacency matrix of a graph
get_all_shortest_paths, igraph_get_all_shortest_paths — Finds all shortest paths (geodesics) from a vertex to all other vertices.
get_all_shortest_paths_dijkstra, igraph_get_all_shortest_paths_dijkstra — Finds all shortest paths (geodesics) from a vertex to all other vertices.
get_edgelist, igraph_get_edgelist — Returns the list of edges in a graph
get_eid, igraph_get_eid — Get the edge id from the end points of an edge.
get_eids, igraph_get_eids — Return edge ids based on the adjacent vertices.
get_eids_multi, igraph_get_eids_multi — Query edge ids based on their adjacent vertices, handle multiple edges.
get_incidence, igraph_get_incidence — Convert a bipartite graph into an incidence matrix
get_isomorphisms_vf2, igraph_get_isomorphisms_vf2 — Collect the isomorphic mappings
get_shortest_path, igraph_get_shortest_path — Shortest path from one vertex to another one.
get_shortest_paths, igraph_get_shortest_paths — Calculates the shortest paths from/to one vertex.
get_shortest_paths_dijkstra, igraph_get_shortest_paths_dijkstra — Calculates the weighted shortest paths from/to one vertex.
get_shortest_path_dijkstra, igraph_get_shortest_path_dijkstra — Weighted shortest path from one vertex to another one.
get_sparsemat, igraph_get_sparsemat — Convert an igraph graph to a sparse matrix
get_stochastic, igraph_get_stochastic — Stochastic adjacency matrix of a graph
get_stochastic_sparsemat, igraph_get_stochastic_sparsemat — Stochastic adjacency matrix of a graph
get_subisomorphisms_vf2, igraph_get_subisomorphisms_vf2 — Return all subgraph isomorphic mappings
girth, igraph_girth — The girth of a graph is the length of the shortest circle in it.
graphlets, igraph_graphlets — Calculate graphlets basis and project the graph on it
graphlets_candidate_basis, igraph_graphlets_candidate_basis — Calculate a candidate graphlets basis
graphlets_project, igraph_graphlets_project — Project a graph on a graphlets basis
grg_game, igraph_grg_game — Generating geometric random graphs.
growing_random_game, igraph_growing_random_game — Generates a growing random graph.


has_multiple, igraph_has_multiple — Check whether the graph has at least one multiple edge.
heap_delete_top, igraph_heap_delete_top — Return and removes the top element
heap_destroy, igraph_heap_destroy — Destroys an initialized heap object.
heap_empty, igraph_heap_empty — Decides whether a heap object is empty.
heap_init, igraph_heap_init — Initializes an empty heap object.
heap_init_array, igraph_heap_init_array — Build a heap from an array.
heap_push, igraph_heap_push — Add an element.
heap_reserve, igraph_heap_reserve — Allocate more memory
heap_size, igraph_heap_size — Number of elements
heap_top, igraph_heap_top — Top element.
hrg_consensus, igraph_hrg_consensus — Calculate a consensus tree for a HRG.
hrg_create, igraph_hrg_create — Create a HRG from an igraph graph.
hrg_dendrogram, igraph_hrg_dendrogram — Create a dendrogram from a hierarchical random graph.
hrg_destroy, igraph_hrg_destroy — Deallocate memory for an HRG.
hrg_fit, igraph_hrg_fit — Fit a hierarchical random graph model to a network
hrg_game, igraph_hrg_game — Generate a hierarchical random graph
hrg_init, igraph_hrg_init — Allocate memory for a HRG.
hrg_predict, igraph_hrg_predict — Predict missing edges in a graph, based on HRG models
hrg_resize, igraph_hrg_resize — Resize a HRG.
hrg_sample, igraph_hrg_sample — Sample from a hierarchical random graph model
hrg_size, igraph_hrg_size — Returns the size of the HRG, the number of leaf nodes.
hrg_t, igraph_hrg_t — Data structure to store a hierarchical random graph
hub_score, igraph_hub_score — Kleinberg's hub scores


incidence, igraph_incidence — Create a bipartite graph from an incidence matrix
incident, igraph_incident — Gives the incident edges of a vertex.
inclist_clear, igraph_inclist_clear — Removes all edges from an incidence list.
inclist_destroy, igraph_inclist_destroy — Frees all memory allocated for an incidence list.
inclist_get, igraph_inclist_get — Query a vector in an incidence list
inclist_init, igraph_inclist_init — Initialize an incidence list of edges
independence_number, igraph_independence_number — Find the independence number of the graph
independent_vertex_sets, igraph_independent_vertex_sets — Find all independent vertex sets in a graph
induced_subgraph, igraph_induced_subgraph — Creates a subgraph induced by the specified vertices.
intersection, igraph_intersection — Collect the common edges from two graphs.
intersection_many, igraph_intersection_many — The intersection of more than two graphs.
isoclass, igraph_isoclass — Determine the isomorphism class of a graph with 3 or 4 vertices
isoclass_create, igraph_isoclass_create — Creates a graph from the given isomorphism class.
isoclass_subgraph, igraph_isoclass_subgraph — The isomorphism class of a subgraph of a graph.
isocompat_t, igraph_isocompat_t — Callback type, called to check whether two vertices or edges are compatible
isohandler_t, igraph_isohandler_t — Callback type, called when an isomorphism was found
isomorphic, igraph_isomorphic — Decides whether two graphs are isomorphic
isomorphic_34, igraph_isomorphic_34 — Graph isomorphism for 3-4 vertices
isomorphic_bliss, igraph_isomorphic_bliss — Graph isomorphism via BLISS
isomorphic_function_vf2, igraph_isomorphic_function_vf2 — The generic VF2 interface
isomorphic_vf2, igraph_isomorphic_vf2 — Isomorphism via VF2
is_bipartite, igraph_is_bipartite — Check whether a graph is bipartite
is_chordal, igraph_is_chordal — Decides whether a graph is chordal
is_connected, igraph_is_connected — Decides whether the graph is (weakly or strongly) connected.
is_dag, igraph_is_dag — Checks whether a graph is a directed acyclic graph (DAG) or not.
is_degree_sequence, igraph_is_degree_sequence — Determines whether a degree sequence is valid.
is_directed, igraph_is_directed — Is this a directed graph?
is_graphical_degree_sequence, igraph_is_graphical_degree_sequence — Determines whether a sequence of integers can be a degree sequence of some
is_loop, igraph_is_loop — Find the loop edges in a graph.
is_matching, igraph_is_matching — Checks whether the given matching is valid for the given graph.
is_maximal_matching, igraph_is_maximal_matching — Checks whether a matching in a graph is maximal.
is_minimal_separator, igraph_is_minimal_separator — Decides whether a set of vertices is a minimal separator
is_multiple, igraph_is_multiple — Find the multiple edges in a graph.
is_mutual, igraph_is_mutual — Check whether the edges of a directed graph are mutual.
is_separator, igraph_is_separator — Decides whether the removal of a set of vertices disconnects the graph
is_simple, igraph_is_simple — Decides whether the input graph is a simple graph.
i_set_attribute_table, igraph_i_set_attribute_table — Attach an attribute table.


lapack_dgeev, igraph_lapack_dgeev — Eigenvalues and optionally eigenvectors of a non-symmetric matrix
lapack_dgeevx, igraph_lapack_dgeevx — Eigenvalues/vectors of nonsymmetric matrices, expert mode
lapack_dgesv, igraph_lapack_dgesv — Solve system of linear equations with LU factorization
lapack_dgetrf, igraph_lapack_dgetrf — LU factorization of a general M-by-N matrix
lapack_dgetrs, igraph_lapack_dgetrs — Solve general system of linear equations using LU factorization
lapack_dsyevr, igraph_lapack_dsyevr — Selected eigenvalues and optionally eigenvectors of a symmetric matrix
laplacian, igraph_laplacian — Returns the Laplacian matrix of a graph
largest_cliques, igraph_largest_cliques — Finds the largest clique(s) in a graph.
largest_independent_vertex_sets, igraph_largest_independent_vertex_sets — Finds the largest independent vertex set(s) in a graph.
lattice, igraph_lattice — Creates most kinds of lattices.
layout_bipartite, igraph_layout_bipartite — Simple layout for bipartite graphs
layout_circle, igraph_layout_circle — Places the vertices uniformly on a circle, in the order of vertex ids.
layout_drl, igraph_layout_drl — The DrL layout generator
layout_drl_3d, igraph_layout_drl_3d — The DrL layout generator, 3d version.
layout_drl_default_t, igraph_layout_drl_default_t — Predefined parameter templates for the DrL layout generator
layout_drl_options_init, igraph_layout_drl_options_init — Initialize parameters for the DrL layout generator
layout_drl_options_t, igraph_layout_drl_options_t — Parameters for the DrL layout generator
layout_fruchterman_reingold, igraph_layout_fruchterman_reingold — Places the vertices on a plane according to the Fruchterman-Reingold algorithm.
layout_fruchterman_reingold_3d, igraph_layout_fruchterman_reingold_3d — 3D Fruchterman-Reingold algorithm.
layout_graphopt, igraph_layout_graphopt — Optimizes vertex layout via the graphopt algorithm.
layout_grid, igraph_layout_grid — Places the vertices on a regular grid on the plane.
layout_grid_3d, igraph_layout_grid_3d — Places the vertices on a regular grid in the 3D space.
layout_grid_fruchterman_reingold, igraph_layout_grid_fruchterman_reingold — Force based layout generator for large graphs.
layout_kamada_kawai, igraph_layout_kamada_kawai — Places the vertices on a plane according the Kamada-Kawai algorithm.
layout_kamada_kawai_3d, igraph_layout_kamada_kawai_3d — 3D version of the force based Kamada-Kawai layout.
layout_lgl, igraph_layout_lgl — Force based layout algorithm for large graphs.
layout_mds, igraph_layout_mds — Place the vertices on a plane using multidimensional scaling.
layout_merge_dla, igraph_layout_merge_dla — Merge multiple layouts by using a DLA algorithm
layout_random, igraph_layout_random — Places the vertices uniform randomly on a plane.
layout_random_3d, igraph_layout_random_3d — Random layout in 3D
layout_reingold_tilford, igraph_layout_reingold_tilford — Reingold-Tilford layout for tree graphs
layout_reingold_tilford_circular, igraph_layout_reingold_tilford_circular — Circular Reingold-Tilford layout for trees
layout_sphere, igraph_layout_sphere — Places vertices (more or less) uniformly on a sphere.
layout_star, igraph_layout_star — Generate a star-like layout
layout_sugiyama, igraph_layout_sugiyama — Sugiyama layout algorithm for layered directed acyclic graphs.
lazy_adjedgelist_destroy, igraph_lazy_adjedgelist_destroy — Frees all memory allocated for an incidence list.
lazy_adjedgelist_get, igraph_lazy_adjedgelist_get — Query a vector in a lazy incidence list
lazy_adjedgelist_init, igraph_lazy_adjedgelist_init — Initializes a lazy incidence list of edges
lazy_adjlist_clear, igraph_lazy_adjlist_clear — Removes all edges from a lazy adjacency list.
lazy_adjlist_destroy, igraph_lazy_adjlist_destroy — Deallocate memory
lazy_adjlist_get, igraph_lazy_adjlist_get — Query neighbor vertices
lazy_adjlist_init, igraph_lazy_adjlist_init — Constructor
lazy_inclist_clear, igraph_lazy_inclist_clear — Removes all edges from a lazy incidence list.
lazy_inclist_destroy, igraph_lazy_inclist_destroy — Deallocates memory
lazy_inclist_get, igraph_lazy_inclist_get — Query incident edges
lazy_inclist_init, igraph_lazy_inclist_init — Initializes a lazy incidence list of edges
lcf, igraph_lcf — Create a graph from LCF notation
lcf_vector, igraph_lcf_vector — Create a graph from LCF notation
le_community_to_membership, igraph_le_community_to_membership — Vertex membership from the leading eigenvector community structure
linegraph, igraph_linegraph — Create the line graph of a graph.


MATRIX, MATRIX — Accessing an element of a matrix.
matrix_add, igraph_matrix_add — Add two matrices.
matrix_add_cols, igraph_matrix_add_cols — Adds columns to a matrix.
matrix_add_constant, igraph_matrix_add_constant — Add a constant to every element.
matrix_add_rows, igraph_matrix_add_rows — Adds rows to a matrix.
matrix_all_e, igraph_matrix_all_e — Are all elements equal?
matrix_all_g, igraph_matrix_all_g — Are all elements greater?
matrix_all_ge, igraph_matrix_all_ge — Are all elements greater or equal?
matrix_all_l, igraph_matrix_all_l — Are all elements less?
matrix_all_le, igraph_matrix_all_le — Are all elements less or equal?
matrix_as_sparsemat, igraph_matrix_as_sparsemat — Convert a dense matrix to a sparse matrix
matrix_capacity, igraph_matrix_capacity — Returns the number of elements allocated for a matrix.
matrix_cbind, igraph_matrix_cbind — Combine matrices columnwise.
matrix_colsum, igraph_matrix_colsum — Columnwise sum.
matrix_contains, igraph_matrix_contains — Search for an element.
matrix_copy, igraph_matrix_copy — Copies a matrix.
matrix_copy_to, igraph_matrix_copy_to — Copies a matrix to a regular C array.
matrix_destroy, igraph_matrix_destroy — Destroys a matrix object.
matrix_div_elements, igraph_matrix_div_elements — Elementwise division.
matrix_e, igraph_matrix_e — Extract an element from a matrix.
matrix_empty, igraph_matrix_empty — Check for an empty matrix.
matrix_e_ptr, igraph_matrix_e_ptr — Pointer to an element of a matrix.
matrix_fill, igraph_matrix_fill — Fill with an element.
matrix_get_col, igraph_matrix_get_col — Select a column.
matrix_get_row, igraph_matrix_get_row — Extract a row.
matrix_init, igraph_matrix_init — Initializes a matrix.
matrix_isnull, igraph_matrix_isnull — Check for a null matrix.
matrix_is_symmetric, igraph_matrix_is_symmetric — Check for symmetric matrix.
matrix_max, igraph_matrix_max — Returns the maximal element of a matrix.
matrix_maxdifference, igraph_matrix_maxdifference — Maximum absolute difference between two matrices.
matrix_min, igraph_matrix_min — Minimum element.
matrix_minmax, igraph_matrix_minmax — Minimum and maximum
matrix_mul_elements, igraph_matrix_mul_elements — Elementwise multiplication.
matrix_ncol, igraph_matrix_ncol — The number of columns in a matrix.
matrix_nrow, igraph_matrix_nrow — The number of rows in a matrix.
matrix_null, igraph_matrix_null — Sets all elements in a matrix to zero.
matrix_prod, igraph_matrix_prod — Product of the elements.
matrix_rbind, igraph_matrix_rbind — Combine two matrices rowwise.
matrix_remove_col, igraph_matrix_remove_col — Removes a column from a matrix.
matrix_remove_row, igraph_matrix_remove_row — Remove a row.
matrix_resize, igraph_matrix_resize — Resizes a matrix.
matrix_resize_min, igraph_matrix_resize_min — Deallocates unused memory for a matrix.
matrix_rowsum, igraph_matrix_rowsum — Rowwise sum.
matrix_scale, igraph_matrix_scale — Multiplies each element of the matrix by a constant.
matrix_search, igraph_matrix_search — Search from a given position.
matrix_select_cols, igraph_matrix_select_cols — Select some columns of a matrix.
matrix_select_rows, igraph_matrix_select_rows — Select some rows of a matrix.
matrix_select_rows_cols, igraph_matrix_select_rows_cols — Select some rows and columns of a matrix.
matrix_set, igraph_matrix_set — Set an element.
matrix_set_col, igraph_matrix_set_col — Set a column from a vector.
matrix_set_row, igraph_matrix_set_row — Set a row from a vector.
matrix_size, igraph_matrix_size — The number of elements in a matrix.
matrix_sub, igraph_matrix_sub — Difference of two matrices.
matrix_sum, igraph_matrix_sum — Sum of elements.
matrix_swap, igraph_matrix_swap — Swap two matrices.
matrix_swap_cols, igraph_matrix_swap_cols — Swap two columns.
matrix_swap_rows, igraph_matrix_swap_rows — Swap two rows.
matrix_transpose, igraph_matrix_transpose — Transpose a matrix.
matrix_update, igraph_matrix_update — Update from another matrix.
matrix_which_max, igraph_matrix_which_max — Indices of the maximum.
matrix_which_min, igraph_matrix_which_min — Indices of the minimum.
matrix_which_minmax, igraph_matrix_which_minmax — Indices of the minimum and maximum
maxdegree, igraph_maxdegree — Calculate the maximum degree in a graph (or set of vertices).
maxflow, igraph_maxflow — Maximum network flow between a pair of vertices
maxflow_stats_t, igraph_maxflow_stats_t — A simple data type to return some statistics from the
maxflow_value, igraph_maxflow_value — Maximum flow in a network with the push/relabel algorithm
maximal_cliques, igraph_maximal_cliques — Find all maximal cliques of a graph
maximal_cliques_count, igraph_maximal_cliques_count — Count the number of maximal cliques in a graph
maximal_independent_vertex_sets, igraph_maximal_independent_vertex_sets — Find all maximal independent vertex sets of a graph
maximum_bipartite_matching, igraph_maximum_bipartite_matching — Calculates a maximum matching in a bipartite graph.
maximum_cardinality_search, igraph_maximum_cardinality_search — Maximum cardinality search
mincut, igraph_mincut — Calculates the minimum cut in a graph.
mincut_value, igraph_mincut_value — The minimum edge cut in a graph
minimum_size_separators, igraph_minimum_size_separators — Find all minimum size separating vertex sets
minimum_spanning_tree, igraph_minimum_spanning_tree — Calculates one minimum spanning tree of a graph.
minimum_spanning_tree_prim, igraph_minimum_spanning_tree_prim — Calculates one minimum spanning tree of a weighted graph.
minimum_spanning_tree_unweighted, igraph_minimum_spanning_tree_unweighted — Calculates one minimum spanning tree of an unweighted graph.
modularity, igraph_modularity — Calculate the modularity of a graph with respect to some vertex types
moran_process, igraph_moran_process — The Moran process in a network setting.
motifs_handler_t, igraph_motifs_handler_t — Callback type for igraph_motifs_randesu_callback
motifs_randesu, igraph_motifs_randesu — Count the number of motifs in a graph
motifs_randesu_callback, igraph_motifs_randesu_callback — Finds motifs in a graph and calls a function for each of them
motifs_randesu_estimate, igraph_motifs_randesu_estimate — Estimate the total number of motifs in a graph
motifs_randesu_no, igraph_motifs_randesu_no — Count the total number of motifs in a graph


radius, igraph_radius — Radius of a graph
random_sample, igraph_random_sample — Generates an increasing random sequence of integers.
read_graph_dimacs, igraph_read_graph_dimacs — Read a graph in DIMACS format.
read_graph_dl, igraph_read_graph_dl — Read a file in the DL format of UCINET
read_graph_edgelist, igraph_read_graph_edgelist — Reads an edge list from a file and creates a graph.
read_graph_gml, igraph_read_graph_gml — Read a graph in GML format.
read_graph_graphdb, igraph_read_graph_graphdb — Read a graph in the binary graph database format.
read_graph_graphml, igraph_read_graph_graphml — Reads a graph from a GraphML file.
read_graph_lgl, igraph_read_graph_lgl — Reads a graph from an .lgl file
read_graph_ncol, igraph_read_graph_ncol — Reads a .ncol file used by LGL.
read_graph_pajek, igraph_read_graph_pajek — Reads a file in Pajek format
recent_degree_aging_game, igraph_recent_degree_aging_game — Preferential attachment based on the number of edges gained recently, with aging of vertices
recent_degree_game, igraph_recent_degree_game — Stochastic graph generator based on the number of incident edges a node has gained recently
reciprocity, igraph_reciprocity — Calculates the reciprocity of a directed graph.
reindex_membership, igraph_reindex_membership — Makes the IDs in a membership vector continuous
rewire, igraph_rewire — Randomly rewires a graph while preserving the degree distribution.
rewire_edges, igraph_rewire_edges — Rewire the edges of a graph with constant probability
ring, igraph_ring — Creates a ring graph, a one dimensional lattice.
rngtype_glibc2, igraph_rngtype_glibc2 — The random number generator type introduced in GNU libc 2
rngtype_mt19937, igraph_rngtype_mt19937 — The MT19937 random number generator
rngtype_rand, igraph_rngtype_rand — The old BSD rand/stand random number generator
rng_default, igraph_rng_default — Query the default random number generator.
rng_destroy, igraph_rng_destroy — Deallocate memory associated with a random number generator
rng_get_binom, igraph_rng_get_binom — Generate binomially distributed random numbers
rng_get_geom, igraph_rng_get_geom — Generate geometrically distributed random numbers
rng_get_integer, igraph_rng_get_integer — Generate an integer random number from an interval
rng_get_normal, igraph_rng_get_normal — Normally distributed random numbers
rng_get_unif, igraph_rng_get_unif — Generate real, uniform random numbers from an interval
rng_get_unif01, igraph_rng_get_unif01 — Generate real, uniform random number from the unit interval
rng_init, igraph_rng_init — Initialize a random number generator
rng_max, igraph_rng_max — Query the maximum possible integer for a random number generator
rng_min, igraph_rng_min — Query the minimum possible integer for a random number generator
rng_name, igraph_rng_name — Query the type of a random number generator
rng_seed, igraph_rng_seed — Set the seed of a random number generator
rng_set_default, igraph_rng_set_default — Set the default igraph random number generator
roulette_wheel_imitation, igraph_roulette_wheel_imitation — Adopt a strategy via roulette wheel selection.
running_mean, igraph_running_mean — Calculates the running mean of a vector.


sbm_game, igraph_sbm_game — Sample from a stochastic block model
scg_adjacency, igraph_scg_adjacency — Spectral coarse graining, symmetric case.
scg_grouping, igraph_scg_grouping — SCG problem solver
scg_laplacian, igraph_scg_laplacian — Spectral coarse graining, laplacian matrix.
scg_norm_eps, igraph_scg_norm_eps — Calculate SCG residuals
scg_semiprojectors, igraph_scg_semiprojectors — Compute SCG semi-projectors for a given partition
scg_stochastic, igraph_scg_stochastic — Spectral coarse graining, stochastic case.
SETEAB, SETEAB — Set a boolean edge attribute
SETEABV, SETEABV — Set a boolean edge attribute for all vertices
SETEAN, SETEAN — Set a numeric edge attribute
SETEANV, SETEANV — Set a numeric edge attribute for all vertices
SETEAS, SETEAS — Set a string edge attribute
SETEASV, SETEASV — Set a string edge attribute for all vertices
SETGAB, SETGAB — Set a boolean graph attribute
SETGAN, SETGAN — Set a numeric graph attribute
SETGAS, SETGAS — Set a string graph attribute
SETVAB, SETVAB — Set a boolean vertex attribute
SETVABV, SETVABV — Set a boolean vertex attribute for all vertices
SETVAN, SETVAN — Set a numeric vertex attribute
SETVANV, SETVANV — Set a numeric vertex attribute for all vertices
SETVAS, SETVAS — Set a string vertex attribute
SETVASV, SETVASV — Set a string vertex attribute for all vertices
set_error_handler, igraph_set_error_handler — Set a new error handler.
set_progress_handler, igraph_set_progress_handler — Install a progress handler, or remove the current handler
set_status_handler, igraph_set_status_handler — Install of uninstall a status handler function.
set_warning_handler, igraph_set_warning_handler — Install a warning handler
shortest_paths, igraph_shortest_paths — The length of the shortest paths between vertices.
shortest_paths_bellman_ford, igraph_shortest_paths_bellman_ford — Weighted shortest paths from some sources allowing negative weights.
shortest_paths_dijkstra, igraph_shortest_paths_dijkstra — Weighted shortest paths from some sources.
shortest_paths_johnson, igraph_shortest_paths_johnson — Calculate shortest paths from some sources using Johnson's algorithm.
similarity_dice, igraph_similarity_dice — Dice similarity coefficient.
similarity_dice_es, igraph_similarity_dice_es — Dice similarity coefficient for a given edge selector.
similarity_dice_pairs, igraph_similarity_dice_pairs — Dice similarity coefficient for given vertex pairs.
similarity_inverse_log_weighted, igraph_similarity_inverse_log_weighted — Vertex similarity based on the inverse logarithm of vertex degrees.
similarity_jaccard, igraph_similarity_jaccard — Jaccard similarity coefficient for the given vertices.
similarity_jaccard_es, igraph_similarity_jaccard_es — Jaccard similarity coefficient for a given edge selector.
similarity_jaccard_pairs, igraph_similarity_jaccard_pairs — Jaccard similarity coefficient for given vertex pairs.
simplify, igraph_simplify — Removes loop and/or multiple edges from the graph.
small, igraph_small — Shorthand to create a short graph, giving the edges as arguments.
sparsemat, igraph_sparsemat — Create an igraph graph from a sparse matrix
sparsemat_add, igraph_sparsemat_add — Sum of two sparse matrices
sparsemat_add_cols, igraph_sparsemat_add_cols — Add columns to a sparse matrix
sparsemat_add_rows, igraph_sparsemat_add_rows — Add rows to a sparse matrix
sparsemat_arpack_rnsolve, igraph_sparsemat_arpack_rnsolve — Eigenvalues and eigenvectors of a nonsymmetric sparse matrix via ARPACK
sparsemat_arpack_rssolve, igraph_sparsemat_arpack_rssolve — Eigenvalues and eigenvectors of a symmetric sparse matrix via ARPACK
sparsemat_as_matrix, igraph_sparsemat_as_matrix — Convert a sparse matrix to a dense matrix
sparsemat_cholsol, igraph_sparsemat_cholsol — Solve a symmetric linear system via Cholesky decomposition
sparsemat_compress, igraph_sparsemat_compress — Compress a sparse matrix, i.e. convert it to column-compress format
sparsemat_copy, igraph_sparsemat_copy — Copy a sparse matrix
sparsemat_destroy, igraph_sparsemat_destroy — Deallocate memory used by a sparse matrix
sparsemat_diag, igraph_sparsemat_diag — Create a sparse diagonal matrix
sparsemat_droptol, igraph_sparsemat_droptol — Drop the almost zero elements of a sparse matrix
sparsemat_dropzeros, igraph_sparsemat_dropzeros — Drop the zero elements from a sparse matrix
sparsemat_dupl, igraph_sparsemat_dupl — Remove duplicate elements from a sparse matrix
sparsemat_entry, igraph_sparsemat_entry — Add an element to a sparse matrix
sparsemat_eye, igraph_sparsemat_eye — Create a sparse identity matrix
sparsemat_fkeep, igraph_sparsemat_fkeep — Filter the elements of a sparse matrix
sparsemat_gaxpy, igraph_sparsemat_gaxpy — Matrix-vector product, added to another vector.
sparsemat_index, igraph_sparsemat_index — Index a sparse matrix, extract a submatrix, or a single element
sparsemat_init, igraph_sparsemat_init — Initialize a sparse matrix, in triplet format
sparsemat_is_cc, igraph_sparsemat_is_cc — Is this sparse matrix in column-compressed format?
sparsemat_is_triplet, igraph_sparsemat_is_triplet — Is this sparse matrix in triplet format?
sparsemat_lsolve, igraph_sparsemat_lsolve — Solve a lower-triangular linear system
sparsemat_ltsolve, igraph_sparsemat_ltsolve — Solve an upper-triangular linear system
sparsemat_lu, igraph_sparsemat_lu — LU decomposition of a sparse matrix
sparsemat_luresol, igraph_sparsemat_luresol — Solve linear system using a precomputed LU decomposition
sparsemat_lusol, igraph_sparsemat_lusol — Solve a linear system via LU decomposition
sparsemat_multiply, igraph_sparsemat_multiply — Matrix multiplication
sparsemat_ncol, igraph_sparsemat_ncol — Number of columns.
sparsemat_nrow, igraph_sparsemat_nrow — Number of rows
sparsemat_numeric_destroy, igraph_sparsemat_numeric_destroy — Deallocate memory for a numeric decomposition
sparsemat_permute, igraph_sparsemat_permute — Permute the rows and columns of a sparse matrix
sparsemat_print, igraph_sparsemat_print — Print a sparse matrix to a file
sparsemat_qr, igraph_sparsemat_qr — QR decomposition of a sparse matrix
sparsemat_qrresol, igraph_sparsemat_qrresol — Solve a linear system using a precomputed QR decomposition
sparsemat_realloc, igraph_sparsemat_realloc — Allocate more (or less) memory for a sparse matrix
sparsemat_resize, igraph_sparsemat_resize — Resize a sparse matrix
sparsemat_scale, igraph_sparsemat_scale — Scale a sparse matrix
sparsemat_symblu, igraph_sparsemat_symblu — Symbolic LU decomposition
sparsemat_symbolic_destroy, igraph_sparsemat_symbolic_destroy — Deallocate memory for a symbolic decomposition
sparsemat_symbqr, igraph_sparsemat_symbqr — Symbolic QR decomposition
sparsemat_transpose, igraph_sparsemat_transpose — Transpose a sparse matrix
sparsemat_type, igraph_sparsemat_type — Type of a sparse matrix (triplet or column-compressed)
sparsemat_usolve, igraph_sparsemat_usolve — Solve an upper-triangular linear system
sparsemat_utsolve, igraph_sparsemat_utsolve — Solve a lower-triangular linear system
split_join_distance, igraph_split_join_distance — Calculates the split-join distance of two community structures
spmatrix_add_cols, igraph_spmatrix_add_cols — Adds columns to a sparse matrix.
spmatrix_add_e, igraph_spmatrix_add_e — Adding a real value to an element of a sparse matrix.
spmatrix_add_rows, igraph_spmatrix_add_rows — Adds rows to a sparse matrix.
spmatrix_colsums, igraph_spmatrix_colsums — Calculates the column sums of the matrix.
spmatrix_copy, igraph_spmatrix_copy — Copies a sparse matrix.
spmatrix_count_nonzero, igraph_spmatrix_count_nonzero — The number of non-zero elements in a sparse matrix.
spmatrix_destroy, igraph_spmatrix_destroy — Destroys a sparse matrix object.
spmatrix_e, igraph_spmatrix_e — Accessing an element of a sparse matrix.
spmatrix_fprint, igraph_spmatrix_fprint — Prints a sparse matrix to the given file.
spmatrix_init, igraph_spmatrix_init — Initializes a sparse matrix.
spmatrix_iter_create, igraph_spmatrix_iter_create — Creates a sparse matrix iterator corresponding to the given matrix.
spmatrix_iter_destroy, igraph_spmatrix_iter_destroy — Frees the memory used by the iterator.
spmatrix_iter_end, igraph_spmatrix_iter_end — Checks whether there are more elements in the iterator.
spmatrix_iter_next, igraph_spmatrix_iter_next — Moves a sparse matrix iterator to the next nonzero element.
spmatrix_iter_reset, igraph_spmatrix_iter_reset — Resets a sparse matrix iterator.
spmatrix_max, igraph_spmatrix_max — Returns the maximum element of a matrix.
spmatrix_ncol, igraph_spmatrix_ncol — The number of columns in a sparse matrix.
spmatrix_nrow, igraph_spmatrix_nrow — The number of rows in a sparse matrix.
spmatrix_print, igraph_spmatrix_print — Prints a sparse matrix.
spmatrix_resize, igraph_spmatrix_resize — Resizes a sparse matrix.
spmatrix_rowsums, igraph_spmatrix_rowsums — Calculates the row sums of the matrix.
spmatrix_scale, igraph_spmatrix_scale — Multiplies each element of the sparse matrix by a constant.
spmatrix_set, igraph_spmatrix_set — Setting an element of a sparse matrix.
spmatrix_size, igraph_spmatrix_size — The number of elements in a sparse matrix.
stack_clear, igraph_stack_clear — Removes all elements from a stack.
stack_destroy, igraph_stack_destroy — Destroys a stack object.
stack_empty, igraph_stack_empty — Decides whether a stack object is empty.
stack_init, igraph_stack_init — Initializes a stack.
stack_pop, igraph_stack_pop — Removes and returns an element from the top of a stack.
stack_push, igraph_stack_push — Places an element on the top of a stack.
stack_reserve, igraph_stack_reserve — Reserve memory.
stack_size, igraph_stack_size — Returns the number of elements in a stack.
stack_top, igraph_stack_top — Query top element.
star, igraph_star — Creates a star graph, every vertex connects only to the center.
static_fitness_game, igraph_static_fitness_game — Generates a non-growing random graph with edge probabilities
static_power_law_game, igraph_static_power_law_game — Generates a non-growing random graph with expected power-law degree distributions.
STATUS, IGRAPH_STATUS — Report the status of an igraph function.
status, igraph_status — Report status from an igraph function.
STATUSF, IGRAPH_STATUSF — Report the status from an igraph function
statusf, igraph_statusf — Report status, more flexible printf-like version.
status_handler_stderr, igraph_status_handler_stderr — A simple predefined status handler function.
status_handler_t, igraph_status_handler_t — The type of the igraph status handler functions
stochastic_imitation, igraph_stochastic_imitation — Adopt a strategy via stochastic imitation with uniform selection.
STR, STR — Indexing string vectors
strength, igraph_strength — Strength of the vertices, weighted vertex degree in other words.
strerror, igraph_strerror — Textual description of an error.
strvector_add, igraph_strvector_add — Adds an element to the back of a string vector.
strvector_append, igraph_strvector_append — Concatenate two string vectors.
strvector_clear, igraph_strvector_clear — Remove all elements
strvector_copy, igraph_strvector_copy — Initialization by copying.
strvector_destroy, igraph_strvector_destroy — Free allocated memory
strvector_get, igraph_strvector_get — Indexing
strvector_init, igraph_strvector_init — Initialize
strvector_remove, igraph_strvector_remove — Removes a single element from a string vector.
strvector_resize, igraph_strvector_resize — Resize
strvector_set, igraph_strvector_set — Set an element
strvector_set2, igraph_strvector_set2 — Sets an element
strvector_size, igraph_strvector_size — Gives the size of a string vector.
st_edge_connectivity, igraph_st_edge_connectivity — Edge connectivity of a pair of vertices
st_mincut, igraph_st_mincut — Minimum cut between a source and a target vertex
st_mincut_value, igraph_st_mincut_value — The minimum s-t cut in a graph
st_vertex_connectivity, igraph_st_vertex_connectivity — The vertex connectivity of a pair of vertices
subcomponent, igraph_subcomponent — The vertices in the same component as a given vertex.
subgraph, igraph_subgraph — Creates a subgraph induced by the specified vertices.
subgraph_edges, igraph_subgraph_edges — Creates a subgraph with the specified edges and their endpoints.
subisomorphic, igraph_subisomorphic — Decide subgraph isomorphism
subisomorphic_function_vf2, igraph_subisomorphic_function_vf2 — Generic VF2 function for subgraph isomorphism problems
subisomorphic_lad, igraph_subisomorphic_lad — Check subgraph isomorphism with the LAD algorithm
subisomorphic_vf2, igraph_subisomorphic_vf2 — Decide subgraph isomorphism using VF2


VAB, VAB — Query a boolean vertex attribute.
VABV, VABV — Query a boolean vertex attribute for all vertices.
VAN, VAN — Query a numeric vertex attribute.
VANV, VANV — Query a numeric vertex attribute for all vertices.
VAS, VAS — Query a string vertex attribute.
VASV, VASV — Query a string vertex attribute for all vertices.
vcount, igraph_vcount — The number of vertices in a graph.
VECTOR, VECTOR — Accessing an element of a vector.
vector_add, igraph_vector_add — Add two vectors.
vector_add_constant, igraph_vector_add_constant — Add a constant to the vector.
vector_all_e, igraph_vector_all_e — Are all elements equal?
vector_all_g, igraph_vector_all_g — Are all elements greater?
vector_all_ge, igraph_vector_all_ge — Are all elements greater or equal?
vector_all_l, igraph_vector_all_l — Are all elements less?
vector_all_le, igraph_vector_all_le — Are all elements less or equal?
vector_append, igraph_vector_append — Append a vector to another one.
vector_binsearch, igraph_vector_binsearch — Finds an element by binary searching a sorted vector.
vector_binsearch2, igraph_vector_binsearch2 — Binary search, without returning the index.
vector_capacity, igraph_vector_capacity — Returns the allocated capacity of the vector
vector_clear, igraph_vector_clear — Removes all elements from a vector.
vector_contains, igraph_vector_contains — Linear search in a vector.
vector_copy, igraph_vector_copy — Initializes a vector from another vector object (constructor).
vector_copy_to, igraph_vector_copy_to — Copies the contents of a vector to a C array.
vector_destroy, igraph_vector_destroy — Destroys a vector object.
vector_difference_sorted, igraph_vector_difference_sorted — Calculates the difference between two sorted vectors (considered as sets)
vector_div, igraph_vector_div — Divide a vector by another one.
vector_e, igraph_vector_e — Access an element of a vector.
vector_empty, igraph_vector_empty — Decides whether the size of the vector is zero.
vector_e_ptr, igraph_vector_e_ptr — Get the address of an element of a vector
vector_fill, igraph_vector_fill — Fill a vector with a constant element
vector_init, igraph_vector_init — Initializes a vector object (constructor).
vector_init_copy, igraph_vector_init_copy — Initializes a vector from an ordinary C array (constructor).
vector_init_seq, igraph_vector_init_seq — Initializes a vector with a sequence.
vector_insert, igraph_vector_insert — Inserts a single element into a vector.
vector_intersect_sorted, igraph_vector_intersect_sorted — Calculates the intersection of two sorted vectors
vector_isininterval, igraph_vector_isininterval — Checks if all elements of a vector are in the given
vector_max, igraph_vector_max — Gives the maximum element of the vector.
vector_maxdifference, igraph_vector_maxdifference — The maximum absolute difference of m1 and m2
vector_min, igraph_vector_min — Smallest element of a vector.
vector_minmax, igraph_vector_minmax — Minimum and maximum elements of a vector.
vector_mul, igraph_vector_mul — Multiply two vectors.
vector_null, igraph_vector_null — Sets each element in the vector to zero.
vector_pop_back, igraph_vector_pop_back — Removes and returns the last element of a vector.
vector_prod, igraph_vector_prod — Calculates the product of the elements in the vector.
vector_ptr_clear, igraph_vector_ptr_clear — Removes all elements from a pointer vector.
vector_ptr_copy, igraph_vector_ptr_copy — Copy a pointer vector (constructor).
vector_ptr_destroy, igraph_vector_ptr_destroy — Destroys a pointer vector.
vector_ptr_destroy_all, igraph_vector_ptr_destroy_all — Frees all the elements and destroys the pointer vector.
vector_ptr_e, igraph_vector_ptr_e — Access an element of a pointer vector.
vector_ptr_free_all, igraph_vector_ptr_free_all — Frees all the elements of a pointer vector.
vector_ptr_get_item_destructor, igraph_vector_ptr_get_item_destructor — Gets the current item destructor for this pointer vector.
vector_ptr_init, igraph_vector_ptr_init — Initialize a pointer vector (constructor).
vector_ptr_push_back, igraph_vector_ptr_push_back — Appends an element to the back of a pointer vector.
vector_ptr_resize, igraph_vector_ptr_resize — Resizes a pointer vector.
vector_ptr_set, igraph_vector_ptr_set — Assign to an element of a pointer vector.
vector_ptr_set_item_destructor, igraph_vector_ptr_set_item_destructor — Sets the item destructor for this pointer vector.
VECTOR_PTR_SET_ITEM_DESTRUCTOR, IGRAPH_VECTOR_PTR_SET_ITEM_DESTRUCTOR — Sets the item destructor for this pointer vector (macro version).
vector_ptr_size, igraph_vector_ptr_size — Gives the number of elements in the pointer vector.
vector_push_back, igraph_vector_push_back — Appends one element to a vector.
vector_remove, igraph_vector_remove — Removes a single element from a vector.
vector_remove_section, igraph_vector_remove_section — Deletes a section from a vector.
vector_reserve, igraph_vector_reserve — Reserves memory for a vector.
vector_resize, igraph_vector_resize — Resize the vector.
vector_resize_min, igraph_vector_resize_min — Deallocate the unused memory of a vector.
vector_reverse, igraph_vector_reverse — Reverse the elements of a vector.
vector_scale, igraph_vector_scale — Multiply all elements of a vector by a constant
vector_search, igraph_vector_search — Search from a given position
vector_set, igraph_vector_set — Assignment to an element of a vector.
vector_shuffle, igraph_vector_shuffle — Shuffles a vector in-place using the Fisher-Yates method
vector_size, igraph_vector_size — Gives the size (=length) of the vector.
vector_sort, igraph_vector_sort — Sorts the elements of the vector into ascending order.
vector_sub, igraph_vector_sub — Subtract a vector from another one.
vector_sum, igraph_vector_sum — Calculates the sum of the elements in the vector.
vector_swap, igraph_vector_swap — Swap elements of two vectors.
vector_swap_elements, igraph_vector_swap_elements — Swap two elements in a vector.
vector_tail, igraph_vector_tail — Returns the last element in a vector.
vector_update, igraph_vector_update — Update a vector from another one.
vector_view, igraph_vector_view — Handle a regular C array as a igraph_vector_t.
vector_which_max, igraph_vector_which_max — Gives the position of the maximum element of the vector.
vector_which_min, igraph_vector_which_min — Index of the smallest element.
vector_which_minmax, igraph_vector_which_minmax — Index of the minimum and maximum elements
version, igraph_version — Return the version of the igraph C library
vertex_connectivity, igraph_vertex_connectivity — The vertex connectivity of a graph
vertex_disjoint_paths, igraph_vertex_disjoint_paths — Maximum number of vertex-disjoint paths between two vertices.
vit_create, igraph_vit_create — Creates a vertex iterator from a vertex selector.
vit_destroy, igraph_vit_destroy — Destroys a vertex iterator.
VIT_END, IGRAPH_VIT_END — Are we at the end?
VIT_GET, IGRAPH_VIT_GET — Query the current position.
VIT_RESET, IGRAPH_VIT_RESET — Reset a vertex iterator.
VIT_SIZE, IGRAPH_VIT_SIZE — Size of a vertex iterator.
vss_1, igraph_vss_1 — Vertex set with a single vertex (immediate version).
vss_all, igraph_vss_all — All vertices of a graph (immediate version).
vss_none, igraph_vss_none — Empty vertex set (immediate version).
vss_seq, igraph_vss_seq — An interval of vertices (immediate version).
vss_vector, igraph_vss_vector — Vertex set based on a vector (immediate version).
vs_1, igraph_vs_1 — Vertex set with a single vertex.
vs_adj, igraph_vs_adj — Adjacent vertices of a vertex.
vs_all, igraph_vs_all — Vertex set, all vertices of a graph.
vs_copy, igraph_vs_copy — Creates a copy of a vertex selector.
vs_destroy, igraph_vs_destroy — Destroy a vertex set.
vs_is_all, igraph_vs_is_all — Check whether all vertices are included.
vs_nonadj, igraph_vs_nonadj — Non-adjacent vertices of a vertex.
vs_none, igraph_vs_none — Empty vertex set.
vs_seq, igraph_vs_seq — Vertex set, an interval of vertices.
vs_size, igraph_vs_size — Returns the size of the vertex selector.
vs_type, igraph_vs_type — Returns the type of the vertex selector.
vs_vector, igraph_vs_vector — Vertex set based on a vector.
vs_vector_copy, igraph_vs_vector_copy — Vertex set based on a vector, with copying.
vs_vector_small, igraph_vs_vector_small — Create a vertex set by giving its elements.