Struct CsrGraph 

pub struct CsrGraph { /* private fields */ }

A compressed sparse row (CSR) graph representation.

Stores edges in three contiguous arrays:

• row_ptr[i]..row_ptr[i+1] gives the range of neighbors for node i
• col_indices[row_ptr[i]..row_ptr[i+1]] are the neighbor node IDs
• values[row_ptr[i]..row_ptr[i+1]] are the corresponding edge weights

This format is identical to the CSR sparse matrix format from numerical linear algebra, enabling direct use in sparse matrix-vector products (e.g., for PageRank).

Implementations

impl CsrGraph

pub fn from_raw( num_nodes: usize, row_ptr: Vec<usize>, col_indices: Vec<usize>, values: Vec<f64>, directed: bool, ) -> Result<Self>

Construct a CSR graph directly from raw arrays.

Safety contract (logical, not unsafe)

The caller must ensure:

• row_ptr.len() == num_nodes + 1
• All values in col_indices are < num_nodes
• col_indices.len() == values.len() == row_ptr[num_nodes]

pub fn from_edges( num_nodes: usize, edges: Vec<(usize, usize, f64)>, directed: bool, ) -> Result<Self>

Construct from an edge list (convenience wrapper).

For undirected graphs, reverse edges are added automatically.

pub fn from_edges_parallel( num_nodes: usize, edges: Vec<(usize, usize, f64)>, directed: bool, ) -> Result<Self>

Construct from an edge list using parallel construction.

pub fn from_unweighted_edges( num_nodes: usize, edges: &[(usize, usize)], directed: bool, ) -> Result<Self>

Construct an unweighted CSR graph from an edge list.

pub fn num_nodes(&self) -> usize

Number of nodes.

pub fn num_edges(&self) -> usize

Number of stored (directed) edges.

For undirected graphs built from n input edges, this returns 2n because both directions are stored.

pub fn num_logical_edges(&self) -> usize

Number of logical edges.

For undirected graphs, returns num_edges / 2 (the original count). For directed graphs, returns num_edges.

pub fn is_directed(&self) -> bool

Whether the graph is directed.

pub fn degree(&self, node: usize) -> usize

Out-degree of a node (number of outgoing edges).

Returns 0 if the node index is out of range.

pub fn neighbors(&self, node: usize) -> NeighborIter<'_>

Iterator over neighbors of node as (neighbor_id, weight) pairs.

Returns an empty iterator if node is out of range.

pub fn has_edge(&self, src: usize, dst: usize) -> bool

Check if an edge exists from src to dst.

Uses binary search on the sorted neighbor list. O(log(degree)).

pub fn edge_weight(&self, src: usize, dst: usize) -> Option<f64>

Get the weight of an edge from src to dst.

Returns None if the edge does not exist.

pub fn row_ptr(&self) -> &[usize]

Get the raw row pointer array (read-only).

pub fn col_indices(&self) -> &[usize]

Get the raw column index array (read-only).

pub fn values(&self) -> &[f64]

Get the raw values array (read-only).

pub fn memory_bytes(&self) -> usize

Memory usage in bytes (approximate).

pub fn spmv(&self, x: &[f64]) -> Result<Vec<f64>>

Sparse matrix-vector product: y = A * x.

This is the core operation for iterative algorithms like PageRank. x and the returned vector both have length num_nodes.

pub fn spmv_parallel(&self, x: &[f64]) -> Result<Vec<f64>>

Parallel sparse matrix-vector product: y = A * x.

pub fn transpose(&self) -> Result<Self>

Transpose the graph (reverse all edge directions).

For undirected graphs, the transpose is the same graph.

impl CsrGraph

pub fn to_adjacency_list(&self) -> AdjacencyList

Convert to an adjacency list representation.

pub fn from_adjacency_list(adj: &AdjacencyList) -> Result<Self>

Construct a CSR graph from an adjacency list.

The adjacency list is consumed and edges are extracted directly. For undirected graphs, the adjacency list should already contain both directions (i.e., if (u,v) is present in adj[u], then (v,u) should be in adj[v]).

impl CsrGraph

pub fn to_graph(&self) -> Graph<usize, f64>

Convert to a Graph<usize, f64> (undirected adjacency-list graph).

For directed CSR graphs, the resulting Graph will be undirected (edges are treated as undirected).

pub fn from_graph(graph: &Graph<usize, f64>) -> Result<Self>

Construct a CSR graph from a Graph<usize, f64>.

pub fn from_digraph(graph: &DiGraph<usize, f64>) -> Result<Self>

Construct a CSR graph from a DiGraph<usize, f64>.

Trait Implementations

impl Clone for CsrGraph

fn clone(&self) -> CsrGraph

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for CsrGraph

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for CsrGraph

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.