# Struct cagra::graph::Graph [−] [src]

`pub struct Graph<A: Scalar>(_);`

Calculation graph based on `petgraph::graph::Graph`

## Methods

### `impl<A: Scalar> Graph<A>`[src]

new graph.

#### `fn variable(&mut self, name: &str) -> NodeIndex`[src]

Create new empty variable

#### `fn scalar_variable(&mut self, name: &str, value: A) -> NodeIndex`[src]

Create new scalar variable

#### `fn vector_variable(&mut self, name: &str, value: Array<A, Ix1>) -> NodeIndex`[src]

Create new vector variable

#### `fn set_value<V: Into<Value<A>>>(    &mut self,     node: NodeIndex,     value: V) -> Result<()>`[src]

Set a value to a variable node, and returns `NodeTypeError` if the node is an operator.

#### `fn get_value(&self, node: NodeIndex) -> Option<&Value<A>>`[src]

Get the value of the node. If the value has not been caluclated, returns `None`

#### `fn get_deriv(&self, node: NodeIndex) -> Option<&Value<A>>`[src]

Get the value of the node. If the value has not been caluclated, returns `None`

#### `fn eval_value(&mut self, node: NodeIndex, use_cached: bool) -> Result<()>`[src]

Evaluate the value of the node recusively.

• `use_cached` - Use the value if already calculated.

#### `fn eval_deriv(&mut self, node: NodeIndex) -> Result<()>`[src]

Evaluate derivative recursively.

## Methods from Deref<Target = Graph<Node<A>, ()>>

#### `fn node_count(&self) -> usize`[src]

Return the number of nodes (vertices) in the graph.

Computes in O(1) time.

#### `fn edge_count(&self) -> usize`[src]

Return the number of edges in the graph.

Computes in O(1) time.

#### `fn is_directed(&self) -> bool`[src]

Whether the graph has directed edges or not.

#### `fn add_node(&mut self, weight: N) -> NodeIndex<Ix>`[src]

Add a node (also called vertex) with associated data `weight` to the graph.

Computes in O(1) time.

Return the index of the new node.

Panics if the Graph is at the maximum number of nodes for its index type (N/A if usize).

#### `fn node_weight(&self, a: NodeIndex<Ix>) -> Option<&N>`[src]

Access the weight for node `a`.

Also available with indexing syntax: `&graph[a]`.

#### `fn node_weight_mut(&mut self, a: NodeIndex<Ix>) -> Option<&mut N>`[src]

Access the weight for node `a`, mutably.

Also available with indexing syntax: `&mut graph[a]`.

#### `fn add_edge(    &mut self,     a: NodeIndex<Ix>,     b: NodeIndex<Ix>,     weight: E) -> EdgeIndex<Ix>`[src]

Add an edge from `a` to `b` to the graph, with its associated data `weight`.

Return the index of the new edge.

Computes in O(1) time.

Panics if any of the nodes don't exist.
Panics if the Graph is at the maximum number of edges for its index type (N/A if usize).

Note: `Graph` allows adding parallel (“duplicate”) edges. If you want to avoid this, use `.update_edge(a, b, weight)` instead.

#### `fn update_edge(    &mut self,     a: NodeIndex<Ix>,     b: NodeIndex<Ix>,     weight: E) -> EdgeIndex<Ix>`[src]

Add or update an edge from `a` to `b`. If the edge already exists, its weight is updated.

Return the index of the affected edge.

Computes in O(e') time, where e' is the number of edges connected to `a` (and `b`, if the graph edges are undirected).

Panics if any of the nodes don't exist.

#### `fn edge_weight(&self, e: EdgeIndex<Ix>) -> Option<&E>`[src]

Access the weight for edge `e`.

Also available with indexing syntax: `&graph[e]`.

#### `fn edge_weight_mut(&mut self, e: EdgeIndex<Ix>) -> Option<&mut E>`[src]

Access the weight for edge `e`, mutably.

Also available with indexing syntax: `&mut graph[e]`.

#### `fn edge_endpoints(    &self,     e: EdgeIndex<Ix>) -> Option<(NodeIndex<Ix>, NodeIndex<Ix>)>`[src]

Access the source and target nodes for `e`.

#### `fn remove_node(&mut self, a: NodeIndex<Ix>) -> Option<N>`[src]

Remove `a` from the graph if it exists, and return its weight. If it doesn't exist in the graph, return `None`.

Apart from `a`, this invalidates the last node index in the graph (that node will adopt the removed node index). Edge indices are invalidated as they would be following the removal of each edge with an endpoint in `a`.

Computes in O(e') time, where e' is the number of affected edges, including n calls to `.remove_edge()` where n is the number of edges with an endpoint in `a`, and including the edges with an endpoint in the displaced node.

#### `fn remove_edge(&mut self, e: EdgeIndex<Ix>) -> Option<E>`[src]

Remove an edge and return its edge weight, or `None` if it didn't exist.

Apart from `e`, this invalidates the last edge index in the graph (that edge will adopt the removed edge index).

Computes in O(e') time, where e' is the size of four particular edge lists, for the vertices of `e` and the vertices of another affected edge.

#### `fn neighbors(&self, a: NodeIndex<Ix>) -> Neighbors<E, Ix>`[src]

Return an iterator of all nodes with an edge starting from `a`.

• `Directed`: Outgoing edges from `a`.
• `Undirected`: All edges from or to `a`.

Produces an empty iterator if the node doesn't exist.
Iterator element type is `NodeIndex<Ix>`.

Use `.neighbors(a).detach()` to get a neighbor walker that does not borrow from the graph.

#### `fn neighbors_directed(    &self,     a: NodeIndex<Ix>,     dir: Direction) -> Neighbors<E, Ix>`[src]

Return an iterator of all neighbors that have an edge between them and `a`, in the specified direction. If the graph's edges are undirected, this is equivalent to .neighbors(a).

• `Directed`, `Outgoing`: All edges from `a`.
• `Directed`, `Incoming`: All edges to `a`.
• `Undirected`: All edges from or to `a`.

Produces an empty iterator if the node doesn't exist.
Iterator element type is `NodeIndex<Ix>`.

For a `Directed` graph, neighbors are listed in reverse order of their addition to the graph, so the most recently added edge's neighbor is listed first. The order in an `Undirected` graph is arbitrary.

Use `.neighbors_directed(a, dir).detach()` to get a neighbor walker that does not borrow from the graph.

#### `fn neighbors_undirected(&self, a: NodeIndex<Ix>) -> Neighbors<E, Ix>`[src]

Return an iterator of all neighbors that have an edge between them and `a`, in either direction. If the graph's edges are undirected, this is equivalent to .neighbors(a).

• `Directed` and `Undirected`: All edges from or to `a`.

Produces an empty iterator if the node doesn't exist.
Iterator element type is `NodeIndex<Ix>`.

Use `.neighbors_undirected(a).detach()` to get a neighbor walker that does not borrow from the graph.

#### `fn edges(&self, a: NodeIndex<Ix>) -> Edges<E, Ty, Ix>`[src]

Return an iterator of all edges of `a`.

• `Directed`: Outgoing edges from `a`.
• `Undirected`: All edges connected to `a`.

Produces an empty iterator if the node doesn't exist.
Iterator element type is `EdgeReference<E, Ix>`.

#### `fn edges_directed(&self, a: NodeIndex<Ix>, dir: Direction) -> Edges<E, Ty, Ix>`[src]

Return an iterator of all edges of `a`, in the specified direction.

• `Directed`, `Outgoing`: All edges from `a`.
• `Directed`, `Incoming`: All edges to `a`.
• `Undirected`: All edges connected to `a`.

Produces an empty iterator if the node `a` doesn't exist.
Iterator element type is `EdgeReference<E, Ix>`.

#### `fn contains_edge(&self, a: NodeIndex<Ix>, b: NodeIndex<Ix>) -> bool`[src]

Lookup if there is an edge from `a` to `b`.

Computes in O(e') time, where e' is the number of edges connected to `a` (and `b`, if the graph edges are undirected).

#### `fn find_edge(&self, a: NodeIndex<Ix>, b: NodeIndex<Ix>) -> Option<EdgeIndex<Ix>>`[src]

Lookup an edge from `a` to `b`.

Computes in O(e') time, where e' is the number of edges connected to `a` (and `b`, if the graph edges are undirected).

#### `fn find_edge_undirected(    &self,     a: NodeIndex<Ix>,     b: NodeIndex<Ix>) -> Option<(EdgeIndex<Ix>, Direction)>`[src]

Lookup an edge between `a` and `b`, in either direction.

If the graph is undirected, then this is equivalent to `.find_edge()`.

Return the edge index and its directionality, with `Outgoing` meaning from `a` to `b` and `Incoming` the reverse, or `None` if the edge does not exist.

#### `fn externals(&self, dir: Direction) -> Externals<N, Ty, Ix>`[src]

Return an iterator over either the nodes without edges to them (`Incoming`) or from them (`Outgoing`).

An internal node has both incoming and outgoing edges. The nodes in `.externals(Incoming)` are the source nodes and `.externals(Outgoing)` are the sinks of the graph.

For a graph with undirected edges, both the sinks and the sources are just the nodes without edges.

The whole iteration computes in O(|V|) time.

#### `fn node_indices(&self) -> NodeIndices<Ix>`[src]

Return an iterator over the node indices of the graph

#### `fn node_weights_mut(&mut self) -> NodeWeightsMut<N, Ix>`[src]

The order in which weights are yielded matches the order of their node indices.

#### `fn edge_indices(&self) -> EdgeIndices<Ix>`[src]

Return an iterator over the edge indices of the graph

#### `fn edge_references(&self) -> EdgeReferences<E, Ix>`[src]

Create an iterator over all edges, in indexed order.

Iterator element type is `EdgeReference<E, Ix>`.

#### `fn edge_weights_mut(&mut self) -> EdgeWeightsMut<E, Ix>`[src]

The order in which weights are yielded matches the order of their edge indices.

#### `fn raw_nodes(&self) -> &[Node<N, Ix>]`[src]

Access the internal node array.

#### `fn raw_edges(&self) -> &[Edge<E, Ix>]`[src]

Access the internal edge array.

#### `fn into_nodes_edges(self) -> (Vec<Node<N, Ix>>, Vec<Edge<E, Ix>>)`[src]

Convert the graph into a vector of Nodes and a vector of Edges

#### `fn first_edge(&self, a: NodeIndex<Ix>, dir: Direction) -> Option<EdgeIndex<Ix>>`[src]

Accessor for data structure internals: the first edge in the given direction.

#### `fn next_edge(&self, e: EdgeIndex<Ix>, dir: Direction) -> Option<EdgeIndex<Ix>>`[src]

Accessor for data structure internals: the next edge for the given direction.

#### `fn index_twice_mut<T, U>(    &mut self,     i: T,     j: U) -> (&mut <Graph<N, E, Ty, Ix> as Index<T>>::Output, &mut <Graph<N, E, Ty, Ix> as Index<U>>::Output) where    T: GraphIndex,    U: GraphIndex,    Graph<N, E, Ty, Ix>: IndexMut<T>,    Graph<N, E, Ty, Ix>: IndexMut<U>, `[src]

Index the `Graph` by two indices, any combination of node or edge indices is fine.

Panics if the indices are equal or if they are out of bounds.

```use petgraph::{Graph, Incoming};
use petgraph::visit::Dfs;

let mut gr = Graph::new();

// walk the graph and sum incoming edges into the node weight
let mut dfs = Dfs::new(&gr, a);
while let Some(node) = dfs.next(&gr) {
// use a walker -- a detached neighbors iterator
let mut edges = gr.neighbors_directed(node, Incoming).detach();
while let Some(edge) = edges.next_edge(&gr) {
let (nw, ew) = gr.index_twice_mut(node, edge);
*nw += *ew;
}
}

// check the result
assert_eq!(gr[a], 0.);
assert_eq!(gr[b], 4.);
assert_eq!(gr[c], 2.);```

#### `fn reverse(&mut self)`[src]

Reverse the direction of all edges

#### `fn clear(&mut self)`[src]

Remove all nodes and edges

Remove all edges

#### `fn capacity(&self) -> (usize, usize)`[src]

Return the current node and edge capacity of the graph.

#### `fn reserve_nodes(&mut self, additional: usize)`[src]

Reserves capacity for at least `additional` more nodes to be inserted in the graph. Graph may reserve more space to avoid frequent reallocations.

Panics if the new capacity overflows `usize`.

#### `fn reserve_edges(&mut self, additional: usize)`[src]

Reserves capacity for at least `additional` more edges to be inserted in the graph. Graph may reserve more space to avoid frequent reallocations.

Panics if the new capacity overflows `usize`.

#### `fn reserve_exact_nodes(&mut self, additional: usize)`[src]

Reserves the minimum capacity for exactly `additional` more nodes to be inserted in the graph. Does nothing if the capacity is already sufficient.

Prefer `reserve_nodes` if future insertions are expected.

Panics if the new capacity overflows `usize`.

#### `fn reserve_exact_edges(&mut self, additional: usize)`[src]

Reserves the minimum capacity for exactly `additional` more edges to be inserted in the graph. Does nothing if the capacity is already sufficient.

Prefer `reserve_edges` if future insertions are expected.

Panics if the new capacity overflows `usize`.

#### `fn shrink_to_fit_nodes(&mut self)`[src]

Shrinks the capacity of the underlying nodes collection as much as possible.

#### `fn shrink_to_fit_edges(&mut self)`[src]

Shrinks the capacity of the underlying edges collection as much as possible.

#### `fn shrink_to_fit(&mut self)`[src]

Shrinks the capacity of the graph as much as possible.

#### `fn retain_nodes<F>(&mut self, visit: F) where    F: FnMut(Frozen<Graph<N, E, Ty, Ix>>, NodeIndex<Ix>) -> bool, `[src]

Keep all nodes that return `true` from the `visit` closure, remove the others.

`visit` is provided a proxy reference to the graph, so that the graph can be walked and associated data modified.

The order nodes are visited is not specified.

#### `fn retain_edges<F>(&mut self, visit: F) where    F: FnMut(Frozen<Graph<N, E, Ty, Ix>>, EdgeIndex<Ix>) -> bool, `[src]

Keep all edges that return `true` from the `visit` closure, remove the others.

`visit` is provided a proxy reference to the graph, so that the graph can be walked and associated data modified.

The order edges are visited is not specified.

#### `fn extend_with_edges<I>(&mut self, iterable: I) where    I: IntoIterator,    N: Default,    <I as IntoIterator>::Item: IntoWeightedEdge<E>,    <<I as IntoIterator>::Item as IntoWeightedEdge<E>>::NodeId: Into<NodeIndex<Ix>>, `[src]

Extend the graph from an iterable of edges.

Node weights `N` are set to default values. Edge weights `E` may either be specified in the list, or they are filled with default values.

Nodes are inserted automatically to match the edges.

#### `fn map<'a, F, G, N2, E2>(    &'a self,     node_map: F,     edge_map: G) -> Graph<N2, E2, Ty, Ix> where    F: FnMut(NodeIndex<Ix>, &'a N) -> N2,    G: FnMut(EdgeIndex<Ix>, &'a E) -> E2, `[src]

Create a new `Graph` by mapping node and edge weights to new values.

The resulting graph has the same structure and the same graph indices as `self`.

#### `fn filter_map<'a, F, G, N2, E2>(    &'a self,     node_map: F,     edge_map: G) -> Graph<N2, E2, Ty, Ix> where    F: FnMut(NodeIndex<Ix>, &'a N) -> Option<N2>,    G: FnMut(EdgeIndex<Ix>, &'a E) -> Option<E2>, `[src]

Create a new `Graph` by mapping nodes and edges. A node or edge may be mapped to `None` to exclude it from the resulting graph.

Nodes are mapped first with the `node_map` closure, then `edge_map` is called for the edges that have not had any endpoint removed.

The resulting graph has the structure of a subgraph of the original graph. If no nodes are removed, the resulting graph has compatible node indices; if neither nodes nor edges are removed, the result has the same graph indices as `self`.

#### `fn into_edge_type<NewTy>(self) -> Graph<N, E, NewTy, Ix> where    NewTy: EdgeType, `[src]

Convert the graph into either undirected or directed. No edge adjustments are done, so you may want to go over the result to remove or add edges.

Computes in O(1) time.

## Trait Implementations

### `impl<A: Debug + Scalar> Debug for Graph<A>`[src]

#### `fn fmt(&self, __arg_0: &mut Formatter) -> Result`[src]

Formats the value using the given formatter.

### `impl<A: Scalar> From<Graph<Node<A>, ()>> for Graph<A>`[src]

#### `fn from(val: Graph<Node<A>, ()>) -> Self`[src]

Performs the conversion.

### `impl<A: Scalar> Deref for Graph<A>`[src]

#### `type Target = Graph<Node<A>, ()>`

The resulting type after dereferencing.

#### `fn deref(&self) -> &Self::Target`[src]

Dereferences the value.

### `impl<A: Scalar> DerefMut for Graph<A>`[src]

#### `fn deref_mut(&mut self) -> &mut Self::Target`[src]

Mutably dereferences the value.