Struct ReductionGraph 

pub struct ReductionGraph { /* private fields */ }

Runtime graph of all registered reductions.

Uses type-erased names for the graph topology, so MaxCut<i32> and MaxCut<f64> map to the same node “MaxCut”. This allows finding reduction paths regardless of weight type parameters.

The graph supports:

• Auto-discovery of reductions from inventory::iter::<ReductionEntry>
• Graph hierarchy from inventory::iter::<GraphSubtypeEntry>
• Set-theoretic validation for path finding
• Dijkstra with custom cost functions

Implementations

impl ReductionGraph

pub fn new() -> Self

Create a new reduction graph with all registered reductions from inventory.

pub fn is_graph_subtype(&self, sub: &str, sup: &str) -> bool

Check if sub is a subtype of sup (or equal).

pub fn rule_applicable( &self, want_source_graph: &str, want_target_graph: &str, rule_source_graph: &str, rule_target_graph: &str, ) -> bool

Check if a reduction rule can be used.

For a reduction from problem A (on graph type G_A) to problem B (on graph type G_B), using a rule that reduces C (on G_C) to D (on G_D):

The rule is applicable if:

• G_A is a subtype of G_C (our source graph is more specific than rule requires)
• G_D is a subtype of G_B (rule produces a graph that fits our target requirement)

pub fn find_cheapest_path<C: PathCostFn>( &self, source: (&str, &str), target: (&str, &str), input_size: &ProblemSize, cost_fn: &C, ) -> Option<ReductionPath>

Find the cheapest path using a custom cost function.

Uses Dijkstra’s algorithm with set-theoretic validation.

Arguments

• source: (problem_name, graph_type) for source
• target: (problem_name, graph_type) for target
• input_size: Initial problem size for cost calculations
• cost_fn: Custom cost function for path optimization

Returns

The cheapest path if one exists that satisfies the graph type constraints.

pub fn find_paths<S: 'static, T: 'static>(&self) -> Vec<ReductionPath>

Find all paths from source to target type.

Uses type-erased names, so find_paths::<MaxCut<i32>, SpinGlass<f64>>() will find paths even though the weight types differ.

pub fn find_paths_by_name(&self, src: &str, dst: &str) -> Vec<ReductionPath>

Find all paths between problem types by name.

pub fn find_shortest_path<S: 'static, T: 'static>( &self, ) -> Option<ReductionPath>

Find the shortest path from source to target type.

pub fn find_shortest_path_by_name( &self, src: &str, dst: &str, ) -> Option<ReductionPath>

Find the shortest path by name.

pub fn has_direct_reduction<S: 'static, T: 'static>(&self) -> bool

Check if a direct reduction exists from S to T.

pub fn has_direct_reduction_by_name(&self, src: &str, dst: &str) -> bool

Check if a direct reduction exists by name.

pub fn problem_types(&self) -> Vec<&'static str>

Get all registered problem type names (base names).

pub fn num_types(&self) -> usize

Get the number of registered problem types.

pub fn num_reductions(&self) -> usize

Get the number of registered reductions.

pub fn graph_hierarchy(&self) -> &HashMap<&'static str, HashSet<&'static str>>

Get the graph hierarchy (for inspection/testing).

impl ReductionGraph

pub fn to_json(&self) -> ReductionGraphJson

Export the reduction graph as a JSON-serializable structure.

pub fn to_json_string(&self) -> Result<String, Error>

Export the reduction graph as a JSON string.

pub fn to_json_file(&self, path: &Path) -> Result<()>

Export the reduction graph to a JSON file.

Trait Implementations

impl Default for ReductionGraph

fn default() -> Self

Returns the “default value” for a type.