Struct MinimumCodeGenerationOneRegister 

pub struct MinimumCodeGenerationOneRegister { /* private fields */ }

Minimum Code Generation on a One-Register Machine.

Given a directed acyclic graph G = (V, A) with maximum out-degree 2, where leaves (out-degree 0) are input values in memory, internal vertices are operations, and roots (in-degree 0) are values to compute, find a program of minimum instructions using LOAD, STORE, and OP.

Representation

The configuration is a permutation of internal (non-leaf) vertices giving their evaluation order. config[i] is the evaluation position for internal vertex i (0-indexed among internal vertices).

Example

use problemreductions::models::misc::MinimumCodeGenerationOneRegister;
use problemreductions::{Problem, Solver, BruteForce, Min};

// 7 vertices: leaves {4,5,6}, internal {0,1,2,3}
// v3 = op(v5, v6), v1 = op(v3, v4), v2 = op(v3, v5), v0 = op(v1, v2)
let problem = MinimumCodeGenerationOneRegister::new(
    7,
    vec![(0,1),(0,2),(1,3),(1,4),(2,3),(2,5),(3,5),(3,6)],
    3,
);
let result = BruteForce::new().solve(&problem);
assert_eq!(result, Min(Some(8)));

Implementations

impl MinimumCodeGenerationOneRegister

pub fn new( num_vertices: usize, edges: Vec<(usize, usize)>, num_leaves: usize, ) -> Self

Create a new instance.

Arguments

• num_vertices - Total number of vertices
• edges - Directed arcs (parent, child); parent depends on child
• num_leaves - Number of leaf vertices (out-degree 0)

Panics

Panics if any edge index is out of bounds, if any vertex has out-degree > 2, or if num_leaves > num_vertices.

pub fn num_vertices(&self) -> usize

Get the number of vertices.

pub fn num_edges(&self) -> usize

Get the number of edges.

pub fn num_leaves(&self) -> usize

Get the number of leaf vertices.

pub fn num_internal(&self) -> usize

Get the number of internal (non-leaf) vertices.

pub fn edges(&self) -> &[(usize, usize)]

Get the edges.

pub fn simulate(&self, config: &[usize]) -> Option<usize>

Simulate the one-register machine for a given evaluation order of internal vertices and return the instruction count, or None if the ordering is invalid (not a permutation or violates dependencies).

Trait Implementations

impl Clone for MinimumCodeGenerationOneRegister

fn clone(&self) -> MinimumCodeGenerationOneRegister

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for MinimumCodeGenerationOneRegister

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for MinimumCodeGenerationOneRegister

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Problem for MinimumCodeGenerationOneRegister

const NAME: &'static str = "MinimumCodeGenerationOneRegister"

Base name of this problem type (e.g., “MaximumIndependentSet”).

type Value = Min<usize>

The evaluation value type.

fn variant() -> Vec<(&'static str, &'static str)>

Returns variant attributes derived from type parameters.

fn dims(&self) -> Vec<usize>

Configuration space dimensions. Each entry is the cardinality of that variable.

fn evaluate(&self, config: &[usize]) -> Min<usize>

Evaluate the problem on a configuration.

fn num_variables(&self) -> usize

Number of variables (derived from dims).

fn problem_type() -> ProblemType

Look up this problem’s catalog entry.

impl Serialize for MinimumCodeGenerationOneRegister

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl DeclaredVariant for MinimumCodeGenerationOneRegister