Struct PreemptiveScheduling 

pub struct PreemptiveScheduling { /* private fields */ }

The Preemptive Scheduling problem.

Given n tasks with processing lengths l(0), ..., l(n-1), m identical processors, and a set of precedence constraints, find a preemptive schedule that minimizes the makespan.

Tasks may be interrupted and resumed at later time slots (preemption). A configuration is a binary vector of length n × D_max where D_max = sum of all lengths is the worst-case makespan.

solution[t][u] = true means task t is processed at time slot u.

A valid schedule satisfies:

• Each task t is active in exactly l(t) time slots.
• At most m tasks are active at any time slot.
• For each precedence (pred, succ), the last active slot of pred is strictly less than the first active slot of succ.

The makespan is max_t (last active slot of t + 1).

Example

use problemreductions::models::misc::PreemptiveScheduling;
use problemreductions::Problem;

let problem = PreemptiveScheduling::new(vec![2, 1], 2, vec![]).unwrap();
// D_max = 3, so the solution is a 2 × 3 task-by-time matrix.
// task 0 active at slots 0,1; task 1 active at slot 0
let solution = vec![
    vec![true, true, false],
    vec![true, false, false],
];
assert_eq!(problem.evaluate(&solution).unwrap(), problemreductions::types::Min(Some(2)));

Implementations

impl PreemptiveScheduling

pub fn new( lengths: Vec<i64>, num_processors: usize, precedences: Vec<(usize, usize)>, ) -> Result<Self, ConstructionError>

Create a new Preemptive Scheduling instance.

Arguments

• lengths - Processing length l(t) for each task (must be positive)
• num_processors - Number of identical processors m (must be positive)
• precedences - Pairs (pred, succ): task pred must finish before task succ starts

pub fn num_tasks(&self) -> usize

Get the number of tasks.

pub fn num_processors(&self) -> usize

Get the number of processors.

pub fn num_precedences(&self) -> usize

Get the number of precedence constraints.

pub fn lengths(&self) -> &[i64]

Get the processing lengths.

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

Get the precedence constraints.

pub fn d_max(&self) -> usize

Compute D_max = sum of all task lengths (worst-case makespan).

Trait Implementations

impl BruteForceProblem for PreemptiveScheduling

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

Cardinality of each coordinate in the brute-force search space.

fn num_variables(&self) -> usize

Number of coordinates in the brute-force search space.

impl Clone for PreemptiveScheduling

fn clone(&self) -> PreemptiveScheduling

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for PreemptiveScheduling

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

Formats the value using the given formatter.

impl DeclaredVariant for PreemptiveScheduling

impl<'de> Deserialize<'de> for PreemptiveScheduling

fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>

where D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Problem for PreemptiveScheduling

const NAME: &'static str = "PreemptiveScheduling"

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

type Solution = Vec<Vec<bool>>

Mathematical witness type for this problem.

type Value = Min<i64>

The evaluation value type.

fn parameter_names() -> &'static [&'static str]

Canonical parameter names for this problem model.

fn parameters(&self) -> ProblemParameters

Measure the complete canonical parameters of this concrete instance.

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

Returns variant attributes derived from type parameters.

fn evaluate( &self, solution: &Self::Solution, ) -> Result<Min<i64>, EvaluationError>

Evaluate the problem on a solution.

fn problem_type() -> ProblemType

Look up this problem’s catalog entry.

impl ReduceTo<ILP<i64>> for PreemptiveScheduling

type Result = ReductionPSToILP

The reduction result type.

fn reduce_to(&self) -> Result<Self::Result, ReductionError>

Reduce this problem to the target problem type.

fn target_construction(error: ConstructionError) -> ReductionError

where Self: Sized,

Attach this reduction edge to a target-construction failure.

fn exact_i64( value: usize, operation: impl Into<String>, ) -> Result<i64, ReductionError>

where Self: Sized,

Convert a structural count used by the target’s exact integer algebra.

impl ReduceTo<PreemptiveScheduling> for KSatisfiability<K3>

type Result = Reduction3SATToPreemptiveScheduling

The reduction result type.

fn reduce_to(&self) -> Result<Self::Result, ReductionError>

Reduce this problem to the target problem type.

fn target_construction(error: ConstructionError) -> ReductionError

where Self: Sized,

Attach this reduction edge to a target-construction failure.

fn exact_i64( value: usize, operation: impl Into<String>, ) -> Result<i64, ReductionError>

where Self: Sized,

Convert a structural count used by the target’s exact integer algebra.

impl Serialize for PreemptiveScheduling

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

where __S: Serializer,

Serialize this value into the given Serde serializer.