Struct Problem 

#[non_exhaustive]
pub struct Problem {
    pub sense: Sense,
    pub objective: Vec<Rational>,
    pub constraints: Vec<Constraint>,
    pub var_names: Vec<String>,
    pub signs: Vec<Sign>,
}

A linear program. Variables are non-negative unless declared free or non_positive.

use simplex_trace::{Problem, Relation};

// max 3x1 + 5x2  s.t.  x1 <= 4,  2x2 <= 12,  3x1 + 2x2 <= 18
let problem = Problem::maximize([3, 5])
    .subject_to([1, 0], Relation::Le, 4)
    .subject_to([0, 2], Relation::Le, 12)
    .subject_to([3, 2], Relation::Le, 18);
assert_eq!(problem.num_vars(), 2);

With the serde feature, numbers are exact strings ("3", "-1/2"), never JSON floats, and var_names and signs may be omitted:

{
  "sense": "maximize",
  "objective": ["3", "5"],
  "constraints": [
    { "coeffs": ["1", "0"], "relation": "<=", "rhs": "4" },
    { "coeffs": ["3", "2"], "relation": "<=", "rhs": "18" }
  ]
}

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

sense: Sense

objective: Vec<Rational>

constraints: Vec<Constraint>

var_names: Vec<String>

Names of the variables. Empty means the defaults x1, x2, …

signs: Vec<Sign>

Sign restriction of each variable. Empty means every variable is non-negative.

Implementations

impl Problem

pub fn maximize<T: IntoRational>(objective: impl IntoIterator<Item = T>) -> Self

pub fn minimize<T: IntoRational>(objective: impl IntoIterator<Item = T>) -> Self

pub fn free(self, j: usize) -> Self

Declares variable j (0-based) free: it may take any sign.

pub fn non_positive(self, j: usize) -> Self

Declares variable j (0-based) non-positive: x_j <= 0.

pub fn with_sign(self, j: usize, sign: Sign) -> Self

Sets the sign restriction of variable j (0-based). An index out of range is reported by solve.

pub fn sign(&self, j: usize) -> Sign

Sign restriction of variable j (0-based).

pub fn subject_to<T: IntoRational>( self, coeffs: impl IntoIterator<Item = T>, relation: Relation, rhs: impl IntoRational, ) -> Self

Adds a constraint. Length mismatches are reported by solve.

pub fn with_names<S: Into<String>>( self, names: impl IntoIterator<Item = S>, ) -> Self

Overrides the default variable names (x1, x2, …). Names must be unique, may not look like a slack or artificial column (s1, a2, …) and may not end in + or - (the columns of free and non-positive variables); solve rejects such problems.

pub fn num_vars(&self) -> usize

pub fn var_name(&self, j: usize) -> String

Name of variable j (0-based): the given name, or x{j+1} by default.

Trait Implementations

impl Clone for Problem

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Problem

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for Problem

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for Problem

impl PartialEq for Problem

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl Serialize for Problem

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

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for Problem