Struct rplex::Constraint

pub struct Constraint { /* fields omitted */ }

A Constraint (row) object for a Problem.

The recommended way to build these is with the con! macro.

#[macro_use]
extern crate rplex;

use rplex::{Env, Problem, Variable};

fn main() {
    let env = Env::new().unwrap();
    let mut prob = Problem::new(&env, "dummy").unwrap();
    let x = prob.add_variable(var!("x" -> 4.0 as Binary)).unwrap();
    let y = prob.add_variable(var!(0.0 <= "y" <= 100.0  -> 3.0 as Integer)).unwrap();
    let z = prob.add_variable(var!(0.0 <= "z" <= 4.5 -> 2.0)).unwrap();
    prob.add_constraint(con!("dummy": 20.0 = 1.0 x + 2.0 y + 3.0 z)).unwrap();
    prob.add_constraint(con!("dummy2": 1.0 <= (-1.0) x + 1.0 y)).unwrap();
}

However, constraints can also be constructed manually from WeightedVariables. This can be useful if your constraints don’t quite fit the grammar allowed by the con! macro. You can create part of the constraint using con!, then augment it with add_wvar to obtain the constraint you need.The following example is identical to the above.

#[macro_use]
extern crate rplex;

use rplex::{Env, Problem, Constraint, ConstraintType, WeightedVariable};

fn main() {
    let env = Env::new().unwrap();
    let mut prob = Problem::new(&env, "dummy").unwrap();
    let x = prob.add_variable(var!("x" -> 4.0 as Binary)).unwrap();
    let y = prob.add_variable(var!(0.0 <= "y" <= 100.0  -> 3.0 as Integer)).unwrap();
    let z = prob.add_variable(var!(0.0 <= "z" <= 4.5 -> 2.0)).unwrap();
    let mut dummy = Constraint::new(ConstraintType::Eq, 20.0, "dummy");
    dummy.add_wvar(WeightedVariable::new_idx(x, 1.0));
    dummy.add_wvar(WeightedVariable::new_idx(y, 2.0));
    dummy.add_wvar(WeightedVariable::new_idx(z, 3.0));
    prob.add_constraint(dummy).unwrap();
    let mut dummy2 = Constraint::new(ConstraintType::GreaterThanEq, 1.0, "dummy2");
    dummy2.add_wvar(WeightedVariable::new_idx(x, -1.0));
    dummy2.add_wvar(WeightedVariable::new_idx(y, 1.0));
    prob.add_constraint(dummy2).unwrap();
}

Implementations

impl Constraint

pub fn new<S, F>(ty: ConstraintType, rhs: F, name: S) -> Constraint where
    S: Into<String>,
    F: Into<f64>, 

pub fn add_wvar(&mut self, wvar: WeightedVariable)

Move a WeightedVariable into the Constraint.

Trait Implementations

impl Clone for Constraint

fn clone(&self) -> Constraint

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Constraint

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

Formats the value using the given formatter.