Struct Solution 

pub struct Solution { /* private fields */ }

A solution of a problem: optimal objective function value and variable values.

Note that a Solution instance contains the whole solver machinery which can require a lot of memory for larger problems. Thus saving the Solution instance (as opposed to getting the values of interest and discarding the solution) is mainly useful if you want to add more constraints to it later.

Implementations

impl Solution

pub fn stop_reason(&self) -> &StopReason

Returns the reason why the solver stopped.

pub fn objective(&self) -> f64

Optimal value of the objective function.

pub fn resume(self, time_limit: Option<Duration>) -> Result<Self, Error>

WARNING: It is recommended to create a new solver with a longer time limit instead of resuming it, as there might be subtle bugs in the stopping/resuming process that were not caught by tests.

Resume solving after the solver stopped due to a time limit.

If the solver previously stopped with StopReason::Limit, this method continues solving with the given time_limit. Pass None to run without a time limit.

If the solver already finished (StopReason::Finished), this is a no-op and returns the solution as-is.

Errors

Will return an error if the problem is infeasible or unbounded.

pub fn var_value_raw(&self, var: Variable) -> &f64

Value of the variable at optimum.

Note that you can use indexing operations to get variable values.

Warning

If the variable is an integer, there might be rounding errors. For example you could see 0.999999999999 instead of 1.0.

pub fn var_value(&self, var: Variable) -> f64

Value of the variable at optimum.

If the variable was defined as an integer or boolean, it rounds it. it removes precision errors

pub fn iter(&self) -> SolutionIter<'_>

Iterate over the variable-value pairs of the solution.

Warning

If you used integer variables, there might be rounding errors in the variable results for example you could see 0.999999999999 instead of 1.0.

pub fn add_constraint( self, expr: impl Into<LinearExpr>, cmp_op: ComparisonOp, rhs: f64, ) -> Result<Self, Error>

Add another constraint and return the solution to the updated problem.

This method will consume the solution and not return it in case of error. See also examples of specifying the left-hand side in the docs for the Problem::add_constraint method.

Errors

Will return an error if the problem becomes infeasible with the additional constraint.

pub fn fix_var(self, var: Variable, val: f64) -> Result<Self, Error>

Fix the variable to the specified value and return the solution to the updated problem.

This method will consume the solution and not return it in case of error.

Errors

Will return an error if the problem becomes infeasible with the additional constraint.

pub fn unfix_var(self, var: Variable) -> (Self, bool)

If the variable was fixed with fix_var before, remove that constraint and return the solution to the updated problem and a boolean indicating if the variable was really fixed before.

pub fn add_gomory_cut(self, var: Variable) -> Result<Self, Error>

Add a Gomory cut constraint to the problem and return the solution.

Errors

Will return an error if the problem becomes infeasible with the additional constraint.

Panics

Will panic if the variable is not basic (variable is basic if it has value other than its bounds).

Trait Implementations

impl Clone for Solution

fn clone(&self) -> Solution

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Solution

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

Formats the value using the given formatter.

impl Index<Variable> for Solution

type Output = f64

The returned type after indexing.

fn index(&self, var: Variable) -> &Self::Output

Performs the indexing (container[index]) operation.

impl<'a> IntoIterator for &'a Solution

type Item = (Variable, &'a f64)

The type of the elements being iterated over.

type IntoIter = SolutionIter<'a>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.