Macro good_lp::variables

macro_rules! variables {
    () => { ... };
}

Instantiates ProblemVariables, to create a set of related variables.

Using a macro allows this crate to give different types to variables that were instantiated at different places in the code.

Working example

use good_lp::variables;

let mut vars = variables!();
let x = vars.add_variable();
let y = vars.add_variable();
let objective = x + y / 2;

Trying to add incompatible variables

You should never create expressions with variabless that come from different ProblemVariables instances.

use good_lp::{variables, default_solver, SolverModel};

let mut pb1 = variables!();
let mut pb2 = variables!();
let x = pb1.add_variable(); // Creating a variable on pb1 ...
pb2.minimise(x) // ... but running the optimization on pb2
  .using(default_solver)
  .solve();

Since pb1 and pb2 have been instanciated at two different places in the code, they are different problems and their variables are not compatible with one another. Trying to solve problems with incompatible problems will panic.