### 7 releases (2 stable)

1.0.1 | Feb 24, 2024 |
---|---|

1.0.0 | Aug 19, 2023 |

0.0.5 | Aug 14, 2023 |

0.0.4 | Apr 1, 2021 |

0.0.3 | Mar 29, 2021 |

#**528** in Algorithms

**89** downloads per month

Used in good_lp

**MIT**license

54KB

1.5K
SLoC

# lp-solvers

Library implementing interaction with various linear programming solvers.

It uses the .lp file format to interact with external solver binaries.

## Supported solvers

- gurobi
- cplex (with the

feature)`cplex` - cbc
- glpk
**auto**: automatically finds which of the above solver is installed at runtime, and uses it.

You need to have the solver you want to use installed on your machine already for this library to work.

## Example

`
``use` `lp_solvers``::``lp_format``::``{`Constraint`,` LpObjective`}``;`
`use` `lp_solvers``::``problem``::``{`Problem`,` StrExpression`,` Variable`}``;`
`use` `lp_solvers``::``solvers``::``{`CbcSolver`,` SolverTrait`}``;`
`use` `lp_solvers``::``solvers``::``Status``::`Optimal`;`
`fn` `solve_integer_problem_with_solver``<`S`:` SolverTrait`>``(``solver``:` S`)`` ``{`
`let` pb `=` Problem `{` `//` Alternatively, you can implement the LpProblem trait on your own structure
name`:` `"`int_problem`"``.``to_string``(``)``,`
sense`:` `LpObjective``::`Maximize`,`
objective`:` StrExpression`(``"`x - y`"``.``to_string``(``)``)``,` `//` You can use other expression representations
variables`:` `vec!``[`
Variable `{`
name`:` `"`x`"``.``to_string``(``)``,`
is_integer`:` `true``,`
lower_bound`:` `-``10.``,`
upper_bound`:` `-``1.``,`
`}``,`
Variable `{`
name`:` `"`y`"``.``to_string``(``)``,`
is_integer`:` `true``,`
lower_bound`:` `4.``,`
upper_bound`:` `7.``,`
`}``,`
`]``,`
constraints`:` `vec!``[`Constraint `{`
lhs`:` StrExpression`(``"`x - y`"``.``to_string``(``)``)``,`
operator`:` `Ordering``::`Less`,`
rhs`:` `-``4.``5``,`
`}``]``,`
`}``;`
`let` solution `=` solver`.``run``(``&`pb`)``.``expect``(``"`Failed to run solver`"``)``;`
`assert_eq!``(`solution`.`status`,` Optimal`)``;`
`//` solution.results is now {"x":-1, "y":4}
`}`
`fn` `main``(``)`` ``{`
`solve_integer_problem_with_solver``(``CbcSolver``::`default`(``)``)`
`}`

#### Dependencies

~2–12MB

~117K SLoC