clj-linear

A nice clojure api for doing linear programming. It uses Apache Commons Math under the covers.

Usage

Put this in your lein depenencies:

[clj-linear "0.1.0-notyet"]

Then add this to your requires:

  [clj-linear.core :as lp]

Then you can use it like this:

(lp/minimize
  (lp/expression (+ (* -2 :x) :y -5))
  (lp/constraints 
    (<= (+ :x (* 2 :y)) 6)
    (<= (+ (* 3 :x) (* 2 :y)) 12)
    (>= :y 0)))

;; => {:x 4.0, :y 0.0}

Details

clj-linear uses two kinds of data under the covers.

Expressions

An linear expression is a map of variables to coefficients. You can make it by hand, or with the expression macro. clj-linear.expressions has some useful code for manipulating linear expressions in this form.

Constraints

Constraint equations are maps of the form {:op :lhs :rhs}, where :op is one of :=, :>=, or :<=. :lhs and :rhs are both linear expressions as described above. These are most easily created with the constraint and constraints macros, but may be manipulated by hand as well. NB: the macros will automatically normalize your constraints to put all the variables on the left-hand side and the constant on the right. The input to the minimize function must be in this form.

Tips

You can you anything that's not a number or map as the variable in your linear systems. In particular, it's useful build up a system using vectors as variables and later merge the results into your own data using assoc-in .

License

Copyright © 2013 Russell Mull

Distributed under the Eclipse Public License, the same as Clojure.