Changelog for math-programming

[0.4.0] -- 5 July 2020

Added

• The RealFrac constraint on LPMonad numeric types.

  This simplifies the constraints necessary in application code.

Removed

• The writeFormulation class method.

  This was impossible to implement correctly without requiring LPMonad to implement MonadIO, which should not be required in general.

[0.3.0] -- 18 June 2020

Initial release.