v1.0.0

General changes

• Rewrote the MIPModel. It should now be faster, more maintainable,
  more stable and it has fewer bugs.
• Added sum_over, a replacement for sum_expr in the MIPModel
• set_bounds for MIPModel now accepts (in)equalities as well (#365)
• MIPModel now supports characters as variable indexes
• A solution object has a new named entry called additional_solver_output.
  In that place solver packages, like ompr.roi can store arbitrary solver
  information. Including solver specific messages and status codes. It should
  be read using the function additional_solver_output().
• A solution can now have the solver_status = "success" which is used
  by the most recent ompr.roi version.

Bugfixes

• Fixed a bug where using the index "e" in sum_expr failed (#327)
• Fixed a bug where coefficients that came after the variable in the
  expression would sometimes not be correctly parsed (#265)
• Fixed a bug where add_variable failed if indexes were in the wrong order
  (#266)

Deprecations

All listed functions will likely be removed at some later point the future.

• sum_expr shall not be used anymore. Please use sum_over instead.
• MIPLModel will likely be removed from the package, as the vectorized
  approach did lead to some problems. Please use MIPModel instead.
• add_variable_, add_constraint_, set_objective_, set_bounds and
  get_solution_ are not needed anymore with the new MIPModel as it is
  powered by rlang.
• The .show_progress_bar parameter is now deprecated in all functions.

Licensing

• ompr is now licensed under the MIT license (#353).

Breaking Changes

• extract_constraints now always returns a sparse matrix, even if there are 0
  constraints or variables.
• The row ordering of the data.frame returned with get_solution(x[i, j]) has
  slightly changed in special cases, but for the majority of calls, it
  should stay the same. One of these special cases is if you created your
  variable similar to add_variable(model, x[i, j], j = ..., i = ...), where
  the indexes in the variable and the quantifiers have different orderings.
  In general, please do not depend on the ordering of the rows, but use the
  indexes to retrieve the correct value. For example by sorting the data.frame
  , before reading.