# 2. Features¶

## 2.1. Problems¶

This package supports two types of optimization problems:

Linear problems

\[\begin{split}\text{Maximize}~& c' x \\ \text{Subject to} & \\ A x &= b \\ x_l \leq x & \leq x_u\end{split}\]Quadratic problems

\[\begin{split}\text{Maximize}~& x' Q x + c' x \\ \text{Subject to} & \\ A x & = b \\ x_l \leq x & \leq x_u\end{split}\]

## 2.3. Variable types¶

This package supports five types of variables:

binary

integer

continuous

semi-integer

semi-continuous

partially-integer

## 2.5. Solvers¶

This package supports several solvers:

Open-source

Non-commercial with free academic licenses

SoPlex via soplex_cython

Commercial with free academic licenses

However, as described below, some of the solvers only support some of these features.

### 2.5.1. Objective types¶

Cbc: only supports linear objectives

GLPK: only supports linear objectives

quadprog: only supports quadratic objectives

### 2.5.2. Variable types¶

Cbc: only supports binary, integer, and continuous variables

CVXOPT: only supports continuous variables

FICO XPRESS: supports all variable types

GLPK: only supports binary, integer, and continuous variables

Gurobi: doesn’t support partially integer variables

IBM CPLEX: doesn’t support partially integer variables

MINOS: only supports continuous variables

MOSEK Optimizer: only supports binary, integer, and continuous variables

quadprog: only supports continuous variables

Scipy: only supports continuous variables

### 2.5.3. Constraint types¶

Cbc, GLPK, and quadprog only support linear constraints. Only SciPy’s COBLYA and SLSQP method support contraints.

### 2.5.4. Python versions¶

CPLEX supports Python 2.7, 3.5, and 3.6

### 2.5.5. Licensing¶

FICO XPRESS: licenses are tied to machines, or a license server must be used

Gurobi: licenses are tied to machines, or a license server must be used

IBM CPLEX: No license file or activation is needed

MINOS: free academic licenses can be obtained from Michael Saunders at Stanford

MOSEL Optimizer: license files can be used on multiple machines

SoPlex: free academic licenses can be automatically obtained from the SoPlex website