Background: Bertini is a general-purpose solver, written in C, that was created for research about polynomial continuation.

Cost: Bertini is distributed free of charge on an ``as is'' basis with no warranties, implied or otherwise, that it is suitable for any purpose. Its intended usage is educational, so that the user may gain a greater understanding of numerical homotopy continuation for solving systems of polynomial equations. Any other use is strictly the user's responsibility.

Key features:

Finds isolated solutions using total-degree start systems, multihomogeneous-degree start systems, and also user defined homotopies.

Implements parameter continuation for families of systems, such as the inverse kinematics of six-revolute serial-link arms, or the forward kinematics of Stewart-Gough parallel-link robots.

Adaptive multiprecision implemented for finding isolated solutions and for the numerical irreducible decomposition.

Treats positive-dimensional solutions by computing witness sets.

Has automatic differentiation which preserves the straightline quality of an input system.

Uses homogenization to accurately compute solutions "at infinity."

Provides endgames to accurately compute singular roots.

Allows for subfunctions.

Allows for witness set manipulation via both sampling and membership testing.

Accepts underdetermined, exactly determined, and overdetermined systems (i.e., the number of variables and equations do not have to be equal).