  A well-known combinatorial algorithm can decide generic rigidity in the plane
by determining if the graph is of Pollaczek-Geiringer-Laman type. Methods from
matroid theory have been used to prove other interesting results, again under
the assumption of generic configurations. However, configurations arising in
applications may not be generic. We present Theorem 5 and its corresponding
Algorithm 1 which decide if a configuration is epsilon-locally rigid, a notion
we define. A configuration which is epsilon-locally rigid may be locally rigid
or flexible, but any continuous deformations remain within a sphere of radius
epsilon in configuration space. Deciding epsilon-local rigidity is possible for
configurations which are smooth or singular, generic or non-generic. We also
present Algorithms 2 and 3 which use numerical algebraic geometry to compute a
discrete-time sample of a continuous flex, providing useful visual information
for the scientist.
