Turns on/off several heuristics that are used to determine if
nonlinear solution will probably not converge in a reasonable number
of steps. These heuristics are a sufficient reduction condition
(i.e. after 10 steps the residual reduces by at least 0.5% on each
subsequent step) and a cap on the growth in the residual (i.e. the
residual does not grow more than a factor of 
between any
two steps).
Regardless of whether or not these tests are turned on, the residual is checked for obvious nonconvergence indicators (i.e. IEEE NaN and infinity) on hardware that supports it.