Because the method above can lead to over-shooting on the step length
, it may lead to a blow-up problem. The Newton method requires a convex function, but for some field data sets that condition may not be met. To overcome this, we use trial and error to avoid step length
being too large. If the hyperbolic penalty function on new
is greater than on original
, the step length
is too large, and we overshoot; in that case, we reduce the step length
by half until the stability condition is met.