enable Tile.apply by non-1.0 amount similar to update
make optimizer use damp parameters, i.e. move tiles by non-1.0 amounts.
In a test, I noticed differences in convergence speed but no difference
in the end-result---this may differ in other tests.  I tested with values
< 1.0 and values > 1.0, both converged with mildly regularized linear
models.