The grid search method simply determine the WSS at each point on the grid of parameter values. It may offer some protection against local minima but it is not very efficient. As more parameters are included in the model the number of determinations can be excessive. With three parameters and 10 points per grid, 10 x 10 x 10 determinations are required.
Example Grid Search Result
Using Boomer (Mac OS X version) and gnuplot the following grid search movie can be prepared.