This is equivalent to [MIGrad]MIGRAD, except that if [MIGrad]MIGRAD fails, it reverts to [SIMplex]SIMPLEX and then calls [MIGrad]MIGRAD again. This is what the old [MIGrad]MIGRAD command used to do, but it was removed from the [MIGrad]MIGRAD command so that users would have a choice, and because it is seldom of any use to call [SIMplex]SIMPLEX when [MIGrad]MIGRAD has failed (there are of course exceptions).