dc.fit( AHat, MixtureDistribution.NNMMethod );
DoubleVector ATilde;
if( paceEstimator == pace6Estimator )
ATilde = dc.pace6( AHat );
else if( paceEstimator == pace2Estimator )
ATilde = dc.pace2( AHat );
else ATilde = dc.pace4( AHat );
aTilde = ATilde.sqrt().times( aHat.sign() );
break;
case olsEstimator:
aTilde = aHat.copy();