Instances primeInsts = new Instances(insts, 0, numPrime);
/* for (int i = 0; i < numPrime; i++) {
primeInsts.add(insts.instance(i));
} */
primeInsts.compactify();
if (forecaster instanceof TSLagUser && artificialTimeStartValue >= 0) {
((TSLagUser)forecaster).getTSLagMaker().
setArtificialTimeStartValue(artificialTimeStartValue - 1 + numPrime);
}