final int[] adds = new int[nParents];
while (tw.next()) {
final int myMode = tw.getRawMode(nParents);
for (int i = 0; i < nParents; i++) {
final int pMode = tw.getRawMode(i);
if (myMode == pMode && tw.idEqual(i, nParents))
continue;
chgs[i]++;
if (pMode == 0 && myMode != 0)
adds[i]++;