if (xi == null) {
throw new IOException(String.format("unable to load mean path xi from %s.",
pcaMeanPath.toString()));
}
xisquaredlen = xi.dot(xi);
Omega omega = new Omega(seed, k + p);
Vector s_b0 = omega.mutlithreadedTRightMultiply(xi);
SSVDHelper.saveVector(s_b0, sbPath =
new Path(pcaBasePath, "somega.seq"), conf);