public void stepUntil(final StoppingCriterion stoppingCriterion) throws IOException {
super.stepUntil(stoppingCriterion);
for (int i = 0; i < order.length; i++) {
if (iterationNumber < order[i] / (1 - alpha))
LOGGER.info(
"Error bound for derivative of order " + order[i] + " (alpha=" + alpha + "): unknown");
else {
final int k = order[i];
final double delta = alpha * iterationNumber / (iterationNumber + k);
final double alphak = Math.pow(alpha, k);
final double nFallingK = Util.falling(iterationNumber, k);
double infinityNorm = 0;
for (int j = 0; j < numNodes; j++)
infinityNorm = Math.max(infinityNorm, nFallingK * (rank[j] - previousRank[j]) / alphak);
LOGGER.info(
"Error bound for derivative of order "
+ k
+ " (alpha="
+ alpha
+ "): "
+ infinityNorm * delta / (1 - delta));
}
}
}
public void init() throws IOException {
super.init();
if (start != null && (coeffBasename != null || order.length > 0))
throw new IllegalArgumentException(
"You cannot choose a preference vector when computing coefficients or derivatives");
// Creates the arrays, if necessary
if (previousRank == null) previousRank = new double[numNodes];
derivative = new double[order.length][subset != null ? subset.length : g.numNodes()];
if (IntArrayList.wrap(order).indexOf(0) != -1)
throw new IllegalArgumentException(
"You cannot compute the derivative of order 0 (use PageRank instead)");
if (coeffBasename != null) BinIO.storeDoubles(rank, coeffBasename + "-" + 0);
logger.info("Completed.");
}
public void clear() {
super.clear();
previousRank = null;
}