/**
* Chooses exactly one random element from successive blocks of <tt>weight</tt> input elements
* each. For example, if weight==2, and the input is 5*2=10 elements long, then chooses 5 random
* elements from the 10 elements such that one is chosen from the first block, one from the
* second, ..., one from the last block.
*
* @param acceptList a bitvector which will be filled with <tt>true</tt> where sampling shall
* occur and <tt>false</tt> where it shall not occur.
*/
private void xsampleNextElements(BooleanArrayList acceptList) {
// manually inlined
int length = acceptList.size();
boolean[] accept = acceptList.elements();
for (int i = 0; i < length; i++) {
if (skip > 0) { // reject
skip--;
accept[i] = false;
continue;
}
if (nextTriggerPos == UNDEFINED) {
if (weight == 1) nextTriggerPos = 0; // tuned for speed
else nextTriggerPos = generator.nextIntFromTo(0, weight - 1);
nextSkip = weight - 1 - nextTriggerPos;
}
if (nextTriggerPos > 0) { // reject
nextTriggerPos--;
accept[i] = false;
continue;
}
// accept
nextTriggerPos = UNDEFINED;
skip = nextSkip;
accept[i] = true;
}
}
/**
* Randomly permutes the part of the receiver between <code>from</code> (inclusive) and <code>to
* </code> (inclusive).
*
* @param from the index of the first element (inclusive) to be permuted.
* @param to the index of the last element (inclusive) to be permuted.
* @exception IndexOutOfBoundsException index is out of range (<tt>size()>0 && (from<0 ||
* from>to || to>=size())</tt>).
*/
public void shuffleFromTo(int from, int to) {
if (size == 0) return;
checkRangeFromTo(from, to, size);
org.ihtsdo.cern.jet.random.Uniform gen =
new org.ihtsdo.cern.jet.random.Uniform(
new org.ihtsdo.cern.jet.random.engine.DRand(new java.util.Date()));
Object tmpElement;
Object[] theElements = elements;
int random;
for (int i = from; i < to; i++) {
random = gen.nextIntFromTo(i, to);
// swap(i, random)
tmpElement = theElements[random];
theElements[random] = theElements[i];
theElements[i] = tmpElement;
}
}
/**
* Chooses exactly one random element from successive blocks of <tt>weight</tt> input elements
* each. For example, if weight==2, and the input is 5*2=10 elements long, then chooses 5 random
* elements from the 10 elements such that one is chosen from the first block, one from the
* second, ..., one from the last block.
*
* @return <tt>true</tt> if the next element shall be sampled (picked), <tt>false</tt> otherwise.
*/
public boolean sampleNextElement() {
if (skip > 0) { // reject
skip--;
return false;
}
if (nextTriggerPos == UNDEFINED) {
if (weight == 1) nextTriggerPos = 0; // tuned for speed
else nextTriggerPos = generator.nextIntFromTo(0, weight - 1);
nextSkip = weight - 1 - nextTriggerPos;
}
if (nextTriggerPos > 0) { // reject
nextTriggerPos--;
return false;
}
// accept
nextTriggerPos = UNDEFINED;
skip = nextSkip;
return true;
}
/**
* Returns a uniformly distributed random number in the closed interval <tt>[from,to]</tt>
* (including <tt>from</tt> and <tt>to</tt>). Pre conditions: <tt>from <= to</tt>.
*/
public static int staticNextIntFromTo(int from, int to) {
synchronized (shared) {
return shared.nextIntFromTo(from, to);
}
}