/**
* This draws a random list of ruptures. Non-poisson sources are not yet implemented
*
* @return
*/
public ArrayList<ProbEqkRupture> drawRandomEqkRuptures() {
ArrayList<ProbEqkRupture> rupList = new ArrayList();
// System.out.println("New Rupture")
if (isPoissonian) {
for (int r = 0; r < getNumRuptures(); r++) {
ProbEqkRupture rup = getRupture(r);
// if(rup.getProbability() > 0.99)
// System.out.println("Problem!");
double expected = -Math.log(1 - rup.getProbability());
// double rand = 0.99;
double rand = Math.random();
double sum = 0;
double factoral = 1;
int maxNum = (int) Math.round(10 * expected) + 2;
int num;
for (num = 0; num < maxNum; num++) {
if (num != 0) factoral *= num;
double prob = Math.pow(expected, num) * Math.exp(-expected) / factoral;
sum += prob;
if (rand <= sum) break;
}
for (int i = 0; i < num; i++) rupList.add((ProbEqkRupture) rup.clone());
/*
* if(num >0) System.out.println("expected="+expected+"\t"+
* "rand="+rand+"\t"+ "num="+num+"\t"+ "mag="+rup.getMag());
*/
}
} else
throw new RuntimeException(
"drawRandomEqkRuptures(): Non poissonsources are not yet supported");
return rupList;
}
/**
* Get rupture probability within a region. It first checks whether the end points are within
* region. If yes, then rupture is considered within the region Else It finds the fraction of
* rupture FAULT TRACE (not the surface) points within the region and then adjusts the probability
* accordingly.
*
* @param tempRup
* @param region
* @return
*/
private double getApproxRupProbWithinRegion(ProbEqkRupture tempRup, Region region) {
int numLocsInside = 0;
int totPoints = 0;
if (region != null) {
// get num surface points inside region
EvenlyGriddedSurfaceAPI rupSurface = tempRup.getRuptureSurface();
Location loc1 = rupSurface.getLocation(0, 0);
Location loc2 = rupSurface.getLocation(0, rupSurface.getNumCols() - 1);
// if both surface points are within region, rupture is considered
// within region
if (region.contains(loc1) && region.contains(loc2)) {
numLocsInside = 1;
totPoints = numLocsInside;
} else { // if both points are not within region, calculate rupProb
Iterator locIt = rupSurface.getColumnIterator(0);
while (locIt.hasNext()) {
if (region.contains((Location) locIt.next())) ++numLocsInside;
++totPoints;
}
}
} else {
numLocsInside = 1;
totPoints = numLocsInside;
}
if (isPoissonian)
return Math.log(1 - tempRup.getProbability() * numLocsInside / (double) totPoints);
else return tempRup.getProbability() * numLocsInside / (double) totPoints;
}
/**
* This computes the total probability of all rutures great than or equal to the given mangitude
*
* @return
*/
public double computeTotalProbAbove(double mag, Region region) {
double totProb = 0;
ProbEqkRupture tempRup;
for (int i = 0; i < getNumRuptures(); i++) {
tempRup = getRupture(i);
if (tempRup.getMag() < mag) continue;
totProb += getRupProbWithinRegion(tempRup, region);
}
if (isPoissonian) return 1 - Math.exp(totProb);
else return totProb;
}
/**
* Get rupture probability within a region. It finds the fraction of rupture surface points within
* the region and then adjusts the probability accordingly.
*
* @param tempRup
* @param region
* @return
*/
private double getRupProbWithinRegion(ProbEqkRupture tempRup, Region region) {
int numLocsInside = 0;
int totPoints = 0;
if (region != null) {
// get num surface points inside region
Iterator locIt = tempRup.getRuptureSurface().getLocationsIterator();
while (locIt.hasNext()) {
if (region.contains((Location) locIt.next())) ++numLocsInside;
++totPoints;
}
} else {
numLocsInside = 1;
totPoints = numLocsInside;
}
if (isPoissonian)
return Math.log(1 - tempRup.getProbability() * numLocsInside / (double) totPoints);
else return tempRup.getProbability() * numLocsInside / (double) totPoints;
}
/**
* this function can be used if a clone is wanted instead of handle to class variable Subsequent
* calls to this function will not affect the result got previously. This is in contrast with the
* getRupture(int i) function
*
* @param nRupture
* @return the clone of the probEqkRupture
*/
public ProbEqkRupture getRuptureClone(int nRupture) {
ProbEqkRupture eqkRupture = getRupture(nRupture);
ProbEqkRupture eqkRuptureClone = (ProbEqkRupture) eqkRupture.clone();
return eqkRuptureClone;
}