private double calcTrimmedMean(PrimitiveDoubleArray vals, int halfTrim) {
final int trimSize = halfTrim * 2;
final int numElements = vals.size();
if (numElements <= trimSize)
throw new IllegalArgumentException(
"number of samples must be greater than number of trimmed values");
final int top = numElements - halfTrim;
double sum = 0;
for (int i = halfTrim; i < top; i++) {
sum += vals.get(i);
}
return sum / (numElements - trimSize);
}
/**
* Computes the median upon the current region of the current function. Note that this method uses
* memory to make a copy of the input values. Larger input regions might require a lot of memory.
*
* @return The measured value
*/
public double median() {
T tmp = func.createOutput();
values.clear();
iter.reset();
while (iter.hasNext()) {
long[] pos = iter.next();
func.compute(pos, tmp);
values.add(tmp.getRealDouble());
}
final int numElements = values.size();
if (numElements <= 0)
throw new IllegalArgumentException("number of samples must be greater than 0");
values.sortValues();
// odd number of elements
if ((numElements % 2) == 1) return values.get(numElements / 2);
// else an even number of elements
double value1 = values.get((numElements / 2) - 1);
double value2 = values.get((numElements / 2));
return (value1 + value2) / 2;
}