code: public SDVariable unsortedSegmentSqrtN(String name, SDVariable data, SDVariable segmentIds, int numSegments) {
          SDVariable ret = f().unsortedSegmentSqrtN(data, segmentIds, numSegments);
          return updateVariableNameAndReference(ret, name);
      }
docs: Unsorted segment sqrtN operation. Simply returns the sqrt of the count of the number of values in each segment<br>
  If data =     [1, 3, 2, 6, 4, 9, 8]<br>
  segmentIds =  [1, 0, 2, 0, 1, 1, 2]<br>
  then output = [1.414, 1.732, 1.414] = [sqrt(2), sqrtN(3), sqrtN(2)]<br>
  
  @param name       Name of the output variable
  @param data       Data (variable) to perform unsorted segment sqrtN on
  @param segmentIds Variable for the segment IDs
  @return Unsorted segment sqrtN output