Cannot sample enough valid points. (more)

\[\sqrt{y - 1} - \sqrt{z - 1}\]
\sqrt{y - 1} - \sqrt{z - 1}
double code(double y, double z) {
	return ((double) (((double) sqrt(((double) (y - 1.0)))) - ((double) sqrt(((double) (z - 1.0))))));
}

Reproduce

herbie shell --seed 2020152 
(FPCore (y z)
  :name "(- (sqrt (- y 1)) (sqrt (- z 1)))"
  :precision binary64
  (- (sqrt (- y 1.0)) (sqrt (- z 1.0))))