Average Error: 9.5 → 0.3
Time: 3.4s
Precision: binary64
\[\]
\[\]
double code(double x) {
	return ((double) (((double) (((double) (1.0 / ((double) (x + 1.0)))) - ((double) (2.0 / x)))) + ((double) (1.0 / ((double) (x - 1.0))))));
}
double code(double x) {
	double VAR;
	if (((x <= -838439.3309523697) || !(x <= 511.7848760495989))) {
		VAR = ((double) (((double) (2.0 / ((double) pow(x, 7.0)))) + ((double) (((double) (2.0 / ((double) pow(x, 5.0)))) + ((double) (2.0 / ((double) pow(x, 3.0))))))));
	} else {
		VAR = ((double) (((double) (((double) (((double) (x - 1.0)) * ((double) (((double) (x * 1.0)) - ((double) (2.0 * ((double) (x + 1.0)))))))) + ((double) (1.0 * ((double) (x * ((double) (x + 1.0)))))))) / ((double) (x * ((double) (((double) (x * x)) - ((double) (1.0 * 1.0))))))));
	}
	return VAR;
}

Error

Bits error versus x

Try it out

Your Program's Arguments

Results

Enter valid numbers for all inputs

Target

Original9.5
Target0.3
Herbie0.3
\[\]

Derivation

  1. Split input into 2 regimes
  2. if x < -838439.330952369724 or 511.78487604959889 < x

    1. Initial program 18.8

      \[\]
    2. Taylor expanded around inf 0.5

      \[\leadsto \]
    3. Simplified0.5

      \[\leadsto \]

    if -838439.330952369724 < x < 511.78487604959889

    1. Initial program 0.2

      \[\]
    2. Using strategy rm
    3. Applied frac-sub0.2

      \[\leadsto \]
    4. Applied frac-add0.0

      \[\leadsto \]
    5. Simplified0.0

      \[\leadsto \]
    6. Simplified0.0

      \[\leadsto \]
  3. Recombined 2 regimes into one program.
  4. Final simplification0.3

    \[\leadsto \]

Reproduce

herbie shell --seed 2020181 
(FPCore (x)
  :name "3frac (problem 3.3.3)"
  :precision binary64

  :herbie-target
  (/ 2.0 (* x (- (* x x) 1.0)))

  (+ (- (/ 1.0 (+ x 1.0)) (/ 2.0 x)) (/ 1.0 (- x 1.0))))