Average Error: 0.2 → 0.0
Time: 2.7s
Precision: binary64
\[\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
↓
\[\left({a}^{4} + \left(\left(b \cdot b\right) \cdot \left(4 + 2 \cdot \left(a \cdot a\right)\right) + {b}^{4}\right)\right) - 1 \]
\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(b \cdot b\right)\right) - 1
↓
\left({a}^{4} + \left(\left(b \cdot b\right) \cdot \left(4 + 2 \cdot \left(a \cdot a\right)\right) + {b}^{4}\right)\right) - 1

(FPCore (a b)
 :precision binary64
 (- (+ (pow (+ (* a a) (* b b)) 2.0) (* 4.0 (* b b))) 1.0))
↓
(FPCore (a b)
 :precision binary64
 (- (+ (pow a 4.0) (+ (* (* b b) (+ 4.0 (* 2.0 (* a a)))) (pow b 4.0))) 1.0))
double code(double a, double b) {
	return (pow(((a * a) + (b * b)), 2.0) + (4.0 * (b * b))) - 1.0;
}
↓
double code(double a, double b) {
	return (pow(a, 4.0) + (((b * b) * (4.0 + (2.0 * (a * a)))) + pow(b, 4.0))) - 1.0;
}

Error

Bits error versus a

Bits error versus b

Try it out

Your Program's Arguments

Results

Enter valid numbers for all inputs

Derivation

  1. Initial program 0.2

    \[\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(b \cdot b\right)\right) - 1 \]

  2. Taylor expanded around 0 0.0

    \[\leadsto \color{blue}{\left(4 \cdot {b}^{2} + \left(2 \cdot \left({a}^{2} \cdot {b}^{2}\right) + \left({b}^{4} + {a}^{4}\right)\right)\right)} - 1 \]

  3. Simplified0.1

    \[\leadsto \color{blue}{\left({a}^{4} + \left(b \cdot b\right) \cdot \left(b \cdot b + \left(4 + 2 \cdot \left(a \cdot a\right)\right)\right)\right)} - 1 \]

  4. Taylor expanded around 0 0.0

    \[\leadsto \left({a}^{4} + \color{blue}{\left(4 \cdot {b}^{2} + \left(2 \cdot \left({a}^{2} \cdot {b}^{2}\right) + {b}^{4}\right)\right)}\right) - 1 \]

  5. Simplified0.0

    \[\leadsto \left({a}^{4} + \color{blue}{\left(\left(b \cdot b\right) \cdot \left(2 \cdot \left(a \cdot a\right) + 4\right) + {b}^{4}\right)}\right) - 1 \]

  6. Final simplification0.0

    \[\leadsto \left({a}^{4} + \left(\left(b \cdot b\right) \cdot \left(4 + 2 \cdot \left(a \cdot a\right)\right) + {b}^{4}\right)\right) - 1 \]

Reproduce

herbie shell --seed 2021196 
(FPCore (a b)
  :name "Bouland and Aaronson, Equation (26)"
  :precision binary64
  (- (+ (pow (+ (* a a) (* b b)) 2.0) (* 4.0 (* b b))) 1.0))