Average Error: 61.8 → 0.3
Time: 18.8s
Precision: 64
\[0.9 \le t \le 1.1\]
\[\left(1 + t \cdot 2 \cdot 10^{-16}\right) \cdot \left(1 + t \cdot 2 \cdot 10^{-16}\right) + \left(-1 - 2 \cdot \left(t \cdot 2 \cdot 10^{-16}\right)\right)\]
↓
\[\left(2 \cdot 10^{-16} \cdot \left(2 \cdot 10^{-16} \cdot t\right)\right) \cdot t\]
\left(1 + t \cdot 2 \cdot 10^{-16}\right) \cdot \left(1 + t \cdot 2 \cdot 10^{-16}\right) + \left(-1 - 2 \cdot \left(t \cdot 2 \cdot 10^{-16}\right)\right)
↓
\left(2 \cdot 10^{-16} \cdot \left(2 \cdot 10^{-16} \cdot t\right)\right) \cdot t
double f(double t) {
        double r1486335 = 1.0;
        double r1486336 = t;
        double r1486337 = 2e-16;
        double r1486338 = r1486336 * r1486337;
        double r1486339 = r1486335 + r1486338;
        double r1486340 = r1486339 * r1486339;
        double r1486341 = -1.0;
        double r1486342 = 2.0;
        double r1486343 = r1486342 * r1486338;
        double r1486344 = r1486341 - r1486343;
        double r1486345 = r1486340 + r1486344;
        return r1486345;
}
↓
double f(double t) {
        double r1486346 = 2e-16;
        double r1486347 = t;
        double r1486348 = r1486346 * r1486347;
        double r1486349 = r1486346 * r1486348;
        double r1486350 = r1486349 * r1486347;
        return r1486350;
}

Error

Bits error versus t

Try it out

Your Program's Arguments

Results

Enter valid numbers for all inputs

Target

Original61.8
Target50.6
Herbie0.3
\[\mathsf{fma}\left(\left(1 + t \cdot 2 \cdot 10^{-16}\right), \left(1 + t \cdot 2 \cdot 10^{-16}\right), \left(-1 - 2 \cdot \left(t \cdot 2 \cdot 10^{-16}\right)\right)\right)\]

Derivation

  1. Initial program 61.8

    \[\left(1 + t \cdot 2 \cdot 10^{-16}\right) \cdot \left(1 + t \cdot 2 \cdot 10^{-16}\right) + \left(-1 - 2 \cdot \left(t \cdot 2 \cdot 10^{-16}\right)\right)\]

  2. Simplified0.4

    \[\leadsto \color{blue}{\left(2 \cdot 10^{-16} \cdot t\right) \cdot \left(2 \cdot 10^{-16} \cdot t\right)}\]
  3. Using strategy rm

  4. Applied associate-*r*0.3

    \[\leadsto \color{blue}{\left(\left(2 \cdot 10^{-16} \cdot t\right) \cdot 2 \cdot 10^{-16}\right) \cdot t}\]

  5. Final simplification0.3

    \[\leadsto \left(2 \cdot 10^{-16} \cdot \left(2 \cdot 10^{-16} \cdot t\right)\right) \cdot t\]

Reproduce

herbie shell --seed 2019132 +o rules:numerics
(FPCore (t)
  :name "fma_test1"
  :pre (<= 0.9 t 1.1)

  :herbie-target
  (fma (+ 1 (* t 2e-16)) (+ 1 (* t 2e-16)) (- -1 (* 2 (* t 2e-16))))

  (+ (* (+ 1 (* t 2e-16)) (+ 1 (* t 2e-16))) (- -1 (* 2 (* t 2e-16)))))