Expression 1, p15

Average Error: 0.4 → 0.0

Time: 14.1s

Precision: 64

\[1 \le a \le 2 \le b \le 4 \le c \le 8 \le d \le 16 \le e \le 32\]

Math

\[\left(\left(\left(e + d\right) + c\right) + b\right) + a\]

↓

\[\log \left(e^{c} \cdot \left(\left(e^{b} \cdot e^{d}\right) \cdot \left(e^{a} \cdot e^{e}\right)\right)\right)\]

C

double f(double a, double b, double c, double d, double e) {
        double r10238725 = e;
        double r10238726 = d;
        double r10238727 = r10238725 + r10238726;
        double r10238728 = c;
        double r10238729 = r10238727 + r10238728;
        double r10238730 = b;
        double r10238731 = r10238729 + r10238730;
        double r10238732 = a;
        double r10238733 = r10238731 + r10238732;
        return r10238733;
}

↓

double f(double a, double b, double c, double d, double e) {
        double r10238734 = c;
        double r10238735 = exp(r10238734);
        double r10238736 = b;
        double r10238737 = exp(r10238736);
        double r10238738 = d;
        double r10238739 = exp(r10238738);
        double r10238740 = r10238737 * r10238739;
        double r10238741 = a;
        double r10238742 = exp(r10238741);
        double r10238743 = e;
        double r10238744 = exp(r10238743);
        double r10238745 = r10238742 * r10238744;
        double r10238746 = r10238740 * r10238745;
        double r10238747 = r10238735 * r10238746;
        double r10238748 = log(r10238747);
        return r10238748;
}

Error

Bits error versus a

Bits error versus b

Bits error versus c

Bits error versus d

Bits error versus e

Target

Original	0.4
Target	0.2
Herbie	0.0

\[\left(d + \left(c + \left(a + b\right)\right)\right) + e\]

Derivation

1. Initial program 0.4

   \[\left(\left(\left(e + d\right) + c\right) + b\right) + a\]
2. Using strategy rm

3. Applied add-log-exp 0.4

   \[\leadsto \left(\left(\left(e + d\right) + c\right) + b\right) + \color{blue}{\log \left(e^{a}\right)}\]

4. Applied add-log-exp 0.4

   \[\leadsto \left(\left(\left(e + d\right) + c\right) + \color{blue}{\log \left(e^{b}\right)}\right) + \log \left(e^{a}\right)\]

5. Applied add-log-exp 0.4

   \[\leadsto \left(\left(\left(e + d\right) + \color{blue}{\log \left(e^{c}\right)}\right) + \log \left(e^{b}\right)\right) + \log \left(e^{a}\right)\]

6. Applied add-log-exp 0.4

   \[\leadsto \left(\left(\left(e + \color{blue}{\log \left(e^{d}\right)}\right) + \log \left(e^{c}\right)\right) + \log \left(e^{b}\right)\right) + \log \left(e^{a}\right)\]

7. Applied add-log-exp 0.4

   \[\leadsto \left(\left(\left(\color{blue}{\log \left(e^{e}\right)} + \log \left(e^{d}\right)\right) + \log \left(e^{c}\right)\right) + \log \left(e^{b}\right)\right) + \log \left(e^{a}\right)\]

8. Applied sum-log 0.4

   \[\leadsto \left(\left(\color{blue}{\log \left(e^{e} \cdot e^{d}\right)} + \log \left(e^{c}\right)\right) + \log \left(e^{b}\right)\right) + \log \left(e^{a}\right)\]

9. Applied sum-log 0.3

   \[\leadsto \left(\color{blue}{\log \left(\left(e^{e} \cdot e^{d}\right) \cdot e^{c}\right)} + \log \left(e^{b}\right)\right) + \log \left(e^{a}\right)\]

10. Applied sum-log 0.3

    \[\leadsto \color{blue}{\log \left(\left(\left(e^{e} \cdot e^{d}\right) \cdot e^{c}\right) \cdot e^{b}\right)} + \log \left(e^{a}\right)\]

11. Applied sum-log 0.0

    \[\leadsto \color{blue}{\log \left(\left(\left(\left(e^{e} \cdot e^{d}\right) \cdot e^{c}\right) \cdot e^{b}\right) \cdot e^{a}\right)}\]

12. Simplified 0.3

    \[\leadsto \log \color{blue}{\left(e^{c + \left(\left(a + e\right) + \left(b + d\right)\right)}\right)}\]
13. Using strategy rm

14. Applied add-log-exp 0.3

    \[\leadsto \log \left(e^{c + \left(\left(a + e\right) + \left(b + \color{blue}{\log \left(e^{d}\right)}\right)\right)}\right)\]

15. Applied add-log-exp 0.3

    \[\leadsto \log \left(e^{c + \left(\left(a + e\right) + \left(\color{blue}{\log \left(e^{b}\right)} + \log \left(e^{d}\right)\right)\right)}\right)\]

16. Applied sum-log 0.3

    \[\leadsto \log \left(e^{c + \left(\left(a + e\right) + \color{blue}{\log \left(e^{b} \cdot e^{d}\right)}\right)}\right)\]

17. Applied add-log-exp 0.3

    \[\leadsto \log \left(e^{c + \left(\left(a + \color{blue}{\log \left(e^{e}\right)}\right) + \log \left(e^{b} \cdot e^{d}\right)\right)}\right)\]

18. Applied add-log-exp 0.3

    \[\leadsto \log \left(e^{c + \left(\left(\color{blue}{\log \left(e^{a}\right)} + \log \left(e^{e}\right)\right) + \log \left(e^{b} \cdot e^{d}\right)\right)}\right)\]

19. Applied sum-log 0.3

    \[\leadsto \log \left(e^{c + \left(\color{blue}{\log \left(e^{a} \cdot e^{e}\right)} + \log \left(e^{b} \cdot e^{d}\right)\right)}\right)\]

20. Applied sum-log 0.2

    \[\leadsto \log \left(e^{c + \color{blue}{\log \left(\left(e^{a} \cdot e^{e}\right) \cdot \left(e^{b} \cdot e^{d}\right)\right)}}\right)\]

21. Applied add-log-exp 0.2

    \[\leadsto \log \left(e^{\color{blue}{\log \left(e^{c}\right)} + \log \left(\left(e^{a} \cdot e^{e}\right) \cdot \left(e^{b} \cdot e^{d}\right)\right)}\right)\]

22. Applied sum-log 0.0

    \[\leadsto \log \left(e^{\color{blue}{\log \left(e^{c} \cdot \left(\left(e^{a} \cdot e^{e}\right) \cdot \left(e^{b} \cdot e^{d}\right)\right)\right)}}\right)\]

23. Applied rem-exp-log 0.0

    \[\leadsto \log \color{blue}{\left(e^{c} \cdot \left(\left(e^{a} \cdot e^{e}\right) \cdot \left(e^{b} \cdot e^{d}\right)\right)\right)}\]

24. Final simplification 0.0

    \[\leadsto \log \left(e^{c} \cdot \left(\left(e^{b} \cdot e^{d}\right) \cdot \left(e^{a} \cdot e^{e}\right)\right)\right)\]

Reproduce

herbie shell --seed 2019158 
(FPCore (a b c d e)
  :name "Expression 1, p15"
  :pre (<= 1 a 2 b 4 c 8 d 16 e 32)

  :herbie-target
  (+ (+ d (+ c (+ a b))) e)

  (+ (+ (+ (+ e d) c) b) a))