Expression 1, p15

Average Error: 0.4 → 0.3

Time: 12.8s

Precision: 64

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

Math

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

↓

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

C

double f(double a, double b, double c, double d, double e) {
        double r5357498 = e;
        double r5357499 = d;
        double r5357500 = r5357498 + r5357499;
        double r5357501 = c;
        double r5357502 = r5357500 + r5357501;
        double r5357503 = b;
        double r5357504 = r5357502 + r5357503;
        double r5357505 = a;
        double r5357506 = r5357504 + r5357505;
        return r5357506;
}

↓

double f(double a, double b, double c, double d, double e) {
        double r5357507 = b;
        double r5357508 = a;
        double r5357509 = r5357507 + r5357508;
        double r5357510 = c;
        double r5357511 = d;
        double r5357512 = e;
        double r5357513 = r5357511 + r5357512;
        double r5357514 = r5357510 + r5357513;
        double r5357515 = r5357509 + r5357514;
        return r5357515;
}

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	0.3

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

Derivation

1. Initial program 0.4

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

3. Applied associate-+l+ 0.3

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

4. Final simplification 0.3

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

Reproduce

herbie shell --seed 2019179 
(FPCore (a b c d e)
  :name "Expression 1, p15"
  :pre (<= 1.0 a 2.0 b 4.0 c 8.0 d 16.0 e 32.0)

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

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