Diagrams.Tangent:$catParam from diagrams-lib-1.3.0.3, E

Average Error: 0.2 → 0.1

Time: 7.7s

Precision: binary64

Cost: 6848

Math

\[\left(3 \cdot \left(2 - x \cdot 3\right)\right) \cdot x \]

↓

\[\mathsf{fma}\left(x, 6, -9 \cdot \left(x \cdot x\right)\right) \]

FPCore

(FPCore (x) :precision binary64 (* (* 3.0 (- 2.0 (* x 3.0))) x))

↓

(FPCore (x) :precision binary64 (fma x 6.0 (* -9.0 (* x x))))

C

double code(double x) {
	return (3.0 * (2.0 - (x * 3.0))) * x;
}

↓

double code(double x) {
	return fma(x, 6.0, (-9.0 * (x * x)));
}

Julia

function code(x)
	return Float64(Float64(3.0 * Float64(2.0 - Float64(x * 3.0))) * x)
end

↓

function code(x)
	return fma(x, 6.0, Float64(-9.0 * Float64(x * x)))
end

Wolfram

code[x_] := N[(N[(3.0 * N[(2.0 - N[(x * 3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * x), $MachinePrecision]

↓

code[x_] := N[(x * 6.0 + N[(-9.0 * N[(x * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]

Target

Original	0.2
Target	0.2
Herbie	0.1

\[6 \cdot x - 9 \cdot \left(x \cdot x\right) \]

Derivation

1. Initial program 0.2

   \[\left(3 \cdot \left(2 - x \cdot 3\right)\right) \cdot x \]

2. Taylor expanded in x around 0 0.2

   \[\leadsto \color{blue}{6 \cdot x + -9 \cdot {x}^{2}} \]

3. Applied egg-rr 0.1

   \[\leadsto \color{blue}{\mathsf{fma}\left(x, 6, -9 \cdot \left(x \cdot x\right)\right)} \]

4. Final simplification 0.1

   \[\leadsto \mathsf{fma}\left(x, 6, -9 \cdot \left(x \cdot x\right)\right) \]

Alternatives

Alternative 1
Error	1.9
Cost	584

\[\begin{array}{l} t_0 := -9 \cdot \left(x \cdot x\right)\\ \mathbf{if}\;x \leq -7.202409520586058:\\ \;\;\;\;t_0\\ \mathbf{elif}\;x \leq 0.06185657187349748:\\ \;\;\;\;x \cdot 6\\ \mathbf{else}:\\ \;\;\;\;t_0\\ \end{array} \]

Alternative 2
Error	1.9
Cost	584

\[\begin{array}{l} t_0 := x \cdot \left(x \cdot -9\right)\\ \mathbf{if}\;x \leq -7.202409520586058:\\ \;\;\;\;t_0\\ \mathbf{elif}\;x \leq 0.06185657187349748:\\ \;\;\;\;x \cdot 6\\ \mathbf{else}:\\ \;\;\;\;t_0\\ \end{array} \]

Alternative 3
Error	0.2
Cost	448

\[x \cdot \left(6 + x \cdot -9\right) \]

Alternative 4
Error	21.4
Cost	192

\[x \cdot 6 \]

Reproduce

herbie shell --seed 2022316 
(FPCore (x)
  :name "Diagrams.Tangent:$catParam from diagrams-lib-1.3.0.3, E"
  :precision binary64

  :herbie-target
  (- (* 6.0 x) (* 9.0 (* x x)))

  (* (* 3.0 (- 2.0 (* x 3.0))) x))