Data.Spline.Key:interpolateKeys from smoothie-0.4.0.2

Average Accuracy: 99.7% → 99.7%

Time: 9.6s

Precision: binary64

Cost: 832

Math

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

↓

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

FPCore

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

↓

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

C

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

↓

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

Fortran

real(8) function code(x)
    real(8), intent (in) :: x
    code = (x * x) * (3.0d0 - (x * 2.0d0))
end function

↓

real(8) function code(x)
    real(8), intent (in) :: x
    code = (x * (x * 3.0d0)) + ((x * x) * (x * (-2.0d0)))
end function

Java

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

↓

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

Python

def code(x):
	return (x * x) * (3.0 - (x * 2.0))

↓

def code(x):
	return (x * (x * 3.0)) + ((x * x) * (x * -2.0))

Julia

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

↓

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

MATLAB

function tmp = code(x)
	tmp = (x * x) * (3.0 - (x * 2.0));
end

↓

function tmp = code(x)
	tmp = (x * (x * 3.0)) + ((x * x) * (x * -2.0));
end

Wolfram

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

↓

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

Target

Original	99.7%
Target	99.7%
Herbie	99.7%

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

Derivation

1. Initial program 99.7%

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

2. Simplified 99.7%

   \[\leadsto \color{blue}{x \cdot \left(x \cdot \left(3 - x \cdot 2\right)\right)} \]
   Proof

   [Start] 99.7	\[ \left(x \cdot x\right) \cdot \left(3 - x \cdot 2\right) \]
   associate-*l* [=>] 99.7	\[ \color{blue}{x \cdot \left(x \cdot \left(3 - x \cdot 2\right)\right)} \]

3. Applied egg-rr 99.7%

   \[\leadsto \color{blue}{\left(x \cdot x\right) \cdot 3 + \left(x \cdot x\right) \cdot \left(x \cdot -2\right)} \]
   Proof

   [Start] 99.7	\[ x \cdot \left(x \cdot \left(3 - x \cdot 2\right)\right) \]
   associate-*r* [=>] 99.7	\[ \color{blue}{\left(x \cdot x\right) \cdot \left(3 - x \cdot 2\right)} \]
   sub-neg [=>] 99.7	\[ \left(x \cdot x\right) \cdot \color{blue}{\left(3 + \left(-x \cdot 2\right)\right)} \]
   distribute-lft-in [=>] 99.7	\[ \color{blue}{\left(x \cdot x\right) \cdot 3 + \left(x \cdot x\right) \cdot \left(-x \cdot 2\right)} \]
   distribute-rgt-neg-in [=>] 99.7	\[ \left(x \cdot x\right) \cdot 3 + \left(x \cdot x\right) \cdot \color{blue}{\left(x \cdot \left(-2\right)\right)} \]
   metadata-eval [=>] 99.7	\[ \left(x \cdot x\right) \cdot 3 + \left(x \cdot x\right) \cdot \left(x \cdot \color{blue}{-2}\right) \]

4. Applied egg-rr 99.7%

   \[\leadsto \color{blue}{\left(0 + x \cdot \left(x \cdot 3\right)\right)} + \left(x \cdot x\right) \cdot \left(x \cdot -2\right) \]
   Proof

   [Start] 99.7	\[ \left(x \cdot x\right) \cdot 3 + \left(x \cdot x\right) \cdot \left(x \cdot -2\right) \]
   add-log-exp [=>] 40.1	\[ \color{blue}{\log \left(e^{\left(x \cdot x\right) \cdot 3}\right)} + \left(x \cdot x\right) \cdot \left(x \cdot -2\right) \]
   *-un-lft-identity [=>] 40.1	\[ \log \color{blue}{\left(1 \cdot e^{\left(x \cdot x\right) \cdot 3}\right)} + \left(x \cdot x\right) \cdot \left(x \cdot -2\right) \]
   log-prod [=>] 40.1	\[ \color{blue}{\left(\log 1 + \log \left(e^{\left(x \cdot x\right) \cdot 3}\right)\right)} + \left(x \cdot x\right) \cdot \left(x \cdot -2\right) \]
   metadata-eval [=>] 40.1	\[ \left(\color{blue}{0} + \log \left(e^{\left(x \cdot x\right) \cdot 3}\right)\right) + \left(x \cdot x\right) \cdot \left(x \cdot -2\right) \]
   add-log-exp [<=] 99.7	\[ \left(0 + \color{blue}{\left(x \cdot x\right) \cdot 3}\right) + \left(x \cdot x\right) \cdot \left(x \cdot -2\right) \]
   associate-*l* [=>] 99.7	\[ \left(0 + \color{blue}{x \cdot \left(x \cdot 3\right)}\right) + \left(x \cdot x\right) \cdot \left(x \cdot -2\right) \]

5. Final simplification 99.7%

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

Alternatives

Alternative 1
Accuracy	96.7%
Cost	713

\[\begin{array}{l} \mathbf{if}\;x \leq -1.5 \lor \neg \left(x \leq 1.5\right):\\ \;\;\;\;x \cdot \left(x \cdot \left(x \cdot -2\right)\right)\\ \mathbf{else}:\\ \;\;\;\;x \cdot \left(x \cdot 3\right)\\ \end{array} \]

Alternative 2
Accuracy	99.7%
Cost	576

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

Alternative 3
Accuracy	74.0%
Cost	320

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

Alternative 4
Accuracy	74.0%
Cost	320

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

Alternative 5
Accuracy	4.7%
Cost	192

\[x \cdot 4.5 \]

Alternative 6
Accuracy	2.8%
Cost	64

\[-6.75 \]

Reproduce

herbie shell --seed 2023142 
(FPCore (x)
  :name "Data.Spline.Key:interpolateKeys from smoothie-0.4.0.2"
  :precision binary64

  :herbie-target
  (* x (* x (- 3.0 (* x 2.0))))

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