Maksimov and Kolovsky, Equation (4)

Average Error: 16.9 → 0.1

Time: 10.5s

Precision: binary64

Cost: 13504

Math

\[\left(J \cdot \left(e^{\ell} - e^{-\ell}\right)\right) \cdot \cos \left(\frac{K}{2}\right) + U \]

↓

\[J \cdot \left(\left(2 \cdot \sinh \ell\right) \cdot \cos \left(0.5 \cdot K\right)\right) + U \]

FPCore

(FPCore (J l K U)
 :precision binary64
 (+ (* (* J (- (exp l) (exp (- l)))) (cos (/ K 2.0))) U))

↓

(FPCore (J l K U)
 :precision binary64
 (+ (* J (* (* 2.0 (sinh l)) (cos (* 0.5 K)))) U))

C

double code(double J, double l, double K, double U) {
	return ((J * (exp(l) - exp(-l))) * cos((K / 2.0))) + U;
}

↓

double code(double J, double l, double K, double U) {
	return (J * ((2.0 * sinh(l)) * cos((0.5 * K)))) + U;
}

Fortran

real(8) function code(j, l, k, u)
    real(8), intent (in) :: j
    real(8), intent (in) :: l
    real(8), intent (in) :: k
    real(8), intent (in) :: u
    code = ((j * (exp(l) - exp(-l))) * cos((k / 2.0d0))) + u
end function

↓

real(8) function code(j, l, k, u)
    real(8), intent (in) :: j
    real(8), intent (in) :: l
    real(8), intent (in) :: k
    real(8), intent (in) :: u
    code = (j * ((2.0d0 * sinh(l)) * cos((0.5d0 * k)))) + u
end function

Java

public static double code(double J, double l, double K, double U) {
	return ((J * (Math.exp(l) - Math.exp(-l))) * Math.cos((K / 2.0))) + U;
}

↓

public static double code(double J, double l, double K, double U) {
	return (J * ((2.0 * Math.sinh(l)) * Math.cos((0.5 * K)))) + U;
}

Python

def code(J, l, K, U):
	return ((J * (math.exp(l) - math.exp(-l))) * math.cos((K / 2.0))) + U

↓

def code(J, l, K, U):
	return (J * ((2.0 * math.sinh(l)) * math.cos((0.5 * K)))) + U

Julia

function code(J, l, K, U)
	return Float64(Float64(Float64(J * Float64(exp(l) - exp(Float64(-l)))) * cos(Float64(K / 2.0))) + U)
end

↓

function code(J, l, K, U)
	return Float64(Float64(J * Float64(Float64(2.0 * sinh(l)) * cos(Float64(0.5 * K)))) + U)
end

MATLAB

function tmp = code(J, l, K, U)
	tmp = ((J * (exp(l) - exp(-l))) * cos((K / 2.0))) + U;
end

↓

function tmp = code(J, l, K, U)
	tmp = (J * ((2.0 * sinh(l)) * cos((0.5 * K)))) + U;
end

Wolfram

code[J_, l_, K_, U_] := N[(N[(N[(J * N[(N[Exp[l], $MachinePrecision] - N[Exp[(-l)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[Cos[N[(K / 2.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] + U), $MachinePrecision]

↓

code[J_, l_, K_, U_] := N[(N[(J * N[(N[(2.0 * N[Sinh[l], $MachinePrecision]), $MachinePrecision] * N[Cos[N[(0.5 * K), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + U), $MachinePrecision]

Derivation

1. Initial program 16.9

   \[\left(J \cdot \left(e^{\ell} - e^{-\ell}\right)\right) \cdot \cos \left(\frac{K}{2}\right) + U \]

2. Applied egg-rr 0.1

   \[\leadsto \color{blue}{{\left(J \cdot \left(\left(2 \cdot \sinh \ell\right) \cdot \cos \left(K \cdot 0.5\right)\right)\right)}^{1}} + U \]

3. Simplified 0.1

   \[\leadsto \color{blue}{J \cdot \left(\left(2 \cdot \sinh \ell\right) \cdot \cos \left(0.5 \cdot K\right)\right)} + U \]
   Proof
   (*.f64 J (*.f64 (*.f64 2 (sinh.f64 l)) (cos.f64 (*.f64 1/2 K)))): 0 points increase in error, 0 points decrease in error
   (*.f64 J (*.f64 (*.f64 2 (sinh.f64 l)) (cos.f64 (Rewrite<= *-commutative_binary64 (*.f64 K 1/2))))): 0 points increase in error, 0 points decrease in error
   (Rewrite<= unpow1_binary64 (pow.f64 (*.f64 J (*.f64 (*.f64 2 (sinh.f64 l)) (cos.f64 (*.f64 K 1/2)))) 1)): 0 points increase in error, 0 points decrease in error

4. Final simplification 0.1

   \[\leadsto J \cdot \left(\left(2 \cdot \sinh \ell\right) \cdot \cos \left(0.5 \cdot K\right)\right) + U \]

Alternatives

Alternative 1
Error	0.7
Cost	7104

\[U + J \cdot \left(\cos \left(0.5 \cdot K\right) \cdot \left(2 \cdot \ell\right)\right) \]

Alternative 2
Error	8.7
Cost	6848

\[U + J \cdot \left(2 \cdot \sinh \ell\right) \]

Alternative 3
Error	18.8
Cost	848

\[\begin{array}{l} t_0 := \ell \cdot \left(J \cdot 2\right)\\ \mathbf{if}\;U \leq -4.2 \cdot 10^{-122}:\\ \;\;\;\;U\\ \mathbf{elif}\;U \leq -1.8 \cdot 10^{-179}:\\ \;\;\;\;t_0\\ \mathbf{elif}\;U \leq -5.5 \cdot 10^{-260}:\\ \;\;\;\;U\\ \mathbf{elif}\;U \leq 10^{-249}:\\ \;\;\;\;t_0\\ \mathbf{else}:\\ \;\;\;\;U\\ \end{array} \]

Alternative 4
Error	8.9
Cost	448

\[U + J \cdot \left(\ell + \ell\right) \]

Alternative 5
Error	18.2
Cost	64

\[U \]

Reproduce

herbie shell --seed 2022325 
(FPCore (J l K U)
  :name "Maksimov and Kolovsky, Equation (4)"
  :precision binary64
  (+ (* (* J (- (exp l) (exp (- l)))) (cos (/ K 2.0))) U))