Average Error: 12.0 → 0.1
Time: 6.2s
Precision: binary64
Cost: 832
\[x - \frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t} \]
\[x + \frac{-2}{\frac{\frac{z}{y}}{0.5} - \frac{t}{z}} \]
(FPCore (x y z t)
 :precision binary64
 (- x (/ (* (* y 2.0) z) (- (* (* z 2.0) z) (* y t)))))
(FPCore (x y z t)
 :precision binary64
 (+ x (/ -2.0 (- (/ (/ z y) 0.5) (/ t z)))))
double code(double x, double y, double z, double t) {
	return x - (((y * 2.0) * z) / (((z * 2.0) * z) - (y * t)));
}
double code(double x, double y, double z, double t) {
	return x + (-2.0 / (((z / y) / 0.5) - (t / z)));
}
real(8) function code(x, y, z, t)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t
    code = x - (((y * 2.0d0) * z) / (((z * 2.0d0) * z) - (y * t)))
end function
real(8) function code(x, y, z, t)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t
    code = x + ((-2.0d0) / (((z / y) / 0.5d0) - (t / z)))
end function
public static double code(double x, double y, double z, double t) {
	return x - (((y * 2.0) * z) / (((z * 2.0) * z) - (y * t)));
}
public static double code(double x, double y, double z, double t) {
	return x + (-2.0 / (((z / y) / 0.5) - (t / z)));
}
def code(x, y, z, t):
	return x - (((y * 2.0) * z) / (((z * 2.0) * z) - (y * t)))
def code(x, y, z, t):
	return x + (-2.0 / (((z / y) / 0.5) - (t / z)))
function code(x, y, z, t)
	return Float64(x - Float64(Float64(Float64(y * 2.0) * z) / Float64(Float64(Float64(z * 2.0) * z) - Float64(y * t))))
end
function code(x, y, z, t)
	return Float64(x + Float64(-2.0 / Float64(Float64(Float64(z / y) / 0.5) - Float64(t / z))))
end
function tmp = code(x, y, z, t)
	tmp = x - (((y * 2.0) * z) / (((z * 2.0) * z) - (y * t)));
end
function tmp = code(x, y, z, t)
	tmp = x + (-2.0 / (((z / y) / 0.5) - (t / z)));
end
code[x_, y_, z_, t_] := N[(x - N[(N[(N[(y * 2.0), $MachinePrecision] * z), $MachinePrecision] / N[(N[(N[(z * 2.0), $MachinePrecision] * z), $MachinePrecision] - N[(y * t), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
code[x_, y_, z_, t_] := N[(x + N[(-2.0 / N[(N[(N[(z / y), $MachinePrecision] / 0.5), $MachinePrecision] - N[(t / z), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
x - \frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t}
x + \frac{-2}{\frac{\frac{z}{y}}{0.5} - \frac{t}{z}}

Error

Try it out

Your Program's Arguments

Results

Enter valid numbers for all inputs

Target

Original12.0
Target0.1
Herbie0.1
\[x - \frac{1}{\frac{z}{y} - \frac{\frac{t}{2}}{z}} \]

Derivation

  1. Initial program 12.0

    \[x - \frac{\left(y \cdot 2\right) \cdot z}{\left(z \cdot 2\right) \cdot z - y \cdot t} \]
  2. Simplified0.1

    \[\leadsto \color{blue}{x + \frac{-2}{\frac{\frac{z}{y}}{0.5} - \frac{t}{z}}} \]
    Proof
    (+.f64 x (/.f64 -2 (-.f64 (/.f64 (/.f64 z y) 1/2) (/.f64 t z)))): 0 points increase in error, 0 points decrease in error
    (+.f64 x (/.f64 (Rewrite<= metadata-eval (neg.f64 2)) (-.f64 (/.f64 (/.f64 z y) 1/2) (/.f64 t z)))): 0 points increase in error, 0 points decrease in error
    (+.f64 x (/.f64 (neg.f64 2) (-.f64 (/.f64 (/.f64 z y) (Rewrite<= metadata-eval (/.f64 1 2))) (/.f64 t z)))): 0 points increase in error, 0 points decrease in error
    (+.f64 x (/.f64 (neg.f64 2) (-.f64 (/.f64 (/.f64 z y) (/.f64 (Rewrite<= *-inverses_binary64 (/.f64 z z)) 2)) (/.f64 t z)))): 0 points increase in error, 0 points decrease in error
    (+.f64 x (/.f64 (neg.f64 2) (-.f64 (/.f64 (/.f64 z y) (Rewrite<= associate-/r*_binary64 (/.f64 z (*.f64 z 2)))) (/.f64 t z)))): 0 points increase in error, 0 points decrease in error
    (+.f64 x (/.f64 (neg.f64 2) (-.f64 (Rewrite<= associate-/r*_binary64 (/.f64 z (*.f64 y (/.f64 z (*.f64 z 2))))) (/.f64 t z)))): 0 points increase in error, 0 points decrease in error
    (+.f64 x (/.f64 (neg.f64 2) (-.f64 (Rewrite<= associate-/l/_binary64 (/.f64 (/.f64 z (/.f64 z (*.f64 z 2))) y)) (/.f64 t z)))): 0 points increase in error, 0 points decrease in error
    (+.f64 x (/.f64 (neg.f64 2) (-.f64 (/.f64 (Rewrite<= associate-/l*_binary64 (/.f64 (*.f64 z (*.f64 z 2)) z)) y) (/.f64 t z)))): 14 points increase in error, 0 points decrease in error
    (+.f64 x (/.f64 (neg.f64 2) (-.f64 (/.f64 (/.f64 (Rewrite<= *-commutative_binary64 (*.f64 (*.f64 z 2) z)) z) y) (/.f64 t z)))): 0 points increase in error, 0 points decrease in error
    (+.f64 x (/.f64 (neg.f64 2) (-.f64 (/.f64 (/.f64 (*.f64 (*.f64 z 2) z) z) y) (Rewrite<= *-lft-identity_binary64 (*.f64 1 (/.f64 t z)))))): 0 points increase in error, 0 points decrease in error
    (+.f64 x (/.f64 (neg.f64 2) (-.f64 (/.f64 (/.f64 (*.f64 (*.f64 z 2) z) z) y) (*.f64 (Rewrite<= *-inverses_binary64 (/.f64 y y)) (/.f64 t z))))): 0 points increase in error, 0 points decrease in error
    (+.f64 x (/.f64 (neg.f64 2) (-.f64 (/.f64 (/.f64 (*.f64 (*.f64 z 2) z) z) y) (Rewrite<= times-frac_binary64 (/.f64 (*.f64 y t) (*.f64 y z)))))): 26 points increase in error, 3 points decrease in error
    (+.f64 x (/.f64 (neg.f64 2) (-.f64 (/.f64 (/.f64 (*.f64 (*.f64 z 2) z) z) y) (Rewrite<= associate-/l/_binary64 (/.f64 (/.f64 (*.f64 y t) z) y))))): 5 points increase in error, 10 points decrease in error
    (+.f64 x (/.f64 (neg.f64 2) (Rewrite<= div-sub_binary64 (/.f64 (-.f64 (/.f64 (*.f64 (*.f64 z 2) z) z) (/.f64 (*.f64 y t) z)) y)))): 0 points increase in error, 0 points decrease in error
    (+.f64 x (/.f64 (neg.f64 2) (/.f64 (Rewrite<= div-sub_binary64 (/.f64 (-.f64 (*.f64 (*.f64 z 2) z) (*.f64 y t)) z)) y))): 0 points increase in error, 0 points decrease in error
    (+.f64 x (Rewrite<= distribute-neg-frac_binary64 (neg.f64 (/.f64 2 (/.f64 (/.f64 (-.f64 (*.f64 (*.f64 z 2) z) (*.f64 y t)) z) y))))): 0 points increase in error, 0 points decrease in error
    (+.f64 x (neg.f64 (Rewrite<= associate-/l*_binary64 (/.f64 (*.f64 2 y) (/.f64 (-.f64 (*.f64 (*.f64 z 2) z) (*.f64 y t)) z))))): 1 points increase in error, 12 points decrease in error
    (+.f64 x (neg.f64 (/.f64 (Rewrite<= *-commutative_binary64 (*.f64 y 2)) (/.f64 (-.f64 (*.f64 (*.f64 z 2) z) (*.f64 y t)) z)))): 0 points increase in error, 0 points decrease in error
    (+.f64 x (neg.f64 (Rewrite<= associate-/l*_binary64 (/.f64 (*.f64 (*.f64 y 2) z) (-.f64 (*.f64 (*.f64 z 2) z) (*.f64 y t)))))): 32 points increase in error, 9 points decrease in error
    (Rewrite<= sub-neg_binary64 (-.f64 x (/.f64 (*.f64 (*.f64 y 2) z) (-.f64 (*.f64 (*.f64 z 2) z) (*.f64 y t))))): 0 points increase in error, 0 points decrease in error
  3. Final simplification0.1

    \[\leadsto x + \frac{-2}{\frac{\frac{z}{y}}{0.5} - \frac{t}{z}} \]

Alternatives

Alternative 1
Error7.5
Cost712
\[\begin{array}{l} t_1 := x - \frac{y}{z}\\ \mathbf{if}\;z \leq -2.8 \cdot 10^{+60}:\\ \;\;\;\;t_1\\ \mathbf{elif}\;z \leq 5.5 \cdot 10^{-56}:\\ \;\;\;\;x + z \cdot \frac{2}{t}\\ \mathbf{else}:\\ \;\;\;\;t_1\\ \end{array} \]
Alternative 2
Error7.4
Cost712
\[\begin{array}{l} t_1 := x - \frac{y}{z}\\ \mathbf{if}\;z \leq -3 \cdot 10^{+60}:\\ \;\;\;\;t_1\\ \mathbf{elif}\;z \leq 4.5 \cdot 10^{-56}:\\ \;\;\;\;x + \frac{z \cdot 2}{t}\\ \mathbf{else}:\\ \;\;\;\;t_1\\ \end{array} \]
Alternative 3
Error11.7
Cost584
\[\begin{array}{l} t_1 := x - \frac{y}{z}\\ \mathbf{if}\;z \leq -1.25 \cdot 10^{-42}:\\ \;\;\;\;t_1\\ \mathbf{elif}\;z \leq 5.5 \cdot 10^{-56}:\\ \;\;\;\;x\\ \mathbf{else}:\\ \;\;\;\;t_1\\ \end{array} \]
Alternative 4
Error15.4
Cost520
\[\begin{array}{l} \mathbf{if}\;x \leq -5.1 \cdot 10^{-266}:\\ \;\;\;\;x\\ \mathbf{elif}\;x \leq 1.5 \cdot 10^{-214}:\\ \;\;\;\;\frac{-y}{z}\\ \mathbf{else}:\\ \;\;\;\;x\\ \end{array} \]
Alternative 5
Error15.8
Cost64
\[x \]

Error

Reproduce

herbie shell --seed 2022325 
(FPCore (x y z t)
  :name "Numeric.AD.Rank1.Halley:findZero from ad-4.2.4"
  :precision binary64

  :herbie-target
  (- x (/ 1.0 (- (/ z y) (/ (/ t 2.0) z))))

  (- x (/ (* (* y 2.0) z) (- (* (* z 2.0) z) (* y t)))))