
(FPCore (x) :precision binary64 (- (/ 1.0 (sqrt x)) (/ 1.0 (sqrt (+ x 1.0)))))
double code(double x) {
return (1.0 / sqrt(x)) - (1.0 / sqrt((x + 1.0)));
}
real(8) function code(x)
real(8), intent (in) :: x
code = (1.0d0 / sqrt(x)) - (1.0d0 / sqrt((x + 1.0d0)))
end function
public static double code(double x) {
return (1.0 / Math.sqrt(x)) - (1.0 / Math.sqrt((x + 1.0)));
}
def code(x): return (1.0 / math.sqrt(x)) - (1.0 / math.sqrt((x + 1.0)))
function code(x) return Float64(Float64(1.0 / sqrt(x)) - Float64(1.0 / sqrt(Float64(x + 1.0)))) end
function tmp = code(x) tmp = (1.0 / sqrt(x)) - (1.0 / sqrt((x + 1.0))); end
code[x_] := N[(N[(1.0 / N[Sqrt[x], $MachinePrecision]), $MachinePrecision] - N[(1.0 / N[Sqrt[N[(x + 1.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{1}{\sqrt{x}} - \frac{1}{\sqrt{x + 1}}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 10 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (x) :precision binary64 (- (/ 1.0 (sqrt x)) (/ 1.0 (sqrt (+ x 1.0)))))
double code(double x) {
return (1.0 / sqrt(x)) - (1.0 / sqrt((x + 1.0)));
}
real(8) function code(x)
real(8), intent (in) :: x
code = (1.0d0 / sqrt(x)) - (1.0d0 / sqrt((x + 1.0d0)))
end function
public static double code(double x) {
return (1.0 / Math.sqrt(x)) - (1.0 / Math.sqrt((x + 1.0)));
}
def code(x): return (1.0 / math.sqrt(x)) - (1.0 / math.sqrt((x + 1.0)))
function code(x) return Float64(Float64(1.0 / sqrt(x)) - Float64(1.0 / sqrt(Float64(x + 1.0)))) end
function tmp = code(x) tmp = (1.0 / sqrt(x)) - (1.0 / sqrt((x + 1.0))); end
code[x_] := N[(N[(1.0 / N[Sqrt[x], $MachinePrecision]), $MachinePrecision] - N[(1.0 / N[Sqrt[N[(x + 1.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{1}{\sqrt{x}} - \frac{1}{\sqrt{x + 1}}
\end{array}
(FPCore (x) :precision binary64 (/ (pow (+ 1.0 x) -0.5) (* x (+ 2.0 (/ (+ 0.5 (/ (+ -0.125 (/ 0.0625 x)) x)) x)))))
double code(double x) {
return pow((1.0 + x), -0.5) / (x * (2.0 + ((0.5 + ((-0.125 + (0.0625 / x)) / x)) / x)));
}
real(8) function code(x)
real(8), intent (in) :: x
code = ((1.0d0 + x) ** (-0.5d0)) / (x * (2.0d0 + ((0.5d0 + (((-0.125d0) + (0.0625d0 / x)) / x)) / x)))
end function
public static double code(double x) {
return Math.pow((1.0 + x), -0.5) / (x * (2.0 + ((0.5 + ((-0.125 + (0.0625 / x)) / x)) / x)));
}
def code(x): return math.pow((1.0 + x), -0.5) / (x * (2.0 + ((0.5 + ((-0.125 + (0.0625 / x)) / x)) / x)))
function code(x) return Float64((Float64(1.0 + x) ^ -0.5) / Float64(x * Float64(2.0 + Float64(Float64(0.5 + Float64(Float64(-0.125 + Float64(0.0625 / x)) / x)) / x)))) end
function tmp = code(x) tmp = ((1.0 + x) ^ -0.5) / (x * (2.0 + ((0.5 + ((-0.125 + (0.0625 / x)) / x)) / x))); end
code[x_] := N[(N[Power[N[(1.0 + x), $MachinePrecision], -0.5], $MachinePrecision] / N[(x * N[(2.0 + N[(N[(0.5 + N[(N[(-0.125 + N[(0.0625 / x), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{{\left(1 + x\right)}^{-0.5}}{x \cdot \left(2 + \frac{0.5 + \frac{-0.125 + \frac{0.0625}{x}}{x}}{x}\right)}
\end{array}
Initial program 37.0%
Applied egg-rr39.2%
associate-/l/N/A
associate--l+N/A
+-inversesN/A
metadata-evalN/A
associate-/r*N/A
pow-flipN/A
metadata-evalN/A
/-lowering-/.f64N/A
pow-lowering-pow.f64N/A
+-lowering-+.f64N/A
+-lowering-+.f64N/A
sqrt-lowering-sqrt.f64N/A
*-lowering-*.f64N/A
+-lowering-+.f6481.6%
Applied egg-rr81.6%
Taylor expanded in x around inf
*-lowering-*.f64N/A
associate-+r+N/A
associate--l+N/A
associate-*r/N/A
metadata-evalN/A
unpow3N/A
unpow2N/A
associate-/r*N/A
unpow2N/A
associate-/r*N/A
metadata-evalN/A
associate-*r/N/A
div-subN/A
Simplified99.0%
*-commutativeN/A
*-lowering-*.f64N/A
associate-+l+N/A
+-lowering-+.f64N/A
div-invN/A
div-invN/A
distribute-rgt-outN/A
*-commutativeN/A
un-div-invN/A
/-lowering-/.f64N/A
+-lowering-+.f64N/A
/-lowering-/.f64N/A
+-lowering-+.f64N/A
/-lowering-/.f6499.0%
Applied egg-rr99.0%
Final simplification99.0%
(FPCore (x) :precision binary64 (/ (pow (+ 1.0 x) -0.5) (* x (+ 2.0 (/ (+ 0.5 (/ -0.125 x)) x)))))
double code(double x) {
return pow((1.0 + x), -0.5) / (x * (2.0 + ((0.5 + (-0.125 / x)) / x)));
}
real(8) function code(x)
real(8), intent (in) :: x
code = ((1.0d0 + x) ** (-0.5d0)) / (x * (2.0d0 + ((0.5d0 + ((-0.125d0) / x)) / x)))
end function
public static double code(double x) {
return Math.pow((1.0 + x), -0.5) / (x * (2.0 + ((0.5 + (-0.125 / x)) / x)));
}
def code(x): return math.pow((1.0 + x), -0.5) / (x * (2.0 + ((0.5 + (-0.125 / x)) / x)))
function code(x) return Float64((Float64(1.0 + x) ^ -0.5) / Float64(x * Float64(2.0 + Float64(Float64(0.5 + Float64(-0.125 / x)) / x)))) end
function tmp = code(x) tmp = ((1.0 + x) ^ -0.5) / (x * (2.0 + ((0.5 + (-0.125 / x)) / x))); end
code[x_] := N[(N[Power[N[(1.0 + x), $MachinePrecision], -0.5], $MachinePrecision] / N[(x * N[(2.0 + N[(N[(0.5 + N[(-0.125 / x), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{{\left(1 + x\right)}^{-0.5}}{x \cdot \left(2 + \frac{0.5 + \frac{-0.125}{x}}{x}\right)}
\end{array}
Initial program 37.0%
Applied egg-rr39.2%
associate-/l/N/A
associate--l+N/A
+-inversesN/A
metadata-evalN/A
associate-/r*N/A
pow-flipN/A
metadata-evalN/A
/-lowering-/.f64N/A
pow-lowering-pow.f64N/A
+-lowering-+.f64N/A
+-lowering-+.f64N/A
sqrt-lowering-sqrt.f64N/A
*-lowering-*.f64N/A
+-lowering-+.f6481.6%
Applied egg-rr81.6%
Taylor expanded in x around inf
*-lowering-*.f64N/A
associate--l+N/A
unpow2N/A
associate-/r*N/A
metadata-evalN/A
associate-*r/N/A
associate-*r/N/A
metadata-evalN/A
div-subN/A
*-commutativeN/A
cancel-sign-sub-invN/A
distribute-neg-frac2N/A
mul-1-negN/A
rem-square-sqrtN/A
unpow2N/A
*-commutativeN/A
*-commutativeN/A
Simplified98.9%
(FPCore (x) :precision binary64 (/ (/ (+ 0.5 (/ (- -0.125 (/ -0.0625 x)) x)) x) (sqrt (+ 1.0 x))))
double code(double x) {
return ((0.5 + ((-0.125 - (-0.0625 / x)) / x)) / x) / sqrt((1.0 + x));
}
real(8) function code(x)
real(8), intent (in) :: x
code = ((0.5d0 + (((-0.125d0) - ((-0.0625d0) / x)) / x)) / x) / sqrt((1.0d0 + x))
end function
public static double code(double x) {
return ((0.5 + ((-0.125 - (-0.0625 / x)) / x)) / x) / Math.sqrt((1.0 + x));
}
def code(x): return ((0.5 + ((-0.125 - (-0.0625 / x)) / x)) / x) / math.sqrt((1.0 + x))
function code(x) return Float64(Float64(Float64(0.5 + Float64(Float64(-0.125 - Float64(-0.0625 / x)) / x)) / x) / sqrt(Float64(1.0 + x))) end
function tmp = code(x) tmp = ((0.5 + ((-0.125 - (-0.0625 / x)) / x)) / x) / sqrt((1.0 + x)); end
code[x_] := N[(N[(N[(0.5 + N[(N[(-0.125 - N[(-0.0625 / x), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision] / N[Sqrt[N[(1.0 + x), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\frac{0.5 + \frac{-0.125 - \frac{-0.0625}{x}}{x}}{x}}{\sqrt{1 + x}}
\end{array}
Initial program 37.0%
Applied egg-rr39.2%
Taylor expanded in x around inf
Simplified98.8%
unpow1/2N/A
sqrt-lowering-sqrt.f64N/A
+-lowering-+.f6498.8%
Applied egg-rr98.8%
(FPCore (x) :precision binary64 (/ (pow (+ 1.0 x) -0.5) (+ x (+ x 0.5))))
double code(double x) {
return pow((1.0 + x), -0.5) / (x + (x + 0.5));
}
real(8) function code(x)
real(8), intent (in) :: x
code = ((1.0d0 + x) ** (-0.5d0)) / (x + (x + 0.5d0))
end function
public static double code(double x) {
return Math.pow((1.0 + x), -0.5) / (x + (x + 0.5));
}
def code(x): return math.pow((1.0 + x), -0.5) / (x + (x + 0.5))
function code(x) return Float64((Float64(1.0 + x) ^ -0.5) / Float64(x + Float64(x + 0.5))) end
function tmp = code(x) tmp = ((1.0 + x) ^ -0.5) / (x + (x + 0.5)); end
code[x_] := N[(N[Power[N[(1.0 + x), $MachinePrecision], -0.5], $MachinePrecision] / N[(x + N[(x + 0.5), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{{\left(1 + x\right)}^{-0.5}}{x + \left(x + 0.5\right)}
\end{array}
Initial program 37.0%
Applied egg-rr39.2%
associate-/l/N/A
associate--l+N/A
+-inversesN/A
metadata-evalN/A
associate-/r*N/A
pow-flipN/A
metadata-evalN/A
/-lowering-/.f64N/A
pow-lowering-pow.f64N/A
+-lowering-+.f64N/A
+-lowering-+.f64N/A
sqrt-lowering-sqrt.f64N/A
*-lowering-*.f64N/A
+-lowering-+.f6481.6%
Applied egg-rr81.6%
Taylor expanded in x around inf
+-commutativeN/A
distribute-rgt-inN/A
associate-*l*N/A
lft-mult-inverseN/A
metadata-evalN/A
*-lft-identityN/A
+-lowering-+.f6498.5%
Simplified98.5%
Final simplification98.5%
(FPCore (x) :precision binary64 (* 0.5 (pow x -1.5)))
double code(double x) {
return 0.5 * pow(x, -1.5);
}
real(8) function code(x)
real(8), intent (in) :: x
code = 0.5d0 * (x ** (-1.5d0))
end function
public static double code(double x) {
return 0.5 * Math.pow(x, -1.5);
}
def code(x): return 0.5 * math.pow(x, -1.5)
function code(x) return Float64(0.5 * (x ^ -1.5)) end
function tmp = code(x) tmp = 0.5 * (x ^ -1.5); end
code[x_] := N[(0.5 * N[Power[x, -1.5], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
0.5 \cdot {x}^{-1.5}
\end{array}
Initial program 37.0%
Taylor expanded in x around inf
Simplified80.2%
Taylor expanded in x around inf
*-lowering-*.f64N/A
sqrt-lowering-sqrt.f6478.9%
Simplified78.9%
associate-/l*N/A
*-commutativeN/A
*-lowering-*.f64N/A
pow1/2N/A
pow2N/A
pow-divN/A
pow-lowering-pow.f64N/A
metadata-eval97.4%
Applied egg-rr97.4%
Final simplification97.4%
(FPCore (x) :precision binary64 (/ (/ (+ 0.5 (/ (- -0.125 (/ -0.0625 x)) x)) x) (+ 1.0 (* x 0.5))))
double code(double x) {
return ((0.5 + ((-0.125 - (-0.0625 / x)) / x)) / x) / (1.0 + (x * 0.5));
}
real(8) function code(x)
real(8), intent (in) :: x
code = ((0.5d0 + (((-0.125d0) - ((-0.0625d0) / x)) / x)) / x) / (1.0d0 + (x * 0.5d0))
end function
public static double code(double x) {
return ((0.5 + ((-0.125 - (-0.0625 / x)) / x)) / x) / (1.0 + (x * 0.5));
}
def code(x): return ((0.5 + ((-0.125 - (-0.0625 / x)) / x)) / x) / (1.0 + (x * 0.5))
function code(x) return Float64(Float64(Float64(0.5 + Float64(Float64(-0.125 - Float64(-0.0625 / x)) / x)) / x) / Float64(1.0 + Float64(x * 0.5))) end
function tmp = code(x) tmp = ((0.5 + ((-0.125 - (-0.0625 / x)) / x)) / x) / (1.0 + (x * 0.5)); end
code[x_] := N[(N[(N[(0.5 + N[(N[(-0.125 - N[(-0.0625 / x), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision] / N[(1.0 + N[(x * 0.5), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\frac{0.5 + \frac{-0.125 - \frac{-0.0625}{x}}{x}}{x}}{1 + x \cdot 0.5}
\end{array}
Initial program 37.0%
Applied egg-rr39.2%
Taylor expanded in x around inf
Simplified98.8%
Taylor expanded in x around 0
+-lowering-+.f64N/A
*-lowering-*.f6435.9%
Simplified35.9%
Final simplification35.9%
(FPCore (x) :precision binary64 (/ (/ (+ 0.5 (/ -0.125 x)) x) (+ 1.0 (* x 0.5))))
double code(double x) {
return ((0.5 + (-0.125 / x)) / x) / (1.0 + (x * 0.5));
}
real(8) function code(x)
real(8), intent (in) :: x
code = ((0.5d0 + ((-0.125d0) / x)) / x) / (1.0d0 + (x * 0.5d0))
end function
public static double code(double x) {
return ((0.5 + (-0.125 / x)) / x) / (1.0 + (x * 0.5));
}
def code(x): return ((0.5 + (-0.125 / x)) / x) / (1.0 + (x * 0.5))
function code(x) return Float64(Float64(Float64(0.5 + Float64(-0.125 / x)) / x) / Float64(1.0 + Float64(x * 0.5))) end
function tmp = code(x) tmp = ((0.5 + (-0.125 / x)) / x) / (1.0 + (x * 0.5)); end
code[x_] := N[(N[(N[(0.5 + N[(-0.125 / x), $MachinePrecision]), $MachinePrecision] / x), $MachinePrecision] / N[(1.0 + N[(x * 0.5), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\frac{0.5 + \frac{-0.125}{x}}{x}}{1 + x \cdot 0.5}
\end{array}
Initial program 37.0%
Applied egg-rr39.2%
Taylor expanded in x around inf
*-commutativeN/A
cancel-sign-sub-invN/A
distribute-neg-frac2N/A
mul-1-negN/A
rem-square-sqrtN/A
unpow2N/A
*-commutativeN/A
*-commutativeN/A
/-lowering-/.f64N/A
Simplified98.4%
Taylor expanded in x around 0
+-commutativeN/A
+-lowering-+.f64N/A
*-commutativeN/A
*-lowering-*.f6435.9%
Simplified35.9%
Final simplification35.9%
(FPCore (x) :precision binary64 (/ 0.0625 (* x (* x x))))
double code(double x) {
return 0.0625 / (x * (x * x));
}
real(8) function code(x)
real(8), intent (in) :: x
code = 0.0625d0 / (x * (x * x))
end function
public static double code(double x) {
return 0.0625 / (x * (x * x));
}
def code(x): return 0.0625 / (x * (x * x))
function code(x) return Float64(0.0625 / Float64(x * Float64(x * x))) end
function tmp = code(x) tmp = 0.0625 / (x * (x * x)); end
code[x_] := N[(0.0625 / N[(x * N[(x * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{0.0625}{x \cdot \left(x \cdot x\right)}
\end{array}
Initial program 37.0%
Applied egg-rr39.2%
Taylor expanded in x around inf
Simplified98.8%
Taylor expanded in x around 0
/-lowering-/.f64N/A
cube-multN/A
unpow2N/A
*-lowering-*.f64N/A
unpow2N/A
*-lowering-*.f6434.7%
Simplified34.7%
(FPCore (x) :precision binary64 (/ -0.125 (* x x)))
double code(double x) {
return -0.125 / (x * x);
}
real(8) function code(x)
real(8), intent (in) :: x
code = (-0.125d0) / (x * x)
end function
public static double code(double x) {
return -0.125 / (x * x);
}
def code(x): return -0.125 / (x * x)
function code(x) return Float64(-0.125 / Float64(x * x)) end
function tmp = code(x) tmp = -0.125 / (x * x); end
code[x_] := N[(-0.125 / N[(x * x), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{-0.125}{x \cdot x}
\end{array}
Initial program 37.0%
Applied egg-rr39.2%
Taylor expanded in x around inf
*-commutativeN/A
cancel-sign-sub-invN/A
distribute-neg-frac2N/A
mul-1-negN/A
rem-square-sqrtN/A
unpow2N/A
*-commutativeN/A
*-commutativeN/A
/-lowering-/.f64N/A
Simplified98.4%
Taylor expanded in x around 0
/-lowering-/.f64N/A
unpow2N/A
*-lowering-*.f6432.9%
Simplified32.9%
(FPCore (x) :precision binary64 (* x (* x 16.0)))
double code(double x) {
return x * (x * 16.0);
}
real(8) function code(x)
real(8), intent (in) :: x
code = x * (x * 16.0d0)
end function
public static double code(double x) {
return x * (x * 16.0);
}
def code(x): return x * (x * 16.0)
function code(x) return Float64(x * Float64(x * 16.0)) end
function tmp = code(x) tmp = x * (x * 16.0); end
code[x_] := N[(x * N[(x * 16.0), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
x \cdot \left(x \cdot 16\right)
\end{array}
Initial program 37.0%
Applied egg-rr39.2%
associate-/l/N/A
associate--l+N/A
+-inversesN/A
metadata-evalN/A
associate-/r*N/A
pow-flipN/A
metadata-evalN/A
/-lowering-/.f64N/A
pow-lowering-pow.f64N/A
+-lowering-+.f64N/A
+-lowering-+.f64N/A
sqrt-lowering-sqrt.f64N/A
*-lowering-*.f64N/A
+-lowering-+.f6481.6%
Applied egg-rr81.6%
Taylor expanded in x around inf
*-lowering-*.f64N/A
associate-+r+N/A
associate--l+N/A
associate-*r/N/A
metadata-evalN/A
unpow3N/A
unpow2N/A
associate-/r*N/A
unpow2N/A
associate-/r*N/A
metadata-evalN/A
associate-*r/N/A
div-subN/A
Simplified99.0%
Taylor expanded in x around 0
*-commutativeN/A
unpow2N/A
associate-*l*N/A
*-lowering-*.f64N/A
*-lowering-*.f643.0%
Simplified3.0%
(FPCore (x) :precision binary64 (/ 1.0 (+ (* (+ x 1.0) (sqrt x)) (* x (sqrt (+ x 1.0))))))
double code(double x) {
return 1.0 / (((x + 1.0) * sqrt(x)) + (x * sqrt((x + 1.0))));
}
real(8) function code(x)
real(8), intent (in) :: x
code = 1.0d0 / (((x + 1.0d0) * sqrt(x)) + (x * sqrt((x + 1.0d0))))
end function
public static double code(double x) {
return 1.0 / (((x + 1.0) * Math.sqrt(x)) + (x * Math.sqrt((x + 1.0))));
}
def code(x): return 1.0 / (((x + 1.0) * math.sqrt(x)) + (x * math.sqrt((x + 1.0))))
function code(x) return Float64(1.0 / Float64(Float64(Float64(x + 1.0) * sqrt(x)) + Float64(x * sqrt(Float64(x + 1.0))))) end
function tmp = code(x) tmp = 1.0 / (((x + 1.0) * sqrt(x)) + (x * sqrt((x + 1.0)))); end
code[x_] := N[(1.0 / N[(N[(N[(x + 1.0), $MachinePrecision] * N[Sqrt[x], $MachinePrecision]), $MachinePrecision] + N[(x * N[Sqrt[N[(x + 1.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{1}{\left(x + 1\right) \cdot \sqrt{x} + x \cdot \sqrt{x + 1}}
\end{array}
herbie shell --seed 2024163
(FPCore (x)
:name "2isqrt (example 3.6)"
:precision binary64
:pre (and (> x 1.0) (< x 1e+308))
:alt
(! :herbie-platform default (/ 1 (+ (* (+ x 1) (sqrt x)) (* x (sqrt (+ x 1))))))
(- (/ 1.0 (sqrt x)) (/ 1.0 (sqrt (+ x 1.0)))))