
(FPCore (x) :precision binary64 (- 1.0 (sqrt (* 0.5 (+ 1.0 (/ 1.0 (hypot 1.0 x)))))))
double code(double x) {
return 1.0 - sqrt((0.5 * (1.0 + (1.0 / hypot(1.0, x)))));
}
public static double code(double x) {
return 1.0 - Math.sqrt((0.5 * (1.0 + (1.0 / Math.hypot(1.0, x)))));
}
def code(x): return 1.0 - math.sqrt((0.5 * (1.0 + (1.0 / math.hypot(1.0, x)))))
function code(x) return Float64(1.0 - sqrt(Float64(0.5 * Float64(1.0 + Float64(1.0 / hypot(1.0, x)))))) end
function tmp = code(x) tmp = 1.0 - sqrt((0.5 * (1.0 + (1.0 / hypot(1.0, x))))); end
code[x_] := N[(1.0 - N[Sqrt[N[(0.5 * N[(1.0 + N[(1.0 / N[Sqrt[1.0 ^ 2 + x ^ 2], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
1 - \sqrt{0.5 \cdot \left(1 + \frac{1}{\mathsf{hypot}\left(1, x\right)}\right)}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 7 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (x) :precision binary64 (- 1.0 (sqrt (* 0.5 (+ 1.0 (/ 1.0 (hypot 1.0 x)))))))
double code(double x) {
return 1.0 - sqrt((0.5 * (1.0 + (1.0 / hypot(1.0, x)))));
}
public static double code(double x) {
return 1.0 - Math.sqrt((0.5 * (1.0 + (1.0 / Math.hypot(1.0, x)))));
}
def code(x): return 1.0 - math.sqrt((0.5 * (1.0 + (1.0 / math.hypot(1.0, x)))))
function code(x) return Float64(1.0 - sqrt(Float64(0.5 * Float64(1.0 + Float64(1.0 / hypot(1.0, x)))))) end
function tmp = code(x) tmp = 1.0 - sqrt((0.5 * (1.0 + (1.0 / hypot(1.0, x))))); end
code[x_] := N[(1.0 - N[Sqrt[N[(0.5 * N[(1.0 + N[(1.0 / N[Sqrt[1.0 ^ 2 + x ^ 2], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
1 - \sqrt{0.5 \cdot \left(1 + \frac{1}{\mathsf{hypot}\left(1, x\right)}\right)}
\end{array}
(FPCore (x)
:precision binary64
(if (<= (hypot 1.0 x) 2.0)
(* (* x x) 0.125)
(/
(- 0.5 (/ 0.5 (hypot 1.0 x)))
(+ (sqrt (- 0.5 (/ -0.5 (hypot 1.0 x)))) 1.0))))
double code(double x) {
double tmp;
if (hypot(1.0, x) <= 2.0) {
tmp = (x * x) * 0.125;
} else {
tmp = (0.5 - (0.5 / hypot(1.0, x))) / (sqrt((0.5 - (-0.5 / hypot(1.0, x)))) + 1.0);
}
return tmp;
}
public static double code(double x) {
double tmp;
if (Math.hypot(1.0, x) <= 2.0) {
tmp = (x * x) * 0.125;
} else {
tmp = (0.5 - (0.5 / Math.hypot(1.0, x))) / (Math.sqrt((0.5 - (-0.5 / Math.hypot(1.0, x)))) + 1.0);
}
return tmp;
}
def code(x): tmp = 0 if math.hypot(1.0, x) <= 2.0: tmp = (x * x) * 0.125 else: tmp = (0.5 - (0.5 / math.hypot(1.0, x))) / (math.sqrt((0.5 - (-0.5 / math.hypot(1.0, x)))) + 1.0) return tmp
function code(x) tmp = 0.0 if (hypot(1.0, x) <= 2.0) tmp = Float64(Float64(x * x) * 0.125); else tmp = Float64(Float64(0.5 - Float64(0.5 / hypot(1.0, x))) / Float64(sqrt(Float64(0.5 - Float64(-0.5 / hypot(1.0, x)))) + 1.0)); end return tmp end
function tmp_2 = code(x) tmp = 0.0; if (hypot(1.0, x) <= 2.0) tmp = (x * x) * 0.125; else tmp = (0.5 - (0.5 / hypot(1.0, x))) / (sqrt((0.5 - (-0.5 / hypot(1.0, x)))) + 1.0); end tmp_2 = tmp; end
code[x_] := If[LessEqual[N[Sqrt[1.0 ^ 2 + x ^ 2], $MachinePrecision], 2.0], N[(N[(x * x), $MachinePrecision] * 0.125), $MachinePrecision], N[(N[(0.5 - N[(0.5 / N[Sqrt[1.0 ^ 2 + x ^ 2], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(N[Sqrt[N[(0.5 - N[(-0.5 / N[Sqrt[1.0 ^ 2 + x ^ 2], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;\mathsf{hypot}\left(1, x\right) \leq 2:\\
\;\;\;\;\left(x \cdot x\right) \cdot 0.125\\
\mathbf{else}:\\
\;\;\;\;\frac{0.5 - \frac{0.5}{\mathsf{hypot}\left(1, x\right)}}{\sqrt{0.5 - \frac{-0.5}{\mathsf{hypot}\left(1, x\right)}} + 1}\\
\end{array}
\end{array}
if (hypot.f64 #s(literal 1 binary64) x) < 2Initial program 54.1%
Applied rewrites54.1%
Taylor expanded in x around 0
lower-*.f64N/A
unpow2N/A
lower-*.f64100.0
Applied rewrites100.0%
if 2 < (hypot.f64 #s(literal 1 binary64) x) Initial program 98.5%
lift-*.f64N/A
lift-+.f64N/A
distribute-lft-inN/A
metadata-evalN/A
lift-/.f64N/A
frac-2negN/A
metadata-evalN/A
associate-*r/N/A
div-invN/A
metadata-evalN/A
metadata-evalN/A
inv-powN/A
metadata-evalN/A
metadata-evalN/A
pow-powN/A
pow2N/A
sqr-negN/A
pow-prod-downN/A
pow-sqrN/A
metadata-evalN/A
metadata-evalN/A
inv-powN/A
lift-/.f64N/A
Applied rewrites98.5%
lift--.f64N/A
flip--N/A
lower-/.f64N/A
metadata-evalN/A
lift-sqrt.f64N/A
lift-sqrt.f64N/A
rem-square-sqrtN/A
lower--.f64N/A
+-commutativeN/A
lower-+.f64100.0
Applied rewrites100.0%
lift--.f64N/A
lift--.f64N/A
associate--r-N/A
metadata-evalN/A
lift-/.f64N/A
div-invN/A
metadata-evalN/A
lift-hypot.f64N/A
metadata-evalN/A
cancel-sign-sub-invN/A
metadata-evalN/A
lift-hypot.f64N/A
div-invN/A
lift-/.f64N/A
lift--.f64100.0
Applied rewrites100.0%
Final simplification100.0%
(FPCore (x) :precision binary64 (if (<= (hypot 1.0 x) 2.0) (* (* x x) 0.125) (- 1.0 (sqrt (- 0.5 (/ -0.5 (hypot 1.0 x)))))))
double code(double x) {
double tmp;
if (hypot(1.0, x) <= 2.0) {
tmp = (x * x) * 0.125;
} else {
tmp = 1.0 - sqrt((0.5 - (-0.5 / hypot(1.0, x))));
}
return tmp;
}
public static double code(double x) {
double tmp;
if (Math.hypot(1.0, x) <= 2.0) {
tmp = (x * x) * 0.125;
} else {
tmp = 1.0 - Math.sqrt((0.5 - (-0.5 / Math.hypot(1.0, x))));
}
return tmp;
}
def code(x): tmp = 0 if math.hypot(1.0, x) <= 2.0: tmp = (x * x) * 0.125 else: tmp = 1.0 - math.sqrt((0.5 - (-0.5 / math.hypot(1.0, x)))) return tmp
function code(x) tmp = 0.0 if (hypot(1.0, x) <= 2.0) tmp = Float64(Float64(x * x) * 0.125); else tmp = Float64(1.0 - sqrt(Float64(0.5 - Float64(-0.5 / hypot(1.0, x))))); end return tmp end
function tmp_2 = code(x) tmp = 0.0; if (hypot(1.0, x) <= 2.0) tmp = (x * x) * 0.125; else tmp = 1.0 - sqrt((0.5 - (-0.5 / hypot(1.0, x)))); end tmp_2 = tmp; end
code[x_] := If[LessEqual[N[Sqrt[1.0 ^ 2 + x ^ 2], $MachinePrecision], 2.0], N[(N[(x * x), $MachinePrecision] * 0.125), $MachinePrecision], N[(1.0 - N[Sqrt[N[(0.5 - N[(-0.5 / N[Sqrt[1.0 ^ 2 + x ^ 2], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;\mathsf{hypot}\left(1, x\right) \leq 2:\\
\;\;\;\;\left(x \cdot x\right) \cdot 0.125\\
\mathbf{else}:\\
\;\;\;\;1 - \sqrt{0.5 - \frac{-0.5}{\mathsf{hypot}\left(1, x\right)}}\\
\end{array}
\end{array}
if (hypot.f64 #s(literal 1 binary64) x) < 2Initial program 54.1%
Applied rewrites54.1%
Taylor expanded in x around 0
lower-*.f64N/A
unpow2N/A
lower-*.f64100.0
Applied rewrites100.0%
if 2 < (hypot.f64 #s(literal 1 binary64) x) Initial program 98.5%
lift-*.f64N/A
lift-+.f64N/A
distribute-lft-inN/A
metadata-evalN/A
lift-/.f64N/A
frac-2negN/A
metadata-evalN/A
associate-*r/N/A
div-invN/A
metadata-evalN/A
metadata-evalN/A
inv-powN/A
metadata-evalN/A
metadata-evalN/A
pow-powN/A
pow2N/A
sqr-negN/A
pow-prod-downN/A
pow-sqrN/A
metadata-evalN/A
metadata-evalN/A
inv-powN/A
lift-/.f64N/A
Applied rewrites98.5%
Final simplification99.2%
(FPCore (x) :precision binary64 (if (<= (hypot 1.0 x) 2.0) (* (* x x) 0.125) (- 1.0 (sqrt (- 0.5 (/ (- (/ 0.25 (* x x)) 0.5) x))))))
double code(double x) {
double tmp;
if (hypot(1.0, x) <= 2.0) {
tmp = (x * x) * 0.125;
} else {
tmp = 1.0 - sqrt((0.5 - (((0.25 / (x * x)) - 0.5) / x)));
}
return tmp;
}
public static double code(double x) {
double tmp;
if (Math.hypot(1.0, x) <= 2.0) {
tmp = (x * x) * 0.125;
} else {
tmp = 1.0 - Math.sqrt((0.5 - (((0.25 / (x * x)) - 0.5) / x)));
}
return tmp;
}
def code(x): tmp = 0 if math.hypot(1.0, x) <= 2.0: tmp = (x * x) * 0.125 else: tmp = 1.0 - math.sqrt((0.5 - (((0.25 / (x * x)) - 0.5) / x))) return tmp
function code(x) tmp = 0.0 if (hypot(1.0, x) <= 2.0) tmp = Float64(Float64(x * x) * 0.125); else tmp = Float64(1.0 - sqrt(Float64(0.5 - Float64(Float64(Float64(0.25 / Float64(x * x)) - 0.5) / x)))); end return tmp end
function tmp_2 = code(x) tmp = 0.0; if (hypot(1.0, x) <= 2.0) tmp = (x * x) * 0.125; else tmp = 1.0 - sqrt((0.5 - (((0.25 / (x * x)) - 0.5) / x))); end tmp_2 = tmp; end
code[x_] := If[LessEqual[N[Sqrt[1.0 ^ 2 + x ^ 2], $MachinePrecision], 2.0], N[(N[(x * x), $MachinePrecision] * 0.125), $MachinePrecision], N[(1.0 - N[Sqrt[N[(0.5 - N[(N[(N[(0.25 / N[(x * x), $MachinePrecision]), $MachinePrecision] - 0.5), $MachinePrecision] / x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;\mathsf{hypot}\left(1, x\right) \leq 2:\\
\;\;\;\;\left(x \cdot x\right) \cdot 0.125\\
\mathbf{else}:\\
\;\;\;\;1 - \sqrt{0.5 - \frac{\frac{0.25}{x \cdot x} - 0.5}{x}}\\
\end{array}
\end{array}
if (hypot.f64 #s(literal 1 binary64) x) < 2Initial program 54.1%
Applied rewrites54.1%
Taylor expanded in x around 0
lower-*.f64N/A
unpow2N/A
lower-*.f64100.0
Applied rewrites100.0%
if 2 < (hypot.f64 #s(literal 1 binary64) x) Initial program 98.5%
lift-*.f64N/A
lift-+.f64N/A
distribute-lft-inN/A
metadata-evalN/A
lift-/.f64N/A
frac-2negN/A
metadata-evalN/A
associate-*r/N/A
div-invN/A
metadata-evalN/A
metadata-evalN/A
inv-powN/A
metadata-evalN/A
metadata-evalN/A
pow-powN/A
pow2N/A
sqr-negN/A
pow-prod-downN/A
pow-sqrN/A
metadata-evalN/A
metadata-evalN/A
inv-powN/A
lift-/.f64N/A
Applied rewrites98.5%
Taylor expanded in x around inf
lower-/.f64N/A
lower--.f64N/A
associate-*r/N/A
metadata-evalN/A
lower-/.f64N/A
unpow2N/A
lower-*.f6496.3
Applied rewrites96.3%
Final simplification98.0%
(FPCore (x) :precision binary64 (if (<= (hypot 1.0 x) 2.0) (* (* x x) 0.125) (/ 0.5 (+ (sqrt 0.5) 1.0))))
double code(double x) {
double tmp;
if (hypot(1.0, x) <= 2.0) {
tmp = (x * x) * 0.125;
} else {
tmp = 0.5 / (sqrt(0.5) + 1.0);
}
return tmp;
}
public static double code(double x) {
double tmp;
if (Math.hypot(1.0, x) <= 2.0) {
tmp = (x * x) * 0.125;
} else {
tmp = 0.5 / (Math.sqrt(0.5) + 1.0);
}
return tmp;
}
def code(x): tmp = 0 if math.hypot(1.0, x) <= 2.0: tmp = (x * x) * 0.125 else: tmp = 0.5 / (math.sqrt(0.5) + 1.0) return tmp
function code(x) tmp = 0.0 if (hypot(1.0, x) <= 2.0) tmp = Float64(Float64(x * x) * 0.125); else tmp = Float64(0.5 / Float64(sqrt(0.5) + 1.0)); end return tmp end
function tmp_2 = code(x) tmp = 0.0; if (hypot(1.0, x) <= 2.0) tmp = (x * x) * 0.125; else tmp = 0.5 / (sqrt(0.5) + 1.0); end tmp_2 = tmp; end
code[x_] := If[LessEqual[N[Sqrt[1.0 ^ 2 + x ^ 2], $MachinePrecision], 2.0], N[(N[(x * x), $MachinePrecision] * 0.125), $MachinePrecision], N[(0.5 / N[(N[Sqrt[0.5], $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;\mathsf{hypot}\left(1, x\right) \leq 2:\\
\;\;\;\;\left(x \cdot x\right) \cdot 0.125\\
\mathbf{else}:\\
\;\;\;\;\frac{0.5}{\sqrt{0.5} + 1}\\
\end{array}
\end{array}
if (hypot.f64 #s(literal 1 binary64) x) < 2Initial program 54.1%
Applied rewrites54.1%
Taylor expanded in x around 0
lower-*.f64N/A
unpow2N/A
lower-*.f64100.0
Applied rewrites100.0%
if 2 < (hypot.f64 #s(literal 1 binary64) x) Initial program 98.5%
Applied rewrites100.0%
Taylor expanded in x around inf
lower-/.f64N/A
+-commutativeN/A
lower-+.f64N/A
lower-sqrt.f6497.7
Applied rewrites97.7%
Final simplification98.8%
(FPCore (x) :precision binary64 (if (<= (/ 1.0 (hypot 1.0 x)) 0.1) (- 1.0 (sqrt 0.5)) (* (* x x) 0.125)))
double code(double x) {
double tmp;
if ((1.0 / hypot(1.0, x)) <= 0.1) {
tmp = 1.0 - sqrt(0.5);
} else {
tmp = (x * x) * 0.125;
}
return tmp;
}
public static double code(double x) {
double tmp;
if ((1.0 / Math.hypot(1.0, x)) <= 0.1) {
tmp = 1.0 - Math.sqrt(0.5);
} else {
tmp = (x * x) * 0.125;
}
return tmp;
}
def code(x): tmp = 0 if (1.0 / math.hypot(1.0, x)) <= 0.1: tmp = 1.0 - math.sqrt(0.5) else: tmp = (x * x) * 0.125 return tmp
function code(x) tmp = 0.0 if (Float64(1.0 / hypot(1.0, x)) <= 0.1) tmp = Float64(1.0 - sqrt(0.5)); else tmp = Float64(Float64(x * x) * 0.125); end return tmp end
function tmp_2 = code(x) tmp = 0.0; if ((1.0 / hypot(1.0, x)) <= 0.1) tmp = 1.0 - sqrt(0.5); else tmp = (x * x) * 0.125; end tmp_2 = tmp; end
code[x_] := If[LessEqual[N[(1.0 / N[Sqrt[1.0 ^ 2 + x ^ 2], $MachinePrecision]), $MachinePrecision], 0.1], N[(1.0 - N[Sqrt[0.5], $MachinePrecision]), $MachinePrecision], N[(N[(x * x), $MachinePrecision] * 0.125), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;\frac{1}{\mathsf{hypot}\left(1, x\right)} \leq 0.1:\\
\;\;\;\;1 - \sqrt{0.5}\\
\mathbf{else}:\\
\;\;\;\;\left(x \cdot x\right) \cdot 0.125\\
\end{array}
\end{array}
if (/.f64 #s(literal 1 binary64) (hypot.f64 #s(literal 1 binary64) x)) < 0.10000000000000001Initial program 98.5%
Taylor expanded in x around inf
Applied rewrites96.2%
if 0.10000000000000001 < (/.f64 #s(literal 1 binary64) (hypot.f64 #s(literal 1 binary64) x)) Initial program 54.1%
Applied rewrites54.1%
Taylor expanded in x around 0
lower-*.f64N/A
unpow2N/A
lower-*.f64100.0
Applied rewrites100.0%
Final simplification98.0%
(FPCore (x) :precision binary64 (* (* x x) 0.125))
double code(double x) {
return (x * x) * 0.125;
}
real(8) function code(x)
real(8), intent (in) :: x
code = (x * x) * 0.125d0
end function
public static double code(double x) {
return (x * x) * 0.125;
}
def code(x): return (x * x) * 0.125
function code(x) return Float64(Float64(x * x) * 0.125) end
function tmp = code(x) tmp = (x * x) * 0.125; end
code[x_] := N[(N[(x * x), $MachinePrecision] * 0.125), $MachinePrecision]
\begin{array}{l}
\\
\left(x \cdot x\right) \cdot 0.125
\end{array}
Initial program 77.9%
Applied rewrites78.7%
Taylor expanded in x around 0
lower-*.f64N/A
unpow2N/A
lower-*.f6448.7
Applied rewrites48.7%
Final simplification48.7%
(FPCore (x) :precision binary64 (- 1.0 1.0))
double code(double x) {
return 1.0 - 1.0;
}
real(8) function code(x)
real(8), intent (in) :: x
code = 1.0d0 - 1.0d0
end function
public static double code(double x) {
return 1.0 - 1.0;
}
def code(x): return 1.0 - 1.0
function code(x) return Float64(1.0 - 1.0) end
function tmp = code(x) tmp = 1.0 - 1.0; end
code[x_] := N[(1.0 - 1.0), $MachinePrecision]
\begin{array}{l}
\\
1 - 1
\end{array}
Initial program 77.9%
lift-*.f64N/A
lift-+.f64N/A
distribute-lft-inN/A
metadata-evalN/A
lift-/.f64N/A
frac-2negN/A
metadata-evalN/A
associate-*r/N/A
div-invN/A
metadata-evalN/A
metadata-evalN/A
inv-powN/A
metadata-evalN/A
metadata-evalN/A
pow-powN/A
pow2N/A
sqr-negN/A
pow-prod-downN/A
pow-sqrN/A
metadata-evalN/A
metadata-evalN/A
inv-powN/A
lift-/.f64N/A
Applied rewrites77.9%
Taylor expanded in x around 0
Applied rewrites26.8%
herbie shell --seed 2024243
(FPCore (x)
:name "Given's Rotation SVD example, simplified"
:precision binary64
(- 1.0 (sqrt (* 0.5 (+ 1.0 (/ 1.0 (hypot 1.0 x)))))))