
(FPCore (p x) :precision binary64 (sqrt (* 0.5 (+ 1.0 (/ x (sqrt (+ (* (* 4.0 p) p) (* x x))))))))
double code(double p, double x) {
return sqrt((0.5 * (1.0 + (x / sqrt((((4.0 * p) * p) + (x * x)))))));
}
real(8) function code(p, x)
real(8), intent (in) :: p
real(8), intent (in) :: x
code = sqrt((0.5d0 * (1.0d0 + (x / sqrt((((4.0d0 * p) * p) + (x * x)))))))
end function
public static double code(double p, double x) {
return Math.sqrt((0.5 * (1.0 + (x / Math.sqrt((((4.0 * p) * p) + (x * x)))))));
}
def code(p, x): return math.sqrt((0.5 * (1.0 + (x / math.sqrt((((4.0 * p) * p) + (x * x)))))))
function code(p, x) return sqrt(Float64(0.5 * Float64(1.0 + Float64(x / sqrt(Float64(Float64(Float64(4.0 * p) * p) + Float64(x * x))))))) end
function tmp = code(p, x) tmp = sqrt((0.5 * (1.0 + (x / sqrt((((4.0 * p) * p) + (x * x))))))); end
code[p_, x_] := N[Sqrt[N[(0.5 * N[(1.0 + N[(x / N[Sqrt[N[(N[(N[(4.0 * p), $MachinePrecision] * p), $MachinePrecision] + N[(x * x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}
\\
\sqrt{0.5 \cdot \left(1 + \frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + x \cdot x}}\right)}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 5 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (p x) :precision binary64 (sqrt (* 0.5 (+ 1.0 (/ x (sqrt (+ (* (* 4.0 p) p) (* x x))))))))
double code(double p, double x) {
return sqrt((0.5 * (1.0 + (x / sqrt((((4.0 * p) * p) + (x * x)))))));
}
real(8) function code(p, x)
real(8), intent (in) :: p
real(8), intent (in) :: x
code = sqrt((0.5d0 * (1.0d0 + (x / sqrt((((4.0d0 * p) * p) + (x * x)))))))
end function
public static double code(double p, double x) {
return Math.sqrt((0.5 * (1.0 + (x / Math.sqrt((((4.0 * p) * p) + (x * x)))))));
}
def code(p, x): return math.sqrt((0.5 * (1.0 + (x / math.sqrt((((4.0 * p) * p) + (x * x)))))))
function code(p, x) return sqrt(Float64(0.5 * Float64(1.0 + Float64(x / sqrt(Float64(Float64(Float64(4.0 * p) * p) + Float64(x * x))))))) end
function tmp = code(p, x) tmp = sqrt((0.5 * (1.0 + (x / sqrt((((4.0 * p) * p) + (x * x))))))); end
code[p_, x_] := N[Sqrt[N[(0.5 * N[(1.0 + N[(x / N[Sqrt[N[(N[(N[(4.0 * p), $MachinePrecision] * p), $MachinePrecision] + N[(x * x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}
\\
\sqrt{0.5 \cdot \left(1 + \frac{x}{\sqrt{\left(4 \cdot p\right) \cdot p + x \cdot x}}\right)}
\end{array}
p_m = (fabs.f64 p) (FPCore (p_m x) :precision binary64 (if (<= (/ x (sqrt (+ (* p_m (* 4.0 p_m)) (* x x)))) -0.9999999) (/ p_m (- x)) (sqrt (* 0.5 (+ 1.0 (/ x (hypot (* p_m 2.0) x)))))))
p_m = fabs(p);
double code(double p_m, double x) {
double tmp;
if ((x / sqrt(((p_m * (4.0 * p_m)) + (x * x)))) <= -0.9999999) {
tmp = p_m / -x;
} else {
tmp = sqrt((0.5 * (1.0 + (x / hypot((p_m * 2.0), x)))));
}
return tmp;
}
p_m = Math.abs(p);
public static double code(double p_m, double x) {
double tmp;
if ((x / Math.sqrt(((p_m * (4.0 * p_m)) + (x * x)))) <= -0.9999999) {
tmp = p_m / -x;
} else {
tmp = Math.sqrt((0.5 * (1.0 + (x / Math.hypot((p_m * 2.0), x)))));
}
return tmp;
}
p_m = math.fabs(p) def code(p_m, x): tmp = 0 if (x / math.sqrt(((p_m * (4.0 * p_m)) + (x * x)))) <= -0.9999999: tmp = p_m / -x else: tmp = math.sqrt((0.5 * (1.0 + (x / math.hypot((p_m * 2.0), x))))) return tmp
p_m = abs(p) function code(p_m, x) tmp = 0.0 if (Float64(x / sqrt(Float64(Float64(p_m * Float64(4.0 * p_m)) + Float64(x * x)))) <= -0.9999999) tmp = Float64(p_m / Float64(-x)); else tmp = sqrt(Float64(0.5 * Float64(1.0 + Float64(x / hypot(Float64(p_m * 2.0), x))))); end return tmp end
p_m = abs(p); function tmp_2 = code(p_m, x) tmp = 0.0; if ((x / sqrt(((p_m * (4.0 * p_m)) + (x * x)))) <= -0.9999999) tmp = p_m / -x; else tmp = sqrt((0.5 * (1.0 + (x / hypot((p_m * 2.0), x))))); end tmp_2 = tmp; end
p_m = N[Abs[p], $MachinePrecision] code[p$95$m_, x_] := If[LessEqual[N[(x / N[Sqrt[N[(N[(p$95$m * N[(4.0 * p$95$m), $MachinePrecision]), $MachinePrecision] + N[(x * x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], -0.9999999], N[(p$95$m / (-x)), $MachinePrecision], N[Sqrt[N[(0.5 * N[(1.0 + N[(x / N[Sqrt[N[(p$95$m * 2.0), $MachinePrecision] ^ 2 + x ^ 2], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]]
\begin{array}{l}
p_m = \left|p\right|
\\
\begin{array}{l}
\mathbf{if}\;\frac{x}{\sqrt{p\_m \cdot \left(4 \cdot p\_m\right) + x \cdot x}} \leq -0.9999999:\\
\;\;\;\;\frac{p\_m}{-x}\\
\mathbf{else}:\\
\;\;\;\;\sqrt{0.5 \cdot \left(1 + \frac{x}{\mathsf{hypot}\left(p\_m \cdot 2, x\right)}\right)}\\
\end{array}
\end{array}
if (/.f64 x (sqrt.f64 (+.f64 (*.f64 (*.f64 #s(literal 4 binary64) p) p) (*.f64 x x)))) < -0.999999900000000053Initial program 12.2%
Taylor expanded in x around -inf 51.6%
Taylor expanded in p around -inf 58.3%
associate-*r/58.3%
mul-1-neg58.3%
Simplified58.3%
if -0.999999900000000053 < (/.f64 x (sqrt.f64 (+.f64 (*.f64 (*.f64 #s(literal 4 binary64) p) p) (*.f64 x x)))) Initial program 99.6%
add-sqr-sqrt99.6%
hypot-define99.6%
associate-*l*99.6%
sqrt-prod99.6%
metadata-eval99.6%
sqrt-unprod47.4%
add-sqr-sqrt99.6%
Applied egg-rr99.6%
Final simplification89.4%
p_m = (fabs.f64 p) (FPCore (p_m x) :precision binary64 (if (<= p_m 4.8e-101) (* p_m (sqrt (pow x -2.0))) (if (<= p_m 9.2e-61) 1.0 (sqrt 0.5))))
p_m = fabs(p);
double code(double p_m, double x) {
double tmp;
if (p_m <= 4.8e-101) {
tmp = p_m * sqrt(pow(x, -2.0));
} else if (p_m <= 9.2e-61) {
tmp = 1.0;
} else {
tmp = sqrt(0.5);
}
return tmp;
}
p_m = abs(p)
real(8) function code(p_m, x)
real(8), intent (in) :: p_m
real(8), intent (in) :: x
real(8) :: tmp
if (p_m <= 4.8d-101) then
tmp = p_m * sqrt((x ** (-2.0d0)))
else if (p_m <= 9.2d-61) then
tmp = 1.0d0
else
tmp = sqrt(0.5d0)
end if
code = tmp
end function
p_m = Math.abs(p);
public static double code(double p_m, double x) {
double tmp;
if (p_m <= 4.8e-101) {
tmp = p_m * Math.sqrt(Math.pow(x, -2.0));
} else if (p_m <= 9.2e-61) {
tmp = 1.0;
} else {
tmp = Math.sqrt(0.5);
}
return tmp;
}
p_m = math.fabs(p) def code(p_m, x): tmp = 0 if p_m <= 4.8e-101: tmp = p_m * math.sqrt(math.pow(x, -2.0)) elif p_m <= 9.2e-61: tmp = 1.0 else: tmp = math.sqrt(0.5) return tmp
p_m = abs(p) function code(p_m, x) tmp = 0.0 if (p_m <= 4.8e-101) tmp = Float64(p_m * sqrt((x ^ -2.0))); elseif (p_m <= 9.2e-61) tmp = 1.0; else tmp = sqrt(0.5); end return tmp end
p_m = abs(p); function tmp_2 = code(p_m, x) tmp = 0.0; if (p_m <= 4.8e-101) tmp = p_m * sqrt((x ^ -2.0)); elseif (p_m <= 9.2e-61) tmp = 1.0; else tmp = sqrt(0.5); end tmp_2 = tmp; end
p_m = N[Abs[p], $MachinePrecision] code[p$95$m_, x_] := If[LessEqual[p$95$m, 4.8e-101], N[(p$95$m * N[Sqrt[N[Power[x, -2.0], $MachinePrecision]], $MachinePrecision]), $MachinePrecision], If[LessEqual[p$95$m, 9.2e-61], 1.0, N[Sqrt[0.5], $MachinePrecision]]]
\begin{array}{l}
p_m = \left|p\right|
\\
\begin{array}{l}
\mathbf{if}\;p\_m \leq 4.8 \cdot 10^{-101}:\\
\;\;\;\;p\_m \cdot \sqrt{{x}^{-2}}\\
\mathbf{elif}\;p\_m \leq 9.2 \cdot 10^{-61}:\\
\;\;\;\;1\\
\mathbf{else}:\\
\;\;\;\;\sqrt{0.5}\\
\end{array}
\end{array}
if p < 4.8e-101Initial program 73.5%
Taylor expanded in x around -inf 16.5%
pow1/216.5%
associate-*r*16.5%
metadata-eval16.5%
*-un-lft-identity16.5%
div-inv16.5%
unpow-prod-down19.6%
pow1/219.6%
sqrt-pow116.9%
metadata-eval16.9%
pow116.9%
pow-flip16.9%
metadata-eval16.9%
Applied egg-rr16.9%
unpow1/216.9%
Simplified16.9%
if 4.8e-101 < p < 9.19999999999999967e-61Initial program 100.0%
add-cbrt-cube100.0%
pow1/3100.0%
Applied egg-rr100.0%
Taylor expanded in x around inf 100.0%
if 9.19999999999999967e-61 < p Initial program 87.4%
Taylor expanded in x around 0 82.7%
p_m = (fabs.f64 p) (FPCore (p_m x) :precision binary64 (if (<= p_m 6.6e-102) (/ p_m (- x)) (if (<= p_m 5e-61) 1.0 (sqrt 0.5))))
p_m = fabs(p);
double code(double p_m, double x) {
double tmp;
if (p_m <= 6.6e-102) {
tmp = p_m / -x;
} else if (p_m <= 5e-61) {
tmp = 1.0;
} else {
tmp = sqrt(0.5);
}
return tmp;
}
p_m = abs(p)
real(8) function code(p_m, x)
real(8), intent (in) :: p_m
real(8), intent (in) :: x
real(8) :: tmp
if (p_m <= 6.6d-102) then
tmp = p_m / -x
else if (p_m <= 5d-61) then
tmp = 1.0d0
else
tmp = sqrt(0.5d0)
end if
code = tmp
end function
p_m = Math.abs(p);
public static double code(double p_m, double x) {
double tmp;
if (p_m <= 6.6e-102) {
tmp = p_m / -x;
} else if (p_m <= 5e-61) {
tmp = 1.0;
} else {
tmp = Math.sqrt(0.5);
}
return tmp;
}
p_m = math.fabs(p) def code(p_m, x): tmp = 0 if p_m <= 6.6e-102: tmp = p_m / -x elif p_m <= 5e-61: tmp = 1.0 else: tmp = math.sqrt(0.5) return tmp
p_m = abs(p) function code(p_m, x) tmp = 0.0 if (p_m <= 6.6e-102) tmp = Float64(p_m / Float64(-x)); elseif (p_m <= 5e-61) tmp = 1.0; else tmp = sqrt(0.5); end return tmp end
p_m = abs(p); function tmp_2 = code(p_m, x) tmp = 0.0; if (p_m <= 6.6e-102) tmp = p_m / -x; elseif (p_m <= 5e-61) tmp = 1.0; else tmp = sqrt(0.5); end tmp_2 = tmp; end
p_m = N[Abs[p], $MachinePrecision] code[p$95$m_, x_] := If[LessEqual[p$95$m, 6.6e-102], N[(p$95$m / (-x)), $MachinePrecision], If[LessEqual[p$95$m, 5e-61], 1.0, N[Sqrt[0.5], $MachinePrecision]]]
\begin{array}{l}
p_m = \left|p\right|
\\
\begin{array}{l}
\mathbf{if}\;p\_m \leq 6.6 \cdot 10^{-102}:\\
\;\;\;\;\frac{p\_m}{-x}\\
\mathbf{elif}\;p\_m \leq 5 \cdot 10^{-61}:\\
\;\;\;\;1\\
\mathbf{else}:\\
\;\;\;\;\sqrt{0.5}\\
\end{array}
\end{array}
if p < 6.6e-102Initial program 73.5%
Taylor expanded in x around -inf 16.5%
Taylor expanded in p around -inf 18.0%
associate-*r/18.0%
mul-1-neg18.0%
Simplified18.0%
if 6.6e-102 < p < 4.9999999999999999e-61Initial program 100.0%
add-cbrt-cube100.0%
pow1/3100.0%
Applied egg-rr100.0%
Taylor expanded in x around inf 100.0%
if 4.9999999999999999e-61 < p Initial program 87.4%
Taylor expanded in x around 0 82.7%
Final simplification39.0%
p_m = (fabs.f64 p) (FPCore (p_m x) :precision binary64 (if (<= x -2.9e-231) (/ p_m (- x)) 1.0))
p_m = fabs(p);
double code(double p_m, double x) {
double tmp;
if (x <= -2.9e-231) {
tmp = p_m / -x;
} else {
tmp = 1.0;
}
return tmp;
}
p_m = abs(p)
real(8) function code(p_m, x)
real(8), intent (in) :: p_m
real(8), intent (in) :: x
real(8) :: tmp
if (x <= (-2.9d-231)) then
tmp = p_m / -x
else
tmp = 1.0d0
end if
code = tmp
end function
p_m = Math.abs(p);
public static double code(double p_m, double x) {
double tmp;
if (x <= -2.9e-231) {
tmp = p_m / -x;
} else {
tmp = 1.0;
}
return tmp;
}
p_m = math.fabs(p) def code(p_m, x): tmp = 0 if x <= -2.9e-231: tmp = p_m / -x else: tmp = 1.0 return tmp
p_m = abs(p) function code(p_m, x) tmp = 0.0 if (x <= -2.9e-231) tmp = Float64(p_m / Float64(-x)); else tmp = 1.0; end return tmp end
p_m = abs(p); function tmp_2 = code(p_m, x) tmp = 0.0; if (x <= -2.9e-231) tmp = p_m / -x; else tmp = 1.0; end tmp_2 = tmp; end
p_m = N[Abs[p], $MachinePrecision] code[p$95$m_, x_] := If[LessEqual[x, -2.9e-231], N[(p$95$m / (-x)), $MachinePrecision], 1.0]
\begin{array}{l}
p_m = \left|p\right|
\\
\begin{array}{l}
\mathbf{if}\;x \leq -2.9 \cdot 10^{-231}:\\
\;\;\;\;\frac{p\_m}{-x}\\
\mathbf{else}:\\
\;\;\;\;1\\
\end{array}
\end{array}
if x < -2.9000000000000001e-231Initial program 57.9%
Taylor expanded in x around -inf 27.8%
Taylor expanded in p around -inf 29.9%
associate-*r/29.9%
mul-1-neg29.9%
Simplified29.9%
if -2.9000000000000001e-231 < x Initial program 100.0%
add-cbrt-cube100.0%
pow1/3100.0%
Applied egg-rr100.0%
Taylor expanded in x around inf 54.4%
Final simplification41.7%
p_m = (fabs.f64 p) (FPCore (p_m x) :precision binary64 1.0)
p_m = fabs(p);
double code(double p_m, double x) {
return 1.0;
}
p_m = abs(p)
real(8) function code(p_m, x)
real(8), intent (in) :: p_m
real(8), intent (in) :: x
code = 1.0d0
end function
p_m = Math.abs(p);
public static double code(double p_m, double x) {
return 1.0;
}
p_m = math.fabs(p) def code(p_m, x): return 1.0
p_m = abs(p) function code(p_m, x) return 1.0 end
p_m = abs(p); function tmp = code(p_m, x) tmp = 1.0; end
p_m = N[Abs[p], $MachinePrecision] code[p$95$m_, x_] := 1.0
\begin{array}{l}
p_m = \left|p\right|
\\
1
\end{array}
Initial program 78.1%
add-cbrt-cube78.1%
pow1/378.1%
Applied egg-rr78.1%
Taylor expanded in x around inf 32.9%
(FPCore (p x) :precision binary64 (sqrt (+ 0.5 (/ (copysign 0.5 x) (hypot 1.0 (/ (* 2.0 p) x))))))
double code(double p, double x) {
return sqrt((0.5 + (copysign(0.5, x) / hypot(1.0, ((2.0 * p) / x)))));
}
public static double code(double p, double x) {
return Math.sqrt((0.5 + (Math.copySign(0.5, x) / Math.hypot(1.0, ((2.0 * p) / x)))));
}
def code(p, x): return math.sqrt((0.5 + (math.copysign(0.5, x) / math.hypot(1.0, ((2.0 * p) / x)))))
function code(p, x) return sqrt(Float64(0.5 + Float64(copysign(0.5, x) / hypot(1.0, Float64(Float64(2.0 * p) / x))))) end
function tmp = code(p, x) tmp = sqrt((0.5 + ((sign(x) * abs(0.5)) / hypot(1.0, ((2.0 * p) / x))))); end
code[p_, x_] := N[Sqrt[N[(0.5 + N[(N[With[{TMP1 = Abs[0.5], TMP2 = Sign[x]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision] / N[Sqrt[1.0 ^ 2 + N[(N[(2.0 * p), $MachinePrecision] / x), $MachinePrecision] ^ 2], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}
\\
\sqrt{0.5 + \frac{\mathsf{copysign}\left(0.5, x\right)}{\mathsf{hypot}\left(1, \frac{2 \cdot p}{x}\right)}}
\end{array}
herbie shell --seed 2024103
(FPCore (p x)
:name "Given's Rotation SVD example"
:precision binary64
:pre (and (< 1e-150 (fabs x)) (< (fabs x) 1e+150))
:alt
(sqrt (+ 0.5 (/ (copysign 0.5 x) (hypot 1.0 (/ (* 2.0 p) x)))))
(sqrt (* 0.5 (+ 1.0 (/ x (sqrt (+ (* (* 4.0 p) p) (* x x))))))))