
(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 4 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 (let* ((t_0 (/ x (sqrt (+ (* p_m (* 4.0 p_m)) (* x x)))))) (if (<= t_0 -1.0) (/ p_m (- x)) (sqrt (* 0.5 (+ t_0 1.0))))))
p_m = fabs(p);
double code(double p_m, double x) {
double t_0 = x / sqrt(((p_m * (4.0 * p_m)) + (x * x)));
double tmp;
if (t_0 <= -1.0) {
tmp = p_m / -x;
} else {
tmp = sqrt((0.5 * (t_0 + 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) :: t_0
real(8) :: tmp
t_0 = x / sqrt(((p_m * (4.0d0 * p_m)) + (x * x)))
if (t_0 <= (-1.0d0)) then
tmp = p_m / -x
else
tmp = sqrt((0.5d0 * (t_0 + 1.0d0)))
end if
code = tmp
end function
p_m = Math.abs(p);
public static double code(double p_m, double x) {
double t_0 = x / Math.sqrt(((p_m * (4.0 * p_m)) + (x * x)));
double tmp;
if (t_0 <= -1.0) {
tmp = p_m / -x;
} else {
tmp = Math.sqrt((0.5 * (t_0 + 1.0)));
}
return tmp;
}
p_m = math.fabs(p) def code(p_m, x): t_0 = x / math.sqrt(((p_m * (4.0 * p_m)) + (x * x))) tmp = 0 if t_0 <= -1.0: tmp = p_m / -x else: tmp = math.sqrt((0.5 * (t_0 + 1.0))) return tmp
p_m = abs(p) function code(p_m, x) t_0 = Float64(x / sqrt(Float64(Float64(p_m * Float64(4.0 * p_m)) + Float64(x * x)))) tmp = 0.0 if (t_0 <= -1.0) tmp = Float64(p_m / Float64(-x)); else tmp = sqrt(Float64(0.5 * Float64(t_0 + 1.0))); end return tmp end
p_m = abs(p); function tmp_2 = code(p_m, x) t_0 = x / sqrt(((p_m * (4.0 * p_m)) + (x * x))); tmp = 0.0; if (t_0 <= -1.0) tmp = p_m / -x; else tmp = sqrt((0.5 * (t_0 + 1.0))); end tmp_2 = tmp; end
p_m = N[Abs[p], $MachinePrecision]
code[p$95$m_, x_] := Block[{t$95$0 = N[(x / N[Sqrt[N[(N[(p$95$m * N[(4.0 * p$95$m), $MachinePrecision]), $MachinePrecision] + N[(x * x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t$95$0, -1.0], N[(p$95$m / (-x)), $MachinePrecision], N[Sqrt[N[(0.5 * N[(t$95$0 + 1.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]]]
\begin{array}{l}
p_m = \left|p\right|
\\
\begin{array}{l}
t_0 := \frac{x}{\sqrt{p\_m \cdot \left(4 \cdot p\_m\right) + x \cdot x}}\\
\mathbf{if}\;t\_0 \leq -1:\\
\;\;\;\;\frac{p\_m}{-x}\\
\mathbf{else}:\\
\;\;\;\;\sqrt{0.5 \cdot \left(t\_0 + 1\right)}\\
\end{array}
\end{array}
if (/.f64 x (sqrt.f64 (+.f64 (*.f64 (*.f64 4 p) p) (*.f64 x x)))) < -1Initial program 13.8%
Taylor expanded in x around -inf 45.5%
mul-1-neg45.5%
Simplified45.5%
sqrt-unprod46.2%
metadata-eval46.2%
metadata-eval46.2%
Applied egg-rr46.2%
if -1 < (/.f64 x (sqrt.f64 (+.f64 (*.f64 (*.f64 4 p) p) (*.f64 x x)))) Initial program 100.0%
Final simplification87.0%
p_m = (fabs.f64 p)
(FPCore (p_m x)
:precision binary64
(let* ((t_0 (/ p_m (- x))))
(if (<= x -3.6e+31)
t_0
(if (<= x -1850.0)
(sqrt 0.5)
(if (<= x -2.45e-51)
t_0
(if (<= x 20000000000000.0) (sqrt 0.5) 1.0))))))p_m = fabs(p);
double code(double p_m, double x) {
double t_0 = p_m / -x;
double tmp;
if (x <= -3.6e+31) {
tmp = t_0;
} else if (x <= -1850.0) {
tmp = sqrt(0.5);
} else if (x <= -2.45e-51) {
tmp = t_0;
} else if (x <= 20000000000000.0) {
tmp = sqrt(0.5);
} 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) :: t_0
real(8) :: tmp
t_0 = p_m / -x
if (x <= (-3.6d+31)) then
tmp = t_0
else if (x <= (-1850.0d0)) then
tmp = sqrt(0.5d0)
else if (x <= (-2.45d-51)) then
tmp = t_0
else if (x <= 20000000000000.0d0) then
tmp = sqrt(0.5d0)
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 t_0 = p_m / -x;
double tmp;
if (x <= -3.6e+31) {
tmp = t_0;
} else if (x <= -1850.0) {
tmp = Math.sqrt(0.5);
} else if (x <= -2.45e-51) {
tmp = t_0;
} else if (x <= 20000000000000.0) {
tmp = Math.sqrt(0.5);
} else {
tmp = 1.0;
}
return tmp;
}
p_m = math.fabs(p) def code(p_m, x): t_0 = p_m / -x tmp = 0 if x <= -3.6e+31: tmp = t_0 elif x <= -1850.0: tmp = math.sqrt(0.5) elif x <= -2.45e-51: tmp = t_0 elif x <= 20000000000000.0: tmp = math.sqrt(0.5) else: tmp = 1.0 return tmp
p_m = abs(p) function code(p_m, x) t_0 = Float64(p_m / Float64(-x)) tmp = 0.0 if (x <= -3.6e+31) tmp = t_0; elseif (x <= -1850.0) tmp = sqrt(0.5); elseif (x <= -2.45e-51) tmp = t_0; elseif (x <= 20000000000000.0) tmp = sqrt(0.5); else tmp = 1.0; end return tmp end
p_m = abs(p); function tmp_2 = code(p_m, x) t_0 = p_m / -x; tmp = 0.0; if (x <= -3.6e+31) tmp = t_0; elseif (x <= -1850.0) tmp = sqrt(0.5); elseif (x <= -2.45e-51) tmp = t_0; elseif (x <= 20000000000000.0) tmp = sqrt(0.5); else tmp = 1.0; end tmp_2 = tmp; end
p_m = N[Abs[p], $MachinePrecision]
code[p$95$m_, x_] := Block[{t$95$0 = N[(p$95$m / (-x)), $MachinePrecision]}, If[LessEqual[x, -3.6e+31], t$95$0, If[LessEqual[x, -1850.0], N[Sqrt[0.5], $MachinePrecision], If[LessEqual[x, -2.45e-51], t$95$0, If[LessEqual[x, 20000000000000.0], N[Sqrt[0.5], $MachinePrecision], 1.0]]]]]
\begin{array}{l}
p_m = \left|p\right|
\\
\begin{array}{l}
t_0 := \frac{p\_m}{-x}\\
\mathbf{if}\;x \leq -3.6 \cdot 10^{+31}:\\
\;\;\;\;t\_0\\
\mathbf{elif}\;x \leq -1850:\\
\;\;\;\;\sqrt{0.5}\\
\mathbf{elif}\;x \leq -2.45 \cdot 10^{-51}:\\
\;\;\;\;t\_0\\
\mathbf{elif}\;x \leq 20000000000000:\\
\;\;\;\;\sqrt{0.5}\\
\mathbf{else}:\\
\;\;\;\;1\\
\end{array}
\end{array}
if x < -3.59999999999999996e31 or -1850 < x < -2.44999999999999987e-51Initial program 37.8%
Taylor expanded in x around -inf 34.5%
mul-1-neg34.5%
Simplified34.5%
sqrt-unprod35.0%
metadata-eval35.0%
metadata-eval35.0%
Applied egg-rr35.0%
if -3.59999999999999996e31 < x < -1850 or -2.44999999999999987e-51 < x < 2e13Initial program 91.6%
Taylor expanded in x around 0 78.0%
if 2e13 < x Initial program 100.0%
Taylor expanded in x around inf 70.3%
Final simplification64.6%
p_m = (fabs.f64 p) (FPCore (p_m x) :precision binary64 (if (<= p_m 2.2e-75) (/ p_m (- x)) (sqrt 0.5)))
p_m = fabs(p);
double code(double p_m, double x) {
double tmp;
if (p_m <= 2.2e-75) {
tmp = p_m / -x;
} 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 <= 2.2d-75) then
tmp = p_m / -x
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 <= 2.2e-75) {
tmp = p_m / -x;
} else {
tmp = Math.sqrt(0.5);
}
return tmp;
}
p_m = math.fabs(p) def code(p_m, x): tmp = 0 if p_m <= 2.2e-75: tmp = p_m / -x else: tmp = math.sqrt(0.5) return tmp
p_m = abs(p) function code(p_m, x) tmp = 0.0 if (p_m <= 2.2e-75) tmp = Float64(p_m / Float64(-x)); 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 <= 2.2e-75) tmp = p_m / -x; 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, 2.2e-75], N[(p$95$m / (-x)), $MachinePrecision], N[Sqrt[0.5], $MachinePrecision]]
\begin{array}{l}
p_m = \left|p\right|
\\
\begin{array}{l}
\mathbf{if}\;p\_m \leq 2.2 \cdot 10^{-75}:\\
\;\;\;\;\frac{p\_m}{-x}\\
\mathbf{else}:\\
\;\;\;\;\sqrt{0.5}\\
\end{array}
\end{array}
if p < 2.20000000000000005e-75Initial program 72.6%
Taylor expanded in x around -inf 15.3%
mul-1-neg15.3%
Simplified15.3%
sqrt-unprod15.4%
metadata-eval15.4%
metadata-eval15.4%
Applied egg-rr15.4%
if 2.20000000000000005e-75 < p Initial program 93.0%
Taylor expanded in x around 0 79.9%
Final simplification36.1%
p_m = (fabs.f64 p) (FPCore (p_m x) :precision binary64 (/ p_m (- x)))
p_m = fabs(p);
double code(double p_m, double x) {
return p_m / -x;
}
p_m = abs(p)
real(8) function code(p_m, x)
real(8), intent (in) :: p_m
real(8), intent (in) :: x
code = p_m / -x
end function
p_m = Math.abs(p);
public static double code(double p_m, double x) {
return p_m / -x;
}
p_m = math.fabs(p) def code(p_m, x): return p_m / -x
p_m = abs(p) function code(p_m, x) return Float64(p_m / Float64(-x)) end
p_m = abs(p); function tmp = code(p_m, x) tmp = p_m / -x; end
p_m = N[Abs[p], $MachinePrecision] code[p$95$m_, x_] := N[(p$95$m / (-x)), $MachinePrecision]
\begin{array}{l}
p_m = \left|p\right|
\\
\frac{p\_m}{-x}
\end{array}
Initial program 79.1%
Taylor expanded in x around -inf 13.4%
mul-1-neg13.4%
Simplified13.4%
sqrt-unprod13.6%
metadata-eval13.6%
metadata-eval13.6%
Applied egg-rr13.6%
Final simplification13.6%
(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 2024076
(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))))))))