
(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 (if (<= (/ x (sqrt (+ (* p_m (* 4.0 p_m)) (* x x)))) -0.5) (/ 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)))) <= -0.5) {
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)))) <= -0.5) {
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)))) <= -0.5: 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)))) <= -0.5) 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)))) <= -0.5) 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], -0.5], 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 -0.5:\\
\;\;\;\;\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)))) < -0.5Initial program 12.7%
expm1-log1p-u12.7%
expm1-undefine12.5%
+-commutative12.5%
add-sqr-sqrt12.5%
hypot-define12.5%
associate-*l*12.5%
sqrt-prod12.5%
metadata-eval12.5%
sqrt-unprod6.8%
add-sqr-sqrt12.5%
Applied egg-rr12.5%
sub-neg12.5%
metadata-eval12.5%
+-commutative12.5%
log1p-undefine12.5%
rem-exp-log12.5%
associate-+r+12.5%
metadata-eval12.5%
Simplified12.5%
add-cbrt-cube12.5%
add-sqr-sqrt12.5%
pow112.5%
pow1/212.5%
pow-prod-up12.5%
associate-+r+12.5%
metadata-eval12.5%
distribute-lft-in12.5%
metadata-eval12.5%
metadata-eval12.5%
Applied egg-rr12.5%
Taylor expanded in x around -inf 50.9%
neg-mul-150.9%
distribute-neg-frac250.9%
Simplified50.9%
if -0.5 < (/.f64 x (sqrt.f64 (+.f64 (*.f64 (*.f64 #s(literal 4 binary64) p) p) (*.f64 x x)))) Initial program 100.0%
add-sqr-sqrt100.0%
hypot-define100.0%
associate-*l*100.0%
sqrt-prod100.0%
metadata-eval100.0%
sqrt-unprod51.3%
add-sqr-sqrt100.0%
Applied egg-rr100.0%
Final simplification87.9%
p_m = (fabs.f64 p)
(FPCore (p_m x)
:precision binary64
(let* ((t_0 (/ p_m (- x))))
(if (<= p_m 3e-219)
t_0
(if (<= p_m 3.1e-176)
1.0
(if (<= p_m 1.55e-171) t_0 (if (<= p_m 1.64e-90) 1.0 (sqrt 0.5)))))))p_m = fabs(p);
double code(double p_m, double x) {
double t_0 = p_m / -x;
double tmp;
if (p_m <= 3e-219) {
tmp = t_0;
} else if (p_m <= 3.1e-176) {
tmp = 1.0;
} else if (p_m <= 1.55e-171) {
tmp = t_0;
} else if (p_m <= 1.64e-90) {
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) :: t_0
real(8) :: tmp
t_0 = p_m / -x
if (p_m <= 3d-219) then
tmp = t_0
else if (p_m <= 3.1d-176) then
tmp = 1.0d0
else if (p_m <= 1.55d-171) then
tmp = t_0
else if (p_m <= 1.64d-90) 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 t_0 = p_m / -x;
double tmp;
if (p_m <= 3e-219) {
tmp = t_0;
} else if (p_m <= 3.1e-176) {
tmp = 1.0;
} else if (p_m <= 1.55e-171) {
tmp = t_0;
} else if (p_m <= 1.64e-90) {
tmp = 1.0;
} else {
tmp = Math.sqrt(0.5);
}
return tmp;
}
p_m = math.fabs(p) def code(p_m, x): t_0 = p_m / -x tmp = 0 if p_m <= 3e-219: tmp = t_0 elif p_m <= 3.1e-176: tmp = 1.0 elif p_m <= 1.55e-171: tmp = t_0 elif p_m <= 1.64e-90: tmp = 1.0 else: tmp = math.sqrt(0.5) return tmp
p_m = abs(p) function code(p_m, x) t_0 = Float64(p_m / Float64(-x)) tmp = 0.0 if (p_m <= 3e-219) tmp = t_0; elseif (p_m <= 3.1e-176) tmp = 1.0; elseif (p_m <= 1.55e-171) tmp = t_0; elseif (p_m <= 1.64e-90) tmp = 1.0; else tmp = sqrt(0.5); end return tmp end
p_m = abs(p); function tmp_2 = code(p_m, x) t_0 = p_m / -x; tmp = 0.0; if (p_m <= 3e-219) tmp = t_0; elseif (p_m <= 3.1e-176) tmp = 1.0; elseif (p_m <= 1.55e-171) tmp = t_0; elseif (p_m <= 1.64e-90) tmp = 1.0; else tmp = sqrt(0.5); 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[p$95$m, 3e-219], t$95$0, If[LessEqual[p$95$m, 3.1e-176], 1.0, If[LessEqual[p$95$m, 1.55e-171], t$95$0, If[LessEqual[p$95$m, 1.64e-90], 1.0, N[Sqrt[0.5], $MachinePrecision]]]]]]
\begin{array}{l}
p_m = \left|p\right|
\\
\begin{array}{l}
t_0 := \frac{p\_m}{-x}\\
\mathbf{if}\;p\_m \leq 3 \cdot 10^{-219}:\\
\;\;\;\;t\_0\\
\mathbf{elif}\;p\_m \leq 3.1 \cdot 10^{-176}:\\
\;\;\;\;1\\
\mathbf{elif}\;p\_m \leq 1.55 \cdot 10^{-171}:\\
\;\;\;\;t\_0\\
\mathbf{elif}\;p\_m \leq 1.64 \cdot 10^{-90}:\\
\;\;\;\;1\\
\mathbf{else}:\\
\;\;\;\;\sqrt{0.5}\\
\end{array}
\end{array}
if p < 3.0000000000000001e-219 or 3.09999999999999992e-176 < p < 1.55e-171Initial program 72.1%
expm1-log1p-u71.6%
expm1-undefine71.6%
+-commutative71.6%
add-sqr-sqrt71.6%
hypot-define71.6%
associate-*l*71.6%
sqrt-prod71.6%
metadata-eval71.6%
sqrt-unprod8.2%
add-sqr-sqrt71.6%
Applied egg-rr71.6%
sub-neg71.6%
metadata-eval71.6%
+-commutative71.6%
log1p-undefine72.0%
rem-exp-log72.0%
associate-+r+72.1%
metadata-eval72.1%
Simplified72.1%
add-cbrt-cube72.0%
add-sqr-sqrt72.0%
pow172.0%
pow1/272.0%
pow-prod-up72.0%
associate-+r+72.0%
metadata-eval72.0%
distribute-lft-in72.0%
metadata-eval72.0%
metadata-eval72.0%
Applied egg-rr72.0%
Taylor expanded in x around -inf 15.3%
neg-mul-115.3%
distribute-neg-frac215.3%
Simplified15.3%
if 3.0000000000000001e-219 < p < 3.09999999999999992e-176 or 1.55e-171 < p < 1.6400000000000001e-90Initial program 74.9%
expm1-log1p-u73.9%
expm1-undefine73.1%
+-commutative73.1%
add-sqr-sqrt73.1%
hypot-define73.1%
associate-*l*73.1%
sqrt-prod73.1%
metadata-eval73.1%
sqrt-unprod73.1%
add-sqr-sqrt73.1%
Applied egg-rr73.1%
sub-neg73.1%
metadata-eval73.1%
+-commutative73.1%
log1p-undefine74.2%
rem-exp-log74.2%
associate-+r+74.2%
metadata-eval74.2%
Simplified74.2%
add-cbrt-cube74.2%
add-sqr-sqrt74.2%
pow174.2%
pow1/274.2%
pow-prod-up74.2%
associate-+r+74.2%
metadata-eval74.2%
distribute-lft-in74.2%
metadata-eval74.2%
metadata-eval74.2%
Applied egg-rr74.2%
Taylor expanded in x around inf 70.7%
if 1.6400000000000001e-90 < p Initial program 91.7%
Taylor expanded in x around 0 80.4%
Final simplification40.7%
p_m = (fabs.f64 p) (FPCore (p_m x) :precision binary64 (if (<= x -5e-142) (/ p_m (- x)) 1.0))
p_m = fabs(p);
double code(double p_m, double x) {
double tmp;
if (x <= -5e-142) {
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 <= (-5d-142)) 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 <= -5e-142) {
tmp = p_m / -x;
} else {
tmp = 1.0;
}
return tmp;
}
p_m = math.fabs(p) def code(p_m, x): tmp = 0 if x <= -5e-142: tmp = p_m / -x else: tmp = 1.0 return tmp
p_m = abs(p) function code(p_m, x) tmp = 0.0 if (x <= -5e-142) 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 <= -5e-142) 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, -5e-142], N[(p$95$m / (-x)), $MachinePrecision], 1.0]
\begin{array}{l}
p_m = \left|p\right|
\\
\begin{array}{l}
\mathbf{if}\;x \leq -5 \cdot 10^{-142}:\\
\;\;\;\;\frac{p\_m}{-x}\\
\mathbf{else}:\\
\;\;\;\;1\\
\end{array}
\end{array}
if x < -5.0000000000000002e-142Initial program 54.2%
expm1-log1p-u54.2%
expm1-undefine54.0%
+-commutative54.0%
add-sqr-sqrt54.0%
hypot-define54.0%
associate-*l*54.0%
sqrt-prod54.0%
metadata-eval54.0%
sqrt-unprod29.4%
add-sqr-sqrt54.0%
Applied egg-rr54.0%
sub-neg54.0%
metadata-eval54.0%
+-commutative54.0%
log1p-undefine54.0%
rem-exp-log54.0%
associate-+r+54.0%
metadata-eval54.0%
Simplified54.0%
add-cbrt-cube54.0%
add-sqr-sqrt54.0%
pow154.0%
pow1/254.0%
pow-prod-up54.0%
associate-+r+54.0%
metadata-eval54.0%
distribute-lft-in54.0%
metadata-eval54.0%
metadata-eval54.0%
Applied egg-rr54.0%
Taylor expanded in x around -inf 28.3%
neg-mul-128.3%
distribute-neg-frac228.3%
Simplified28.3%
if -5.0000000000000002e-142 < x Initial program 100.0%
expm1-log1p-u99.2%
expm1-undefine99.2%
+-commutative99.2%
add-sqr-sqrt99.2%
hypot-define99.2%
associate-*l*99.2%
sqrt-prod99.2%
metadata-eval99.2%
sqrt-unprod49.6%
add-sqr-sqrt99.2%
Applied egg-rr99.2%
sub-neg99.2%
metadata-eval99.2%
+-commutative99.2%
log1p-undefine100.0%
rem-exp-log100.0%
associate-+r+100.0%
metadata-eval100.0%
Simplified100.0%
add-cbrt-cube99.9%
add-sqr-sqrt99.9%
pow199.9%
pow1/299.9%
pow-prod-up99.9%
associate-+r+99.9%
metadata-eval99.9%
distribute-lft-in99.9%
metadata-eval99.9%
metadata-eval99.9%
Applied egg-rr99.9%
Taylor expanded in x around inf 59.1%
Final simplification44.7%
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 78.5%
expm1-log1p-u78.1%
expm1-undefine78.0%
+-commutative78.0%
add-sqr-sqrt78.0%
hypot-define78.0%
associate-*l*78.0%
sqrt-prod78.0%
metadata-eval78.0%
sqrt-unprod40.1%
add-sqr-sqrt78.0%
Applied egg-rr78.0%
sub-neg78.0%
metadata-eval78.0%
+-commutative78.0%
log1p-undefine78.4%
rem-exp-log78.4%
associate-+r+78.4%
metadata-eval78.4%
Simplified78.4%
add-cbrt-cube78.4%
add-sqr-sqrt78.4%
pow178.4%
pow1/278.4%
pow-prod-up78.4%
associate-+r+78.4%
metadata-eval78.4%
distribute-lft-in78.4%
metadata-eval78.4%
metadata-eval78.4%
Applied egg-rr78.4%
Taylor expanded in x around inf 37.2%
Final simplification37.2%
(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 2024112
(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))))))))