
(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)))) -0.99) (/ 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)))) <= -0.99) {
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)))) <= -0.99) {
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)))) <= -0.99: 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)))) <= -0.99) 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)))) <= -0.99) 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], -0.99], 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 -0.99:\\
\;\;\;\;\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)))) < -0.98999999999999999Initial program 16.1%
add-sqr-sqrt16.1%
hypot-define16.1%
associate-*l*16.1%
sqrt-prod16.1%
metadata-eval16.1%
sqrt-unprod4.8%
add-sqr-sqrt16.1%
Applied egg-rr16.1%
sqrt-prod16.1%
add-sqr-sqrt0.0%
metadata-eval0.0%
add-sqr-sqrt16.1%
hypot-undefine16.1%
+-commutative16.1%
hypot-undefine16.1%
associate-+r+16.0%
*-un-lft-identity16.0%
*-un-lft-identity16.0%
sqrt-prod16.0%
add-cbrt-cube16.0%
Applied egg-rr16.1%
Taylor expanded in x around -inf 54.4%
mul-1-neg54.4%
distribute-neg-frac254.4%
Simplified54.4%
if -0.98999999999999999 < (/.f64 x (sqrt.f64 (+.f64 (*.f64 (*.f64 #s(literal 4 binary64) p) p) (*.f64 x x)))) Initial program 99.9%
add-sqr-sqrt99.9%
hypot-define100.0%
associate-*l*100.0%
sqrt-prod100.0%
metadata-eval100.0%
sqrt-unprod55.7%
add-sqr-sqrt100.0%
Applied egg-rr100.0%
Final simplification87.3%
p_m = (fabs.f64 p)
(FPCore (p_m x)
:precision binary64
(let* ((t_0 (/ p_m (- x))))
(if (<= p_m 1.6e-237)
1.0
(if (<= p_m 2.2e-198)
t_0
(if (<= p_m 4.5e-161) 1.0 (if (<= p_m 5.7e-39) t_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 <= 1.6e-237) {
tmp = 1.0;
} else if (p_m <= 2.2e-198) {
tmp = t_0;
} else if (p_m <= 4.5e-161) {
tmp = 1.0;
} else if (p_m <= 5.7e-39) {
tmp = t_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 <= 1.6d-237) then
tmp = 1.0d0
else if (p_m <= 2.2d-198) then
tmp = t_0
else if (p_m <= 4.5d-161) then
tmp = 1.0d0
else if (p_m <= 5.7d-39) then
tmp = t_0
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 <= 1.6e-237) {
tmp = 1.0;
} else if (p_m <= 2.2e-198) {
tmp = t_0;
} else if (p_m <= 4.5e-161) {
tmp = 1.0;
} else if (p_m <= 5.7e-39) {
tmp = t_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 <= 1.6e-237: tmp = 1.0 elif p_m <= 2.2e-198: tmp = t_0 elif p_m <= 4.5e-161: tmp = 1.0 elif p_m <= 5.7e-39: tmp = t_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 <= 1.6e-237) tmp = 1.0; elseif (p_m <= 2.2e-198) tmp = t_0; elseif (p_m <= 4.5e-161) tmp = 1.0; elseif (p_m <= 5.7e-39) tmp = t_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 <= 1.6e-237) tmp = 1.0; elseif (p_m <= 2.2e-198) tmp = t_0; elseif (p_m <= 4.5e-161) tmp = 1.0; elseif (p_m <= 5.7e-39) tmp = t_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, 1.6e-237], 1.0, If[LessEqual[p$95$m, 2.2e-198], t$95$0, If[LessEqual[p$95$m, 4.5e-161], 1.0, If[LessEqual[p$95$m, 5.7e-39], t$95$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 1.6 \cdot 10^{-237}:\\
\;\;\;\;1\\
\mathbf{elif}\;p\_m \leq 2.2 \cdot 10^{-198}:\\
\;\;\;\;t\_0\\
\mathbf{elif}\;p\_m \leq 4.5 \cdot 10^{-161}:\\
\;\;\;\;1\\
\mathbf{elif}\;p\_m \leq 5.7 \cdot 10^{-39}:\\
\;\;\;\;t\_0\\
\mathbf{else}:\\
\;\;\;\;\sqrt{0.5}\\
\end{array}
\end{array}
if p < 1.6e-237 or 2.2e-198 < p < 4.4999999999999996e-161Initial program 73.0%
add-sqr-sqrt73.0%
hypot-define73.0%
associate-*l*73.0%
sqrt-prod73.0%
metadata-eval73.0%
sqrt-unprod10.1%
add-sqr-sqrt73.0%
Applied egg-rr73.0%
sqrt-prod72.5%
add-sqr-sqrt51.3%
metadata-eval51.3%
add-sqr-sqrt72.5%
hypot-undefine72.5%
+-commutative72.5%
hypot-undefine72.5%
associate-+r+72.5%
*-un-lft-identity72.5%
*-un-lft-identity72.5%
sqrt-prod73.0%
add-cbrt-cube73.0%
Applied egg-rr73.0%
Taylor expanded in x around inf 39.8%
if 1.6e-237 < p < 2.2e-198 or 4.4999999999999996e-161 < p < 5.6999999999999997e-39Initial program 53.3%
add-sqr-sqrt53.3%
hypot-define53.3%
associate-*l*53.3%
sqrt-prod53.3%
metadata-eval53.3%
sqrt-unprod53.3%
add-sqr-sqrt53.3%
Applied egg-rr53.3%
sqrt-prod52.8%
add-sqr-sqrt38.9%
metadata-eval38.9%
add-sqr-sqrt52.8%
hypot-undefine52.8%
+-commutative52.8%
hypot-undefine52.8%
associate-+r+52.8%
*-un-lft-identity52.8%
*-un-lft-identity52.8%
sqrt-prod53.3%
add-cbrt-cube53.4%
Applied egg-rr53.4%
Taylor expanded in x around -inf 54.1%
mul-1-neg54.1%
distribute-neg-frac254.1%
Simplified54.1%
if 5.6999999999999997e-39 < p Initial program 95.6%
Taylor expanded in x around 0 88.7%
Final simplification56.2%
p_m = (fabs.f64 p) (FPCore (p_m x) :precision binary64 (if (<= x -2.3e-194) (/ p_m (- x)) 1.0))
p_m = fabs(p);
double code(double p_m, double x) {
double tmp;
if (x <= -2.3e-194) {
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 <= (-2.3d-194)) 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 <= -2.3e-194) {
tmp = p_m / -x;
} else {
tmp = 1.0;
}
return tmp;
}
p_m = math.fabs(p) def code(p_m, x): tmp = 0 if x <= -2.3e-194: tmp = p_m / -x else: tmp = 1.0 return tmp
p_m = abs(p) function code(p_m, x) tmp = 0.0 if (x <= -2.3e-194) 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 <= -2.3e-194) 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, -2.3e-194], N[(p$95$m / (-x)), $MachinePrecision], 1.0]
\begin{array}{l}
p_m = \left|p\right|
\\
\begin{array}{l}
\mathbf{if}\;x \leq -2.3 \cdot 10^{-194}:\\
\;\;\;\;\frac{p\_m}{-x}\\
\mathbf{else}:\\
\;\;\;\;1\\
\end{array}
\end{array}
if x < -2.30000000000000003e-194Initial program 54.1%
add-sqr-sqrt54.1%
hypot-define54.1%
associate-*l*54.1%
sqrt-prod54.1%
metadata-eval54.1%
sqrt-unprod29.5%
add-sqr-sqrt54.1%
Applied egg-rr54.1%
sqrt-prod54.1%
add-sqr-sqrt5.4%
metadata-eval5.4%
add-sqr-sqrt54.1%
hypot-undefine54.1%
+-commutative54.1%
hypot-undefine54.1%
associate-+r+54.1%
*-un-lft-identity54.1%
*-un-lft-identity54.1%
sqrt-prod54.1%
add-cbrt-cube54.1%
Applied egg-rr54.1%
Taylor expanded in x around -inf 31.3%
mul-1-neg31.3%
distribute-neg-frac231.3%
Simplified31.3%
if -2.30000000000000003e-194 < x Initial program 100.0%
add-sqr-sqrt100.0%
hypot-define100.0%
associate-*l*100.0%
sqrt-prod100.0%
metadata-eval100.0%
sqrt-unprod54.0%
add-sqr-sqrt100.0%
Applied egg-rr100.0%
sqrt-prod99.2%
add-sqr-sqrt99.2%
metadata-eval99.2%
add-sqr-sqrt99.2%
hypot-undefine99.2%
+-commutative99.2%
hypot-undefine99.2%
associate-+r+99.2%
*-un-lft-identity99.2%
*-un-lft-identity99.2%
sqrt-prod100.0%
add-cbrt-cube99.9%
Applied egg-rr100.0%
Taylor expanded in x around inf 59.6%
Final simplification45.2%
p_m = (fabs.f64 p) (FPCore (p_m x) :precision binary64 (if (<= x -3.4e+82) (/ p_m x) 1.0))
p_m = fabs(p);
double code(double p_m, double x) {
double tmp;
if (x <= -3.4e+82) {
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 <= (-3.4d+82)) 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 <= -3.4e+82) {
tmp = p_m / x;
} else {
tmp = 1.0;
}
return tmp;
}
p_m = math.fabs(p) def code(p_m, x): tmp = 0 if x <= -3.4e+82: tmp = p_m / x else: tmp = 1.0 return tmp
p_m = abs(p) function code(p_m, x) tmp = 0.0 if (x <= -3.4e+82) tmp = Float64(p_m / 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 <= -3.4e+82) 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, -3.4e+82], N[(p$95$m / x), $MachinePrecision], 1.0]
\begin{array}{l}
p_m = \left|p\right|
\\
\begin{array}{l}
\mathbf{if}\;x \leq -3.4 \cdot 10^{+82}:\\
\;\;\;\;\frac{p\_m}{x}\\
\mathbf{else}:\\
\;\;\;\;1\\
\end{array}
\end{array}
if x < -3.39999999999999994e82Initial program 50.4%
Taylor expanded in x around -inf 45.4%
mul-1-neg45.4%
associate-/l*45.4%
distribute-rgt-neg-in45.4%
associate-/l*45.5%
Simplified45.5%
pow145.5%
add-sqr-sqrt45.5%
sqrt-unprod45.5%
sqr-neg45.5%
sqrt-unprod0.0%
add-sqr-sqrt58.6%
associate-*r/58.3%
sqrt-unprod58.9%
metadata-eval58.9%
metadata-eval58.9%
Applied egg-rr58.9%
unpow158.9%
associate-*r/59.0%
*-rgt-identity59.0%
Simplified59.0%
if -3.39999999999999994e82 < x Initial program 80.2%
add-sqr-sqrt80.2%
hypot-define80.2%
associate-*l*80.2%
sqrt-prod80.2%
metadata-eval80.2%
sqrt-unprod44.1%
add-sqr-sqrt80.2%
Applied egg-rr80.2%
sqrt-prod79.8%
add-sqr-sqrt58.4%
metadata-eval58.4%
add-sqr-sqrt79.8%
hypot-undefine79.7%
+-commutative79.7%
hypot-undefine79.8%
associate-+r+79.7%
*-un-lft-identity79.7%
*-un-lft-identity79.7%
sqrt-prod80.2%
add-cbrt-cube80.1%
Applied egg-rr80.2%
Taylor expanded in x around inf 39.1%
Final simplification41.4%
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 76.7%
add-sqr-sqrt76.7%
hypot-define76.7%
associate-*l*76.7%
sqrt-prod76.7%
metadata-eval76.7%
sqrt-unprod41.5%
add-sqr-sqrt76.7%
Applied egg-rr76.7%
sqrt-prod76.3%
add-sqr-sqrt51.6%
metadata-eval51.6%
add-sqr-sqrt76.3%
hypot-undefine76.3%
+-commutative76.3%
hypot-undefine76.3%
associate-+r+76.3%
*-un-lft-identity76.3%
*-un-lft-identity76.3%
sqrt-prod76.7%
add-cbrt-cube76.7%
Applied egg-rr76.7%
Taylor expanded in x around inf 35.4%
Final simplification35.4%
(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 2024075
(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))))))))