
(FPCore (x y z) :precision binary64 (* 2.0 (sqrt (+ (+ (* x y) (* x z)) (* y z)))))
double code(double x, double y, double z) {
return 2.0 * sqrt((((x * y) + (x * z)) + (y * z)));
}
real(8) function code(x, y, z)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
code = 2.0d0 * sqrt((((x * y) + (x * z)) + (y * z)))
end function
public static double code(double x, double y, double z) {
return 2.0 * Math.sqrt((((x * y) + (x * z)) + (y * z)));
}
def code(x, y, z): return 2.0 * math.sqrt((((x * y) + (x * z)) + (y * z)))
function code(x, y, z) return Float64(2.0 * sqrt(Float64(Float64(Float64(x * y) + Float64(x * z)) + Float64(y * z)))) end
function tmp = code(x, y, z) tmp = 2.0 * sqrt((((x * y) + (x * z)) + (y * z))); end
code[x_, y_, z_] := N[(2.0 * N[Sqrt[N[(N[(N[(x * y), $MachinePrecision] + N[(x * z), $MachinePrecision]), $MachinePrecision] + N[(y * z), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
2 \cdot \sqrt{\left(x \cdot y + x \cdot z\right) + y \cdot z}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 6 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (x y z) :precision binary64 (* 2.0 (sqrt (+ (+ (* x y) (* x z)) (* y z)))))
double code(double x, double y, double z) {
return 2.0 * sqrt((((x * y) + (x * z)) + (y * z)));
}
real(8) function code(x, y, z)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
code = 2.0d0 * sqrt((((x * y) + (x * z)) + (y * z)))
end function
public static double code(double x, double y, double z) {
return 2.0 * Math.sqrt((((x * y) + (x * z)) + (y * z)));
}
def code(x, y, z): return 2.0 * math.sqrt((((x * y) + (x * z)) + (y * z)))
function code(x, y, z) return Float64(2.0 * sqrt(Float64(Float64(Float64(x * y) + Float64(x * z)) + Float64(y * z)))) end
function tmp = code(x, y, z) tmp = 2.0 * sqrt((((x * y) + (x * z)) + (y * z))); end
code[x_, y_, z_] := N[(2.0 * N[Sqrt[N[(N[(N[(x * y), $MachinePrecision] + N[(x * z), $MachinePrecision]), $MachinePrecision] + N[(y * z), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
2 \cdot \sqrt{\left(x \cdot y + x \cdot z\right) + y \cdot z}
\end{array}
NOTE: x, y, and z should be sorted in increasing order before calling this function.
(FPCore (x y z)
:precision binary64
(if (<= y 8.2e+22)
(* (sqrt (fma (+ y x) z (* y x))) 2.0)
(*
(fma
(sqrt (/ (pow (+ y x) -1.0) (pow z 3.0)))
(* y x)
(* (sqrt (/ (+ y x) z)) 2.0))
z)))assert(x < y && y < z);
double code(double x, double y, double z) {
double tmp;
if (y <= 8.2e+22) {
tmp = sqrt(fma((y + x), z, (y * x))) * 2.0;
} else {
tmp = fma(sqrt((pow((y + x), -1.0) / pow(z, 3.0))), (y * x), (sqrt(((y + x) / z)) * 2.0)) * z;
}
return tmp;
}
x, y, z = sort([x, y, z]) function code(x, y, z) tmp = 0.0 if (y <= 8.2e+22) tmp = Float64(sqrt(fma(Float64(y + x), z, Float64(y * x))) * 2.0); else tmp = Float64(fma(sqrt(Float64((Float64(y + x) ^ -1.0) / (z ^ 3.0))), Float64(y * x), Float64(sqrt(Float64(Float64(y + x) / z)) * 2.0)) * z); end return tmp end
NOTE: x, y, and z should be sorted in increasing order before calling this function. code[x_, y_, z_] := If[LessEqual[y, 8.2e+22], N[(N[Sqrt[N[(N[(y + x), $MachinePrecision] * z + N[(y * x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * 2.0), $MachinePrecision], N[(N[(N[Sqrt[N[(N[Power[N[(y + x), $MachinePrecision], -1.0], $MachinePrecision] / N[Power[z, 3.0], $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * N[(y * x), $MachinePrecision] + N[(N[Sqrt[N[(N[(y + x), $MachinePrecision] / z), $MachinePrecision]], $MachinePrecision] * 2.0), $MachinePrecision]), $MachinePrecision] * z), $MachinePrecision]]
\begin{array}{l}
[x, y, z] = \mathsf{sort}([x, y, z])\\
\\
\begin{array}{l}
\mathbf{if}\;y \leq 8.2 \cdot 10^{+22}:\\
\;\;\;\;\sqrt{\mathsf{fma}\left(y + x, z, y \cdot x\right)} \cdot 2\\
\mathbf{else}:\\
\;\;\;\;\mathsf{fma}\left(\sqrt{\frac{{\left(y + x\right)}^{-1}}{{z}^{3}}}, y \cdot x, \sqrt{\frac{y + x}{z}} \cdot 2\right) \cdot z\\
\end{array}
\end{array}
if y < 8.19999999999999958e22Initial program 73.9%
lift-*.f64N/A
*-commutativeN/A
lower-*.f6473.9
lift-+.f64N/A
lift-+.f64N/A
associate-+l+N/A
+-commutativeN/A
lift-*.f64N/A
lift-*.f64N/A
distribute-rgt-outN/A
*-commutativeN/A
lower-fma.f64N/A
+-commutativeN/A
lower-+.f6474.0
lift-*.f64N/A
*-commutativeN/A
lower-*.f6474.0
Applied rewrites74.0%
if 8.19999999999999958e22 < y Initial program 46.3%
Taylor expanded in z around inf
*-commutativeN/A
lower-*.f64N/A
Applied rewrites29.9%
Final simplification64.8%
NOTE: x, y, and z should be sorted in increasing order before calling this function. (FPCore (x y z) :precision binary64 (if (<= y -4.9e-278) (* 2.0 (sqrt (* (+ z y) x))) (* 2.0 (sqrt (* (+ y x) z)))))
assert(x < y && y < z);
double code(double x, double y, double z) {
double tmp;
if (y <= -4.9e-278) {
tmp = 2.0 * sqrt(((z + y) * x));
} else {
tmp = 2.0 * sqrt(((y + x) * z));
}
return tmp;
}
NOTE: x, y, and z should be sorted in increasing order before calling this function.
real(8) function code(x, y, z)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
real(8) :: tmp
if (y <= (-4.9d-278)) then
tmp = 2.0d0 * sqrt(((z + y) * x))
else
tmp = 2.0d0 * sqrt(((y + x) * z))
end if
code = tmp
end function
assert x < y && y < z;
public static double code(double x, double y, double z) {
double tmp;
if (y <= -4.9e-278) {
tmp = 2.0 * Math.sqrt(((z + y) * x));
} else {
tmp = 2.0 * Math.sqrt(((y + x) * z));
}
return tmp;
}
[x, y, z] = sort([x, y, z]) def code(x, y, z): tmp = 0 if y <= -4.9e-278: tmp = 2.0 * math.sqrt(((z + y) * x)) else: tmp = 2.0 * math.sqrt(((y + x) * z)) return tmp
x, y, z = sort([x, y, z]) function code(x, y, z) tmp = 0.0 if (y <= -4.9e-278) tmp = Float64(2.0 * sqrt(Float64(Float64(z + y) * x))); else tmp = Float64(2.0 * sqrt(Float64(Float64(y + x) * z))); end return tmp end
x, y, z = num2cell(sort([x, y, z])){:}
function tmp_2 = code(x, y, z)
tmp = 0.0;
if (y <= -4.9e-278)
tmp = 2.0 * sqrt(((z + y) * x));
else
tmp = 2.0 * sqrt(((y + x) * z));
end
tmp_2 = tmp;
end
NOTE: x, y, and z should be sorted in increasing order before calling this function. code[x_, y_, z_] := If[LessEqual[y, -4.9e-278], N[(2.0 * N[Sqrt[N[(N[(z + y), $MachinePrecision] * x), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(2.0 * N[Sqrt[N[(N[(y + x), $MachinePrecision] * z), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
[x, y, z] = \mathsf{sort}([x, y, z])\\
\\
\begin{array}{l}
\mathbf{if}\;y \leq -4.9 \cdot 10^{-278}:\\
\;\;\;\;2 \cdot \sqrt{\left(z + y\right) \cdot x}\\
\mathbf{else}:\\
\;\;\;\;2 \cdot \sqrt{\left(y + x\right) \cdot z}\\
\end{array}
\end{array}
if y < -4.9000000000000002e-278Initial program 72.2%
Taylor expanded in x around inf
lower-sqrt.f64N/A
*-commutativeN/A
lower-*.f64N/A
+-commutativeN/A
lower-+.f6453.0
Applied rewrites53.0%
if -4.9000000000000002e-278 < y Initial program 64.2%
Taylor expanded in z around inf
*-commutativeN/A
lower-*.f64N/A
+-commutativeN/A
lower-+.f6444.6
Applied rewrites44.6%
NOTE: x, y, and z should be sorted in increasing order before calling this function. (FPCore (x y z) :precision binary64 (if (<= y -4.9e-278) (* 2.0 (sqrt (* (+ z y) x))) (* 2.0 (sqrt (* z y)))))
assert(x < y && y < z);
double code(double x, double y, double z) {
double tmp;
if (y <= -4.9e-278) {
tmp = 2.0 * sqrt(((z + y) * x));
} else {
tmp = 2.0 * sqrt((z * y));
}
return tmp;
}
NOTE: x, y, and z should be sorted in increasing order before calling this function.
real(8) function code(x, y, z)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
real(8) :: tmp
if (y <= (-4.9d-278)) then
tmp = 2.0d0 * sqrt(((z + y) * x))
else
tmp = 2.0d0 * sqrt((z * y))
end if
code = tmp
end function
assert x < y && y < z;
public static double code(double x, double y, double z) {
double tmp;
if (y <= -4.9e-278) {
tmp = 2.0 * Math.sqrt(((z + y) * x));
} else {
tmp = 2.0 * Math.sqrt((z * y));
}
return tmp;
}
[x, y, z] = sort([x, y, z]) def code(x, y, z): tmp = 0 if y <= -4.9e-278: tmp = 2.0 * math.sqrt(((z + y) * x)) else: tmp = 2.0 * math.sqrt((z * y)) return tmp
x, y, z = sort([x, y, z]) function code(x, y, z) tmp = 0.0 if (y <= -4.9e-278) tmp = Float64(2.0 * sqrt(Float64(Float64(z + y) * x))); else tmp = Float64(2.0 * sqrt(Float64(z * y))); end return tmp end
x, y, z = num2cell(sort([x, y, z])){:}
function tmp_2 = code(x, y, z)
tmp = 0.0;
if (y <= -4.9e-278)
tmp = 2.0 * sqrt(((z + y) * x));
else
tmp = 2.0 * sqrt((z * y));
end
tmp_2 = tmp;
end
NOTE: x, y, and z should be sorted in increasing order before calling this function. code[x_, y_, z_] := If[LessEqual[y, -4.9e-278], N[(2.0 * N[Sqrt[N[(N[(z + y), $MachinePrecision] * x), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(2.0 * N[Sqrt[N[(z * y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
[x, y, z] = \mathsf{sort}([x, y, z])\\
\\
\begin{array}{l}
\mathbf{if}\;y \leq -4.9 \cdot 10^{-278}:\\
\;\;\;\;2 \cdot \sqrt{\left(z + y\right) \cdot x}\\
\mathbf{else}:\\
\;\;\;\;2 \cdot \sqrt{z \cdot y}\\
\end{array}
\end{array}
if y < -4.9000000000000002e-278Initial program 72.2%
Taylor expanded in x around inf
lower-sqrt.f64N/A
*-commutativeN/A
lower-*.f64N/A
+-commutativeN/A
lower-+.f6453.0
Applied rewrites53.0%
if -4.9000000000000002e-278 < y Initial program 64.2%
Taylor expanded in x around 0
*-commutativeN/A
lower-*.f6419.7
Applied rewrites19.7%
NOTE: x, y, and z should be sorted in increasing order before calling this function. (FPCore (x y z) :precision binary64 (* (sqrt (fma (+ y x) z (* y x))) 2.0))
assert(x < y && y < z);
double code(double x, double y, double z) {
return sqrt(fma((y + x), z, (y * x))) * 2.0;
}
x, y, z = sort([x, y, z]) function code(x, y, z) return Float64(sqrt(fma(Float64(y + x), z, Float64(y * x))) * 2.0) end
NOTE: x, y, and z should be sorted in increasing order before calling this function. code[x_, y_, z_] := N[(N[Sqrt[N[(N[(y + x), $MachinePrecision] * z + N[(y * x), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * 2.0), $MachinePrecision]
\begin{array}{l}
[x, y, z] = \mathsf{sort}([x, y, z])\\
\\
\sqrt{\mathsf{fma}\left(y + x, z, y \cdot x\right)} \cdot 2
\end{array}
Initial program 68.2%
lift-*.f64N/A
*-commutativeN/A
lower-*.f6468.2
lift-+.f64N/A
lift-+.f64N/A
associate-+l+N/A
+-commutativeN/A
lift-*.f64N/A
lift-*.f64N/A
distribute-rgt-outN/A
*-commutativeN/A
lower-fma.f64N/A
+-commutativeN/A
lower-+.f6468.3
lift-*.f64N/A
*-commutativeN/A
lower-*.f6468.3
Applied rewrites68.3%
NOTE: x, y, and z should be sorted in increasing order before calling this function. (FPCore (x y z) :precision binary64 (if (<= y -4.9e-278) (* 2.0 (sqrt (* y x))) (* 2.0 (sqrt (* z y)))))
assert(x < y && y < z);
double code(double x, double y, double z) {
double tmp;
if (y <= -4.9e-278) {
tmp = 2.0 * sqrt((y * x));
} else {
tmp = 2.0 * sqrt((z * y));
}
return tmp;
}
NOTE: x, y, and z should be sorted in increasing order before calling this function.
real(8) function code(x, y, z)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
real(8) :: tmp
if (y <= (-4.9d-278)) then
tmp = 2.0d0 * sqrt((y * x))
else
tmp = 2.0d0 * sqrt((z * y))
end if
code = tmp
end function
assert x < y && y < z;
public static double code(double x, double y, double z) {
double tmp;
if (y <= -4.9e-278) {
tmp = 2.0 * Math.sqrt((y * x));
} else {
tmp = 2.0 * Math.sqrt((z * y));
}
return tmp;
}
[x, y, z] = sort([x, y, z]) def code(x, y, z): tmp = 0 if y <= -4.9e-278: tmp = 2.0 * math.sqrt((y * x)) else: tmp = 2.0 * math.sqrt((z * y)) return tmp
x, y, z = sort([x, y, z]) function code(x, y, z) tmp = 0.0 if (y <= -4.9e-278) tmp = Float64(2.0 * sqrt(Float64(y * x))); else tmp = Float64(2.0 * sqrt(Float64(z * y))); end return tmp end
x, y, z = num2cell(sort([x, y, z])){:}
function tmp_2 = code(x, y, z)
tmp = 0.0;
if (y <= -4.9e-278)
tmp = 2.0 * sqrt((y * x));
else
tmp = 2.0 * sqrt((z * y));
end
tmp_2 = tmp;
end
NOTE: x, y, and z should be sorted in increasing order before calling this function. code[x_, y_, z_] := If[LessEqual[y, -4.9e-278], N[(2.0 * N[Sqrt[N[(y * x), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(2.0 * N[Sqrt[N[(z * y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
[x, y, z] = \mathsf{sort}([x, y, z])\\
\\
\begin{array}{l}
\mathbf{if}\;y \leq -4.9 \cdot 10^{-278}:\\
\;\;\;\;2 \cdot \sqrt{y \cdot x}\\
\mathbf{else}:\\
\;\;\;\;2 \cdot \sqrt{z \cdot y}\\
\end{array}
\end{array}
if y < -4.9000000000000002e-278Initial program 72.2%
Taylor expanded in z around 0
lower-sqrt.f64N/A
*-commutativeN/A
lower-*.f6425.9
Applied rewrites25.9%
if -4.9000000000000002e-278 < y Initial program 64.2%
Taylor expanded in x around 0
*-commutativeN/A
lower-*.f6419.7
Applied rewrites19.7%
NOTE: x, y, and z should be sorted in increasing order before calling this function. (FPCore (x y z) :precision binary64 (* 2.0 (sqrt (* y x))))
assert(x < y && y < z);
double code(double x, double y, double z) {
return 2.0 * sqrt((y * x));
}
NOTE: x, y, and z should be sorted in increasing order before calling this function.
real(8) function code(x, y, z)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
code = 2.0d0 * sqrt((y * x))
end function
assert x < y && y < z;
public static double code(double x, double y, double z) {
return 2.0 * Math.sqrt((y * x));
}
[x, y, z] = sort([x, y, z]) def code(x, y, z): return 2.0 * math.sqrt((y * x))
x, y, z = sort([x, y, z]) function code(x, y, z) return Float64(2.0 * sqrt(Float64(y * x))) end
x, y, z = num2cell(sort([x, y, z])){:}
function tmp = code(x, y, z)
tmp = 2.0 * sqrt((y * x));
end
NOTE: x, y, and z should be sorted in increasing order before calling this function. code[x_, y_, z_] := N[(2.0 * N[Sqrt[N[(y * x), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
[x, y, z] = \mathsf{sort}([x, y, z])\\
\\
2 \cdot \sqrt{y \cdot x}
\end{array}
Initial program 68.2%
Taylor expanded in z around 0
lower-sqrt.f64N/A
*-commutativeN/A
lower-*.f6424.1
Applied rewrites24.1%
(FPCore (x y z)
:precision binary64
(let* ((t_0
(+
(* 0.25 (* (* (pow y -0.75) (* (pow z -0.75) x)) (+ y z)))
(* (pow z 0.25) (pow y 0.25)))))
(if (< z 7.636950090573675e+176)
(* 2.0 (sqrt (+ (* (+ x y) z) (* x y))))
(* (* t_0 t_0) 2.0))))
double code(double x, double y, double z) {
double t_0 = (0.25 * ((pow(y, -0.75) * (pow(z, -0.75) * x)) * (y + z))) + (pow(z, 0.25) * pow(y, 0.25));
double tmp;
if (z < 7.636950090573675e+176) {
tmp = 2.0 * sqrt((((x + y) * z) + (x * y)));
} else {
tmp = (t_0 * t_0) * 2.0;
}
return tmp;
}
real(8) function code(x, y, z)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8), intent (in) :: z
real(8) :: t_0
real(8) :: tmp
t_0 = (0.25d0 * (((y ** (-0.75d0)) * ((z ** (-0.75d0)) * x)) * (y + z))) + ((z ** 0.25d0) * (y ** 0.25d0))
if (z < 7.636950090573675d+176) then
tmp = 2.0d0 * sqrt((((x + y) * z) + (x * y)))
else
tmp = (t_0 * t_0) * 2.0d0
end if
code = tmp
end function
public static double code(double x, double y, double z) {
double t_0 = (0.25 * ((Math.pow(y, -0.75) * (Math.pow(z, -0.75) * x)) * (y + z))) + (Math.pow(z, 0.25) * Math.pow(y, 0.25));
double tmp;
if (z < 7.636950090573675e+176) {
tmp = 2.0 * Math.sqrt((((x + y) * z) + (x * y)));
} else {
tmp = (t_0 * t_0) * 2.0;
}
return tmp;
}
def code(x, y, z): t_0 = (0.25 * ((math.pow(y, -0.75) * (math.pow(z, -0.75) * x)) * (y + z))) + (math.pow(z, 0.25) * math.pow(y, 0.25)) tmp = 0 if z < 7.636950090573675e+176: tmp = 2.0 * math.sqrt((((x + y) * z) + (x * y))) else: tmp = (t_0 * t_0) * 2.0 return tmp
function code(x, y, z) t_0 = Float64(Float64(0.25 * Float64(Float64((y ^ -0.75) * Float64((z ^ -0.75) * x)) * Float64(y + z))) + Float64((z ^ 0.25) * (y ^ 0.25))) tmp = 0.0 if (z < 7.636950090573675e+176) tmp = Float64(2.0 * sqrt(Float64(Float64(Float64(x + y) * z) + Float64(x * y)))); else tmp = Float64(Float64(t_0 * t_0) * 2.0); end return tmp end
function tmp_2 = code(x, y, z) t_0 = (0.25 * (((y ^ -0.75) * ((z ^ -0.75) * x)) * (y + z))) + ((z ^ 0.25) * (y ^ 0.25)); tmp = 0.0; if (z < 7.636950090573675e+176) tmp = 2.0 * sqrt((((x + y) * z) + (x * y))); else tmp = (t_0 * t_0) * 2.0; end tmp_2 = tmp; end
code[x_, y_, z_] := Block[{t$95$0 = N[(N[(0.25 * N[(N[(N[Power[y, -0.75], $MachinePrecision] * N[(N[Power[z, -0.75], $MachinePrecision] * x), $MachinePrecision]), $MachinePrecision] * N[(y + z), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(N[Power[z, 0.25], $MachinePrecision] * N[Power[y, 0.25], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, If[Less[z, 7.636950090573675e+176], N[(2.0 * N[Sqrt[N[(N[(N[(x + y), $MachinePrecision] * z), $MachinePrecision] + N[(x * y), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[(N[(t$95$0 * t$95$0), $MachinePrecision] * 2.0), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := 0.25 \cdot \left(\left({y}^{-0.75} \cdot \left({z}^{-0.75} \cdot x\right)\right) \cdot \left(y + z\right)\right) + {z}^{0.25} \cdot {y}^{0.25}\\
\mathbf{if}\;z < 7.636950090573675 \cdot 10^{+176}:\\
\;\;\;\;2 \cdot \sqrt{\left(x + y\right) \cdot z + x \cdot y}\\
\mathbf{else}:\\
\;\;\;\;\left(t\_0 \cdot t\_0\right) \cdot 2\\
\end{array}
\end{array}
herbie shell --seed 2024324
(FPCore (x y z)
:name "Diagrams.TwoD.Apollonian:descartes from diagrams-contrib-1.3.0.5"
:precision binary64
:alt
(! :herbie-platform default (if (< z 763695009057367500000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000) (* 2 (sqrt (+ (* (+ x y) z) (* x y)))) (* (* (+ (* 1/4 (* (* (pow y -3/4) (* (pow z -3/4) x)) (+ y z))) (* (pow z 1/4) (pow y 1/4))) (+ (* 1/4 (* (* (pow y -3/4) (* (pow z -3/4) x)) (+ y z))) (* (pow z 1/4) (pow y 1/4)))) 2)))
(* 2.0 (sqrt (+ (+ (* x y) (* x z)) (* y z)))))