
(FPCore (a1 a2 th) :precision binary64 (let* ((t_1 (/ (cos th) (sqrt 2.0)))) (+ (* t_1 (* a1 a1)) (* t_1 (* a2 a2)))))
double code(double a1, double a2, double th) {
double t_1 = cos(th) / sqrt(2.0);
return (t_1 * (a1 * a1)) + (t_1 * (a2 * a2));
}
real(8) function code(a1, a2, th)
real(8), intent (in) :: a1
real(8), intent (in) :: a2
real(8), intent (in) :: th
real(8) :: t_1
t_1 = cos(th) / sqrt(2.0d0)
code = (t_1 * (a1 * a1)) + (t_1 * (a2 * a2))
end function
public static double code(double a1, double a2, double th) {
double t_1 = Math.cos(th) / Math.sqrt(2.0);
return (t_1 * (a1 * a1)) + (t_1 * (a2 * a2));
}
def code(a1, a2, th): t_1 = math.cos(th) / math.sqrt(2.0) return (t_1 * (a1 * a1)) + (t_1 * (a2 * a2))
function code(a1, a2, th) t_1 = Float64(cos(th) / sqrt(2.0)) return Float64(Float64(t_1 * Float64(a1 * a1)) + Float64(t_1 * Float64(a2 * a2))) end
function tmp = code(a1, a2, th) t_1 = cos(th) / sqrt(2.0); tmp = (t_1 * (a1 * a1)) + (t_1 * (a2 * a2)); end
code[a1_, a2_, th_] := Block[{t$95$1 = N[(N[Cos[th], $MachinePrecision] / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]}, N[(N[(t$95$1 * N[(a1 * a1), $MachinePrecision]), $MachinePrecision] + N[(t$95$1 * N[(a2 * a2), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_1 := \frac{\cos th}{\sqrt{2}}\\
t\_1 \cdot \left(a1 \cdot a1\right) + t\_1 \cdot \left(a2 \cdot a2\right)
\end{array}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 7 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (a1 a2 th) :precision binary64 (let* ((t_1 (/ (cos th) (sqrt 2.0)))) (+ (* t_1 (* a1 a1)) (* t_1 (* a2 a2)))))
double code(double a1, double a2, double th) {
double t_1 = cos(th) / sqrt(2.0);
return (t_1 * (a1 * a1)) + (t_1 * (a2 * a2));
}
real(8) function code(a1, a2, th)
real(8), intent (in) :: a1
real(8), intent (in) :: a2
real(8), intent (in) :: th
real(8) :: t_1
t_1 = cos(th) / sqrt(2.0d0)
code = (t_1 * (a1 * a1)) + (t_1 * (a2 * a2))
end function
public static double code(double a1, double a2, double th) {
double t_1 = Math.cos(th) / Math.sqrt(2.0);
return (t_1 * (a1 * a1)) + (t_1 * (a2 * a2));
}
def code(a1, a2, th): t_1 = math.cos(th) / math.sqrt(2.0) return (t_1 * (a1 * a1)) + (t_1 * (a2 * a2))
function code(a1, a2, th) t_1 = Float64(cos(th) / sqrt(2.0)) return Float64(Float64(t_1 * Float64(a1 * a1)) + Float64(t_1 * Float64(a2 * a2))) end
function tmp = code(a1, a2, th) t_1 = cos(th) / sqrt(2.0); tmp = (t_1 * (a1 * a1)) + (t_1 * (a2 * a2)); end
code[a1_, a2_, th_] := Block[{t$95$1 = N[(N[Cos[th], $MachinePrecision] / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]}, N[(N[(t$95$1 * N[(a1 * a1), $MachinePrecision]), $MachinePrecision] + N[(t$95$1 * N[(a2 * a2), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_1 := \frac{\cos th}{\sqrt{2}}\\
t\_1 \cdot \left(a1 \cdot a1\right) + t\_1 \cdot \left(a2 \cdot a2\right)
\end{array}
\end{array}
a1_m = (fabs.f64 a1) a2_m = (fabs.f64 a2) NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function. (FPCore (a1_m a2_m th) :precision binary64 (* (cos th) (/ (fma a2_m a2_m (* a1_m a1_m)) (sqrt 2.0))))
a1_m = fabs(a1);
a2_m = fabs(a2);
assert(a1_m < a2_m && a2_m < th);
double code(double a1_m, double a2_m, double th) {
return cos(th) * (fma(a2_m, a2_m, (a1_m * a1_m)) / sqrt(2.0));
}
a1_m = abs(a1) a2_m = abs(a2) a1_m, a2_m, th = sort([a1_m, a2_m, th]) function code(a1_m, a2_m, th) return Float64(cos(th) * Float64(fma(a2_m, a2_m, Float64(a1_m * a1_m)) / sqrt(2.0))) end
a1_m = N[Abs[a1], $MachinePrecision] a2_m = N[Abs[a2], $MachinePrecision] NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function. code[a1$95$m_, a2$95$m_, th_] := N[(N[Cos[th], $MachinePrecision] * N[(N[(a2$95$m * a2$95$m + N[(a1$95$m * a1$95$m), $MachinePrecision]), $MachinePrecision] / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
a1_m = \left|a1\right|
\\
a2_m = \left|a2\right|
\\
[a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\
\\
\cos th \cdot \frac{\mathsf{fma}\left(a2\_m, a2\_m, a1\_m \cdot a1\_m\right)}{\sqrt{2}}
\end{array}
Initial program 99.5%
distribute-lft-out99.5%
cos-neg99.5%
associate-*l/99.6%
associate-/l*99.6%
cos-neg99.6%
+-commutative99.6%
fma-define99.6%
Simplified99.6%
a1_m = (fabs.f64 a1) a2_m = (fabs.f64 a2) NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function. (FPCore (a1_m a2_m th) :precision binary64 (* (* (cos th) (sqrt 0.5)) (+ (* a1_m a1_m) (* a2_m a2_m))))
a1_m = fabs(a1);
a2_m = fabs(a2);
assert(a1_m < a2_m && a2_m < th);
double code(double a1_m, double a2_m, double th) {
return (cos(th) * sqrt(0.5)) * ((a1_m * a1_m) + (a2_m * a2_m));
}
a1_m = abs(a1)
a2_m = abs(a2)
NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function.
real(8) function code(a1_m, a2_m, th)
real(8), intent (in) :: a1_m
real(8), intent (in) :: a2_m
real(8), intent (in) :: th
code = (cos(th) * sqrt(0.5d0)) * ((a1_m * a1_m) + (a2_m * a2_m))
end function
a1_m = Math.abs(a1);
a2_m = Math.abs(a2);
assert a1_m < a2_m && a2_m < th;
public static double code(double a1_m, double a2_m, double th) {
return (Math.cos(th) * Math.sqrt(0.5)) * ((a1_m * a1_m) + (a2_m * a2_m));
}
a1_m = math.fabs(a1) a2_m = math.fabs(a2) [a1_m, a2_m, th] = sort([a1_m, a2_m, th]) def code(a1_m, a2_m, th): return (math.cos(th) * math.sqrt(0.5)) * ((a1_m * a1_m) + (a2_m * a2_m))
a1_m = abs(a1) a2_m = abs(a2) a1_m, a2_m, th = sort([a1_m, a2_m, th]) function code(a1_m, a2_m, th) return Float64(Float64(cos(th) * sqrt(0.5)) * Float64(Float64(a1_m * a1_m) + Float64(a2_m * a2_m))) end
a1_m = abs(a1);
a2_m = abs(a2);
a1_m, a2_m, th = num2cell(sort([a1_m, a2_m, th])){:}
function tmp = code(a1_m, a2_m, th)
tmp = (cos(th) * sqrt(0.5)) * ((a1_m * a1_m) + (a2_m * a2_m));
end
a1_m = N[Abs[a1], $MachinePrecision] a2_m = N[Abs[a2], $MachinePrecision] NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function. code[a1$95$m_, a2$95$m_, th_] := N[(N[(N[Cos[th], $MachinePrecision] * N[Sqrt[0.5], $MachinePrecision]), $MachinePrecision] * N[(N[(a1$95$m * a1$95$m), $MachinePrecision] + N[(a2$95$m * a2$95$m), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
a1_m = \left|a1\right|
\\
a2_m = \left|a2\right|
\\
[a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\
\\
\left(\cos th \cdot \sqrt{0.5}\right) \cdot \left(a1\_m \cdot a1\_m + a2\_m \cdot a2\_m\right)
\end{array}
Initial program 99.5%
distribute-lft-out99.5%
Simplified99.5%
clear-num99.5%
associate-/r/99.5%
pow1/299.5%
pow-flip99.6%
metadata-eval99.6%
Applied egg-rr99.6%
Taylor expanded in th around inf 99.6%
*-commutative99.6%
Simplified99.6%
Final simplification99.6%
a1_m = (fabs.f64 a1) a2_m = (fabs.f64 a2) NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function. (FPCore (a1_m a2_m th) :precision binary64 (* (cos th) (/ a2_m (/ (sqrt 2.0) a2_m))))
a1_m = fabs(a1);
a2_m = fabs(a2);
assert(a1_m < a2_m && a2_m < th);
double code(double a1_m, double a2_m, double th) {
return cos(th) * (a2_m / (sqrt(2.0) / a2_m));
}
a1_m = abs(a1)
a2_m = abs(a2)
NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function.
real(8) function code(a1_m, a2_m, th)
real(8), intent (in) :: a1_m
real(8), intent (in) :: a2_m
real(8), intent (in) :: th
code = cos(th) * (a2_m / (sqrt(2.0d0) / a2_m))
end function
a1_m = Math.abs(a1);
a2_m = Math.abs(a2);
assert a1_m < a2_m && a2_m < th;
public static double code(double a1_m, double a2_m, double th) {
return Math.cos(th) * (a2_m / (Math.sqrt(2.0) / a2_m));
}
a1_m = math.fabs(a1) a2_m = math.fabs(a2) [a1_m, a2_m, th] = sort([a1_m, a2_m, th]) def code(a1_m, a2_m, th): return math.cos(th) * (a2_m / (math.sqrt(2.0) / a2_m))
a1_m = abs(a1) a2_m = abs(a2) a1_m, a2_m, th = sort([a1_m, a2_m, th]) function code(a1_m, a2_m, th) return Float64(cos(th) * Float64(a2_m / Float64(sqrt(2.0) / a2_m))) end
a1_m = abs(a1);
a2_m = abs(a2);
a1_m, a2_m, th = num2cell(sort([a1_m, a2_m, th])){:}
function tmp = code(a1_m, a2_m, th)
tmp = cos(th) * (a2_m / (sqrt(2.0) / a2_m));
end
a1_m = N[Abs[a1], $MachinePrecision] a2_m = N[Abs[a2], $MachinePrecision] NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function. code[a1$95$m_, a2$95$m_, th_] := N[(N[Cos[th], $MachinePrecision] * N[(a2$95$m / N[(N[Sqrt[2.0], $MachinePrecision] / a2$95$m), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
a1_m = \left|a1\right|
\\
a2_m = \left|a2\right|
\\
[a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\
\\
\cos th \cdot \frac{a2\_m}{\frac{\sqrt{2}}{a2\_m}}
\end{array}
Initial program 99.5%
distribute-lft-out99.5%
cos-neg99.5%
associate-*l/99.6%
associate-/l*99.6%
cos-neg99.6%
+-commutative99.6%
fma-define99.6%
Simplified99.6%
Taylor expanded in a2 around inf 61.5%
pow261.5%
associate-/l*61.5%
Applied egg-rr61.5%
clear-num61.5%
un-div-inv61.5%
Applied egg-rr61.5%
a1_m = (fabs.f64 a1) a2_m = (fabs.f64 a2) NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function. (FPCore (a1_m a2_m th) :precision binary64 (* (cos th) (* a2_m (/ a2_m (sqrt 2.0)))))
a1_m = fabs(a1);
a2_m = fabs(a2);
assert(a1_m < a2_m && a2_m < th);
double code(double a1_m, double a2_m, double th) {
return cos(th) * (a2_m * (a2_m / sqrt(2.0)));
}
a1_m = abs(a1)
a2_m = abs(a2)
NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function.
real(8) function code(a1_m, a2_m, th)
real(8), intent (in) :: a1_m
real(8), intent (in) :: a2_m
real(8), intent (in) :: th
code = cos(th) * (a2_m * (a2_m / sqrt(2.0d0)))
end function
a1_m = Math.abs(a1);
a2_m = Math.abs(a2);
assert a1_m < a2_m && a2_m < th;
public static double code(double a1_m, double a2_m, double th) {
return Math.cos(th) * (a2_m * (a2_m / Math.sqrt(2.0)));
}
a1_m = math.fabs(a1) a2_m = math.fabs(a2) [a1_m, a2_m, th] = sort([a1_m, a2_m, th]) def code(a1_m, a2_m, th): return math.cos(th) * (a2_m * (a2_m / math.sqrt(2.0)))
a1_m = abs(a1) a2_m = abs(a2) a1_m, a2_m, th = sort([a1_m, a2_m, th]) function code(a1_m, a2_m, th) return Float64(cos(th) * Float64(a2_m * Float64(a2_m / sqrt(2.0)))) end
a1_m = abs(a1);
a2_m = abs(a2);
a1_m, a2_m, th = num2cell(sort([a1_m, a2_m, th])){:}
function tmp = code(a1_m, a2_m, th)
tmp = cos(th) * (a2_m * (a2_m / sqrt(2.0)));
end
a1_m = N[Abs[a1], $MachinePrecision] a2_m = N[Abs[a2], $MachinePrecision] NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function. code[a1$95$m_, a2$95$m_, th_] := N[(N[Cos[th], $MachinePrecision] * N[(a2$95$m * N[(a2$95$m / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
a1_m = \left|a1\right|
\\
a2_m = \left|a2\right|
\\
[a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\
\\
\cos th \cdot \left(a2\_m \cdot \frac{a2\_m}{\sqrt{2}}\right)
\end{array}
Initial program 99.5%
distribute-lft-out99.5%
cos-neg99.5%
associate-*l/99.6%
associate-/l*99.6%
cos-neg99.6%
+-commutative99.6%
fma-define99.6%
Simplified99.6%
Taylor expanded in a2 around inf 61.5%
pow261.5%
associate-/l*61.5%
Applied egg-rr61.5%
a1_m = (fabs.f64 a1) a2_m = (fabs.f64 a2) NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function. (FPCore (a1_m a2_m th) :precision binary64 (/ a2_m (/ (sqrt 2.0) a2_m)))
a1_m = fabs(a1);
a2_m = fabs(a2);
assert(a1_m < a2_m && a2_m < th);
double code(double a1_m, double a2_m, double th) {
return a2_m / (sqrt(2.0) / a2_m);
}
a1_m = abs(a1)
a2_m = abs(a2)
NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function.
real(8) function code(a1_m, a2_m, th)
real(8), intent (in) :: a1_m
real(8), intent (in) :: a2_m
real(8), intent (in) :: th
code = a2_m / (sqrt(2.0d0) / a2_m)
end function
a1_m = Math.abs(a1);
a2_m = Math.abs(a2);
assert a1_m < a2_m && a2_m < th;
public static double code(double a1_m, double a2_m, double th) {
return a2_m / (Math.sqrt(2.0) / a2_m);
}
a1_m = math.fabs(a1) a2_m = math.fabs(a2) [a1_m, a2_m, th] = sort([a1_m, a2_m, th]) def code(a1_m, a2_m, th): return a2_m / (math.sqrt(2.0) / a2_m)
a1_m = abs(a1) a2_m = abs(a2) a1_m, a2_m, th = sort([a1_m, a2_m, th]) function code(a1_m, a2_m, th) return Float64(a2_m / Float64(sqrt(2.0) / a2_m)) end
a1_m = abs(a1);
a2_m = abs(a2);
a1_m, a2_m, th = num2cell(sort([a1_m, a2_m, th])){:}
function tmp = code(a1_m, a2_m, th)
tmp = a2_m / (sqrt(2.0) / a2_m);
end
a1_m = N[Abs[a1], $MachinePrecision] a2_m = N[Abs[a2], $MachinePrecision] NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function. code[a1$95$m_, a2$95$m_, th_] := N[(a2$95$m / N[(N[Sqrt[2.0], $MachinePrecision] / a2$95$m), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
a1_m = \left|a1\right|
\\
a2_m = \left|a2\right|
\\
[a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\
\\
\frac{a2\_m}{\frac{\sqrt{2}}{a2\_m}}
\end{array}
Initial program 99.5%
distribute-lft-out99.5%
Simplified99.5%
Taylor expanded in th around 0 65.9%
Taylor expanded in a1 around 0 44.3%
pow261.5%
associate-/l*61.5%
Applied egg-rr44.3%
clear-num61.5%
un-div-inv61.5%
Applied egg-rr44.3%
a1_m = (fabs.f64 a1) a2_m = (fabs.f64 a2) NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function. (FPCore (a1_m a2_m th) :precision binary64 (* a2_m (/ a2_m (sqrt 2.0))))
a1_m = fabs(a1);
a2_m = fabs(a2);
assert(a1_m < a2_m && a2_m < th);
double code(double a1_m, double a2_m, double th) {
return a2_m * (a2_m / sqrt(2.0));
}
a1_m = abs(a1)
a2_m = abs(a2)
NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function.
real(8) function code(a1_m, a2_m, th)
real(8), intent (in) :: a1_m
real(8), intent (in) :: a2_m
real(8), intent (in) :: th
code = a2_m * (a2_m / sqrt(2.0d0))
end function
a1_m = Math.abs(a1);
a2_m = Math.abs(a2);
assert a1_m < a2_m && a2_m < th;
public static double code(double a1_m, double a2_m, double th) {
return a2_m * (a2_m / Math.sqrt(2.0));
}
a1_m = math.fabs(a1) a2_m = math.fabs(a2) [a1_m, a2_m, th] = sort([a1_m, a2_m, th]) def code(a1_m, a2_m, th): return a2_m * (a2_m / math.sqrt(2.0))
a1_m = abs(a1) a2_m = abs(a2) a1_m, a2_m, th = sort([a1_m, a2_m, th]) function code(a1_m, a2_m, th) return Float64(a2_m * Float64(a2_m / sqrt(2.0))) end
a1_m = abs(a1);
a2_m = abs(a2);
a1_m, a2_m, th = num2cell(sort([a1_m, a2_m, th])){:}
function tmp = code(a1_m, a2_m, th)
tmp = a2_m * (a2_m / sqrt(2.0));
end
a1_m = N[Abs[a1], $MachinePrecision] a2_m = N[Abs[a2], $MachinePrecision] NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function. code[a1$95$m_, a2$95$m_, th_] := N[(a2$95$m * N[(a2$95$m / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
a1_m = \left|a1\right|
\\
a2_m = \left|a2\right|
\\
[a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\
\\
a2\_m \cdot \frac{a2\_m}{\sqrt{2}}
\end{array}
Initial program 99.5%
distribute-lft-out99.5%
Simplified99.5%
Taylor expanded in th around 0 65.9%
Taylor expanded in a1 around 0 44.3%
pow261.5%
associate-/l*61.5%
Applied egg-rr44.3%
a1_m = (fabs.f64 a1) a2_m = (fabs.f64 a2) NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function. (FPCore (a1_m a2_m th) :precision binary64 (* a1_m (/ a1_m (sqrt 2.0))))
a1_m = fabs(a1);
a2_m = fabs(a2);
assert(a1_m < a2_m && a2_m < th);
double code(double a1_m, double a2_m, double th) {
return a1_m * (a1_m / sqrt(2.0));
}
a1_m = abs(a1)
a2_m = abs(a2)
NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function.
real(8) function code(a1_m, a2_m, th)
real(8), intent (in) :: a1_m
real(8), intent (in) :: a2_m
real(8), intent (in) :: th
code = a1_m * (a1_m / sqrt(2.0d0))
end function
a1_m = Math.abs(a1);
a2_m = Math.abs(a2);
assert a1_m < a2_m && a2_m < th;
public static double code(double a1_m, double a2_m, double th) {
return a1_m * (a1_m / Math.sqrt(2.0));
}
a1_m = math.fabs(a1) a2_m = math.fabs(a2) [a1_m, a2_m, th] = sort([a1_m, a2_m, th]) def code(a1_m, a2_m, th): return a1_m * (a1_m / math.sqrt(2.0))
a1_m = abs(a1) a2_m = abs(a2) a1_m, a2_m, th = sort([a1_m, a2_m, th]) function code(a1_m, a2_m, th) return Float64(a1_m * Float64(a1_m / sqrt(2.0))) end
a1_m = abs(a1);
a2_m = abs(a2);
a1_m, a2_m, th = num2cell(sort([a1_m, a2_m, th])){:}
function tmp = code(a1_m, a2_m, th)
tmp = a1_m * (a1_m / sqrt(2.0));
end
a1_m = N[Abs[a1], $MachinePrecision] a2_m = N[Abs[a2], $MachinePrecision] NOTE: a1_m, a2_m, and th should be sorted in increasing order before calling this function. code[a1$95$m_, a2$95$m_, th_] := N[(a1$95$m * N[(a1$95$m / N[Sqrt[2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
a1_m = \left|a1\right|
\\
a2_m = \left|a2\right|
\\
[a1_m, a2_m, th] = \mathsf{sort}([a1_m, a2_m, th])\\
\\
a1\_m \cdot \frac{a1\_m}{\sqrt{2}}
\end{array}
Initial program 99.5%
distribute-lft-out99.5%
Simplified99.5%
Taylor expanded in th around 0 65.9%
Taylor expanded in a1 around inf 35.7%
unpow235.7%
associate-/l*35.7%
Applied egg-rr35.7%
herbie shell --seed 2024088
(FPCore (a1 a2 th)
:name "Migdal et al, Equation (64)"
:precision binary64
(+ (* (/ (cos th) (sqrt 2.0)) (* a1 a1)) (* (/ (cos th) (sqrt 2.0)) (* a2 a2))))