
(FPCore (a b) :precision binary64 (* (* (/ PI 2.0) (/ 1.0 (- (* b b) (* a a)))) (- (/ 1.0 a) (/ 1.0 b))))
double code(double a, double b) {
return ((((double) M_PI) / 2.0) * (1.0 / ((b * b) - (a * a)))) * ((1.0 / a) - (1.0 / b));
}
public static double code(double a, double b) {
return ((Math.PI / 2.0) * (1.0 / ((b * b) - (a * a)))) * ((1.0 / a) - (1.0 / b));
}
def code(a, b): return ((math.pi / 2.0) * (1.0 / ((b * b) - (a * a)))) * ((1.0 / a) - (1.0 / b))
function code(a, b) return Float64(Float64(Float64(pi / 2.0) * Float64(1.0 / Float64(Float64(b * b) - Float64(a * a)))) * Float64(Float64(1.0 / a) - Float64(1.0 / b))) end
function tmp = code(a, b) tmp = ((pi / 2.0) * (1.0 / ((b * b) - (a * a)))) * ((1.0 / a) - (1.0 / b)); end
code[a_, b_] := N[(N[(N[(Pi / 2.0), $MachinePrecision] * N[(1.0 / N[(N[(b * b), $MachinePrecision] - N[(a * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[(N[(1.0 / a), $MachinePrecision] - N[(1.0 / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right)
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 7 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (a b) :precision binary64 (* (* (/ PI 2.0) (/ 1.0 (- (* b b) (* a a)))) (- (/ 1.0 a) (/ 1.0 b))))
double code(double a, double b) {
return ((((double) M_PI) / 2.0) * (1.0 / ((b * b) - (a * a)))) * ((1.0 / a) - (1.0 / b));
}
public static double code(double a, double b) {
return ((Math.PI / 2.0) * (1.0 / ((b * b) - (a * a)))) * ((1.0 / a) - (1.0 / b));
}
def code(a, b): return ((math.pi / 2.0) * (1.0 / ((b * b) - (a * a)))) * ((1.0 / a) - (1.0 / b))
function code(a, b) return Float64(Float64(Float64(pi / 2.0) * Float64(1.0 / Float64(Float64(b * b) - Float64(a * a)))) * Float64(Float64(1.0 / a) - Float64(1.0 / b))) end
function tmp = code(a, b) tmp = ((pi / 2.0) * (1.0 / ((b * b) - (a * a)))) * ((1.0 / a) - (1.0 / b)); end
code[a_, b_] := N[(N[(N[(Pi / 2.0), $MachinePrecision] * N[(1.0 / N[(N[(b * b), $MachinePrecision] - N[(a * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[(N[(1.0 / a), $MachinePrecision] - N[(1.0 / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\left(\frac{\pi}{2} \cdot \frac{1}{b \cdot b - a \cdot a}\right) \cdot \left(\frac{1}{a} - \frac{1}{b}\right)
\end{array}
(FPCore (a b) :precision binary64 (/ (/ (* 0.5 PI) (* a b)) (+ a b)))
double code(double a, double b) {
return ((0.5 * ((double) M_PI)) / (a * b)) / (a + b);
}
public static double code(double a, double b) {
return ((0.5 * Math.PI) / (a * b)) / (a + b);
}
def code(a, b): return ((0.5 * math.pi) / (a * b)) / (a + b)
function code(a, b) return Float64(Float64(Float64(0.5 * pi) / Float64(a * b)) / Float64(a + b)) end
function tmp = code(a, b) tmp = ((0.5 * pi) / (a * b)) / (a + b); end
code[a_, b_] := N[(N[(N[(0.5 * Pi), $MachinePrecision] / N[(a * b), $MachinePrecision]), $MachinePrecision] / N[(a + b), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\frac{0.5 \cdot \pi}{a \cdot b}}{a + b}
\end{array}
Initial program 79.3%
*-commutative79.3%
associate-*r*79.3%
associate-*r/79.4%
associate-*r*79.4%
*-rgt-identity79.4%
sub-neg79.4%
distribute-neg-frac79.4%
metadata-eval79.4%
Simplified79.4%
*-un-lft-identity79.4%
difference-of-squares88.0%
times-frac99.5%
Applied egg-rr67.8%
associate-*l/67.9%
*-lft-identity67.9%
associate-*r*67.9%
distribute-rgt-out67.9%
associate-*l/67.9%
*-lft-identity67.9%
*-commutative67.9%
associate-*r/67.9%
associate-*l/67.9%
*-lft-identity67.9%
*-commutative67.9%
associate-*r/67.9%
fma-define67.9%
associate-*r/67.9%
+-commutative67.9%
Simplified67.9%
Taylor expanded in a around 0 99.7%
associate-*r/99.7%
Simplified99.7%
(FPCore (a b) :precision binary64 (if (<= b 1.3e+72) (* 0.5 (/ PI (* a (* b (+ a b))))) (/ (/ (* 0.5 PI) (* a b)) b)))
double code(double a, double b) {
double tmp;
if (b <= 1.3e+72) {
tmp = 0.5 * (((double) M_PI) / (a * (b * (a + b))));
} else {
tmp = ((0.5 * ((double) M_PI)) / (a * b)) / b;
}
return tmp;
}
public static double code(double a, double b) {
double tmp;
if (b <= 1.3e+72) {
tmp = 0.5 * (Math.PI / (a * (b * (a + b))));
} else {
tmp = ((0.5 * Math.PI) / (a * b)) / b;
}
return tmp;
}
def code(a, b): tmp = 0 if b <= 1.3e+72: tmp = 0.5 * (math.pi / (a * (b * (a + b)))) else: tmp = ((0.5 * math.pi) / (a * b)) / b return tmp
function code(a, b) tmp = 0.0 if (b <= 1.3e+72) tmp = Float64(0.5 * Float64(pi / Float64(a * Float64(b * Float64(a + b))))); else tmp = Float64(Float64(Float64(0.5 * pi) / Float64(a * b)) / b); end return tmp end
function tmp_2 = code(a, b) tmp = 0.0; if (b <= 1.3e+72) tmp = 0.5 * (pi / (a * (b * (a + b)))); else tmp = ((0.5 * pi) / (a * b)) / b; end tmp_2 = tmp; end
code[a_, b_] := If[LessEqual[b, 1.3e+72], N[(0.5 * N[(Pi / N[(a * N[(b * N[(a + b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(N[(0.5 * Pi), $MachinePrecision] / N[(a * b), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq 1.3 \cdot 10^{+72}:\\
\;\;\;\;0.5 \cdot \frac{\pi}{a \cdot \left(b \cdot \left(a + b\right)\right)}\\
\mathbf{else}:\\
\;\;\;\;\frac{\frac{0.5 \cdot \pi}{a \cdot b}}{b}\\
\end{array}
\end{array}
if b < 1.29999999999999991e72Initial program 79.7%
*-commutative79.7%
associate-*r*79.7%
associate-*r/79.7%
associate-*r*79.7%
*-rgt-identity79.7%
sub-neg79.7%
distribute-neg-frac79.7%
metadata-eval79.7%
Simplified79.7%
*-un-lft-identity79.7%
difference-of-squares86.8%
times-frac99.5%
Applied egg-rr61.3%
associate-*l/61.3%
*-lft-identity61.3%
associate-*r*61.3%
distribute-rgt-out61.3%
associate-*l/61.3%
*-lft-identity61.3%
*-commutative61.3%
associate-*r/61.3%
associate-*l/61.3%
*-lft-identity61.3%
*-commutative61.3%
associate-*r/61.3%
fma-define61.3%
associate-*r/61.3%
+-commutative61.3%
Simplified61.3%
Taylor expanded in a around 0 99.6%
associate-*r/99.6%
Simplified99.6%
Taylor expanded in a around 0 99.6%
associate-/r*99.6%
Simplified99.6%
associate-/r*99.6%
associate-/l*99.6%
Applied egg-rr99.6%
associate-/l/99.1%
*-commutative99.1%
associate-*l*95.1%
Simplified95.1%
if 1.29999999999999991e72 < b Initial program 77.5%
*-commutative77.5%
associate-*r*77.5%
associate-*r/77.6%
associate-*r*77.6%
*-rgt-identity77.6%
sub-neg77.6%
distribute-neg-frac77.6%
metadata-eval77.6%
Simplified77.6%
*-un-lft-identity77.6%
difference-of-squares93.5%
times-frac99.6%
Applied egg-rr99.6%
associate-*l/99.7%
*-lft-identity99.7%
associate-*r*99.7%
distribute-rgt-out99.7%
associate-*l/99.8%
*-lft-identity99.8%
*-commutative99.8%
associate-*r/99.8%
associate-*l/99.8%
*-lft-identity99.8%
*-commutative99.8%
associate-*r/99.8%
fma-define99.8%
associate-*r/99.8%
+-commutative99.8%
Simplified99.8%
Taylor expanded in a around 0 99.8%
associate-*r/99.8%
Simplified99.8%
Taylor expanded in a around 0 99.8%
(FPCore (a b) :precision binary64 (if (<= a -4.6e-54) (* (/ PI a) (/ 0.5 (* a b))) (/ (/ (* 0.5 PI) (* a b)) b)))
double code(double a, double b) {
double tmp;
if (a <= -4.6e-54) {
tmp = (((double) M_PI) / a) * (0.5 / (a * b));
} else {
tmp = ((0.5 * ((double) M_PI)) / (a * b)) / b;
}
return tmp;
}
public static double code(double a, double b) {
double tmp;
if (a <= -4.6e-54) {
tmp = (Math.PI / a) * (0.5 / (a * b));
} else {
tmp = ((0.5 * Math.PI) / (a * b)) / b;
}
return tmp;
}
def code(a, b): tmp = 0 if a <= -4.6e-54: tmp = (math.pi / a) * (0.5 / (a * b)) else: tmp = ((0.5 * math.pi) / (a * b)) / b return tmp
function code(a, b) tmp = 0.0 if (a <= -4.6e-54) tmp = Float64(Float64(pi / a) * Float64(0.5 / Float64(a * b))); else tmp = Float64(Float64(Float64(0.5 * pi) / Float64(a * b)) / b); end return tmp end
function tmp_2 = code(a, b) tmp = 0.0; if (a <= -4.6e-54) tmp = (pi / a) * (0.5 / (a * b)); else tmp = ((0.5 * pi) / (a * b)) / b; end tmp_2 = tmp; end
code[a_, b_] := If[LessEqual[a, -4.6e-54], N[(N[(Pi / a), $MachinePrecision] * N[(0.5 / N[(a * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(N[(0.5 * Pi), $MachinePrecision] / N[(a * b), $MachinePrecision]), $MachinePrecision] / b), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;a \leq -4.6 \cdot 10^{-54}:\\
\;\;\;\;\frac{\pi}{a} \cdot \frac{0.5}{a \cdot b}\\
\mathbf{else}:\\
\;\;\;\;\frac{\frac{0.5 \cdot \pi}{a \cdot b}}{b}\\
\end{array}
\end{array}
if a < -4.5999999999999998e-54Initial program 72.3%
*-commutative72.3%
associate-*r*72.2%
associate-*r/72.3%
associate-*r*72.3%
*-rgt-identity72.3%
sub-neg72.3%
distribute-neg-frac72.3%
metadata-eval72.3%
Simplified72.3%
*-un-lft-identity72.3%
difference-of-squares84.8%
times-frac99.6%
Applied egg-rr58.9%
associate-*l/58.8%
*-lft-identity58.8%
associate-*r*58.8%
distribute-rgt-out58.8%
associate-*l/58.8%
*-lft-identity58.8%
*-commutative58.8%
associate-*r/58.8%
associate-*l/58.8%
*-lft-identity58.8%
*-commutative58.8%
associate-*r/58.8%
fma-define58.8%
associate-*r/58.8%
+-commutative58.8%
Simplified58.8%
Taylor expanded in a around 0 99.7%
associate-*r/99.7%
Simplified99.7%
Taylor expanded in a around inf 88.3%
associate-/l/88.5%
*-commutative88.5%
times-frac88.3%
Applied egg-rr88.3%
if -4.5999999999999998e-54 < a Initial program 82.1%
*-commutative82.1%
associate-*r*82.1%
associate-*r/82.1%
associate-*r*82.1%
*-rgt-identity82.1%
sub-neg82.1%
distribute-neg-frac82.1%
metadata-eval82.1%
Simplified82.1%
*-un-lft-identity82.1%
difference-of-squares89.2%
times-frac99.5%
Applied egg-rr71.4%
associate-*l/71.4%
*-lft-identity71.4%
associate-*r*71.4%
distribute-rgt-out71.4%
associate-*l/71.5%
*-lft-identity71.5%
*-commutative71.5%
associate-*r/71.5%
associate-*l/71.5%
*-lft-identity71.5%
*-commutative71.5%
associate-*r/71.5%
fma-define71.5%
associate-*r/71.5%
+-commutative71.5%
Simplified71.5%
Taylor expanded in a around 0 99.7%
associate-*r/99.7%
Simplified99.7%
Taylor expanded in a around 0 70.2%
(FPCore (a b) :precision binary64 (if (<= a -4.2e-54) (* (/ PI a) (/ 0.5 (* a b))) (/ (* 0.5 (/ PI a)) (* b b))))
double code(double a, double b) {
double tmp;
if (a <= -4.2e-54) {
tmp = (((double) M_PI) / a) * (0.5 / (a * b));
} else {
tmp = (0.5 * (((double) M_PI) / a)) / (b * b);
}
return tmp;
}
public static double code(double a, double b) {
double tmp;
if (a <= -4.2e-54) {
tmp = (Math.PI / a) * (0.5 / (a * b));
} else {
tmp = (0.5 * (Math.PI / a)) / (b * b);
}
return tmp;
}
def code(a, b): tmp = 0 if a <= -4.2e-54: tmp = (math.pi / a) * (0.5 / (a * b)) else: tmp = (0.5 * (math.pi / a)) / (b * b) return tmp
function code(a, b) tmp = 0.0 if (a <= -4.2e-54) tmp = Float64(Float64(pi / a) * Float64(0.5 / Float64(a * b))); else tmp = Float64(Float64(0.5 * Float64(pi / a)) / Float64(b * b)); end return tmp end
function tmp_2 = code(a, b) tmp = 0.0; if (a <= -4.2e-54) tmp = (pi / a) * (0.5 / (a * b)); else tmp = (0.5 * (pi / a)) / (b * b); end tmp_2 = tmp; end
code[a_, b_] := If[LessEqual[a, -4.2e-54], N[(N[(Pi / a), $MachinePrecision] * N[(0.5 / N[(a * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(0.5 * N[(Pi / a), $MachinePrecision]), $MachinePrecision] / N[(b * b), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;a \leq -4.2 \cdot 10^{-54}:\\
\;\;\;\;\frac{\pi}{a} \cdot \frac{0.5}{a \cdot b}\\
\mathbf{else}:\\
\;\;\;\;\frac{0.5 \cdot \frac{\pi}{a}}{b \cdot b}\\
\end{array}
\end{array}
if a < -4.2e-54Initial program 72.3%
*-commutative72.3%
associate-*r*72.2%
associate-*r/72.3%
associate-*r*72.3%
*-rgt-identity72.3%
sub-neg72.3%
distribute-neg-frac72.3%
metadata-eval72.3%
Simplified72.3%
*-un-lft-identity72.3%
difference-of-squares84.8%
times-frac99.6%
Applied egg-rr58.9%
associate-*l/58.8%
*-lft-identity58.8%
associate-*r*58.8%
distribute-rgt-out58.8%
associate-*l/58.8%
*-lft-identity58.8%
*-commutative58.8%
associate-*r/58.8%
associate-*l/58.8%
*-lft-identity58.8%
*-commutative58.8%
associate-*r/58.8%
fma-define58.8%
associate-*r/58.8%
+-commutative58.8%
Simplified58.8%
Taylor expanded in a around 0 99.7%
associate-*r/99.7%
Simplified99.7%
Taylor expanded in a around inf 88.3%
associate-/l/88.5%
*-commutative88.5%
times-frac88.3%
Applied egg-rr88.3%
if -4.2e-54 < a Initial program 82.1%
*-commutative82.1%
associate-*r*82.1%
associate-*r/82.1%
associate-*r*82.1%
*-rgt-identity82.1%
sub-neg82.1%
distribute-neg-frac82.1%
metadata-eval82.1%
Simplified82.1%
difference-of-squares89.2%
times-frac99.6%
add-sqr-sqrt51.9%
sqrt-unprod81.6%
frac-times81.6%
metadata-eval81.6%
metadata-eval81.6%
frac-times81.6%
sqrt-unprod35.5%
add-sqr-sqrt71.5%
div-inv71.5%
metadata-eval71.5%
Applied egg-rr71.5%
+-commutative71.5%
+-commutative71.5%
*-commutative71.5%
Simplified71.5%
Taylor expanded in b around 0 71.4%
frac-times70.9%
*-un-lft-identity70.9%
Applied egg-rr70.9%
*-commutative70.9%
*-rgt-identity70.9%
times-frac71.4%
associate-/r*71.5%
times-frac65.1%
associate-*r/65.2%
*-rgt-identity65.2%
associate-*r/65.2%
*-commutative65.2%
Simplified65.2%
Taylor expanded in b around inf 63.9%
(FPCore (a b) :precision binary64 (/ (* 0.5 (/ (/ PI a) b)) (+ a b)))
double code(double a, double b) {
return (0.5 * ((((double) M_PI) / a) / b)) / (a + b);
}
public static double code(double a, double b) {
return (0.5 * ((Math.PI / a) / b)) / (a + b);
}
def code(a, b): return (0.5 * ((math.pi / a) / b)) / (a + b)
function code(a, b) return Float64(Float64(0.5 * Float64(Float64(pi / a) / b)) / Float64(a + b)) end
function tmp = code(a, b) tmp = (0.5 * ((pi / a) / b)) / (a + b); end
code[a_, b_] := N[(N[(0.5 * N[(N[(Pi / a), $MachinePrecision] / b), $MachinePrecision]), $MachinePrecision] / N[(a + b), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{0.5 \cdot \frac{\frac{\pi}{a}}{b}}{a + b}
\end{array}
Initial program 79.3%
*-commutative79.3%
associate-*r*79.3%
associate-*r/79.4%
associate-*r*79.4%
*-rgt-identity79.4%
sub-neg79.4%
distribute-neg-frac79.4%
metadata-eval79.4%
Simplified79.4%
*-un-lft-identity79.4%
difference-of-squares88.0%
times-frac99.5%
Applied egg-rr67.8%
associate-*l/67.9%
*-lft-identity67.9%
associate-*r*67.9%
distribute-rgt-out67.9%
associate-*l/67.9%
*-lft-identity67.9%
*-commutative67.9%
associate-*r/67.9%
associate-*l/67.9%
*-lft-identity67.9%
*-commutative67.9%
associate-*r/67.9%
fma-define67.9%
associate-*r/67.9%
+-commutative67.9%
Simplified67.9%
Taylor expanded in a around 0 99.7%
associate-*r/99.7%
Simplified99.7%
Taylor expanded in a around 0 99.7%
associate-/r*99.6%
Simplified99.6%
(FPCore (a b) :precision binary64 (* 0.5 (/ PI (* (* a b) (+ a b)))))
double code(double a, double b) {
return 0.5 * (((double) M_PI) / ((a * b) * (a + b)));
}
public static double code(double a, double b) {
return 0.5 * (Math.PI / ((a * b) * (a + b)));
}
def code(a, b): return 0.5 * (math.pi / ((a * b) * (a + b)))
function code(a, b) return Float64(0.5 * Float64(pi / Float64(Float64(a * b) * Float64(a + b)))) end
function tmp = code(a, b) tmp = 0.5 * (pi / ((a * b) * (a + b))); end
code[a_, b_] := N[(0.5 * N[(Pi / N[(N[(a * b), $MachinePrecision] * N[(a + b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
0.5 \cdot \frac{\pi}{\left(a \cdot b\right) \cdot \left(a + b\right)}
\end{array}
Initial program 79.3%
*-commutative79.3%
associate-*r*79.3%
associate-*r/79.4%
associate-*r*79.4%
*-rgt-identity79.4%
sub-neg79.4%
distribute-neg-frac79.4%
metadata-eval79.4%
Simplified79.4%
*-un-lft-identity79.4%
difference-of-squares88.0%
times-frac99.5%
Applied egg-rr67.8%
associate-*l/67.9%
*-lft-identity67.9%
associate-*r*67.9%
distribute-rgt-out67.9%
associate-*l/67.9%
*-lft-identity67.9%
*-commutative67.9%
associate-*r/67.9%
associate-*l/67.9%
*-lft-identity67.9%
*-commutative67.9%
associate-*r/67.9%
fma-define67.9%
associate-*r/67.9%
+-commutative67.9%
Simplified67.9%
Taylor expanded in a around 0 99.7%
associate-*r/99.7%
Simplified99.7%
*-un-lft-identity99.7%
associate-/l/99.0%
Applied egg-rr99.0%
*-lft-identity99.0%
associate-/l*99.0%
*-commutative99.0%
Simplified99.0%
(FPCore (a b) :precision binary64 (* (/ PI a) (/ 0.5 (* a b))))
double code(double a, double b) {
return (((double) M_PI) / a) * (0.5 / (a * b));
}
public static double code(double a, double b) {
return (Math.PI / a) * (0.5 / (a * b));
}
def code(a, b): return (math.pi / a) * (0.5 / (a * b))
function code(a, b) return Float64(Float64(pi / a) * Float64(0.5 / Float64(a * b))) end
function tmp = code(a, b) tmp = (pi / a) * (0.5 / (a * b)); end
code[a_, b_] := N[(N[(Pi / a), $MachinePrecision] * N[(0.5 / N[(a * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\pi}{a} \cdot \frac{0.5}{a \cdot b}
\end{array}
Initial program 79.3%
*-commutative79.3%
associate-*r*79.3%
associate-*r/79.4%
associate-*r*79.4%
*-rgt-identity79.4%
sub-neg79.4%
distribute-neg-frac79.4%
metadata-eval79.4%
Simplified79.4%
*-un-lft-identity79.4%
difference-of-squares88.0%
times-frac99.5%
Applied egg-rr67.8%
associate-*l/67.9%
*-lft-identity67.9%
associate-*r*67.9%
distribute-rgt-out67.9%
associate-*l/67.9%
*-lft-identity67.9%
*-commutative67.9%
associate-*r/67.9%
associate-*l/67.9%
*-lft-identity67.9%
*-commutative67.9%
associate-*r/67.9%
fma-define67.9%
associate-*r/67.9%
+-commutative67.9%
Simplified67.9%
Taylor expanded in a around 0 99.7%
associate-*r/99.7%
Simplified99.7%
Taylor expanded in a around inf 58.8%
associate-/l/58.8%
*-commutative58.8%
times-frac58.8%
Applied egg-rr58.8%
herbie shell --seed 2024145
(FPCore (a b)
:name "NMSE Section 6.1 mentioned, B"
:precision binary64
(* (* (/ PI 2.0) (/ 1.0 (- (* b b) (* a a)))) (- (/ 1.0 a) (/ 1.0 b))))