
(FPCore (a b eps) :precision binary64 (/ (* eps (- (exp (* (+ a b) eps)) 1.0)) (* (- (exp (* a eps)) 1.0) (- (exp (* b eps)) 1.0))))
double code(double a, double b, double eps) {
return (eps * (exp(((a + b) * eps)) - 1.0)) / ((exp((a * eps)) - 1.0) * (exp((b * eps)) - 1.0));
}
real(8) function code(a, b, eps)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: eps
code = (eps * (exp(((a + b) * eps)) - 1.0d0)) / ((exp((a * eps)) - 1.0d0) * (exp((b * eps)) - 1.0d0))
end function
public static double code(double a, double b, double eps) {
return (eps * (Math.exp(((a + b) * eps)) - 1.0)) / ((Math.exp((a * eps)) - 1.0) * (Math.exp((b * eps)) - 1.0));
}
def code(a, b, eps): return (eps * (math.exp(((a + b) * eps)) - 1.0)) / ((math.exp((a * eps)) - 1.0) * (math.exp((b * eps)) - 1.0))
function code(a, b, eps) return Float64(Float64(eps * Float64(exp(Float64(Float64(a + b) * eps)) - 1.0)) / Float64(Float64(exp(Float64(a * eps)) - 1.0) * Float64(exp(Float64(b * eps)) - 1.0))) end
function tmp = code(a, b, eps) tmp = (eps * (exp(((a + b) * eps)) - 1.0)) / ((exp((a * eps)) - 1.0) * (exp((b * eps)) - 1.0)); end
code[a_, b_, eps_] := N[(N[(eps * N[(N[Exp[N[(N[(a + b), $MachinePrecision] * eps), $MachinePrecision]], $MachinePrecision] - 1.0), $MachinePrecision]), $MachinePrecision] / N[(N[(N[Exp[N[(a * eps), $MachinePrecision]], $MachinePrecision] - 1.0), $MachinePrecision] * N[(N[Exp[N[(b * eps), $MachinePrecision]], $MachinePrecision] - 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\varepsilon \cdot \left(e^{\left(a + b\right) \cdot \varepsilon} - 1\right)}{\left(e^{a \cdot \varepsilon} - 1\right) \cdot \left(e^{b \cdot \varepsilon} - 1\right)}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 3 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (a b eps) :precision binary64 (/ (* eps (- (exp (* (+ a b) eps)) 1.0)) (* (- (exp (* a eps)) 1.0) (- (exp (* b eps)) 1.0))))
double code(double a, double b, double eps) {
return (eps * (exp(((a + b) * eps)) - 1.0)) / ((exp((a * eps)) - 1.0) * (exp((b * eps)) - 1.0));
}
real(8) function code(a, b, eps)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: eps
code = (eps * (exp(((a + b) * eps)) - 1.0d0)) / ((exp((a * eps)) - 1.0d0) * (exp((b * eps)) - 1.0d0))
end function
public static double code(double a, double b, double eps) {
return (eps * (Math.exp(((a + b) * eps)) - 1.0)) / ((Math.exp((a * eps)) - 1.0) * (Math.exp((b * eps)) - 1.0));
}
def code(a, b, eps): return (eps * (math.exp(((a + b) * eps)) - 1.0)) / ((math.exp((a * eps)) - 1.0) * (math.exp((b * eps)) - 1.0))
function code(a, b, eps) return Float64(Float64(eps * Float64(exp(Float64(Float64(a + b) * eps)) - 1.0)) / Float64(Float64(exp(Float64(a * eps)) - 1.0) * Float64(exp(Float64(b * eps)) - 1.0))) end
function tmp = code(a, b, eps) tmp = (eps * (exp(((a + b) * eps)) - 1.0)) / ((exp((a * eps)) - 1.0) * (exp((b * eps)) - 1.0)); end
code[a_, b_, eps_] := N[(N[(eps * N[(N[Exp[N[(N[(a + b), $MachinePrecision] * eps), $MachinePrecision]], $MachinePrecision] - 1.0), $MachinePrecision]), $MachinePrecision] / N[(N[(N[Exp[N[(a * eps), $MachinePrecision]], $MachinePrecision] - 1.0), $MachinePrecision] * N[(N[Exp[N[(b * eps), $MachinePrecision]], $MachinePrecision] - 1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\varepsilon \cdot \left(e^{\left(a + b\right) \cdot \varepsilon} - 1\right)}{\left(e^{a \cdot \varepsilon} - 1\right) \cdot \left(e^{b \cdot \varepsilon} - 1\right)}
\end{array}
(FPCore (a b eps) :precision binary64 (+ (/ 1.0 a) (/ 1.0 b)))
double code(double a, double b, double eps) {
return (1.0 / a) + (1.0 / b);
}
real(8) function code(a, b, eps)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: eps
code = (1.0d0 / a) + (1.0d0 / b)
end function
public static double code(double a, double b, double eps) {
return (1.0 / a) + (1.0 / b);
}
def code(a, b, eps): return (1.0 / a) + (1.0 / b)
function code(a, b, eps) return Float64(Float64(1.0 / a) + Float64(1.0 / b)) end
function tmp = code(a, b, eps) tmp = (1.0 / a) + (1.0 / b); end
code[a_, b_, eps_] := N[(N[(1.0 / a), $MachinePrecision] + N[(1.0 / b), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{1}{a} + \frac{1}{b}
\end{array}
Initial program 0.0%
*-commutative0.0%
associate-/l*0.0%
expm1-define1.5%
*-commutative1.5%
expm1-define1.7%
*-commutative1.7%
expm1-define11.0%
*-commutative11.0%
Simplified11.0%
Taylor expanded in eps around 0 61.9%
Taylor expanded in a around inf 99.9%
Final simplification99.9%
(FPCore (a b eps) :precision binary64 (if (or (<= b 1.9e-235) (and (not (<= b 3.4e-226)) (<= b 7.5e-167))) (/ 1.0 b) (/ 1.0 a)))
double code(double a, double b, double eps) {
double tmp;
if ((b <= 1.9e-235) || (!(b <= 3.4e-226) && (b <= 7.5e-167))) {
tmp = 1.0 / b;
} else {
tmp = 1.0 / a;
}
return tmp;
}
real(8) function code(a, b, eps)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: eps
real(8) :: tmp
if ((b <= 1.9d-235) .or. (.not. (b <= 3.4d-226)) .and. (b <= 7.5d-167)) then
tmp = 1.0d0 / b
else
tmp = 1.0d0 / a
end if
code = tmp
end function
public static double code(double a, double b, double eps) {
double tmp;
if ((b <= 1.9e-235) || (!(b <= 3.4e-226) && (b <= 7.5e-167))) {
tmp = 1.0 / b;
} else {
tmp = 1.0 / a;
}
return tmp;
}
def code(a, b, eps): tmp = 0 if (b <= 1.9e-235) or (not (b <= 3.4e-226) and (b <= 7.5e-167)): tmp = 1.0 / b else: tmp = 1.0 / a return tmp
function code(a, b, eps) tmp = 0.0 if ((b <= 1.9e-235) || (!(b <= 3.4e-226) && (b <= 7.5e-167))) tmp = Float64(1.0 / b); else tmp = Float64(1.0 / a); end return tmp end
function tmp_2 = code(a, b, eps) tmp = 0.0; if ((b <= 1.9e-235) || (~((b <= 3.4e-226)) && (b <= 7.5e-167))) tmp = 1.0 / b; else tmp = 1.0 / a; end tmp_2 = tmp; end
code[a_, b_, eps_] := If[Or[LessEqual[b, 1.9e-235], And[N[Not[LessEqual[b, 3.4e-226]], $MachinePrecision], LessEqual[b, 7.5e-167]]], N[(1.0 / b), $MachinePrecision], N[(1.0 / a), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq 1.9 \cdot 10^{-235} \lor \neg \left(b \leq 3.4 \cdot 10^{-226}\right) \land b \leq 7.5 \cdot 10^{-167}:\\
\;\;\;\;\frac{1}{b}\\
\mathbf{else}:\\
\;\;\;\;\frac{1}{a}\\
\end{array}
\end{array}
if b < 1.90000000000000013e-235 or 3.40000000000000007e-226 < b < 7.5000000000000007e-167Initial program 0.0%
*-commutative0.0%
associate-/l*0.0%
expm1-define1.3%
*-commutative1.3%
expm1-define0.8%
*-commutative0.8%
expm1-define6.3%
*-commutative6.3%
Simplified6.3%
Taylor expanded in b around 0 59.8%
if 1.90000000000000013e-235 < b < 3.40000000000000007e-226 or 7.5000000000000007e-167 < b Initial program 0.0%
*-commutative0.0%
associate-/l*0.0%
expm1-define1.9%
*-commutative1.9%
expm1-define3.2%
*-commutative3.2%
expm1-define18.9%
*-commutative18.9%
Simplified18.9%
Taylor expanded in a around 0 67.8%
Final simplification62.7%
(FPCore (a b eps) :precision binary64 (/ 1.0 a))
double code(double a, double b, double eps) {
return 1.0 / a;
}
real(8) function code(a, b, eps)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: eps
code = 1.0d0 / a
end function
public static double code(double a, double b, double eps) {
return 1.0 / a;
}
def code(a, b, eps): return 1.0 / a
function code(a, b, eps) return Float64(1.0 / a) end
function tmp = code(a, b, eps) tmp = 1.0 / a; end
code[a_, b_, eps_] := N[(1.0 / a), $MachinePrecision]
\begin{array}{l}
\\
\frac{1}{a}
\end{array}
Initial program 0.0%
*-commutative0.0%
associate-/l*0.0%
expm1-define1.5%
*-commutative1.5%
expm1-define1.7%
*-commutative1.7%
expm1-define11.0%
*-commutative11.0%
Simplified11.0%
Taylor expanded in a around 0 48.4%
Final simplification48.4%
(FPCore (a b eps) :precision binary64 (+ (/ 1.0 a) (/ 1.0 b)))
double code(double a, double b, double eps) {
return (1.0 / a) + (1.0 / b);
}
real(8) function code(a, b, eps)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: eps
code = (1.0d0 / a) + (1.0d0 / b)
end function
public static double code(double a, double b, double eps) {
return (1.0 / a) + (1.0 / b);
}
def code(a, b, eps): return (1.0 / a) + (1.0 / b)
function code(a, b, eps) return Float64(Float64(1.0 / a) + Float64(1.0 / b)) end
function tmp = code(a, b, eps) tmp = (1.0 / a) + (1.0 / b); end
code[a_, b_, eps_] := N[(N[(1.0 / a), $MachinePrecision] + N[(1.0 / b), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{1}{a} + \frac{1}{b}
\end{array}
herbie shell --seed 2024095
(FPCore (a b eps)
:name "expq3 (problem 3.4.2)"
:precision binary64
:pre (and (and (<= (fabs a) 710.0) (<= (fabs b) 710.0)) (and (<= (* 1e-27 (fmin (fabs a) (fabs b))) eps) (<= eps (fmin (fabs a) (fabs b)))))
:alt
(+ (/ 1.0 a) (/ 1.0 b))
(/ (* eps (- (exp (* (+ a b) eps)) 1.0)) (* (- (exp (* a eps)) 1.0) (- (exp (* b eps)) 1.0))))