
(FPCore (f) :precision binary64 (let* ((t_0 (* (/ PI 4.0) f)) (t_1 (exp t_0)) (t_2 (exp (- t_0)))) (- (* (/ 1.0 (/ PI 4.0)) (log (/ (+ t_1 t_2) (- t_1 t_2)))))))
double code(double f) {
double t_0 = (((double) M_PI) / 4.0) * f;
double t_1 = exp(t_0);
double t_2 = exp(-t_0);
return -((1.0 / (((double) M_PI) / 4.0)) * log(((t_1 + t_2) / (t_1 - t_2))));
}
public static double code(double f) {
double t_0 = (Math.PI / 4.0) * f;
double t_1 = Math.exp(t_0);
double t_2 = Math.exp(-t_0);
return -((1.0 / (Math.PI / 4.0)) * Math.log(((t_1 + t_2) / (t_1 - t_2))));
}
def code(f): t_0 = (math.pi / 4.0) * f t_1 = math.exp(t_0) t_2 = math.exp(-t_0) return -((1.0 / (math.pi / 4.0)) * math.log(((t_1 + t_2) / (t_1 - t_2))))
function code(f) t_0 = Float64(Float64(pi / 4.0) * f) t_1 = exp(t_0) t_2 = exp(Float64(-t_0)) return Float64(-Float64(Float64(1.0 / Float64(pi / 4.0)) * log(Float64(Float64(t_1 + t_2) / Float64(t_1 - t_2))))) end
function tmp = code(f) t_0 = (pi / 4.0) * f; t_1 = exp(t_0); t_2 = exp(-t_0); tmp = -((1.0 / (pi / 4.0)) * log(((t_1 + t_2) / (t_1 - t_2)))); end
code[f_] := Block[{t$95$0 = N[(N[(Pi / 4.0), $MachinePrecision] * f), $MachinePrecision]}, Block[{t$95$1 = N[Exp[t$95$0], $MachinePrecision]}, Block[{t$95$2 = N[Exp[(-t$95$0)], $MachinePrecision]}, (-N[(N[(1.0 / N[(Pi / 4.0), $MachinePrecision]), $MachinePrecision] * N[Log[N[(N[(t$95$1 + t$95$2), $MachinePrecision] / N[(t$95$1 - t$95$2), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision])]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{\pi}{4} \cdot f\\
t_1 := e^{t_0}\\
t_2 := e^{-t_0}\\
-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{t_1 + t_2}{t_1 - t_2}\right)
\end{array}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 14 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (f) :precision binary64 (let* ((t_0 (* (/ PI 4.0) f)) (t_1 (exp t_0)) (t_2 (exp (- t_0)))) (- (* (/ 1.0 (/ PI 4.0)) (log (/ (+ t_1 t_2) (- t_1 t_2)))))))
double code(double f) {
double t_0 = (((double) M_PI) / 4.0) * f;
double t_1 = exp(t_0);
double t_2 = exp(-t_0);
return -((1.0 / (((double) M_PI) / 4.0)) * log(((t_1 + t_2) / (t_1 - t_2))));
}
public static double code(double f) {
double t_0 = (Math.PI / 4.0) * f;
double t_1 = Math.exp(t_0);
double t_2 = Math.exp(-t_0);
return -((1.0 / (Math.PI / 4.0)) * Math.log(((t_1 + t_2) / (t_1 - t_2))));
}
def code(f): t_0 = (math.pi / 4.0) * f t_1 = math.exp(t_0) t_2 = math.exp(-t_0) return -((1.0 / (math.pi / 4.0)) * math.log(((t_1 + t_2) / (t_1 - t_2))))
function code(f) t_0 = Float64(Float64(pi / 4.0) * f) t_1 = exp(t_0) t_2 = exp(Float64(-t_0)) return Float64(-Float64(Float64(1.0 / Float64(pi / 4.0)) * log(Float64(Float64(t_1 + t_2) / Float64(t_1 - t_2))))) end
function tmp = code(f) t_0 = (pi / 4.0) * f; t_1 = exp(t_0); t_2 = exp(-t_0); tmp = -((1.0 / (pi / 4.0)) * log(((t_1 + t_2) / (t_1 - t_2)))); end
code[f_] := Block[{t$95$0 = N[(N[(Pi / 4.0), $MachinePrecision] * f), $MachinePrecision]}, Block[{t$95$1 = N[Exp[t$95$0], $MachinePrecision]}, Block[{t$95$2 = N[Exp[(-t$95$0)], $MachinePrecision]}, (-N[(N[(1.0 / N[(Pi / 4.0), $MachinePrecision]), $MachinePrecision] * N[Log[N[(N[(t$95$1 + t$95$2), $MachinePrecision] / N[(t$95$1 - t$95$2), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision])]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{\pi}{4} \cdot f\\
t_1 := e^{t_0}\\
t_2 := e^{-t_0}\\
-\frac{1}{\frac{\pi}{4}} \cdot \log \left(\frac{t_1 + t_2}{t_1 - t_2}\right)
\end{array}
\end{array}
(FPCore (f)
:precision binary64
(*
(/
(log
(/
(+ (exp (* 0.25 (* PI (- f)))) (exp (* 0.25 (* f PI))))
(fma
f
(* PI 0.5)
(fma
(pow f 3.0)
(* (pow PI 3.0) 0.005208333333333333)
(fma
(pow f 7.0)
(* (pow PI 7.0) 2.422030009920635e-8)
(* 1.6276041666666666e-5 (* (pow f 5.0) (pow PI 5.0))))))))
PI)
-4.0))
double code(double f) {
return (log(((exp((0.25 * (((double) M_PI) * -f))) + exp((0.25 * (f * ((double) M_PI))))) / fma(f, (((double) M_PI) * 0.5), fma(pow(f, 3.0), (pow(((double) M_PI), 3.0) * 0.005208333333333333), fma(pow(f, 7.0), (pow(((double) M_PI), 7.0) * 2.422030009920635e-8), (1.6276041666666666e-5 * (pow(f, 5.0) * pow(((double) M_PI), 5.0)))))))) / ((double) M_PI)) * -4.0;
}
function code(f) return Float64(Float64(log(Float64(Float64(exp(Float64(0.25 * Float64(pi * Float64(-f)))) + exp(Float64(0.25 * Float64(f * pi)))) / fma(f, Float64(pi * 0.5), fma((f ^ 3.0), Float64((pi ^ 3.0) * 0.005208333333333333), fma((f ^ 7.0), Float64((pi ^ 7.0) * 2.422030009920635e-8), Float64(1.6276041666666666e-5 * Float64((f ^ 5.0) * (pi ^ 5.0)))))))) / pi) * -4.0) end
code[f_] := N[(N[(N[Log[N[(N[(N[Exp[N[(0.25 * N[(Pi * (-f)), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + N[Exp[N[(0.25 * N[(f * Pi), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(f * N[(Pi * 0.5), $MachinePrecision] + N[(N[Power[f, 3.0], $MachinePrecision] * N[(N[Power[Pi, 3.0], $MachinePrecision] * 0.005208333333333333), $MachinePrecision] + N[(N[Power[f, 7.0], $MachinePrecision] * N[(N[Power[Pi, 7.0], $MachinePrecision] * 2.422030009920635e-8), $MachinePrecision] + N[(1.6276041666666666e-5 * N[(N[Power[f, 5.0], $MachinePrecision] * N[Power[Pi, 5.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] / Pi), $MachinePrecision] * -4.0), $MachinePrecision]
\begin{array}{l}
\\
\frac{\log \left(\frac{e^{0.25 \cdot \left(\pi \cdot \left(-f\right)\right)} + e^{0.25 \cdot \left(f \cdot \pi\right)}}{\mathsf{fma}\left(f, \pi \cdot 0.5, \mathsf{fma}\left({f}^{3}, {\pi}^{3} \cdot 0.005208333333333333, \mathsf{fma}\left({f}^{7}, {\pi}^{7} \cdot 2.422030009920635 \cdot 10^{-8}, 1.6276041666666666 \cdot 10^{-5} \cdot \left({f}^{5} \cdot {\pi}^{5}\right)\right)\right)\right)}\right)}{\pi} \cdot -4
\end{array}
(FPCore (f)
:precision binary64
(*
(/
(log
(/
(+ (exp (* 0.25 (* PI (- f)))) (exp (* 0.25 (* f PI))))
(fma
f
(* PI 0.5)
(fma
(pow f 3.0)
(* (pow PI 3.0) 0.005208333333333333)
(* (pow f 5.0) (* 1.6276041666666666e-5 (pow PI 5.0)))))))
PI)
-4.0))
double code(double f) {
return (log(((exp((0.25 * (((double) M_PI) * -f))) + exp((0.25 * (f * ((double) M_PI))))) / fma(f, (((double) M_PI) * 0.5), fma(pow(f, 3.0), (pow(((double) M_PI), 3.0) * 0.005208333333333333), (pow(f, 5.0) * (1.6276041666666666e-5 * pow(((double) M_PI), 5.0))))))) / ((double) M_PI)) * -4.0;
}
function code(f) return Float64(Float64(log(Float64(Float64(exp(Float64(0.25 * Float64(pi * Float64(-f)))) + exp(Float64(0.25 * Float64(f * pi)))) / fma(f, Float64(pi * 0.5), fma((f ^ 3.0), Float64((pi ^ 3.0) * 0.005208333333333333), Float64((f ^ 5.0) * Float64(1.6276041666666666e-5 * (pi ^ 5.0))))))) / pi) * -4.0) end
code[f_] := N[(N[(N[Log[N[(N[(N[Exp[N[(0.25 * N[(Pi * (-f)), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + N[Exp[N[(0.25 * N[(f * Pi), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(f * N[(Pi * 0.5), $MachinePrecision] + N[(N[Power[f, 3.0], $MachinePrecision] * N[(N[Power[Pi, 3.0], $MachinePrecision] * 0.005208333333333333), $MachinePrecision] + N[(N[Power[f, 5.0], $MachinePrecision] * N[(1.6276041666666666e-5 * N[Power[Pi, 5.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] / Pi), $MachinePrecision] * -4.0), $MachinePrecision]
\begin{array}{l}
\\
\frac{\log \left(\frac{e^{0.25 \cdot \left(\pi \cdot \left(-f\right)\right)} + e^{0.25 \cdot \left(f \cdot \pi\right)}}{\mathsf{fma}\left(f, \pi \cdot 0.5, \mathsf{fma}\left({f}^{3}, {\pi}^{3} \cdot 0.005208333333333333, {f}^{5} \cdot \left(1.6276041666666666 \cdot 10^{-5} \cdot {\pi}^{5}\right)\right)\right)}\right)}{\pi} \cdot -4
\end{array}
(FPCore (f)
:precision binary64
(*
(/
(log
(/
(+ (exp (* 0.25 (* PI (- f)))) (exp (* 0.25 (* f PI))))
(fma f (* PI 0.5) (* (pow f 3.0) (* (pow PI 3.0) 0.005208333333333333)))))
PI)
-4.0))
double code(double f) {
return (log(((exp((0.25 * (((double) M_PI) * -f))) + exp((0.25 * (f * ((double) M_PI))))) / fma(f, (((double) M_PI) * 0.5), (pow(f, 3.0) * (pow(((double) M_PI), 3.0) * 0.005208333333333333))))) / ((double) M_PI)) * -4.0;
}
function code(f) return Float64(Float64(log(Float64(Float64(exp(Float64(0.25 * Float64(pi * Float64(-f)))) + exp(Float64(0.25 * Float64(f * pi)))) / fma(f, Float64(pi * 0.5), Float64((f ^ 3.0) * Float64((pi ^ 3.0) * 0.005208333333333333))))) / pi) * -4.0) end
code[f_] := N[(N[(N[Log[N[(N[(N[Exp[N[(0.25 * N[(Pi * (-f)), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] + N[Exp[N[(0.25 * N[(f * Pi), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(f * N[(Pi * 0.5), $MachinePrecision] + N[(N[Power[f, 3.0], $MachinePrecision] * N[(N[Power[Pi, 3.0], $MachinePrecision] * 0.005208333333333333), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] / Pi), $MachinePrecision] * -4.0), $MachinePrecision]
\begin{array}{l}
\\
\frac{\log \left(\frac{e^{0.25 \cdot \left(\pi \cdot \left(-f\right)\right)} + e^{0.25 \cdot \left(f \cdot \pi\right)}}{\mathsf{fma}\left(f, \pi \cdot 0.5, {f}^{3} \cdot \left({\pi}^{3} \cdot 0.005208333333333333\right)\right)}\right)}{\pi} \cdot -4
\end{array}
(FPCore (f) :precision binary64 (- (fma 4.0 (/ (- (log (/ 4.0 PI)) (log f)) PI) (* (pow f 2.0) (* PI 0.08333333333333333)))))
double code(double f) {
return -fma(4.0, ((log((4.0 / ((double) M_PI))) - log(f)) / ((double) M_PI)), (pow(f, 2.0) * (((double) M_PI) * 0.08333333333333333)));
}
function code(f) return Float64(-fma(4.0, Float64(Float64(log(Float64(4.0 / pi)) - log(f)) / pi), Float64((f ^ 2.0) * Float64(pi * 0.08333333333333333)))) end
code[f_] := (-N[(4.0 * N[(N[(N[Log[N[(4.0 / Pi), $MachinePrecision]], $MachinePrecision] - N[Log[f], $MachinePrecision]), $MachinePrecision] / Pi), $MachinePrecision] + N[(N[Power[f, 2.0], $MachinePrecision] * N[(Pi * 0.08333333333333333), $MachinePrecision]), $MachinePrecision]), $MachinePrecision])
\begin{array}{l}
\\
-\mathsf{fma}\left(4, \frac{\log \left(\frac{4}{\pi}\right) - \log f}{\pi}, {f}^{2} \cdot \left(\pi \cdot 0.08333333333333333\right)\right)
\end{array}
(FPCore (f) :precision binary64 (- (* 4.0 (/ (- (log f) (log (/ 4.0 PI))) PI)) (* 0.125 (* PI (pow f 2.0)))))
double code(double f) {
return (4.0 * ((log(f) - log((4.0 / ((double) M_PI)))) / ((double) M_PI))) - (0.125 * (((double) M_PI) * pow(f, 2.0)));
}
public static double code(double f) {
return (4.0 * ((Math.log(f) - Math.log((4.0 / Math.PI))) / Math.PI)) - (0.125 * (Math.PI * Math.pow(f, 2.0)));
}
def code(f): return (4.0 * ((math.log(f) - math.log((4.0 / math.pi))) / math.pi)) - (0.125 * (math.pi * math.pow(f, 2.0)))
function code(f) return Float64(Float64(4.0 * Float64(Float64(log(f) - log(Float64(4.0 / pi))) / pi)) - Float64(0.125 * Float64(pi * (f ^ 2.0)))) end
function tmp = code(f) tmp = (4.0 * ((log(f) - log((4.0 / pi))) / pi)) - (0.125 * (pi * (f ^ 2.0))); end
code[f_] := N[(N[(4.0 * N[(N[(N[Log[f], $MachinePrecision] - N[Log[N[(4.0 / Pi), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / Pi), $MachinePrecision]), $MachinePrecision] - N[(0.125 * N[(Pi * N[Power[f, 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
4 \cdot \frac{\log f - \log \left(\frac{4}{\pi}\right)}{\pi} - 0.125 \cdot \left(\pi \cdot {f}^{2}\right)
\end{array}
(FPCore (f) :precision binary64 (* 4.0 (/ (- (log f) (log (/ 4.0 PI))) PI)))
double code(double f) {
return 4.0 * ((log(f) - log((4.0 / ((double) M_PI)))) / ((double) M_PI));
}
public static double code(double f) {
return 4.0 * ((Math.log(f) - Math.log((4.0 / Math.PI))) / Math.PI);
}
def code(f): return 4.0 * ((math.log(f) - math.log((4.0 / math.pi))) / math.pi)
function code(f) return Float64(4.0 * Float64(Float64(log(f) - log(Float64(4.0 / pi))) / pi)) end
function tmp = code(f) tmp = 4.0 * ((log(f) - log((4.0 / pi))) / pi); end
code[f_] := N[(4.0 * N[(N[(N[Log[f], $MachinePrecision] - N[Log[N[(4.0 / Pi), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / Pi), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
4 \cdot \frac{\log f - \log \left(\frac{4}{\pi}\right)}{\pi}
\end{array}
(FPCore (f) :precision binary64 (* (/ (log (/ (/ 4.0 PI) f)) PI) -4.0))
double code(double f) {
return (log(((4.0 / ((double) M_PI)) / f)) / ((double) M_PI)) * -4.0;
}
public static double code(double f) {
return (Math.log(((4.0 / Math.PI) / f)) / Math.PI) * -4.0;
}
def code(f): return (math.log(((4.0 / math.pi) / f)) / math.pi) * -4.0
function code(f) return Float64(Float64(log(Float64(Float64(4.0 / pi) / f)) / pi) * -4.0) end
function tmp = code(f) tmp = (log(((4.0 / pi) / f)) / pi) * -4.0; end
code[f_] := N[(N[(N[Log[N[(N[(4.0 / Pi), $MachinePrecision] / f), $MachinePrecision]], $MachinePrecision] / Pi), $MachinePrecision] * -4.0), $MachinePrecision]
\begin{array}{l}
\\
\frac{\log \left(\frac{\frac{4}{\pi}}{f}\right)}{\pi} \cdot -4
\end{array}
(FPCore (f) :precision binary64 (* 4.0 (/ (- (log f) 0.25) PI)))
double code(double f) {
return 4.0 * ((log(f) - 0.25) / ((double) M_PI));
}
public static double code(double f) {
return 4.0 * ((Math.log(f) - 0.25) / Math.PI);
}
def code(f): return 4.0 * ((math.log(f) - 0.25) / math.pi)
function code(f) return Float64(4.0 * Float64(Float64(log(f) - 0.25) / pi)) end
function tmp = code(f) tmp = 4.0 * ((log(f) - 0.25) / pi); end
code[f_] := N[(4.0 * N[(N[(N[Log[f], $MachinePrecision] - 0.25), $MachinePrecision] / Pi), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
4 \cdot \frac{\log f - 0.25}{\pi}
\end{array}
(FPCore (f) :precision binary64 0.0)
double code(double f) {
return 0.0;
}
real(8) function code(f)
real(8), intent (in) :: f
code = 0.0d0
end function
public static double code(double f) {
return 0.0;
}
def code(f): return 0.0
function code(f) return 0.0 end
function tmp = code(f) tmp = 0.0; end
code[f_] := 0.0
\begin{array}{l}
\\
0
\end{array}
(FPCore (f) :precision binary64 -0.001953125)
double code(double f) {
return -0.001953125;
}
real(8) function code(f)
real(8), intent (in) :: f
code = -0.001953125d0
end function
public static double code(double f) {
return -0.001953125;
}
def code(f): return -0.001953125
function code(f) return -0.001953125 end
function tmp = code(f) tmp = -0.001953125; end
code[f_] := -0.001953125
\begin{array}{l}
\\
-0.001953125
\end{array}
(FPCore (f) :precision binary64 -4.0)
double code(double f) {
return -4.0;
}
real(8) function code(f)
real(8), intent (in) :: f
code = -4.0d0
end function
public static double code(double f) {
return -4.0;
}
def code(f): return -4.0
function code(f) return -4.0 end
function tmp = code(f) tmp = -4.0; end
code[f_] := -4.0
\begin{array}{l}
\\
-4
\end{array}
(FPCore (f) :precision binary64 -6.0)
double code(double f) {
return -6.0;
}
real(8) function code(f)
real(8), intent (in) :: f
code = -6.0d0
end function
public static double code(double f) {
return -6.0;
}
def code(f): return -6.0
function code(f) return -6.0 end
function tmp = code(f) tmp = -6.0; end
code[f_] := -6.0
\begin{array}{l}
\\
-6
\end{array}
(FPCore (f) :precision binary64 -16.0)
double code(double f) {
return -16.0;
}
real(8) function code(f)
real(8), intent (in) :: f
code = -16.0d0
end function
public static double code(double f) {
return -16.0;
}
def code(f): return -16.0
function code(f) return -16.0 end
function tmp = code(f) tmp = -16.0; end
code[f_] := -16.0
\begin{array}{l}
\\
-16
\end{array}
(FPCore (f) :precision binary64 -64.0)
double code(double f) {
return -64.0;
}
real(8) function code(f)
real(8), intent (in) :: f
code = -64.0d0
end function
public static double code(double f) {
return -64.0;
}
def code(f): return -64.0
function code(f) return -64.0 end
function tmp = code(f) tmp = -64.0; end
code[f_] := -64.0
\begin{array}{l}
\\
-64
\end{array}
herbie shell --seed 2024010
(FPCore (f)
:name "VandenBroeck and Keller, Equation (20)"
:precision binary64
(- (* (/ 1.0 (/ PI 4.0)) (log (/ (+ (exp (* (/ PI 4.0) f)) (exp (- (* (/ PI 4.0) f)))) (- (exp (* (/ PI 4.0) f)) (exp (- (* (/ PI 4.0) f)))))))))