
(FPCore (x)
:precision binary64
(let* ((t_0 (/ 1.0 (fabs x)))
(t_1 (* (* t_0 t_0) t_0))
(t_2 (* (* t_1 t_0) t_0)))
(*
(* (/ 1.0 (sqrt PI)) (exp (* (fabs x) (fabs x))))
(+
(+ (+ t_0 (* (/ 1.0 2.0) t_1)) (* (/ 3.0 4.0) t_2))
(* (/ 15.0 8.0) (* (* t_2 t_0) t_0))))))
double code(double x) {
double t_0 = 1.0 / fabs(x);
double t_1 = (t_0 * t_0) * t_0;
double t_2 = (t_1 * t_0) * t_0;
return ((1.0 / sqrt(((double) M_PI))) * exp((fabs(x) * fabs(x)))) * (((t_0 + ((1.0 / 2.0) * t_1)) + ((3.0 / 4.0) * t_2)) + ((15.0 / 8.0) * ((t_2 * t_0) * t_0)));
}
public static double code(double x) {
double t_0 = 1.0 / Math.abs(x);
double t_1 = (t_0 * t_0) * t_0;
double t_2 = (t_1 * t_0) * t_0;
return ((1.0 / Math.sqrt(Math.PI)) * Math.exp((Math.abs(x) * Math.abs(x)))) * (((t_0 + ((1.0 / 2.0) * t_1)) + ((3.0 / 4.0) * t_2)) + ((15.0 / 8.0) * ((t_2 * t_0) * t_0)));
}
def code(x): t_0 = 1.0 / math.fabs(x) t_1 = (t_0 * t_0) * t_0 t_2 = (t_1 * t_0) * t_0 return ((1.0 / math.sqrt(math.pi)) * math.exp((math.fabs(x) * math.fabs(x)))) * (((t_0 + ((1.0 / 2.0) * t_1)) + ((3.0 / 4.0) * t_2)) + ((15.0 / 8.0) * ((t_2 * t_0) * t_0)))
function code(x) t_0 = Float64(1.0 / abs(x)) t_1 = Float64(Float64(t_0 * t_0) * t_0) t_2 = Float64(Float64(t_1 * t_0) * t_0) return Float64(Float64(Float64(1.0 / sqrt(pi)) * exp(Float64(abs(x) * abs(x)))) * Float64(Float64(Float64(t_0 + Float64(Float64(1.0 / 2.0) * t_1)) + Float64(Float64(3.0 / 4.0) * t_2)) + Float64(Float64(15.0 / 8.0) * Float64(Float64(t_2 * t_0) * t_0)))) end
function tmp = code(x) t_0 = 1.0 / abs(x); t_1 = (t_0 * t_0) * t_0; t_2 = (t_1 * t_0) * t_0; tmp = ((1.0 / sqrt(pi)) * exp((abs(x) * abs(x)))) * (((t_0 + ((1.0 / 2.0) * t_1)) + ((3.0 / 4.0) * t_2)) + ((15.0 / 8.0) * ((t_2 * t_0) * t_0))); end
code[x_] := Block[{t$95$0 = N[(1.0 / N[Abs[x], $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(N[(t$95$0 * t$95$0), $MachinePrecision] * t$95$0), $MachinePrecision]}, Block[{t$95$2 = N[(N[(t$95$1 * t$95$0), $MachinePrecision] * t$95$0), $MachinePrecision]}, N[(N[(N[(1.0 / N[Sqrt[Pi], $MachinePrecision]), $MachinePrecision] * N[Exp[N[(N[Abs[x], $MachinePrecision] * N[Abs[x], $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * N[(N[(N[(t$95$0 + N[(N[(1.0 / 2.0), $MachinePrecision] * t$95$1), $MachinePrecision]), $MachinePrecision] + N[(N[(3.0 / 4.0), $MachinePrecision] * t$95$2), $MachinePrecision]), $MachinePrecision] + N[(N[(15.0 / 8.0), $MachinePrecision] * N[(N[(t$95$2 * t$95$0), $MachinePrecision] * t$95$0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{1}{\left|x\right|}\\
t_1 := \left(t\_0 \cdot t\_0\right) \cdot t\_0\\
t_2 := \left(t\_1 \cdot t\_0\right) \cdot t\_0\\
\left(\frac{1}{\sqrt{\pi}} \cdot e^{\left|x\right| \cdot \left|x\right|}\right) \cdot \left(\left(\left(t\_0 + \frac{1}{2} \cdot t\_1\right) + \frac{3}{4} \cdot t\_2\right) + \frac{15}{8} \cdot \left(\left(t\_2 \cdot t\_0\right) \cdot t\_0\right)\right)
\end{array}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 14 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (x)
:precision binary64
(let* ((t_0 (/ 1.0 (fabs x)))
(t_1 (* (* t_0 t_0) t_0))
(t_2 (* (* t_1 t_0) t_0)))
(*
(* (/ 1.0 (sqrt PI)) (exp (* (fabs x) (fabs x))))
(+
(+ (+ t_0 (* (/ 1.0 2.0) t_1)) (* (/ 3.0 4.0) t_2))
(* (/ 15.0 8.0) (* (* t_2 t_0) t_0))))))
double code(double x) {
double t_0 = 1.0 / fabs(x);
double t_1 = (t_0 * t_0) * t_0;
double t_2 = (t_1 * t_0) * t_0;
return ((1.0 / sqrt(((double) M_PI))) * exp((fabs(x) * fabs(x)))) * (((t_0 + ((1.0 / 2.0) * t_1)) + ((3.0 / 4.0) * t_2)) + ((15.0 / 8.0) * ((t_2 * t_0) * t_0)));
}
public static double code(double x) {
double t_0 = 1.0 / Math.abs(x);
double t_1 = (t_0 * t_0) * t_0;
double t_2 = (t_1 * t_0) * t_0;
return ((1.0 / Math.sqrt(Math.PI)) * Math.exp((Math.abs(x) * Math.abs(x)))) * (((t_0 + ((1.0 / 2.0) * t_1)) + ((3.0 / 4.0) * t_2)) + ((15.0 / 8.0) * ((t_2 * t_0) * t_0)));
}
def code(x): t_0 = 1.0 / math.fabs(x) t_1 = (t_0 * t_0) * t_0 t_2 = (t_1 * t_0) * t_0 return ((1.0 / math.sqrt(math.pi)) * math.exp((math.fabs(x) * math.fabs(x)))) * (((t_0 + ((1.0 / 2.0) * t_1)) + ((3.0 / 4.0) * t_2)) + ((15.0 / 8.0) * ((t_2 * t_0) * t_0)))
function code(x) t_0 = Float64(1.0 / abs(x)) t_1 = Float64(Float64(t_0 * t_0) * t_0) t_2 = Float64(Float64(t_1 * t_0) * t_0) return Float64(Float64(Float64(1.0 / sqrt(pi)) * exp(Float64(abs(x) * abs(x)))) * Float64(Float64(Float64(t_0 + Float64(Float64(1.0 / 2.0) * t_1)) + Float64(Float64(3.0 / 4.0) * t_2)) + Float64(Float64(15.0 / 8.0) * Float64(Float64(t_2 * t_0) * t_0)))) end
function tmp = code(x) t_0 = 1.0 / abs(x); t_1 = (t_0 * t_0) * t_0; t_2 = (t_1 * t_0) * t_0; tmp = ((1.0 / sqrt(pi)) * exp((abs(x) * abs(x)))) * (((t_0 + ((1.0 / 2.0) * t_1)) + ((3.0 / 4.0) * t_2)) + ((15.0 / 8.0) * ((t_2 * t_0) * t_0))); end
code[x_] := Block[{t$95$0 = N[(1.0 / N[Abs[x], $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(N[(t$95$0 * t$95$0), $MachinePrecision] * t$95$0), $MachinePrecision]}, Block[{t$95$2 = N[(N[(t$95$1 * t$95$0), $MachinePrecision] * t$95$0), $MachinePrecision]}, N[(N[(N[(1.0 / N[Sqrt[Pi], $MachinePrecision]), $MachinePrecision] * N[Exp[N[(N[Abs[x], $MachinePrecision] * N[Abs[x], $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * N[(N[(N[(t$95$0 + N[(N[(1.0 / 2.0), $MachinePrecision] * t$95$1), $MachinePrecision]), $MachinePrecision] + N[(N[(3.0 / 4.0), $MachinePrecision] * t$95$2), $MachinePrecision]), $MachinePrecision] + N[(N[(15.0 / 8.0), $MachinePrecision] * N[(N[(t$95$2 * t$95$0), $MachinePrecision] * t$95$0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{1}{\left|x\right|}\\
t_1 := \left(t\_0 \cdot t\_0\right) \cdot t\_0\\
t_2 := \left(t\_1 \cdot t\_0\right) \cdot t\_0\\
\left(\frac{1}{\sqrt{\pi}} \cdot e^{\left|x\right| \cdot \left|x\right|}\right) \cdot \left(\left(\left(t\_0 + \frac{1}{2} \cdot t\_1\right) + \frac{3}{4} \cdot t\_2\right) + \frac{15}{8} \cdot \left(\left(t\_2 \cdot t\_0\right) \cdot t\_0\right)\right)
\end{array}
\end{array}
(FPCore (x)
:precision binary64
(let* ((t_0 (* (fabs x) (* (* x x) (* x x)))))
(*
(/ (pow (exp (+ x x)) (* x 0.5)) (sqrt PI))
(+
(/ 1.875 (* (* x x) t_0))
(+ (/ (+ (/ 0.5 (* x x)) 1.0) (fabs x)) (/ 0.75 t_0))))))
double code(double x) {
double t_0 = fabs(x) * ((x * x) * (x * x));
return (pow(exp((x + x)), (x * 0.5)) / sqrt(((double) M_PI))) * ((1.875 / ((x * x) * t_0)) + ((((0.5 / (x * x)) + 1.0) / fabs(x)) + (0.75 / t_0)));
}
public static double code(double x) {
double t_0 = Math.abs(x) * ((x * x) * (x * x));
return (Math.pow(Math.exp((x + x)), (x * 0.5)) / Math.sqrt(Math.PI)) * ((1.875 / ((x * x) * t_0)) + ((((0.5 / (x * x)) + 1.0) / Math.abs(x)) + (0.75 / t_0)));
}
def code(x): t_0 = math.fabs(x) * ((x * x) * (x * x)) return (math.pow(math.exp((x + x)), (x * 0.5)) / math.sqrt(math.pi)) * ((1.875 / ((x * x) * t_0)) + ((((0.5 / (x * x)) + 1.0) / math.fabs(x)) + (0.75 / t_0)))
function code(x) t_0 = Float64(abs(x) * Float64(Float64(x * x) * Float64(x * x))) return Float64(Float64((exp(Float64(x + x)) ^ Float64(x * 0.5)) / sqrt(pi)) * Float64(Float64(1.875 / Float64(Float64(x * x) * t_0)) + Float64(Float64(Float64(Float64(0.5 / Float64(x * x)) + 1.0) / abs(x)) + Float64(0.75 / t_0)))) end
function tmp = code(x) t_0 = abs(x) * ((x * x) * (x * x)); tmp = ((exp((x + x)) ^ (x * 0.5)) / sqrt(pi)) * ((1.875 / ((x * x) * t_0)) + ((((0.5 / (x * x)) + 1.0) / abs(x)) + (0.75 / t_0))); end
code[x_] := Block[{t$95$0 = N[(N[Abs[x], $MachinePrecision] * N[(N[(x * x), $MachinePrecision] * N[(x * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, N[(N[(N[Power[N[Exp[N[(x + x), $MachinePrecision]], $MachinePrecision], N[(x * 0.5), $MachinePrecision]], $MachinePrecision] / N[Sqrt[Pi], $MachinePrecision]), $MachinePrecision] * N[(N[(1.875 / N[(N[(x * x), $MachinePrecision] * t$95$0), $MachinePrecision]), $MachinePrecision] + N[(N[(N[(N[(0.5 / N[(x * x), $MachinePrecision]), $MachinePrecision] + 1.0), $MachinePrecision] / N[Abs[x], $MachinePrecision]), $MachinePrecision] + N[(0.75 / t$95$0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left|x\right| \cdot \left(\left(x \cdot x\right) \cdot \left(x \cdot x\right)\right)\\
\frac{{\left(e^{x + x}\right)}^{\left(x \cdot 0.5\right)}}{\sqrt{\pi}} \cdot \left(\frac{1.875}{\left(x \cdot x\right) \cdot t\_0} + \left(\frac{\frac{0.5}{x \cdot x} + 1}{\left|x\right|} + \frac{0.75}{t\_0}\right)\right)
\end{array}
\end{array}
Initial program 100.0%
Applied rewrites100.0%
lift-*.f64N/A
*-commutativeN/A
lift-/.f64N/A
un-div-invN/A
lower-/.f64100.0
lift-*.f64N/A
lift-fabs.f64N/A
lift-fabs.f64N/A
sqr-absN/A
lift-*.f64100.0
Applied rewrites100.0%
lift-exp.f64N/A
lift-*.f64N/A
exp-prodN/A
lower-pow.f64N/A
lower-exp.f64100.0
Applied rewrites100.0%
lift-pow.f64N/A
sqr-powN/A
pow-prod-downN/A
lower-pow.f64N/A
lift-exp.f64N/A
lift-exp.f64N/A
prod-expN/A
lower-exp.f64N/A
lower-+.f64N/A
div-invN/A
metadata-evalN/A
lower-*.f64100.0
Applied rewrites100.0%
(FPCore (x)
:precision binary64
(let* ((t_0 (* (fabs x) (* (* x x) (* x x)))))
(*
(+
(/ 1.875 (* (* x x) t_0))
(+ (/ (+ (/ 0.5 (* x x)) 1.0) (fabs x)) (/ 0.75 t_0)))
(/ (pow (exp x) x) (sqrt PI)))))
double code(double x) {
double t_0 = fabs(x) * ((x * x) * (x * x));
return ((1.875 / ((x * x) * t_0)) + ((((0.5 / (x * x)) + 1.0) / fabs(x)) + (0.75 / t_0))) * (pow(exp(x), x) / sqrt(((double) M_PI)));
}
public static double code(double x) {
double t_0 = Math.abs(x) * ((x * x) * (x * x));
return ((1.875 / ((x * x) * t_0)) + ((((0.5 / (x * x)) + 1.0) / Math.abs(x)) + (0.75 / t_0))) * (Math.pow(Math.exp(x), x) / Math.sqrt(Math.PI));
}
def code(x): t_0 = math.fabs(x) * ((x * x) * (x * x)) return ((1.875 / ((x * x) * t_0)) + ((((0.5 / (x * x)) + 1.0) / math.fabs(x)) + (0.75 / t_0))) * (math.pow(math.exp(x), x) / math.sqrt(math.pi))
function code(x) t_0 = Float64(abs(x) * Float64(Float64(x * x) * Float64(x * x))) return Float64(Float64(Float64(1.875 / Float64(Float64(x * x) * t_0)) + Float64(Float64(Float64(Float64(0.5 / Float64(x * x)) + 1.0) / abs(x)) + Float64(0.75 / t_0))) * Float64((exp(x) ^ x) / sqrt(pi))) end
function tmp = code(x) t_0 = abs(x) * ((x * x) * (x * x)); tmp = ((1.875 / ((x * x) * t_0)) + ((((0.5 / (x * x)) + 1.0) / abs(x)) + (0.75 / t_0))) * ((exp(x) ^ x) / sqrt(pi)); end
code[x_] := Block[{t$95$0 = N[(N[Abs[x], $MachinePrecision] * N[(N[(x * x), $MachinePrecision] * N[(x * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, N[(N[(N[(1.875 / N[(N[(x * x), $MachinePrecision] * t$95$0), $MachinePrecision]), $MachinePrecision] + N[(N[(N[(N[(0.5 / N[(x * x), $MachinePrecision]), $MachinePrecision] + 1.0), $MachinePrecision] / N[Abs[x], $MachinePrecision]), $MachinePrecision] + N[(0.75 / t$95$0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[(N[Power[N[Exp[x], $MachinePrecision], x], $MachinePrecision] / N[Sqrt[Pi], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left|x\right| \cdot \left(\left(x \cdot x\right) \cdot \left(x \cdot x\right)\right)\\
\left(\frac{1.875}{\left(x \cdot x\right) \cdot t\_0} + \left(\frac{\frac{0.5}{x \cdot x} + 1}{\left|x\right|} + \frac{0.75}{t\_0}\right)\right) \cdot \frac{{\left(e^{x}\right)}^{x}}{\sqrt{\pi}}
\end{array}
\end{array}
Initial program 100.0%
Applied rewrites100.0%
lift-*.f64N/A
*-commutativeN/A
lift-/.f64N/A
un-div-invN/A
lower-/.f64100.0
lift-*.f64N/A
lift-fabs.f64N/A
lift-fabs.f64N/A
sqr-absN/A
lift-*.f64100.0
Applied rewrites100.0%
lift-exp.f64N/A
lift-*.f64N/A
exp-prodN/A
lower-pow.f64N/A
lower-exp.f64100.0
Applied rewrites100.0%
Final simplification100.0%
herbie shell --seed 2024226
(FPCore (x)
:name "Jmat.Real.erfi, branch x greater than or equal to 5"
:precision binary64
:pre (>= x 0.5)
(* (* (/ 1.0 (sqrt PI)) (exp (* (fabs x) (fabs x)))) (+ (+ (+ (/ 1.0 (fabs x)) (* (/ 1.0 2.0) (* (* (/ 1.0 (fabs x)) (/ 1.0 (fabs x))) (/ 1.0 (fabs x))))) (* (/ 3.0 4.0) (* (* (* (* (/ 1.0 (fabs x)) (/ 1.0 (fabs x))) (/ 1.0 (fabs x))) (/ 1.0 (fabs x))) (/ 1.0 (fabs x))))) (* (/ 15.0 8.0) (* (* (* (* (* (* (/ 1.0 (fabs x)) (/ 1.0 (fabs x))) (/ 1.0 (fabs x))) (/ 1.0 (fabs x))) (/ 1.0 (fabs x))) (/ 1.0 (fabs x))) (/ 1.0 (fabs x)))))))