
(FPCore (x) :precision binary64 (let* ((t_0 (exp (- x)))) (/ (- (exp x) t_0) (+ (exp x) t_0))))
double code(double x) {
double t_0 = exp(-x);
return (exp(x) - t_0) / (exp(x) + t_0);
}
real(8) function code(x)
real(8), intent (in) :: x
real(8) :: t_0
t_0 = exp(-x)
code = (exp(x) - t_0) / (exp(x) + t_0)
end function
public static double code(double x) {
double t_0 = Math.exp(-x);
return (Math.exp(x) - t_0) / (Math.exp(x) + t_0);
}
def code(x): t_0 = math.exp(-x) return (math.exp(x) - t_0) / (math.exp(x) + t_0)
function code(x) t_0 = exp(Float64(-x)) return Float64(Float64(exp(x) - t_0) / Float64(exp(x) + t_0)) end
function tmp = code(x) t_0 = exp(-x); tmp = (exp(x) - t_0) / (exp(x) + t_0); end
code[x_] := Block[{t$95$0 = N[Exp[(-x)], $MachinePrecision]}, N[(N[(N[Exp[x], $MachinePrecision] - t$95$0), $MachinePrecision] / N[(N[Exp[x], $MachinePrecision] + t$95$0), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := e^{-x}\\
\frac{e^{x} - t\_0}{e^{x} + t\_0}
\end{array}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 6 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (x) :precision binary64 (let* ((t_0 (exp (- x)))) (/ (- (exp x) t_0) (+ (exp x) t_0))))
double code(double x) {
double t_0 = exp(-x);
return (exp(x) - t_0) / (exp(x) + t_0);
}
real(8) function code(x)
real(8), intent (in) :: x
real(8) :: t_0
t_0 = exp(-x)
code = (exp(x) - t_0) / (exp(x) + t_0)
end function
public static double code(double x) {
double t_0 = Math.exp(-x);
return (Math.exp(x) - t_0) / (Math.exp(x) + t_0);
}
def code(x): t_0 = math.exp(-x) return (math.exp(x) - t_0) / (math.exp(x) + t_0)
function code(x) t_0 = exp(Float64(-x)) return Float64(Float64(exp(x) - t_0) / Float64(exp(x) + t_0)) end
function tmp = code(x) t_0 = exp(-x); tmp = (exp(x) - t_0) / (exp(x) + t_0); end
code[x_] := Block[{t$95$0 = N[Exp[(-x)], $MachinePrecision]}, N[(N[(N[Exp[x], $MachinePrecision] - t$95$0), $MachinePrecision] / N[(N[Exp[x], $MachinePrecision] + t$95$0), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := e^{-x}\\
\frac{e^{x} - t\_0}{e^{x} + t\_0}
\end{array}
\end{array}
(FPCore (x) :precision binary64 (tanh x))
double code(double x) {
return tanh(x);
}
real(8) function code(x)
real(8), intent (in) :: x
code = tanh(x)
end function
public static double code(double x) {
return Math.tanh(x);
}
def code(x): return math.tanh(x)
function code(x) return tanh(x) end
function tmp = code(x) tmp = tanh(x); end
code[x_] := N[Tanh[x], $MachinePrecision]
\begin{array}{l}
\\
\tanh x
\end{array}
Initial program 10.2%
tanh-undefN/A
tanh-lowering-tanh.f64100.0%
Applied egg-rr100.0%
(FPCore (x)
:precision binary64
(let* ((t_0
(*
x
(*
x
(+
-0.3333333333333333
(*
x
(*
x
(+ 0.13333333333333333 (* (* x x) -0.05396825396825397)))))))))
(*
x
(/
(+
1.0
(*
t_0
(*
(+ 0.1111111111111111 (* x (* x -0.08888888888888889)))
(* x (* x (* x x))))))
(+ 1.0 (* t_0 (+ t_0 -1.0)))))))
double code(double x) {
double t_0 = x * (x * (-0.3333333333333333 + (x * (x * (0.13333333333333333 + ((x * x) * -0.05396825396825397))))));
return x * ((1.0 + (t_0 * ((0.1111111111111111 + (x * (x * -0.08888888888888889))) * (x * (x * (x * x)))))) / (1.0 + (t_0 * (t_0 + -1.0))));
}
real(8) function code(x)
real(8), intent (in) :: x
real(8) :: t_0
t_0 = x * (x * ((-0.3333333333333333d0) + (x * (x * (0.13333333333333333d0 + ((x * x) * (-0.05396825396825397d0)))))))
code = x * ((1.0d0 + (t_0 * ((0.1111111111111111d0 + (x * (x * (-0.08888888888888889d0)))) * (x * (x * (x * x)))))) / (1.0d0 + (t_0 * (t_0 + (-1.0d0)))))
end function
public static double code(double x) {
double t_0 = x * (x * (-0.3333333333333333 + (x * (x * (0.13333333333333333 + ((x * x) * -0.05396825396825397))))));
return x * ((1.0 + (t_0 * ((0.1111111111111111 + (x * (x * -0.08888888888888889))) * (x * (x * (x * x)))))) / (1.0 + (t_0 * (t_0 + -1.0))));
}
def code(x): t_0 = x * (x * (-0.3333333333333333 + (x * (x * (0.13333333333333333 + ((x * x) * -0.05396825396825397)))))) return x * ((1.0 + (t_0 * ((0.1111111111111111 + (x * (x * -0.08888888888888889))) * (x * (x * (x * x)))))) / (1.0 + (t_0 * (t_0 + -1.0))))
function code(x) t_0 = Float64(x * Float64(x * Float64(-0.3333333333333333 + Float64(x * Float64(x * Float64(0.13333333333333333 + Float64(Float64(x * x) * -0.05396825396825397))))))) return Float64(x * Float64(Float64(1.0 + Float64(t_0 * Float64(Float64(0.1111111111111111 + Float64(x * Float64(x * -0.08888888888888889))) * Float64(x * Float64(x * Float64(x * x)))))) / Float64(1.0 + Float64(t_0 * Float64(t_0 + -1.0))))) end
function tmp = code(x) t_0 = x * (x * (-0.3333333333333333 + (x * (x * (0.13333333333333333 + ((x * x) * -0.05396825396825397)))))); tmp = x * ((1.0 + (t_0 * ((0.1111111111111111 + (x * (x * -0.08888888888888889))) * (x * (x * (x * x)))))) / (1.0 + (t_0 * (t_0 + -1.0)))); end
code[x_] := Block[{t$95$0 = N[(x * N[(x * N[(-0.3333333333333333 + N[(x * N[(x * N[(0.13333333333333333 + N[(N[(x * x), $MachinePrecision] * -0.05396825396825397), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, N[(x * N[(N[(1.0 + N[(t$95$0 * N[(N[(0.1111111111111111 + N[(x * N[(x * -0.08888888888888889), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[(x * N[(x * N[(x * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(1.0 + N[(t$95$0 * N[(t$95$0 + -1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := x \cdot \left(x \cdot \left(-0.3333333333333333 + x \cdot \left(x \cdot \left(0.13333333333333333 + \left(x \cdot x\right) \cdot -0.05396825396825397\right)\right)\right)\right)\\
x \cdot \frac{1 + t\_0 \cdot \left(\left(0.1111111111111111 + x \cdot \left(x \cdot -0.08888888888888889\right)\right) \cdot \left(x \cdot \left(x \cdot \left(x \cdot x\right)\right)\right)\right)}{1 + t\_0 \cdot \left(t\_0 + -1\right)}
\end{array}
\end{array}
Initial program 10.2%
div-subN/A
--lowering--.f64N/A
Simplified11.7%
Taylor expanded in x around 0
*-lowering-*.f64N/A
+-lowering-+.f64N/A
*-lowering-*.f64N/A
unpow2N/A
*-lowering-*.f64N/A
sub-negN/A
metadata-evalN/A
+-commutativeN/A
+-lowering-+.f64N/A
*-lowering-*.f64N/A
unpow2N/A
*-lowering-*.f64N/A
+-lowering-+.f64N/A
*-commutativeN/A
*-lowering-*.f64N/A
unpow2N/A
*-lowering-*.f6497.1%
Simplified97.1%
flip3-+N/A
/-lowering-/.f64N/A
Applied egg-rr97.0%
Taylor expanded in x around 0
*-commutativeN/A
metadata-evalN/A
pow-sqrN/A
*-lowering-*.f64N/A
+-lowering-+.f64N/A
*-commutativeN/A
unpow2N/A
associate-*l*N/A
*-lowering-*.f64N/A
*-lowering-*.f64N/A
unpow2N/A
associate-*l*N/A
*-lowering-*.f64N/A
*-lowering-*.f64N/A
unpow2N/A
*-lowering-*.f6497.4%
Simplified97.4%
Final simplification97.4%
(FPCore (x)
:precision binary64
(let* ((t_0
(*
x
(*
x
(+
-0.3333333333333333
(*
x
(*
x
(+ 0.13333333333333333 (* (* x x) -0.05396825396825397)))))))))
(*
x
(/
(+
1.0
(*
(*
(+ 0.1111111111111111 (* x (* x -0.08888888888888889)))
(* x (* x (* x x))))
(* x (* x -0.3333333333333333))))
(+ 1.0 (* t_0 (+ t_0 -1.0)))))))
double code(double x) {
double t_0 = x * (x * (-0.3333333333333333 + (x * (x * (0.13333333333333333 + ((x * x) * -0.05396825396825397))))));
return x * ((1.0 + (((0.1111111111111111 + (x * (x * -0.08888888888888889))) * (x * (x * (x * x)))) * (x * (x * -0.3333333333333333)))) / (1.0 + (t_0 * (t_0 + -1.0))));
}
real(8) function code(x)
real(8), intent (in) :: x
real(8) :: t_0
t_0 = x * (x * ((-0.3333333333333333d0) + (x * (x * (0.13333333333333333d0 + ((x * x) * (-0.05396825396825397d0)))))))
code = x * ((1.0d0 + (((0.1111111111111111d0 + (x * (x * (-0.08888888888888889d0)))) * (x * (x * (x * x)))) * (x * (x * (-0.3333333333333333d0))))) / (1.0d0 + (t_0 * (t_0 + (-1.0d0)))))
end function
public static double code(double x) {
double t_0 = x * (x * (-0.3333333333333333 + (x * (x * (0.13333333333333333 + ((x * x) * -0.05396825396825397))))));
return x * ((1.0 + (((0.1111111111111111 + (x * (x * -0.08888888888888889))) * (x * (x * (x * x)))) * (x * (x * -0.3333333333333333)))) / (1.0 + (t_0 * (t_0 + -1.0))));
}
def code(x): t_0 = x * (x * (-0.3333333333333333 + (x * (x * (0.13333333333333333 + ((x * x) * -0.05396825396825397)))))) return x * ((1.0 + (((0.1111111111111111 + (x * (x * -0.08888888888888889))) * (x * (x * (x * x)))) * (x * (x * -0.3333333333333333)))) / (1.0 + (t_0 * (t_0 + -1.0))))
function code(x) t_0 = Float64(x * Float64(x * Float64(-0.3333333333333333 + Float64(x * Float64(x * Float64(0.13333333333333333 + Float64(Float64(x * x) * -0.05396825396825397))))))) return Float64(x * Float64(Float64(1.0 + Float64(Float64(Float64(0.1111111111111111 + Float64(x * Float64(x * -0.08888888888888889))) * Float64(x * Float64(x * Float64(x * x)))) * Float64(x * Float64(x * -0.3333333333333333)))) / Float64(1.0 + Float64(t_0 * Float64(t_0 + -1.0))))) end
function tmp = code(x) t_0 = x * (x * (-0.3333333333333333 + (x * (x * (0.13333333333333333 + ((x * x) * -0.05396825396825397)))))); tmp = x * ((1.0 + (((0.1111111111111111 + (x * (x * -0.08888888888888889))) * (x * (x * (x * x)))) * (x * (x * -0.3333333333333333)))) / (1.0 + (t_0 * (t_0 + -1.0)))); end
code[x_] := Block[{t$95$0 = N[(x * N[(x * N[(-0.3333333333333333 + N[(x * N[(x * N[(0.13333333333333333 + N[(N[(x * x), $MachinePrecision] * -0.05396825396825397), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, N[(x * N[(N[(1.0 + N[(N[(N[(0.1111111111111111 + N[(x * N[(x * -0.08888888888888889), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[(x * N[(x * N[(x * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] * N[(x * N[(x * -0.3333333333333333), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N[(1.0 + N[(t$95$0 * N[(t$95$0 + -1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := x \cdot \left(x \cdot \left(-0.3333333333333333 + x \cdot \left(x \cdot \left(0.13333333333333333 + \left(x \cdot x\right) \cdot -0.05396825396825397\right)\right)\right)\right)\\
x \cdot \frac{1 + \left(\left(0.1111111111111111 + x \cdot \left(x \cdot -0.08888888888888889\right)\right) \cdot \left(x \cdot \left(x \cdot \left(x \cdot x\right)\right)\right)\right) \cdot \left(x \cdot \left(x \cdot -0.3333333333333333\right)\right)}{1 + t\_0 \cdot \left(t\_0 + -1\right)}
\end{array}
\end{array}
Initial program 10.2%
div-subN/A
--lowering--.f64N/A
Simplified11.7%
Taylor expanded in x around 0
*-lowering-*.f64N/A
+-lowering-+.f64N/A
*-lowering-*.f64N/A
unpow2N/A
*-lowering-*.f64N/A
sub-negN/A
metadata-evalN/A
+-commutativeN/A
+-lowering-+.f64N/A
*-lowering-*.f64N/A
unpow2N/A
*-lowering-*.f64N/A
+-lowering-+.f64N/A
*-commutativeN/A
*-lowering-*.f64N/A
unpow2N/A
*-lowering-*.f6497.1%
Simplified97.1%
flip3-+N/A
/-lowering-/.f64N/A
Applied egg-rr97.0%
Taylor expanded in x around 0
*-commutativeN/A
metadata-evalN/A
pow-sqrN/A
*-lowering-*.f64N/A
+-lowering-+.f64N/A
*-commutativeN/A
unpow2N/A
associate-*l*N/A
*-lowering-*.f64N/A
*-lowering-*.f64N/A
unpow2N/A
associate-*l*N/A
*-lowering-*.f64N/A
*-lowering-*.f64N/A
unpow2N/A
*-lowering-*.f6497.4%
Simplified97.4%
Taylor expanded in x around 0
*-commutativeN/A
*-lowering-*.f6497.4%
Simplified97.4%
Final simplification97.4%
(FPCore (x) :precision binary64 (* x (+ 1.0 (* (* x x) (+ -0.3333333333333333 (* x (* x 0.13333333333333333)))))))
double code(double x) {
return x * (1.0 + ((x * x) * (-0.3333333333333333 + (x * (x * 0.13333333333333333)))));
}
real(8) function code(x)
real(8), intent (in) :: x
code = x * (1.0d0 + ((x * x) * ((-0.3333333333333333d0) + (x * (x * 0.13333333333333333d0)))))
end function
public static double code(double x) {
return x * (1.0 + ((x * x) * (-0.3333333333333333 + (x * (x * 0.13333333333333333)))));
}
def code(x): return x * (1.0 + ((x * x) * (-0.3333333333333333 + (x * (x * 0.13333333333333333)))))
function code(x) return Float64(x * Float64(1.0 + Float64(Float64(x * x) * Float64(-0.3333333333333333 + Float64(x * Float64(x * 0.13333333333333333)))))) end
function tmp = code(x) tmp = x * (1.0 + ((x * x) * (-0.3333333333333333 + (x * (x * 0.13333333333333333))))); end
code[x_] := N[(x * N[(1.0 + N[(N[(x * x), $MachinePrecision] * N[(-0.3333333333333333 + N[(x * N[(x * 0.13333333333333333), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
x \cdot \left(1 + \left(x \cdot x\right) \cdot \left(-0.3333333333333333 + x \cdot \left(x \cdot 0.13333333333333333\right)\right)\right)
\end{array}
Initial program 10.2%
div-subN/A
--lowering--.f64N/A
Simplified11.7%
Taylor expanded in x around 0
*-lowering-*.f64N/A
+-lowering-+.f64N/A
*-lowering-*.f64N/A
unpow2N/A
*-lowering-*.f64N/A
sub-negN/A
metadata-evalN/A
+-commutativeN/A
+-lowering-+.f64N/A
*-commutativeN/A
unpow2N/A
associate-*l*N/A
*-lowering-*.f64N/A
*-lowering-*.f6497.2%
Simplified97.2%
(FPCore (x) :precision binary64 (* x (+ 1.0 (* -0.3333333333333333 (* x x)))))
double code(double x) {
return x * (1.0 + (-0.3333333333333333 * (x * x)));
}
real(8) function code(x)
real(8), intent (in) :: x
code = x * (1.0d0 + ((-0.3333333333333333d0) * (x * x)))
end function
public static double code(double x) {
return x * (1.0 + (-0.3333333333333333 * (x * x)));
}
def code(x): return x * (1.0 + (-0.3333333333333333 * (x * x)))
function code(x) return Float64(x * Float64(1.0 + Float64(-0.3333333333333333 * Float64(x * x)))) end
function tmp = code(x) tmp = x * (1.0 + (-0.3333333333333333 * (x * x))); end
code[x_] := N[(x * N[(1.0 + N[(-0.3333333333333333 * N[(x * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
x \cdot \left(1 + -0.3333333333333333 \cdot \left(x \cdot x\right)\right)
\end{array}
Initial program 10.2%
div-subN/A
--lowering--.f64N/A
Simplified11.7%
Taylor expanded in x around 0
*-lowering-*.f64N/A
+-lowering-+.f64N/A
*-lowering-*.f64N/A
unpow2N/A
*-lowering-*.f6496.9%
Simplified96.9%
(FPCore (x) :precision binary64 x)
double code(double x) {
return x;
}
real(8) function code(x)
real(8), intent (in) :: x
code = x
end function
public static double code(double x) {
return x;
}
def code(x): return x
function code(x) return x end
function tmp = code(x) tmp = x; end
code[x_] := x
\begin{array}{l}
\\
x
\end{array}
Initial program 10.2%
div-subN/A
--lowering--.f64N/A
Simplified11.7%
Taylor expanded in x around 0
Simplified96.7%
herbie shell --seed 2024162
(FPCore (x)
:name "Hyperbolic tangent"
:precision binary64
(/ (- (exp x) (exp (- x))) (+ (exp x) (exp (- x)))))