Hyperbolic secant

Percentage Accurate: 100.0% → 100.0%
Time: 5.7s
Alternatives: 9
Speedup: 1.9×

Specification

?
\[\begin{array}{l} \\ \frac{2}{e^{x} + e^{-x}} \end{array} \]
(FPCore (x) :precision binary64 (/ 2.0 (+ (exp x) (exp (- x)))))
double code(double x) {
	return 2.0 / (exp(x) + exp(-x));
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = 2.0d0 / (exp(x) + exp(-x))
end function
public static double code(double x) {
	return 2.0 / (Math.exp(x) + Math.exp(-x));
}
def code(x):
	return 2.0 / (math.exp(x) + math.exp(-x))
function code(x)
	return Float64(2.0 / Float64(exp(x) + exp(Float64(-x))))
end
function tmp = code(x)
	tmp = 2.0 / (exp(x) + exp(-x));
end
code[x_] := N[(2.0 / N[(N[Exp[x], $MachinePrecision] + N[Exp[(-x)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{2}{e^{x} + e^{-x}}
\end{array}

Sampling outcomes in binary64 precision:

Local Percentage Accuracy vs ?

The average percentage accuracy by input value. Horizontal axis shows value of an input variable; the variable is choosen in the title. Vertical axis is accuracy; higher is better. Red represent the original program, while blue represents Herbie's suggestion. These can be toggled with buttons below the plot. The line is an average while dots represent individual samples.

Accuracy vs Speed?

Herbie found 9 alternatives:

AlternativeAccuracySpeedup
The accuracy (vertical axis) and speed (horizontal axis) of each alternatives. Up and to the right is better. The red square shows the initial program, and each blue circle shows an alternative.The line shows the best available speed-accuracy tradeoffs.

Initial Program: 100.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{2}{e^{x} + e^{-x}} \end{array} \]
(FPCore (x) :precision binary64 (/ 2.0 (+ (exp x) (exp (- x)))))
double code(double x) {
	return 2.0 / (exp(x) + exp(-x));
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = 2.0d0 / (exp(x) + exp(-x))
end function
public static double code(double x) {
	return 2.0 / (Math.exp(x) + Math.exp(-x));
}
def code(x):
	return 2.0 / (math.exp(x) + math.exp(-x))
function code(x)
	return Float64(2.0 / Float64(exp(x) + exp(Float64(-x))))
end
function tmp = code(x)
	tmp = 2.0 / (exp(x) + exp(-x));
end
code[x_] := N[(2.0 / N[(N[Exp[x], $MachinePrecision] + N[Exp[(-x)], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{2}{e^{x} + e^{-x}}
\end{array}

Alternative 1: 100.0% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \frac{1}{\cosh x} \end{array} \]
(FPCore (x) :precision binary64 (/ 1.0 (cosh x)))
double code(double x) {
	return 1.0 / cosh(x);
}
real(8) function code(x)
    real(8), intent (in) :: x
    code = 1.0d0 / cosh(x)
end function
public static double code(double x) {
	return 1.0 / Math.cosh(x);
}
def code(x):
	return 1.0 / math.cosh(x)
function code(x)
	return Float64(1.0 / cosh(x))
end
function tmp = code(x)
	tmp = 1.0 / cosh(x);
end
code[x_] := N[(1.0 / N[Cosh[x], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{1}{\cosh x}
\end{array}
Derivation
  1. Initial program 100.0%

    \[\frac{2}{e^{x} + e^{-x}} \]
  2. Add Preprocessing
  3. Step-by-step derivation
    1. lift-/.f64N/A

      \[\leadsto \color{blue}{\frac{2}{e^{x} + e^{-x}}} \]
    2. clear-numN/A

      \[\leadsto \color{blue}{\frac{1}{\frac{e^{x} + e^{-x}}{2}}} \]
    3. lift-+.f64N/A

      \[\leadsto \frac{1}{\frac{\color{blue}{e^{x} + e^{-x}}}{2}} \]
    4. lift-exp.f64N/A

      \[\leadsto \frac{1}{\frac{\color{blue}{e^{x}} + e^{-x}}{2}} \]
    5. lift-exp.f64N/A

      \[\leadsto \frac{1}{\frac{e^{x} + \color{blue}{e^{-x}}}{2}} \]
    6. lift-neg.f64N/A

      \[\leadsto \frac{1}{\frac{e^{x} + e^{\color{blue}{\mathsf{neg}\left(x\right)}}}{2}} \]
    7. cosh-defN/A

      \[\leadsto \frac{1}{\color{blue}{\cosh x}} \]
    8. lower-/.f64N/A

      \[\leadsto \color{blue}{\frac{1}{\cosh x}} \]
    9. lower-cosh.f64100.0

      \[\leadsto \frac{1}{\color{blue}{\cosh x}} \]
  4. Applied rewrites100.0%

    \[\leadsto \color{blue}{\frac{1}{\cosh x}} \]
  5. Add Preprocessing

Alternative 2: 87.0% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;e^{-x} + e^{x} \leq 4:\\ \;\;\;\;\mathsf{fma}\left(x \cdot x, -0.5, 1\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{\left(\left(\left(x \cdot x\right) \cdot 0.041666666666666664\right) \cdot x\right) \cdot x}\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (if (<= (+ (exp (- x)) (exp x)) 4.0)
   (fma (* x x) -0.5 1.0)
   (/ 1.0 (* (* (* (* x x) 0.041666666666666664) x) x))))
double code(double x) {
	double tmp;
	if ((exp(-x) + exp(x)) <= 4.0) {
		tmp = fma((x * x), -0.5, 1.0);
	} else {
		tmp = 1.0 / ((((x * x) * 0.041666666666666664) * x) * x);
	}
	return tmp;
}
function code(x)
	tmp = 0.0
	if (Float64(exp(Float64(-x)) + exp(x)) <= 4.0)
		tmp = fma(Float64(x * x), -0.5, 1.0);
	else
		tmp = Float64(1.0 / Float64(Float64(Float64(Float64(x * x) * 0.041666666666666664) * x) * x));
	end
	return tmp
end
code[x_] := If[LessEqual[N[(N[Exp[(-x)], $MachinePrecision] + N[Exp[x], $MachinePrecision]), $MachinePrecision], 4.0], N[(N[(x * x), $MachinePrecision] * -0.5 + 1.0), $MachinePrecision], N[(1.0 / N[(N[(N[(N[(x * x), $MachinePrecision] * 0.041666666666666664), $MachinePrecision] * x), $MachinePrecision] * x), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;e^{-x} + e^{x} \leq 4:\\
\;\;\;\;\mathsf{fma}\left(x \cdot x, -0.5, 1\right)\\

\mathbf{else}:\\
\;\;\;\;\frac{1}{\left(\left(\left(x \cdot x\right) \cdot 0.041666666666666664\right) \cdot x\right) \cdot x}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (+.f64 (exp.f64 x) (exp.f64 (neg.f64 x))) < 4

    1. Initial program 100.0%

      \[\frac{2}{e^{x} + e^{-x}} \]
    2. Add Preprocessing
    3. Taylor expanded in x around 0

      \[\leadsto \color{blue}{1 + \frac{-1}{2} \cdot {x}^{2}} \]
    4. Step-by-step derivation
      1. +-commutativeN/A

        \[\leadsto \color{blue}{\frac{-1}{2} \cdot {x}^{2} + 1} \]
      2. *-commutativeN/A

        \[\leadsto \color{blue}{{x}^{2} \cdot \frac{-1}{2}} + 1 \]
      3. lower-fma.f64N/A

        \[\leadsto \color{blue}{\mathsf{fma}\left({x}^{2}, \frac{-1}{2}, 1\right)} \]
      4. unpow2N/A

        \[\leadsto \mathsf{fma}\left(\color{blue}{x \cdot x}, \frac{-1}{2}, 1\right) \]
      5. lower-*.f64100.0

        \[\leadsto \mathsf{fma}\left(\color{blue}{x \cdot x}, -0.5, 1\right) \]
    5. Applied rewrites100.0%

      \[\leadsto \color{blue}{\mathsf{fma}\left(x \cdot x, -0.5, 1\right)} \]

    if 4 < (+.f64 (exp.f64 x) (exp.f64 (neg.f64 x)))

    1. Initial program 100.0%

      \[\frac{2}{e^{x} + e^{-x}} \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. lift-/.f64N/A

        \[\leadsto \color{blue}{\frac{2}{e^{x} + e^{-x}}} \]
      2. clear-numN/A

        \[\leadsto \color{blue}{\frac{1}{\frac{e^{x} + e^{-x}}{2}}} \]
      3. lift-+.f64N/A

        \[\leadsto \frac{1}{\frac{\color{blue}{e^{x} + e^{-x}}}{2}} \]
      4. lift-exp.f64N/A

        \[\leadsto \frac{1}{\frac{\color{blue}{e^{x}} + e^{-x}}{2}} \]
      5. lift-exp.f64N/A

        \[\leadsto \frac{1}{\frac{e^{x} + \color{blue}{e^{-x}}}{2}} \]
      6. lift-neg.f64N/A

        \[\leadsto \frac{1}{\frac{e^{x} + e^{\color{blue}{\mathsf{neg}\left(x\right)}}}{2}} \]
      7. cosh-defN/A

        \[\leadsto \frac{1}{\color{blue}{\cosh x}} \]
      8. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{1}{\cosh x}} \]
      9. lower-cosh.f64100.0

        \[\leadsto \frac{1}{\color{blue}{\cosh x}} \]
    4. Applied rewrites100.0%

      \[\leadsto \color{blue}{\frac{1}{\cosh x}} \]
    5. Taylor expanded in x around 0

      \[\leadsto \frac{1}{\color{blue}{1 + {x}^{2} \cdot \left(\frac{1}{2} + \frac{1}{24} \cdot {x}^{2}\right)}} \]
    6. Step-by-step derivation
      1. +-commutativeN/A

        \[\leadsto \frac{1}{\color{blue}{{x}^{2} \cdot \left(\frac{1}{2} + \frac{1}{24} \cdot {x}^{2}\right) + 1}} \]
      2. *-commutativeN/A

        \[\leadsto \frac{1}{\color{blue}{\left(\frac{1}{2} + \frac{1}{24} \cdot {x}^{2}\right) \cdot {x}^{2}} + 1} \]
      3. lower-fma.f64N/A

        \[\leadsto \frac{1}{\color{blue}{\mathsf{fma}\left(\frac{1}{2} + \frac{1}{24} \cdot {x}^{2}, {x}^{2}, 1\right)}} \]
      4. +-commutativeN/A

        \[\leadsto \frac{1}{\mathsf{fma}\left(\color{blue}{\frac{1}{24} \cdot {x}^{2} + \frac{1}{2}}, {x}^{2}, 1\right)} \]
      5. lower-fma.f64N/A

        \[\leadsto \frac{1}{\mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(\frac{1}{24}, {x}^{2}, \frac{1}{2}\right)}, {x}^{2}, 1\right)} \]
      6. unpow2N/A

        \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{24}, \color{blue}{x \cdot x}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
      7. lower-*.f64N/A

        \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{24}, \color{blue}{x \cdot x}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
      8. unpow2N/A

        \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{24}, x \cdot x, \frac{1}{2}\right), \color{blue}{x \cdot x}, 1\right)} \]
      9. lower-*.f6474.4

        \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(0.041666666666666664, x \cdot x, 0.5\right), \color{blue}{x \cdot x}, 1\right)} \]
    7. Applied rewrites74.4%

      \[\leadsto \frac{1}{\color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(0.041666666666666664, x \cdot x, 0.5\right), x \cdot x, 1\right)}} \]
    8. Taylor expanded in x around inf

      \[\leadsto \frac{1}{{x}^{4} \cdot \color{blue}{\left(\frac{1}{24} + \frac{1}{2} \cdot \frac{1}{{x}^{2}}\right)}} \]
    9. Step-by-step derivation
      1. Applied rewrites74.4%

        \[\leadsto \frac{1}{\left(\mathsf{fma}\left(0.041666666666666664, x \cdot x, 0.5\right) \cdot x\right) \cdot \color{blue}{x}} \]
      2. Taylor expanded in x around inf

        \[\leadsto \frac{1}{\left(\left(\frac{1}{24} \cdot {x}^{2}\right) \cdot x\right) \cdot x} \]
      3. Step-by-step derivation
        1. Applied rewrites74.4%

          \[\leadsto \frac{1}{\left(\left(0.041666666666666664 \cdot \left(x \cdot x\right)\right) \cdot x\right) \cdot x} \]
      4. Recombined 2 regimes into one program.
      5. Final simplification85.7%

        \[\leadsto \begin{array}{l} \mathbf{if}\;e^{-x} + e^{x} \leq 4:\\ \;\;\;\;\mathsf{fma}\left(x \cdot x, -0.5, 1\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{1}{\left(\left(\left(x \cdot x\right) \cdot 0.041666666666666664\right) \cdot x\right) \cdot x}\\ \end{array} \]
      6. Add Preprocessing

      Alternative 3: 74.8% accurate, 1.0× speedup?

      \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;e^{-x} + e^{x} \leq 4:\\ \;\;\;\;\mathsf{fma}\left(x \cdot x, -0.5, 1\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{2}{x \cdot x}\\ \end{array} \end{array} \]
      (FPCore (x)
       :precision binary64
       (if (<= (+ (exp (- x)) (exp x)) 4.0) (fma (* x x) -0.5 1.0) (/ 2.0 (* x x))))
      double code(double x) {
      	double tmp;
      	if ((exp(-x) + exp(x)) <= 4.0) {
      		tmp = fma((x * x), -0.5, 1.0);
      	} else {
      		tmp = 2.0 / (x * x);
      	}
      	return tmp;
      }
      
      function code(x)
      	tmp = 0.0
      	if (Float64(exp(Float64(-x)) + exp(x)) <= 4.0)
      		tmp = fma(Float64(x * x), -0.5, 1.0);
      	else
      		tmp = Float64(2.0 / Float64(x * x));
      	end
      	return tmp
      end
      
      code[x_] := If[LessEqual[N[(N[Exp[(-x)], $MachinePrecision] + N[Exp[x], $MachinePrecision]), $MachinePrecision], 4.0], N[(N[(x * x), $MachinePrecision] * -0.5 + 1.0), $MachinePrecision], N[(2.0 / N[(x * x), $MachinePrecision]), $MachinePrecision]]
      
      \begin{array}{l}
      
      \\
      \begin{array}{l}
      \mathbf{if}\;e^{-x} + e^{x} \leq 4:\\
      \;\;\;\;\mathsf{fma}\left(x \cdot x, -0.5, 1\right)\\
      
      \mathbf{else}:\\
      \;\;\;\;\frac{2}{x \cdot x}\\
      
      
      \end{array}
      \end{array}
      
      Derivation
      1. Split input into 2 regimes
      2. if (+.f64 (exp.f64 x) (exp.f64 (neg.f64 x))) < 4

        1. Initial program 100.0%

          \[\frac{2}{e^{x} + e^{-x}} \]
        2. Add Preprocessing
        3. Taylor expanded in x around 0

          \[\leadsto \color{blue}{1 + \frac{-1}{2} \cdot {x}^{2}} \]
        4. Step-by-step derivation
          1. +-commutativeN/A

            \[\leadsto \color{blue}{\frac{-1}{2} \cdot {x}^{2} + 1} \]
          2. *-commutativeN/A

            \[\leadsto \color{blue}{{x}^{2} \cdot \frac{-1}{2}} + 1 \]
          3. lower-fma.f64N/A

            \[\leadsto \color{blue}{\mathsf{fma}\left({x}^{2}, \frac{-1}{2}, 1\right)} \]
          4. unpow2N/A

            \[\leadsto \mathsf{fma}\left(\color{blue}{x \cdot x}, \frac{-1}{2}, 1\right) \]
          5. lower-*.f64100.0

            \[\leadsto \mathsf{fma}\left(\color{blue}{x \cdot x}, -0.5, 1\right) \]
        5. Applied rewrites100.0%

          \[\leadsto \color{blue}{\mathsf{fma}\left(x \cdot x, -0.5, 1\right)} \]

        if 4 < (+.f64 (exp.f64 x) (exp.f64 (neg.f64 x)))

        1. Initial program 100.0%

          \[\frac{2}{e^{x} + e^{-x}} \]
        2. Add Preprocessing
        3. Taylor expanded in x around 0

          \[\leadsto \frac{2}{\color{blue}{2 + {x}^{2}}} \]
        4. Step-by-step derivation
          1. +-commutativeN/A

            \[\leadsto \frac{2}{\color{blue}{{x}^{2} + 2}} \]
          2. unpow2N/A

            \[\leadsto \frac{2}{\color{blue}{x \cdot x} + 2} \]
          3. lower-fma.f6451.1

            \[\leadsto \frac{2}{\color{blue}{\mathsf{fma}\left(x, x, 2\right)}} \]
        5. Applied rewrites51.1%

          \[\leadsto \frac{2}{\color{blue}{\mathsf{fma}\left(x, x, 2\right)}} \]
        6. Taylor expanded in x around inf

          \[\leadsto \frac{2}{{x}^{\color{blue}{2}}} \]
        7. Step-by-step derivation
          1. Applied rewrites51.1%

            \[\leadsto \frac{2}{x \cdot \color{blue}{x}} \]
        8. Recombined 2 regimes into one program.
        9. Final simplification72.7%

          \[\leadsto \begin{array}{l} \mathbf{if}\;e^{-x} + e^{x} \leq 4:\\ \;\;\;\;\mathsf{fma}\left(x \cdot x, -0.5, 1\right)\\ \mathbf{else}:\\ \;\;\;\;\frac{2}{x \cdot x}\\ \end{array} \]
        10. Add Preprocessing

        Alternative 4: 90.8% accurate, 4.9× speedup?

        \[\begin{array}{l} \\ \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\left(x \cdot x\right) \cdot 0.001388888888888889, x \cdot x, 0.5\right) \cdot x, x, 1\right)} \end{array} \]
        (FPCore (x)
         :precision binary64
         (/ 1.0 (fma (* (fma (* (* x x) 0.001388888888888889) (* x x) 0.5) x) x 1.0)))
        double code(double x) {
        	return 1.0 / fma((fma(((x * x) * 0.001388888888888889), (x * x), 0.5) * x), x, 1.0);
        }
        
        function code(x)
        	return Float64(1.0 / fma(Float64(fma(Float64(Float64(x * x) * 0.001388888888888889), Float64(x * x), 0.5) * x), x, 1.0))
        end
        
        code[x_] := N[(1.0 / N[(N[(N[(N[(N[(x * x), $MachinePrecision] * 0.001388888888888889), $MachinePrecision] * N[(x * x), $MachinePrecision] + 0.5), $MachinePrecision] * x), $MachinePrecision] * x + 1.0), $MachinePrecision]), $MachinePrecision]
        
        \begin{array}{l}
        
        \\
        \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\left(x \cdot x\right) \cdot 0.001388888888888889, x \cdot x, 0.5\right) \cdot x, x, 1\right)}
        \end{array}
        
        Derivation
        1. Initial program 100.0%

          \[\frac{2}{e^{x} + e^{-x}} \]
        2. Add Preprocessing
        3. Step-by-step derivation
          1. lift-/.f64N/A

            \[\leadsto \color{blue}{\frac{2}{e^{x} + e^{-x}}} \]
          2. clear-numN/A

            \[\leadsto \color{blue}{\frac{1}{\frac{e^{x} + e^{-x}}{2}}} \]
          3. lift-+.f64N/A

            \[\leadsto \frac{1}{\frac{\color{blue}{e^{x} + e^{-x}}}{2}} \]
          4. lift-exp.f64N/A

            \[\leadsto \frac{1}{\frac{\color{blue}{e^{x}} + e^{-x}}{2}} \]
          5. lift-exp.f64N/A

            \[\leadsto \frac{1}{\frac{e^{x} + \color{blue}{e^{-x}}}{2}} \]
          6. lift-neg.f64N/A

            \[\leadsto \frac{1}{\frac{e^{x} + e^{\color{blue}{\mathsf{neg}\left(x\right)}}}{2}} \]
          7. cosh-defN/A

            \[\leadsto \frac{1}{\color{blue}{\cosh x}} \]
          8. lower-/.f64N/A

            \[\leadsto \color{blue}{\frac{1}{\cosh x}} \]
          9. lower-cosh.f64100.0

            \[\leadsto \frac{1}{\color{blue}{\cosh x}} \]
        4. Applied rewrites100.0%

          \[\leadsto \color{blue}{\frac{1}{\cosh x}} \]
        5. Taylor expanded in x around 0

          \[\leadsto \frac{1}{\color{blue}{1 + {x}^{2} \cdot \left(\frac{1}{2} + {x}^{2} \cdot \left(\frac{1}{24} + \frac{1}{720} \cdot {x}^{2}\right)\right)}} \]
        6. Step-by-step derivation
          1. +-commutativeN/A

            \[\leadsto \frac{1}{\color{blue}{{x}^{2} \cdot \left(\frac{1}{2} + {x}^{2} \cdot \left(\frac{1}{24} + \frac{1}{720} \cdot {x}^{2}\right)\right) + 1}} \]
          2. *-commutativeN/A

            \[\leadsto \frac{1}{\color{blue}{\left(\frac{1}{2} + {x}^{2} \cdot \left(\frac{1}{24} + \frac{1}{720} \cdot {x}^{2}\right)\right) \cdot {x}^{2}} + 1} \]
          3. lower-fma.f64N/A

            \[\leadsto \frac{1}{\color{blue}{\mathsf{fma}\left(\frac{1}{2} + {x}^{2} \cdot \left(\frac{1}{24} + \frac{1}{720} \cdot {x}^{2}\right), {x}^{2}, 1\right)}} \]
          4. +-commutativeN/A

            \[\leadsto \frac{1}{\mathsf{fma}\left(\color{blue}{{x}^{2} \cdot \left(\frac{1}{24} + \frac{1}{720} \cdot {x}^{2}\right) + \frac{1}{2}}, {x}^{2}, 1\right)} \]
          5. *-commutativeN/A

            \[\leadsto \frac{1}{\mathsf{fma}\left(\color{blue}{\left(\frac{1}{24} + \frac{1}{720} \cdot {x}^{2}\right) \cdot {x}^{2}} + \frac{1}{2}, {x}^{2}, 1\right)} \]
          6. lower-fma.f64N/A

            \[\leadsto \frac{1}{\mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(\frac{1}{24} + \frac{1}{720} \cdot {x}^{2}, {x}^{2}, \frac{1}{2}\right)}, {x}^{2}, 1\right)} \]
          7. +-commutativeN/A

            \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\color{blue}{\frac{1}{720} \cdot {x}^{2} + \frac{1}{24}}, {x}^{2}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
          8. lower-fma.f64N/A

            \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(\frac{1}{720}, {x}^{2}, \frac{1}{24}\right)}, {x}^{2}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
          9. unpow2N/A

            \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{720}, \color{blue}{x \cdot x}, \frac{1}{24}\right), {x}^{2}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
          10. lower-*.f64N/A

            \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{720}, \color{blue}{x \cdot x}, \frac{1}{24}\right), {x}^{2}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
          11. unpow2N/A

            \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{720}, x \cdot x, \frac{1}{24}\right), \color{blue}{x \cdot x}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
          12. lower-*.f64N/A

            \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{720}, x \cdot x, \frac{1}{24}\right), \color{blue}{x \cdot x}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
          13. unpow2N/A

            \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{720}, x \cdot x, \frac{1}{24}\right), x \cdot x, \frac{1}{2}\right), \color{blue}{x \cdot x}, 1\right)} \]
          14. lower-*.f6492.9

            \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889, x \cdot x, 0.041666666666666664\right), x \cdot x, 0.5\right), \color{blue}{x \cdot x}, 1\right)} \]
        7. Applied rewrites92.9%

          \[\leadsto \frac{1}{\color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889, x \cdot x, 0.041666666666666664\right), x \cdot x, 0.5\right), x \cdot x, 1\right)}} \]
        8. Step-by-step derivation
          1. Applied rewrites92.9%

            \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889, x \cdot x, 0.041666666666666664\right), x \cdot x, 0.5\right) \cdot x, \color{blue}{x}, 1\right)} \]
          2. Taylor expanded in x around inf

            \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{720} \cdot {x}^{2}, x \cdot x, \frac{1}{2}\right) \cdot x, x, 1\right)} \]
          3. Step-by-step derivation
            1. Applied rewrites92.9%

              \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889 \cdot \left(x \cdot x\right), x \cdot x, 0.5\right) \cdot x, x, 1\right)} \]
            2. Final simplification92.9%

              \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\left(x \cdot x\right) \cdot 0.001388888888888889, x \cdot x, 0.5\right) \cdot x, x, 1\right)} \]
            3. Add Preprocessing

            Alternative 5: 90.6% accurate, 5.0× speedup?

            \[\begin{array}{l} \\ \frac{1}{\mathsf{fma}\left(\left(\left(\left(x \cdot x\right) \cdot 0.001388888888888889\right) \cdot x\right) \cdot x, x \cdot x, 1\right)} \end{array} \]
            (FPCore (x)
             :precision binary64
             (/ 1.0 (fma (* (* (* (* x x) 0.001388888888888889) x) x) (* x x) 1.0)))
            double code(double x) {
            	return 1.0 / fma(((((x * x) * 0.001388888888888889) * x) * x), (x * x), 1.0);
            }
            
            function code(x)
            	return Float64(1.0 / fma(Float64(Float64(Float64(Float64(x * x) * 0.001388888888888889) * x) * x), Float64(x * x), 1.0))
            end
            
            code[x_] := N[(1.0 / N[(N[(N[(N[(N[(x * x), $MachinePrecision] * 0.001388888888888889), $MachinePrecision] * x), $MachinePrecision] * x), $MachinePrecision] * N[(x * x), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision]
            
            \begin{array}{l}
            
            \\
            \frac{1}{\mathsf{fma}\left(\left(\left(\left(x \cdot x\right) \cdot 0.001388888888888889\right) \cdot x\right) \cdot x, x \cdot x, 1\right)}
            \end{array}
            
            Derivation
            1. Initial program 100.0%

              \[\frac{2}{e^{x} + e^{-x}} \]
            2. Add Preprocessing
            3. Step-by-step derivation
              1. lift-/.f64N/A

                \[\leadsto \color{blue}{\frac{2}{e^{x} + e^{-x}}} \]
              2. clear-numN/A

                \[\leadsto \color{blue}{\frac{1}{\frac{e^{x} + e^{-x}}{2}}} \]
              3. lift-+.f64N/A

                \[\leadsto \frac{1}{\frac{\color{blue}{e^{x} + e^{-x}}}{2}} \]
              4. lift-exp.f64N/A

                \[\leadsto \frac{1}{\frac{\color{blue}{e^{x}} + e^{-x}}{2}} \]
              5. lift-exp.f64N/A

                \[\leadsto \frac{1}{\frac{e^{x} + \color{blue}{e^{-x}}}{2}} \]
              6. lift-neg.f64N/A

                \[\leadsto \frac{1}{\frac{e^{x} + e^{\color{blue}{\mathsf{neg}\left(x\right)}}}{2}} \]
              7. cosh-defN/A

                \[\leadsto \frac{1}{\color{blue}{\cosh x}} \]
              8. lower-/.f64N/A

                \[\leadsto \color{blue}{\frac{1}{\cosh x}} \]
              9. lower-cosh.f64100.0

                \[\leadsto \frac{1}{\color{blue}{\cosh x}} \]
            4. Applied rewrites100.0%

              \[\leadsto \color{blue}{\frac{1}{\cosh x}} \]
            5. Taylor expanded in x around 0

              \[\leadsto \frac{1}{\color{blue}{1 + {x}^{2} \cdot \left(\frac{1}{2} + {x}^{2} \cdot \left(\frac{1}{24} + \frac{1}{720} \cdot {x}^{2}\right)\right)}} \]
            6. Step-by-step derivation
              1. +-commutativeN/A

                \[\leadsto \frac{1}{\color{blue}{{x}^{2} \cdot \left(\frac{1}{2} + {x}^{2} \cdot \left(\frac{1}{24} + \frac{1}{720} \cdot {x}^{2}\right)\right) + 1}} \]
              2. *-commutativeN/A

                \[\leadsto \frac{1}{\color{blue}{\left(\frac{1}{2} + {x}^{2} \cdot \left(\frac{1}{24} + \frac{1}{720} \cdot {x}^{2}\right)\right) \cdot {x}^{2}} + 1} \]
              3. lower-fma.f64N/A

                \[\leadsto \frac{1}{\color{blue}{\mathsf{fma}\left(\frac{1}{2} + {x}^{2} \cdot \left(\frac{1}{24} + \frac{1}{720} \cdot {x}^{2}\right), {x}^{2}, 1\right)}} \]
              4. +-commutativeN/A

                \[\leadsto \frac{1}{\mathsf{fma}\left(\color{blue}{{x}^{2} \cdot \left(\frac{1}{24} + \frac{1}{720} \cdot {x}^{2}\right) + \frac{1}{2}}, {x}^{2}, 1\right)} \]
              5. *-commutativeN/A

                \[\leadsto \frac{1}{\mathsf{fma}\left(\color{blue}{\left(\frac{1}{24} + \frac{1}{720} \cdot {x}^{2}\right) \cdot {x}^{2}} + \frac{1}{2}, {x}^{2}, 1\right)} \]
              6. lower-fma.f64N/A

                \[\leadsto \frac{1}{\mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(\frac{1}{24} + \frac{1}{720} \cdot {x}^{2}, {x}^{2}, \frac{1}{2}\right)}, {x}^{2}, 1\right)} \]
              7. +-commutativeN/A

                \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\color{blue}{\frac{1}{720} \cdot {x}^{2} + \frac{1}{24}}, {x}^{2}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
              8. lower-fma.f64N/A

                \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(\frac{1}{720}, {x}^{2}, \frac{1}{24}\right)}, {x}^{2}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
              9. unpow2N/A

                \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{720}, \color{blue}{x \cdot x}, \frac{1}{24}\right), {x}^{2}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
              10. lower-*.f64N/A

                \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{720}, \color{blue}{x \cdot x}, \frac{1}{24}\right), {x}^{2}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
              11. unpow2N/A

                \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{720}, x \cdot x, \frac{1}{24}\right), \color{blue}{x \cdot x}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
              12. lower-*.f64N/A

                \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{720}, x \cdot x, \frac{1}{24}\right), \color{blue}{x \cdot x}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
              13. unpow2N/A

                \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{720}, x \cdot x, \frac{1}{24}\right), x \cdot x, \frac{1}{2}\right), \color{blue}{x \cdot x}, 1\right)} \]
              14. lower-*.f6492.9

                \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889, x \cdot x, 0.041666666666666664\right), x \cdot x, 0.5\right), \color{blue}{x \cdot x}, 1\right)} \]
            7. Applied rewrites92.9%

              \[\leadsto \frac{1}{\color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(\mathsf{fma}\left(0.001388888888888889, x \cdot x, 0.041666666666666664\right), x \cdot x, 0.5\right), x \cdot x, 1\right)}} \]
            8. Taylor expanded in x around inf

              \[\leadsto \frac{1}{\mathsf{fma}\left({x}^{4} \cdot \left(\frac{1}{720} + \frac{1}{24} \cdot \frac{1}{{x}^{2}}\right), \color{blue}{x} \cdot x, 1\right)} \]
            9. Step-by-step derivation
              1. Applied rewrites92.7%

                \[\leadsto \frac{1}{\mathsf{fma}\left(\left(\mathsf{fma}\left(0.001388888888888889, x \cdot x, 0.041666666666666664\right) \cdot x\right) \cdot x, \color{blue}{x} \cdot x, 1\right)} \]
              2. Taylor expanded in x around inf

                \[\leadsto \frac{1}{\mathsf{fma}\left(\left(\left(\frac{1}{720} \cdot {x}^{2}\right) \cdot x\right) \cdot x, x \cdot x, 1\right)} \]
              3. Step-by-step derivation
                1. Applied rewrites92.7%

                  \[\leadsto \frac{1}{\mathsf{fma}\left(\left(\left(0.001388888888888889 \cdot \left(x \cdot x\right)\right) \cdot x\right) \cdot x, x \cdot x, 1\right)} \]
                2. Final simplification92.7%

                  \[\leadsto \frac{1}{\mathsf{fma}\left(\left(\left(\left(x \cdot x\right) \cdot 0.001388888888888889\right) \cdot x\right) \cdot x, x \cdot x, 1\right)} \]
                3. Add Preprocessing

                Alternative 6: 87.1% accurate, 6.4× speedup?

                \[\begin{array}{l} \\ \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(0.041666666666666664, x \cdot x, 0.5\right), x \cdot x, 1\right)} \end{array} \]
                (FPCore (x)
                 :precision binary64
                 (/ 1.0 (fma (fma 0.041666666666666664 (* x x) 0.5) (* x x) 1.0)))
                double code(double x) {
                	return 1.0 / fma(fma(0.041666666666666664, (x * x), 0.5), (x * x), 1.0);
                }
                
                function code(x)
                	return Float64(1.0 / fma(fma(0.041666666666666664, Float64(x * x), 0.5), Float64(x * x), 1.0))
                end
                
                code[x_] := N[(1.0 / N[(N[(0.041666666666666664 * N[(x * x), $MachinePrecision] + 0.5), $MachinePrecision] * N[(x * x), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision]
                
                \begin{array}{l}
                
                \\
                \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(0.041666666666666664, x \cdot x, 0.5\right), x \cdot x, 1\right)}
                \end{array}
                
                Derivation
                1. Initial program 100.0%

                  \[\frac{2}{e^{x} + e^{-x}} \]
                2. Add Preprocessing
                3. Step-by-step derivation
                  1. lift-/.f64N/A

                    \[\leadsto \color{blue}{\frac{2}{e^{x} + e^{-x}}} \]
                  2. clear-numN/A

                    \[\leadsto \color{blue}{\frac{1}{\frac{e^{x} + e^{-x}}{2}}} \]
                  3. lift-+.f64N/A

                    \[\leadsto \frac{1}{\frac{\color{blue}{e^{x} + e^{-x}}}{2}} \]
                  4. lift-exp.f64N/A

                    \[\leadsto \frac{1}{\frac{\color{blue}{e^{x}} + e^{-x}}{2}} \]
                  5. lift-exp.f64N/A

                    \[\leadsto \frac{1}{\frac{e^{x} + \color{blue}{e^{-x}}}{2}} \]
                  6. lift-neg.f64N/A

                    \[\leadsto \frac{1}{\frac{e^{x} + e^{\color{blue}{\mathsf{neg}\left(x\right)}}}{2}} \]
                  7. cosh-defN/A

                    \[\leadsto \frac{1}{\color{blue}{\cosh x}} \]
                  8. lower-/.f64N/A

                    \[\leadsto \color{blue}{\frac{1}{\cosh x}} \]
                  9. lower-cosh.f64100.0

                    \[\leadsto \frac{1}{\color{blue}{\cosh x}} \]
                4. Applied rewrites100.0%

                  \[\leadsto \color{blue}{\frac{1}{\cosh x}} \]
                5. Taylor expanded in x around 0

                  \[\leadsto \frac{1}{\color{blue}{1 + {x}^{2} \cdot \left(\frac{1}{2} + \frac{1}{24} \cdot {x}^{2}\right)}} \]
                6. Step-by-step derivation
                  1. +-commutativeN/A

                    \[\leadsto \frac{1}{\color{blue}{{x}^{2} \cdot \left(\frac{1}{2} + \frac{1}{24} \cdot {x}^{2}\right) + 1}} \]
                  2. *-commutativeN/A

                    \[\leadsto \frac{1}{\color{blue}{\left(\frac{1}{2} + \frac{1}{24} \cdot {x}^{2}\right) \cdot {x}^{2}} + 1} \]
                  3. lower-fma.f64N/A

                    \[\leadsto \frac{1}{\color{blue}{\mathsf{fma}\left(\frac{1}{2} + \frac{1}{24} \cdot {x}^{2}, {x}^{2}, 1\right)}} \]
                  4. +-commutativeN/A

                    \[\leadsto \frac{1}{\mathsf{fma}\left(\color{blue}{\frac{1}{24} \cdot {x}^{2} + \frac{1}{2}}, {x}^{2}, 1\right)} \]
                  5. lower-fma.f64N/A

                    \[\leadsto \frac{1}{\mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(\frac{1}{24}, {x}^{2}, \frac{1}{2}\right)}, {x}^{2}, 1\right)} \]
                  6. unpow2N/A

                    \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{24}, \color{blue}{x \cdot x}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
                  7. lower-*.f64N/A

                    \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{24}, \color{blue}{x \cdot x}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
                  8. unpow2N/A

                    \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{24}, x \cdot x, \frac{1}{2}\right), \color{blue}{x \cdot x}, 1\right)} \]
                  9. lower-*.f6485.7

                    \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(0.041666666666666664, x \cdot x, 0.5\right), \color{blue}{x \cdot x}, 1\right)} \]
                7. Applied rewrites85.7%

                  \[\leadsto \frac{1}{\color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(0.041666666666666664, x \cdot x, 0.5\right), x \cdot x, 1\right)}} \]
                8. Add Preprocessing

                Alternative 7: 86.7% accurate, 6.6× speedup?

                \[\begin{array}{l} \\ \frac{1}{\mathsf{fma}\left(\left(x \cdot x\right) \cdot 0.041666666666666664, x \cdot x, 1\right)} \end{array} \]
                (FPCore (x)
                 :precision binary64
                 (/ 1.0 (fma (* (* x x) 0.041666666666666664) (* x x) 1.0)))
                double code(double x) {
                	return 1.0 / fma(((x * x) * 0.041666666666666664), (x * x), 1.0);
                }
                
                function code(x)
                	return Float64(1.0 / fma(Float64(Float64(x * x) * 0.041666666666666664), Float64(x * x), 1.0))
                end
                
                code[x_] := N[(1.0 / N[(N[(N[(x * x), $MachinePrecision] * 0.041666666666666664), $MachinePrecision] * N[(x * x), $MachinePrecision] + 1.0), $MachinePrecision]), $MachinePrecision]
                
                \begin{array}{l}
                
                \\
                \frac{1}{\mathsf{fma}\left(\left(x \cdot x\right) \cdot 0.041666666666666664, x \cdot x, 1\right)}
                \end{array}
                
                Derivation
                1. Initial program 100.0%

                  \[\frac{2}{e^{x} + e^{-x}} \]
                2. Add Preprocessing
                3. Step-by-step derivation
                  1. lift-/.f64N/A

                    \[\leadsto \color{blue}{\frac{2}{e^{x} + e^{-x}}} \]
                  2. clear-numN/A

                    \[\leadsto \color{blue}{\frac{1}{\frac{e^{x} + e^{-x}}{2}}} \]
                  3. lift-+.f64N/A

                    \[\leadsto \frac{1}{\frac{\color{blue}{e^{x} + e^{-x}}}{2}} \]
                  4. lift-exp.f64N/A

                    \[\leadsto \frac{1}{\frac{\color{blue}{e^{x}} + e^{-x}}{2}} \]
                  5. lift-exp.f64N/A

                    \[\leadsto \frac{1}{\frac{e^{x} + \color{blue}{e^{-x}}}{2}} \]
                  6. lift-neg.f64N/A

                    \[\leadsto \frac{1}{\frac{e^{x} + e^{\color{blue}{\mathsf{neg}\left(x\right)}}}{2}} \]
                  7. cosh-defN/A

                    \[\leadsto \frac{1}{\color{blue}{\cosh x}} \]
                  8. lower-/.f64N/A

                    \[\leadsto \color{blue}{\frac{1}{\cosh x}} \]
                  9. lower-cosh.f64100.0

                    \[\leadsto \frac{1}{\color{blue}{\cosh x}} \]
                4. Applied rewrites100.0%

                  \[\leadsto \color{blue}{\frac{1}{\cosh x}} \]
                5. Taylor expanded in x around 0

                  \[\leadsto \frac{1}{\color{blue}{1 + {x}^{2} \cdot \left(\frac{1}{2} + \frac{1}{24} \cdot {x}^{2}\right)}} \]
                6. Step-by-step derivation
                  1. +-commutativeN/A

                    \[\leadsto \frac{1}{\color{blue}{{x}^{2} \cdot \left(\frac{1}{2} + \frac{1}{24} \cdot {x}^{2}\right) + 1}} \]
                  2. *-commutativeN/A

                    \[\leadsto \frac{1}{\color{blue}{\left(\frac{1}{2} + \frac{1}{24} \cdot {x}^{2}\right) \cdot {x}^{2}} + 1} \]
                  3. lower-fma.f64N/A

                    \[\leadsto \frac{1}{\color{blue}{\mathsf{fma}\left(\frac{1}{2} + \frac{1}{24} \cdot {x}^{2}, {x}^{2}, 1\right)}} \]
                  4. +-commutativeN/A

                    \[\leadsto \frac{1}{\mathsf{fma}\left(\color{blue}{\frac{1}{24} \cdot {x}^{2} + \frac{1}{2}}, {x}^{2}, 1\right)} \]
                  5. lower-fma.f64N/A

                    \[\leadsto \frac{1}{\mathsf{fma}\left(\color{blue}{\mathsf{fma}\left(\frac{1}{24}, {x}^{2}, \frac{1}{2}\right)}, {x}^{2}, 1\right)} \]
                  6. unpow2N/A

                    \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{24}, \color{blue}{x \cdot x}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
                  7. lower-*.f64N/A

                    \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{24}, \color{blue}{x \cdot x}, \frac{1}{2}\right), {x}^{2}, 1\right)} \]
                  8. unpow2N/A

                    \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(\frac{1}{24}, x \cdot x, \frac{1}{2}\right), \color{blue}{x \cdot x}, 1\right)} \]
                  9. lower-*.f6485.7

                    \[\leadsto \frac{1}{\mathsf{fma}\left(\mathsf{fma}\left(0.041666666666666664, x \cdot x, 0.5\right), \color{blue}{x \cdot x}, 1\right)} \]
                7. Applied rewrites85.7%

                  \[\leadsto \frac{1}{\color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(0.041666666666666664, x \cdot x, 0.5\right), x \cdot x, 1\right)}} \]
                8. Taylor expanded in x around inf

                  \[\leadsto \frac{1}{\mathsf{fma}\left(\frac{1}{24} \cdot {x}^{2}, \color{blue}{x} \cdot x, 1\right)} \]
                9. Step-by-step derivation
                  1. Applied rewrites85.5%

                    \[\leadsto \frac{1}{\mathsf{fma}\left(0.041666666666666664 \cdot \left(x \cdot x\right), \color{blue}{x} \cdot x, 1\right)} \]
                  2. Final simplification85.5%

                    \[\leadsto \frac{1}{\mathsf{fma}\left(\left(x \cdot x\right) \cdot 0.041666666666666664, x \cdot x, 1\right)} \]
                  3. Add Preprocessing

                  Alternative 8: 74.8% accurate, 12.1× speedup?

                  \[\begin{array}{l} \\ \frac{2}{\mathsf{fma}\left(x, x, 2\right)} \end{array} \]
                  (FPCore (x) :precision binary64 (/ 2.0 (fma x x 2.0)))
                  double code(double x) {
                  	return 2.0 / fma(x, x, 2.0);
                  }
                  
                  function code(x)
                  	return Float64(2.0 / fma(x, x, 2.0))
                  end
                  
                  code[x_] := N[(2.0 / N[(x * x + 2.0), $MachinePrecision]), $MachinePrecision]
                  
                  \begin{array}{l}
                  
                  \\
                  \frac{2}{\mathsf{fma}\left(x, x, 2\right)}
                  \end{array}
                  
                  Derivation
                  1. Initial program 100.0%

                    \[\frac{2}{e^{x} + e^{-x}} \]
                  2. Add Preprocessing
                  3. Taylor expanded in x around 0

                    \[\leadsto \frac{2}{\color{blue}{2 + {x}^{2}}} \]
                  4. Step-by-step derivation
                    1. +-commutativeN/A

                      \[\leadsto \frac{2}{\color{blue}{{x}^{2} + 2}} \]
                    2. unpow2N/A

                      \[\leadsto \frac{2}{\color{blue}{x \cdot x} + 2} \]
                    3. lower-fma.f6472.6

                      \[\leadsto \frac{2}{\color{blue}{\mathsf{fma}\left(x, x, 2\right)}} \]
                  5. Applied rewrites72.6%

                    \[\leadsto \frac{2}{\color{blue}{\mathsf{fma}\left(x, x, 2\right)}} \]
                  6. Add Preprocessing

                  Alternative 9: 49.1% accurate, 217.0× speedup?

                  \[\begin{array}{l} \\ 1 \end{array} \]
                  (FPCore (x) :precision binary64 1.0)
                  double code(double x) {
                  	return 1.0;
                  }
                  
                  real(8) function code(x)
                      real(8), intent (in) :: x
                      code = 1.0d0
                  end function
                  
                  public static double code(double x) {
                  	return 1.0;
                  }
                  
                  def code(x):
                  	return 1.0
                  
                  function code(x)
                  	return 1.0
                  end
                  
                  function tmp = code(x)
                  	tmp = 1.0;
                  end
                  
                  code[x_] := 1.0
                  
                  \begin{array}{l}
                  
                  \\
                  1
                  \end{array}
                  
                  Derivation
                  1. Initial program 100.0%

                    \[\frac{2}{e^{x} + e^{-x}} \]
                  2. Add Preprocessing
                  3. Taylor expanded in x around 0

                    \[\leadsto \color{blue}{1} \]
                  4. Step-by-step derivation
                    1. Applied rewrites45.6%

                      \[\leadsto \color{blue}{1} \]
                    2. Add Preprocessing

                    Reproduce

                    ?
                    herbie shell --seed 2024268 
                    (FPCore (x)
                      :name "Hyperbolic secant"
                      :precision binary64
                      (/ 2.0 (+ (exp x) (exp (- x)))))