Bouland and Aaronson, Equation (26)

Percentage Accurate: 99.9% → 100.0%
Time: 8.0s
Alternatives: 8
Speedup: 2.2×

Specification

?
\[\begin{array}{l} \\ \left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(b \cdot b\right)\right) - 1 \end{array} \]
(FPCore (a b)
 :precision binary64
 (- (+ (pow (+ (* a a) (* b b)) 2.0) (* 4.0 (* b b))) 1.0))
double code(double a, double b) {
	return (pow(((a * a) + (b * b)), 2.0) + (4.0 * (b * b))) - 1.0;
}
real(8) function code(a, b)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    code = ((((a * a) + (b * b)) ** 2.0d0) + (4.0d0 * (b * b))) - 1.0d0
end function
public static double code(double a, double b) {
	return (Math.pow(((a * a) + (b * b)), 2.0) + (4.0 * (b * b))) - 1.0;
}
def code(a, b):
	return (math.pow(((a * a) + (b * b)), 2.0) + (4.0 * (b * b))) - 1.0
function code(a, b)
	return Float64(Float64((Float64(Float64(a * a) + Float64(b * b)) ^ 2.0) + Float64(4.0 * Float64(b * b))) - 1.0)
end
function tmp = code(a, b)
	tmp = ((((a * a) + (b * b)) ^ 2.0) + (4.0 * (b * b))) - 1.0;
end
code[a_, b_] := N[(N[(N[Power[N[(N[(a * a), $MachinePrecision] + N[(b * b), $MachinePrecision]), $MachinePrecision], 2.0], $MachinePrecision] + N[(4.0 * N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - 1.0), $MachinePrecision]
\begin{array}{l}

\\
\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(b \cdot b\right)\right) - 1
\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 8 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: 99.9% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(b \cdot b\right)\right) - 1 \end{array} \]
(FPCore (a b)
 :precision binary64
 (- (+ (pow (+ (* a a) (* b b)) 2.0) (* 4.0 (* b b))) 1.0))
double code(double a, double b) {
	return (pow(((a * a) + (b * b)), 2.0) + (4.0 * (b * b))) - 1.0;
}
real(8) function code(a, b)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    code = ((((a * a) + (b * b)) ** 2.0d0) + (4.0d0 * (b * b))) - 1.0d0
end function
public static double code(double a, double b) {
	return (Math.pow(((a * a) + (b * b)), 2.0) + (4.0 * (b * b))) - 1.0;
}
def code(a, b):
	return (math.pow(((a * a) + (b * b)), 2.0) + (4.0 * (b * b))) - 1.0
function code(a, b)
	return Float64(Float64((Float64(Float64(a * a) + Float64(b * b)) ^ 2.0) + Float64(4.0 * Float64(b * b))) - 1.0)
end
function tmp = code(a, b)
	tmp = ((((a * a) + (b * b)) ^ 2.0) + (4.0 * (b * b))) - 1.0;
end
code[a_, b_] := N[(N[(N[Power[N[(N[(a * a), $MachinePrecision] + N[(b * b), $MachinePrecision]), $MachinePrecision], 2.0], $MachinePrecision] + N[(4.0 * N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - 1.0), $MachinePrecision]
\begin{array}{l}

\\
\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(b \cdot b\right)\right) - 1
\end{array}

Alternative 1: 100.0% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \left(\mathsf{fma}\left(\mathsf{fma}\left(b \cdot b, 2, a \cdot a\right) \cdot a, a, {b}^{4}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \end{array} \]
(FPCore (a b)
 :precision binary64
 (-
  (+ (fma (* (fma (* b b) 2.0 (* a a)) a) a (pow b 4.0)) (* 4.0 (* b b)))
  1.0))
double code(double a, double b) {
	return (fma((fma((b * b), 2.0, (a * a)) * a), a, pow(b, 4.0)) + (4.0 * (b * b))) - 1.0;
}
function code(a, b)
	return Float64(Float64(fma(Float64(fma(Float64(b * b), 2.0, Float64(a * a)) * a), a, (b ^ 4.0)) + Float64(4.0 * Float64(b * b))) - 1.0)
end
code[a_, b_] := N[(N[(N[(N[(N[(N[(b * b), $MachinePrecision] * 2.0 + N[(a * a), $MachinePrecision]), $MachinePrecision] * a), $MachinePrecision] * a + N[Power[b, 4.0], $MachinePrecision]), $MachinePrecision] + N[(4.0 * N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - 1.0), $MachinePrecision]
\begin{array}{l}

\\
\left(\mathsf{fma}\left(\mathsf{fma}\left(b \cdot b, 2, a \cdot a\right) \cdot a, a, {b}^{4}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1
\end{array}
Derivation
  1. Initial program 99.9%

    \[\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
  2. Add Preprocessing
  3. Taylor expanded in a around 0

    \[\leadsto \left(\color{blue}{\left({a}^{2} \cdot \left(2 \cdot {b}^{2} + {a}^{2}\right) + {b}^{4}\right)} + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
  4. Step-by-step derivation
    1. unpow2N/A

      \[\leadsto \left(\left(\color{blue}{\left(a \cdot a\right)} \cdot \left(2 \cdot {b}^{2} + {a}^{2}\right) + {b}^{4}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
    2. associate-*l*N/A

      \[\leadsto \left(\left(\color{blue}{a \cdot \left(a \cdot \left(2 \cdot {b}^{2} + {a}^{2}\right)\right)} + {b}^{4}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
    3. *-commutativeN/A

      \[\leadsto \left(\left(\color{blue}{\left(a \cdot \left(2 \cdot {b}^{2} + {a}^{2}\right)\right) \cdot a} + {b}^{4}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
    4. lower-fma.f64N/A

      \[\leadsto \left(\color{blue}{\mathsf{fma}\left(a \cdot \left(2 \cdot {b}^{2} + {a}^{2}\right), a, {b}^{4}\right)} + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
    5. *-commutativeN/A

      \[\leadsto \left(\mathsf{fma}\left(\color{blue}{\left(2 \cdot {b}^{2} + {a}^{2}\right) \cdot a}, a, {b}^{4}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
    6. lower-*.f64N/A

      \[\leadsto \left(\mathsf{fma}\left(\color{blue}{\left(2 \cdot {b}^{2} + {a}^{2}\right) \cdot a}, a, {b}^{4}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
    7. *-commutativeN/A

      \[\leadsto \left(\mathsf{fma}\left(\left(\color{blue}{{b}^{2} \cdot 2} + {a}^{2}\right) \cdot a, a, {b}^{4}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
    8. lower-fma.f64N/A

      \[\leadsto \left(\mathsf{fma}\left(\color{blue}{\mathsf{fma}\left({b}^{2}, 2, {a}^{2}\right)} \cdot a, a, {b}^{4}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
    9. unpow2N/A

      \[\leadsto \left(\mathsf{fma}\left(\mathsf{fma}\left(\color{blue}{b \cdot b}, 2, {a}^{2}\right) \cdot a, a, {b}^{4}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
    10. lower-*.f64N/A

      \[\leadsto \left(\mathsf{fma}\left(\mathsf{fma}\left(\color{blue}{b \cdot b}, 2, {a}^{2}\right) \cdot a, a, {b}^{4}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
    11. unpow2N/A

      \[\leadsto \left(\mathsf{fma}\left(\mathsf{fma}\left(b \cdot b, 2, \color{blue}{a \cdot a}\right) \cdot a, a, {b}^{4}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
    12. lower-*.f64N/A

      \[\leadsto \left(\mathsf{fma}\left(\mathsf{fma}\left(b \cdot b, 2, \color{blue}{a \cdot a}\right) \cdot a, a, {b}^{4}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
    13. lower-pow.f6499.9

      \[\leadsto \left(\mathsf{fma}\left(\mathsf{fma}\left(b \cdot b, 2, a \cdot a\right) \cdot a, a, \color{blue}{{b}^{4}}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
  5. Applied rewrites99.9%

    \[\leadsto \left(\color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(b \cdot b, 2, a \cdot a\right) \cdot a, a, {b}^{4}\right)} + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
  6. Add Preprocessing

Alternative 2: 99.9% accurate, 2.2× speedup?

\[\begin{array}{l} \\ \left(\mathsf{fma}\left(b \cdot b, b \cdot b, \left(\mathsf{fma}\left(2, b \cdot b, a \cdot a\right) \cdot a\right) \cdot a\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \end{array} \]
(FPCore (a b)
 :precision binary64
 (-
  (+
   (fma (* b b) (* b b) (* (* (fma 2.0 (* b b) (* a a)) a) a))
   (* 4.0 (* b b)))
  1.0))
double code(double a, double b) {
	return (fma((b * b), (b * b), ((fma(2.0, (b * b), (a * a)) * a) * a)) + (4.0 * (b * b))) - 1.0;
}
function code(a, b)
	return Float64(Float64(fma(Float64(b * b), Float64(b * b), Float64(Float64(fma(2.0, Float64(b * b), Float64(a * a)) * a) * a)) + Float64(4.0 * Float64(b * b))) - 1.0)
end
code[a_, b_] := N[(N[(N[(N[(b * b), $MachinePrecision] * N[(b * b), $MachinePrecision] + N[(N[(N[(2.0 * N[(b * b), $MachinePrecision] + N[(a * a), $MachinePrecision]), $MachinePrecision] * a), $MachinePrecision] * a), $MachinePrecision]), $MachinePrecision] + N[(4.0 * N[(b * b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - 1.0), $MachinePrecision]
\begin{array}{l}

\\
\left(\mathsf{fma}\left(b \cdot b, b \cdot b, \left(\mathsf{fma}\left(2, b \cdot b, a \cdot a\right) \cdot a\right) \cdot a\right) + 4 \cdot \left(b \cdot b\right)\right) - 1
\end{array}
Derivation
  1. Initial program 99.9%

    \[\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
  2. Add Preprocessing
  3. Taylor expanded in a around 0

    \[\leadsto \left(\color{blue}{\left({a}^{2} \cdot \left(2 \cdot {b}^{2} + {a}^{2}\right) + {b}^{4}\right)} + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
  4. Step-by-step derivation
    1. unpow2N/A

      \[\leadsto \left(\left(\color{blue}{\left(a \cdot a\right)} \cdot \left(2 \cdot {b}^{2} + {a}^{2}\right) + {b}^{4}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
    2. associate-*l*N/A

      \[\leadsto \left(\left(\color{blue}{a \cdot \left(a \cdot \left(2 \cdot {b}^{2} + {a}^{2}\right)\right)} + {b}^{4}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
    3. *-commutativeN/A

      \[\leadsto \left(\left(\color{blue}{\left(a \cdot \left(2 \cdot {b}^{2} + {a}^{2}\right)\right) \cdot a} + {b}^{4}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
    4. lower-fma.f64N/A

      \[\leadsto \left(\color{blue}{\mathsf{fma}\left(a \cdot \left(2 \cdot {b}^{2} + {a}^{2}\right), a, {b}^{4}\right)} + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
    5. *-commutativeN/A

      \[\leadsto \left(\mathsf{fma}\left(\color{blue}{\left(2 \cdot {b}^{2} + {a}^{2}\right) \cdot a}, a, {b}^{4}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
    6. lower-*.f64N/A

      \[\leadsto \left(\mathsf{fma}\left(\color{blue}{\left(2 \cdot {b}^{2} + {a}^{2}\right) \cdot a}, a, {b}^{4}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
    7. *-commutativeN/A

      \[\leadsto \left(\mathsf{fma}\left(\left(\color{blue}{{b}^{2} \cdot 2} + {a}^{2}\right) \cdot a, a, {b}^{4}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
    8. lower-fma.f64N/A

      \[\leadsto \left(\mathsf{fma}\left(\color{blue}{\mathsf{fma}\left({b}^{2}, 2, {a}^{2}\right)} \cdot a, a, {b}^{4}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
    9. unpow2N/A

      \[\leadsto \left(\mathsf{fma}\left(\mathsf{fma}\left(\color{blue}{b \cdot b}, 2, {a}^{2}\right) \cdot a, a, {b}^{4}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
    10. lower-*.f64N/A

      \[\leadsto \left(\mathsf{fma}\left(\mathsf{fma}\left(\color{blue}{b \cdot b}, 2, {a}^{2}\right) \cdot a, a, {b}^{4}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
    11. unpow2N/A

      \[\leadsto \left(\mathsf{fma}\left(\mathsf{fma}\left(b \cdot b, 2, \color{blue}{a \cdot a}\right) \cdot a, a, {b}^{4}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
    12. lower-*.f64N/A

      \[\leadsto \left(\mathsf{fma}\left(\mathsf{fma}\left(b \cdot b, 2, \color{blue}{a \cdot a}\right) \cdot a, a, {b}^{4}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
    13. lower-pow.f6499.9

      \[\leadsto \left(\mathsf{fma}\left(\mathsf{fma}\left(b \cdot b, 2, a \cdot a\right) \cdot a, a, \color{blue}{{b}^{4}}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
  5. Applied rewrites99.9%

    \[\leadsto \left(\color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(b \cdot b, 2, a \cdot a\right) \cdot a, a, {b}^{4}\right)} + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
  6. Step-by-step derivation
    1. Applied rewrites99.9%

      \[\leadsto \left(\mathsf{fma}\left(b \cdot b, \color{blue}{b \cdot b}, \left(\mathsf{fma}\left(2, b \cdot b, a \cdot a\right) \cdot a\right) \cdot a\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
    2. Add Preprocessing

    Alternative 3: 98.2% accurate, 2.5× speedup?

    \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \cdot b \leq 2 \cdot 10^{-20}:\\ \;\;\;\;\mathsf{fma}\left(b \cdot b, 4, \left(\mathsf{fma}\left(b \cdot b, 2, a \cdot a\right) \cdot a\right) \cdot a - 1\right)\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(b, b, \mathsf{fma}\left(a \cdot a, 2, 4\right)\right), b \cdot b, -1\right)\\ \end{array} \end{array} \]
    (FPCore (a b)
     :precision binary64
     (if (<= (* b b) 2e-20)
       (fma (* b b) 4.0 (- (* (* (fma (* b b) 2.0 (* a a)) a) a) 1.0))
       (fma (fma b b (fma (* a a) 2.0 4.0)) (* b b) -1.0)))
    double code(double a, double b) {
    	double tmp;
    	if ((b * b) <= 2e-20) {
    		tmp = fma((b * b), 4.0, (((fma((b * b), 2.0, (a * a)) * a) * a) - 1.0));
    	} else {
    		tmp = fma(fma(b, b, fma((a * a), 2.0, 4.0)), (b * b), -1.0);
    	}
    	return tmp;
    }
    
    function code(a, b)
    	tmp = 0.0
    	if (Float64(b * b) <= 2e-20)
    		tmp = fma(Float64(b * b), 4.0, Float64(Float64(Float64(fma(Float64(b * b), 2.0, Float64(a * a)) * a) * a) - 1.0));
    	else
    		tmp = fma(fma(b, b, fma(Float64(a * a), 2.0, 4.0)), Float64(b * b), -1.0);
    	end
    	return tmp
    end
    
    code[a_, b_] := If[LessEqual[N[(b * b), $MachinePrecision], 2e-20], N[(N[(b * b), $MachinePrecision] * 4.0 + N[(N[(N[(N[(N[(b * b), $MachinePrecision] * 2.0 + N[(a * a), $MachinePrecision]), $MachinePrecision] * a), $MachinePrecision] * a), $MachinePrecision] - 1.0), $MachinePrecision]), $MachinePrecision], N[(N[(b * b + N[(N[(a * a), $MachinePrecision] * 2.0 + 4.0), $MachinePrecision]), $MachinePrecision] * N[(b * b), $MachinePrecision] + -1.0), $MachinePrecision]]
    
    \begin{array}{l}
    
    \\
    \begin{array}{l}
    \mathbf{if}\;b \cdot b \leq 2 \cdot 10^{-20}:\\
    \;\;\;\;\mathsf{fma}\left(b \cdot b, 4, \left(\mathsf{fma}\left(b \cdot b, 2, a \cdot a\right) \cdot a\right) \cdot a - 1\right)\\
    
    \mathbf{else}:\\
    \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(b, b, \mathsf{fma}\left(a \cdot a, 2, 4\right)\right), b \cdot b, -1\right)\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 2 regimes
    2. if (*.f64 b b) < 1.99999999999999989e-20

      1. Initial program 99.9%

        \[\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
      2. Add Preprocessing
      3. Taylor expanded in b around 0

        \[\leadsto \left(\color{blue}{\left(2 \cdot \left({a}^{2} \cdot {b}^{2}\right) + {a}^{4}\right)} + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
      4. Step-by-step derivation
        1. count-2-revN/A

          \[\leadsto \left(\left(\color{blue}{\left({a}^{2} \cdot {b}^{2} + {a}^{2} \cdot {b}^{2}\right)} + {a}^{4}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
        2. distribute-lft-inN/A

          \[\leadsto \left(\left(\color{blue}{{a}^{2} \cdot \left({b}^{2} + {b}^{2}\right)} + {a}^{4}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
        3. count-2-revN/A

          \[\leadsto \left(\left({a}^{2} \cdot \color{blue}{\left(2 \cdot {b}^{2}\right)} + {a}^{4}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
        4. metadata-evalN/A

          \[\leadsto \left(\left({a}^{2} \cdot \left(2 \cdot {b}^{2}\right) + {a}^{\color{blue}{\left(2 \cdot 2\right)}}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
        5. pow-sqrN/A

          \[\leadsto \left(\left({a}^{2} \cdot \left(2 \cdot {b}^{2}\right) + \color{blue}{{a}^{2} \cdot {a}^{2}}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
        6. distribute-lft-inN/A

          \[\leadsto \left(\color{blue}{{a}^{2} \cdot \left(2 \cdot {b}^{2} + {a}^{2}\right)} + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
        7. unpow2N/A

          \[\leadsto \left(\color{blue}{\left(a \cdot a\right)} \cdot \left(2 \cdot {b}^{2} + {a}^{2}\right) + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
        8. associate-*l*N/A

          \[\leadsto \left(\color{blue}{a \cdot \left(a \cdot \left(2 \cdot {b}^{2} + {a}^{2}\right)\right)} + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
        9. *-commutativeN/A

          \[\leadsto \left(\color{blue}{\left(a \cdot \left(2 \cdot {b}^{2} + {a}^{2}\right)\right) \cdot a} + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
        10. lower-*.f64N/A

          \[\leadsto \left(\color{blue}{\left(a \cdot \left(2 \cdot {b}^{2} + {a}^{2}\right)\right) \cdot a} + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
        11. *-commutativeN/A

          \[\leadsto \left(\color{blue}{\left(\left(2 \cdot {b}^{2} + {a}^{2}\right) \cdot a\right)} \cdot a + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
        12. lower-*.f64N/A

          \[\leadsto \left(\color{blue}{\left(\left(2 \cdot {b}^{2} + {a}^{2}\right) \cdot a\right)} \cdot a + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
        13. *-commutativeN/A

          \[\leadsto \left(\left(\left(\color{blue}{{b}^{2} \cdot 2} + {a}^{2}\right) \cdot a\right) \cdot a + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
        14. lower-fma.f64N/A

          \[\leadsto \left(\left(\color{blue}{\mathsf{fma}\left({b}^{2}, 2, {a}^{2}\right)} \cdot a\right) \cdot a + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
        15. unpow2N/A

          \[\leadsto \left(\left(\mathsf{fma}\left(\color{blue}{b \cdot b}, 2, {a}^{2}\right) \cdot a\right) \cdot a + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
        16. lower-*.f64N/A

          \[\leadsto \left(\left(\mathsf{fma}\left(\color{blue}{b \cdot b}, 2, {a}^{2}\right) \cdot a\right) \cdot a + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
        17. unpow2N/A

          \[\leadsto \left(\left(\mathsf{fma}\left(b \cdot b, 2, \color{blue}{a \cdot a}\right) \cdot a\right) \cdot a + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
        18. lower-*.f6499.9

          \[\leadsto \left(\left(\mathsf{fma}\left(b \cdot b, 2, \color{blue}{a \cdot a}\right) \cdot a\right) \cdot a + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
      5. Applied rewrites99.9%

        \[\leadsto \left(\color{blue}{\left(\mathsf{fma}\left(b \cdot b, 2, a \cdot a\right) \cdot a\right) \cdot a} + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
      6. Step-by-step derivation
        1. lift--.f64N/A

          \[\leadsto \color{blue}{\left(\left(\mathsf{fma}\left(b \cdot b, 2, a \cdot a\right) \cdot a\right) \cdot a + 4 \cdot \left(b \cdot b\right)\right) - 1} \]
        2. lift-+.f64N/A

          \[\leadsto \color{blue}{\left(\left(\mathsf{fma}\left(b \cdot b, 2, a \cdot a\right) \cdot a\right) \cdot a + 4 \cdot \left(b \cdot b\right)\right)} - 1 \]
        3. +-commutativeN/A

          \[\leadsto \color{blue}{\left(4 \cdot \left(b \cdot b\right) + \left(\mathsf{fma}\left(b \cdot b, 2, a \cdot a\right) \cdot a\right) \cdot a\right)} - 1 \]
        4. associate--l+N/A

          \[\leadsto \color{blue}{4 \cdot \left(b \cdot b\right) + \left(\left(\mathsf{fma}\left(b \cdot b, 2, a \cdot a\right) \cdot a\right) \cdot a - 1\right)} \]
        5. lift-*.f64N/A

          \[\leadsto \color{blue}{4 \cdot \left(b \cdot b\right)} + \left(\left(\mathsf{fma}\left(b \cdot b, 2, a \cdot a\right) \cdot a\right) \cdot a - 1\right) \]
        6. *-commutativeN/A

          \[\leadsto \color{blue}{\left(b \cdot b\right) \cdot 4} + \left(\left(\mathsf{fma}\left(b \cdot b, 2, a \cdot a\right) \cdot a\right) \cdot a - 1\right) \]
        7. lower-fma.f64N/A

          \[\leadsto \color{blue}{\mathsf{fma}\left(b \cdot b, 4, \left(\mathsf{fma}\left(b \cdot b, 2, a \cdot a\right) \cdot a\right) \cdot a - 1\right)} \]
        8. lower--.f6499.9

          \[\leadsto \mathsf{fma}\left(b \cdot b, 4, \color{blue}{\left(\mathsf{fma}\left(b \cdot b, 2, a \cdot a\right) \cdot a\right) \cdot a - 1}\right) \]
      7. Applied rewrites99.9%

        \[\leadsto \color{blue}{\mathsf{fma}\left(b \cdot b, 4, \left(\mathsf{fma}\left(b \cdot b, 2, a \cdot a\right) \cdot a\right) \cdot a - 1\right)} \]

      if 1.99999999999999989e-20 < (*.f64 b b)

      1. Initial program 99.8%

        \[\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
      2. Add Preprocessing
      3. Taylor expanded in a around 0

        \[\leadsto \color{blue}{\left(2 \cdot \left({a}^{2} \cdot {b}^{2}\right) + \left(4 \cdot {b}^{2} + {b}^{4}\right)\right) - 1} \]
      4. Step-by-step derivation
        1. sub-negN/A

          \[\leadsto \color{blue}{\left(2 \cdot \left({a}^{2} \cdot {b}^{2}\right) + \left(4 \cdot {b}^{2} + {b}^{4}\right)\right) + \left(\mathsf{neg}\left(1\right)\right)} \]
        2. associate-+r+N/A

          \[\leadsto \color{blue}{\left(\left(2 \cdot \left({a}^{2} \cdot {b}^{2}\right) + 4 \cdot {b}^{2}\right) + {b}^{4}\right)} + \left(\mathsf{neg}\left(1\right)\right) \]
        3. associate-*r*N/A

          \[\leadsto \left(\left(\color{blue}{\left(2 \cdot {a}^{2}\right) \cdot {b}^{2}} + 4 \cdot {b}^{2}\right) + {b}^{4}\right) + \left(\mathsf{neg}\left(1\right)\right) \]
        4. distribute-rgt-inN/A

          \[\leadsto \left(\color{blue}{{b}^{2} \cdot \left(2 \cdot {a}^{2} + 4\right)} + {b}^{4}\right) + \left(\mathsf{neg}\left(1\right)\right) \]
        5. +-commutativeN/A

          \[\leadsto \left({b}^{2} \cdot \color{blue}{\left(4 + 2 \cdot {a}^{2}\right)} + {b}^{4}\right) + \left(\mathsf{neg}\left(1\right)\right) \]
        6. metadata-evalN/A

          \[\leadsto \left({b}^{2} \cdot \left(4 + 2 \cdot {a}^{2}\right) + {b}^{\color{blue}{\left(2 \cdot 2\right)}}\right) + \left(\mathsf{neg}\left(1\right)\right) \]
        7. pow-sqrN/A

          \[\leadsto \left({b}^{2} \cdot \left(4 + 2 \cdot {a}^{2}\right) + \color{blue}{{b}^{2} \cdot {b}^{2}}\right) + \left(\mathsf{neg}\left(1\right)\right) \]
        8. distribute-lft-inN/A

          \[\leadsto \color{blue}{{b}^{2} \cdot \left(\left(4 + 2 \cdot {a}^{2}\right) + {b}^{2}\right)} + \left(\mathsf{neg}\left(1\right)\right) \]
        9. associate-+r+N/A

          \[\leadsto {b}^{2} \cdot \color{blue}{\left(4 + \left(2 \cdot {a}^{2} + {b}^{2}\right)\right)} + \left(\mathsf{neg}\left(1\right)\right) \]
        10. *-commutativeN/A

          \[\leadsto \color{blue}{\left(4 + \left(2 \cdot {a}^{2} + {b}^{2}\right)\right) \cdot {b}^{2}} + \left(\mathsf{neg}\left(1\right)\right) \]
        11. lower-fma.f64N/A

          \[\leadsto \color{blue}{\mathsf{fma}\left(4 + \left(2 \cdot {a}^{2} + {b}^{2}\right), {b}^{2}, \mathsf{neg}\left(1\right)\right)} \]
      5. Applied rewrites97.3%

        \[\leadsto \color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(b, b, \mathsf{fma}\left(a \cdot a, 2, 4\right)\right), b \cdot b, -1\right)} \]
    3. Recombined 2 regimes into one program.
    4. Add Preprocessing

    Alternative 4: 98.2% accurate, 3.3× speedup?

    \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \cdot b \leq 2 \cdot 10^{-20}:\\ \;\;\;\;\left(a \cdot a\right) \cdot \left(a \cdot a\right) - 1\\ \mathbf{else}:\\ \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(b, b, \mathsf{fma}\left(a \cdot a, 2, 4\right)\right), b \cdot b, -1\right)\\ \end{array} \end{array} \]
    (FPCore (a b)
     :precision binary64
     (if (<= (* b b) 2e-20)
       (- (* (* a a) (* a a)) 1.0)
       (fma (fma b b (fma (* a a) 2.0 4.0)) (* b b) -1.0)))
    double code(double a, double b) {
    	double tmp;
    	if ((b * b) <= 2e-20) {
    		tmp = ((a * a) * (a * a)) - 1.0;
    	} else {
    		tmp = fma(fma(b, b, fma((a * a), 2.0, 4.0)), (b * b), -1.0);
    	}
    	return tmp;
    }
    
    function code(a, b)
    	tmp = 0.0
    	if (Float64(b * b) <= 2e-20)
    		tmp = Float64(Float64(Float64(a * a) * Float64(a * a)) - 1.0);
    	else
    		tmp = fma(fma(b, b, fma(Float64(a * a), 2.0, 4.0)), Float64(b * b), -1.0);
    	end
    	return tmp
    end
    
    code[a_, b_] := If[LessEqual[N[(b * b), $MachinePrecision], 2e-20], N[(N[(N[(a * a), $MachinePrecision] * N[(a * a), $MachinePrecision]), $MachinePrecision] - 1.0), $MachinePrecision], N[(N[(b * b + N[(N[(a * a), $MachinePrecision] * 2.0 + 4.0), $MachinePrecision]), $MachinePrecision] * N[(b * b), $MachinePrecision] + -1.0), $MachinePrecision]]
    
    \begin{array}{l}
    
    \\
    \begin{array}{l}
    \mathbf{if}\;b \cdot b \leq 2 \cdot 10^{-20}:\\
    \;\;\;\;\left(a \cdot a\right) \cdot \left(a \cdot a\right) - 1\\
    
    \mathbf{else}:\\
    \;\;\;\;\mathsf{fma}\left(\mathsf{fma}\left(b, b, \mathsf{fma}\left(a \cdot a, 2, 4\right)\right), b \cdot b, -1\right)\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 2 regimes
    2. if (*.f64 b b) < 1.99999999999999989e-20

      1. Initial program 99.9%

        \[\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
      2. Add Preprocessing
      3. Taylor expanded in a around inf

        \[\leadsto \color{blue}{{a}^{4}} - 1 \]
      4. Step-by-step derivation
        1. lower-pow.f64100.0

          \[\leadsto \color{blue}{{a}^{4}} - 1 \]
      5. Applied rewrites100.0%

        \[\leadsto \color{blue}{{a}^{4}} - 1 \]
      6. Step-by-step derivation
        1. Applied rewrites99.9%

          \[\leadsto \left(a \cdot a\right) \cdot \color{blue}{\left(a \cdot a\right)} - 1 \]

        if 1.99999999999999989e-20 < (*.f64 b b)

        1. Initial program 99.8%

          \[\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
        2. Add Preprocessing
        3. Taylor expanded in a around 0

          \[\leadsto \color{blue}{\left(2 \cdot \left({a}^{2} \cdot {b}^{2}\right) + \left(4 \cdot {b}^{2} + {b}^{4}\right)\right) - 1} \]
        4. Step-by-step derivation
          1. sub-negN/A

            \[\leadsto \color{blue}{\left(2 \cdot \left({a}^{2} \cdot {b}^{2}\right) + \left(4 \cdot {b}^{2} + {b}^{4}\right)\right) + \left(\mathsf{neg}\left(1\right)\right)} \]
          2. associate-+r+N/A

            \[\leadsto \color{blue}{\left(\left(2 \cdot \left({a}^{2} \cdot {b}^{2}\right) + 4 \cdot {b}^{2}\right) + {b}^{4}\right)} + \left(\mathsf{neg}\left(1\right)\right) \]
          3. associate-*r*N/A

            \[\leadsto \left(\left(\color{blue}{\left(2 \cdot {a}^{2}\right) \cdot {b}^{2}} + 4 \cdot {b}^{2}\right) + {b}^{4}\right) + \left(\mathsf{neg}\left(1\right)\right) \]
          4. distribute-rgt-inN/A

            \[\leadsto \left(\color{blue}{{b}^{2} \cdot \left(2 \cdot {a}^{2} + 4\right)} + {b}^{4}\right) + \left(\mathsf{neg}\left(1\right)\right) \]
          5. +-commutativeN/A

            \[\leadsto \left({b}^{2} \cdot \color{blue}{\left(4 + 2 \cdot {a}^{2}\right)} + {b}^{4}\right) + \left(\mathsf{neg}\left(1\right)\right) \]
          6. metadata-evalN/A

            \[\leadsto \left({b}^{2} \cdot \left(4 + 2 \cdot {a}^{2}\right) + {b}^{\color{blue}{\left(2 \cdot 2\right)}}\right) + \left(\mathsf{neg}\left(1\right)\right) \]
          7. pow-sqrN/A

            \[\leadsto \left({b}^{2} \cdot \left(4 + 2 \cdot {a}^{2}\right) + \color{blue}{{b}^{2} \cdot {b}^{2}}\right) + \left(\mathsf{neg}\left(1\right)\right) \]
          8. distribute-lft-inN/A

            \[\leadsto \color{blue}{{b}^{2} \cdot \left(\left(4 + 2 \cdot {a}^{2}\right) + {b}^{2}\right)} + \left(\mathsf{neg}\left(1\right)\right) \]
          9. associate-+r+N/A

            \[\leadsto {b}^{2} \cdot \color{blue}{\left(4 + \left(2 \cdot {a}^{2} + {b}^{2}\right)\right)} + \left(\mathsf{neg}\left(1\right)\right) \]
          10. *-commutativeN/A

            \[\leadsto \color{blue}{\left(4 + \left(2 \cdot {a}^{2} + {b}^{2}\right)\right) \cdot {b}^{2}} + \left(\mathsf{neg}\left(1\right)\right) \]
          11. lower-fma.f64N/A

            \[\leadsto \color{blue}{\mathsf{fma}\left(4 + \left(2 \cdot {a}^{2} + {b}^{2}\right), {b}^{2}, \mathsf{neg}\left(1\right)\right)} \]
        5. Applied rewrites97.3%

          \[\leadsto \color{blue}{\mathsf{fma}\left(\mathsf{fma}\left(b, b, \mathsf{fma}\left(a \cdot a, 2, 4\right)\right), b \cdot b, -1\right)} \]
      7. Recombined 2 regimes into one program.
      8. Add Preprocessing

      Alternative 5: 94.7% accurate, 4.4× speedup?

      \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;a \cdot a \leq 0.00135:\\ \;\;\;\;\mathsf{fma}\left(b \cdot b, \mathsf{fma}\left(b, b, 4\right), -1\right)\\ \mathbf{else}:\\ \;\;\;\;\left(a \cdot a\right) \cdot \left(a \cdot a\right) - 1\\ \end{array} \end{array} \]
      (FPCore (a b)
       :precision binary64
       (if (<= (* a a) 0.00135)
         (fma (* b b) (fma b b 4.0) -1.0)
         (- (* (* a a) (* a a)) 1.0)))
      double code(double a, double b) {
      	double tmp;
      	if ((a * a) <= 0.00135) {
      		tmp = fma((b * b), fma(b, b, 4.0), -1.0);
      	} else {
      		tmp = ((a * a) * (a * a)) - 1.0;
      	}
      	return tmp;
      }
      
      function code(a, b)
      	tmp = 0.0
      	if (Float64(a * a) <= 0.00135)
      		tmp = fma(Float64(b * b), fma(b, b, 4.0), -1.0);
      	else
      		tmp = Float64(Float64(Float64(a * a) * Float64(a * a)) - 1.0);
      	end
      	return tmp
      end
      
      code[a_, b_] := If[LessEqual[N[(a * a), $MachinePrecision], 0.00135], N[(N[(b * b), $MachinePrecision] * N[(b * b + 4.0), $MachinePrecision] + -1.0), $MachinePrecision], N[(N[(N[(a * a), $MachinePrecision] * N[(a * a), $MachinePrecision]), $MachinePrecision] - 1.0), $MachinePrecision]]
      
      \begin{array}{l}
      
      \\
      \begin{array}{l}
      \mathbf{if}\;a \cdot a \leq 0.00135:\\
      \;\;\;\;\mathsf{fma}\left(b \cdot b, \mathsf{fma}\left(b, b, 4\right), -1\right)\\
      
      \mathbf{else}:\\
      \;\;\;\;\left(a \cdot a\right) \cdot \left(a \cdot a\right) - 1\\
      
      
      \end{array}
      \end{array}
      
      Derivation
      1. Split input into 2 regimes
      2. if (*.f64 a a) < 0.0013500000000000001

        1. Initial program 99.9%

          \[\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
        2. Add Preprocessing
        3. Taylor expanded in a around 0

          \[\leadsto \color{blue}{\left(4 \cdot {b}^{2} + {b}^{4}\right) - 1} \]
        4. Step-by-step derivation
          1. sub-negN/A

            \[\leadsto \color{blue}{\left(4 \cdot {b}^{2} + {b}^{4}\right) + \left(\mathsf{neg}\left(1\right)\right)} \]
          2. metadata-evalN/A

            \[\leadsto \left(4 \cdot {b}^{2} + {b}^{\color{blue}{\left(2 \cdot 2\right)}}\right) + \left(\mathsf{neg}\left(1\right)\right) \]
          3. pow-sqrN/A

            \[\leadsto \left(4 \cdot {b}^{2} + \color{blue}{{b}^{2} \cdot {b}^{2}}\right) + \left(\mathsf{neg}\left(1\right)\right) \]
          4. distribute-rgt-outN/A

            \[\leadsto \color{blue}{{b}^{2} \cdot \left(4 + {b}^{2}\right)} + \left(\mathsf{neg}\left(1\right)\right) \]
          5. lower-fma.f64N/A

            \[\leadsto \color{blue}{\mathsf{fma}\left({b}^{2}, 4 + {b}^{2}, \mathsf{neg}\left(1\right)\right)} \]
          6. unpow2N/A

            \[\leadsto \mathsf{fma}\left(\color{blue}{b \cdot b}, 4 + {b}^{2}, \mathsf{neg}\left(1\right)\right) \]
          7. lower-*.f64N/A

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

            \[\leadsto \mathsf{fma}\left(b \cdot b, \color{blue}{{b}^{2} + 4}, \mathsf{neg}\left(1\right)\right) \]
          9. unpow2N/A

            \[\leadsto \mathsf{fma}\left(b \cdot b, \color{blue}{b \cdot b} + 4, \mathsf{neg}\left(1\right)\right) \]
          10. lower-fma.f64N/A

            \[\leadsto \mathsf{fma}\left(b \cdot b, \color{blue}{\mathsf{fma}\left(b, b, 4\right)}, \mathsf{neg}\left(1\right)\right) \]
          11. metadata-eval99.9

            \[\leadsto \mathsf{fma}\left(b \cdot b, \mathsf{fma}\left(b, b, 4\right), \color{blue}{-1}\right) \]
        5. Applied rewrites99.9%

          \[\leadsto \color{blue}{\mathsf{fma}\left(b \cdot b, \mathsf{fma}\left(b, b, 4\right), -1\right)} \]

        if 0.0013500000000000001 < (*.f64 a a)

        1. Initial program 99.8%

          \[\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
        2. Add Preprocessing
        3. Taylor expanded in a around inf

          \[\leadsto \color{blue}{{a}^{4}} - 1 \]
        4. Step-by-step derivation
          1. lower-pow.f6491.9

            \[\leadsto \color{blue}{{a}^{4}} - 1 \]
        5. Applied rewrites91.9%

          \[\leadsto \color{blue}{{a}^{4}} - 1 \]
        6. Step-by-step derivation
          1. Applied rewrites91.7%

            \[\leadsto \left(a \cdot a\right) \cdot \color{blue}{\left(a \cdot a\right)} - 1 \]
        7. Recombined 2 regimes into one program.
        8. Add Preprocessing

        Alternative 6: 70.8% accurate, 7.3× speedup?

        \[\begin{array}{l} \\ \mathsf{fma}\left(b \cdot b, \mathsf{fma}\left(b, b, 4\right), -1\right) \end{array} \]
        (FPCore (a b) :precision binary64 (fma (* b b) (fma b b 4.0) -1.0))
        double code(double a, double b) {
        	return fma((b * b), fma(b, b, 4.0), -1.0);
        }
        
        function code(a, b)
        	return fma(Float64(b * b), fma(b, b, 4.0), -1.0)
        end
        
        code[a_, b_] := N[(N[(b * b), $MachinePrecision] * N[(b * b + 4.0), $MachinePrecision] + -1.0), $MachinePrecision]
        
        \begin{array}{l}
        
        \\
        \mathsf{fma}\left(b \cdot b, \mathsf{fma}\left(b, b, 4\right), -1\right)
        \end{array}
        
        Derivation
        1. Initial program 99.9%

          \[\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
        2. Add Preprocessing
        3. Taylor expanded in a around 0

          \[\leadsto \color{blue}{\left(4 \cdot {b}^{2} + {b}^{4}\right) - 1} \]
        4. Step-by-step derivation
          1. sub-negN/A

            \[\leadsto \color{blue}{\left(4 \cdot {b}^{2} + {b}^{4}\right) + \left(\mathsf{neg}\left(1\right)\right)} \]
          2. metadata-evalN/A

            \[\leadsto \left(4 \cdot {b}^{2} + {b}^{\color{blue}{\left(2 \cdot 2\right)}}\right) + \left(\mathsf{neg}\left(1\right)\right) \]
          3. pow-sqrN/A

            \[\leadsto \left(4 \cdot {b}^{2} + \color{blue}{{b}^{2} \cdot {b}^{2}}\right) + \left(\mathsf{neg}\left(1\right)\right) \]
          4. distribute-rgt-outN/A

            \[\leadsto \color{blue}{{b}^{2} \cdot \left(4 + {b}^{2}\right)} + \left(\mathsf{neg}\left(1\right)\right) \]
          5. lower-fma.f64N/A

            \[\leadsto \color{blue}{\mathsf{fma}\left({b}^{2}, 4 + {b}^{2}, \mathsf{neg}\left(1\right)\right)} \]
          6. unpow2N/A

            \[\leadsto \mathsf{fma}\left(\color{blue}{b \cdot b}, 4 + {b}^{2}, \mathsf{neg}\left(1\right)\right) \]
          7. lower-*.f64N/A

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

            \[\leadsto \mathsf{fma}\left(b \cdot b, \color{blue}{{b}^{2} + 4}, \mathsf{neg}\left(1\right)\right) \]
          9. unpow2N/A

            \[\leadsto \mathsf{fma}\left(b \cdot b, \color{blue}{b \cdot b} + 4, \mathsf{neg}\left(1\right)\right) \]
          10. lower-fma.f64N/A

            \[\leadsto \mathsf{fma}\left(b \cdot b, \color{blue}{\mathsf{fma}\left(b, b, 4\right)}, \mathsf{neg}\left(1\right)\right) \]
          11. metadata-eval69.0

            \[\leadsto \mathsf{fma}\left(b \cdot b, \mathsf{fma}\left(b, b, 4\right), \color{blue}{-1}\right) \]
        5. Applied rewrites69.0%

          \[\leadsto \color{blue}{\mathsf{fma}\left(b \cdot b, \mathsf{fma}\left(b, b, 4\right), -1\right)} \]
        6. Add Preprocessing

        Alternative 7: 52.7% accurate, 10.9× speedup?

        \[\begin{array}{l} \\ \mathsf{fma}\left(b \cdot b, 4, -1\right) \end{array} \]
        (FPCore (a b) :precision binary64 (fma (* b b) 4.0 -1.0))
        double code(double a, double b) {
        	return fma((b * b), 4.0, -1.0);
        }
        
        function code(a, b)
        	return fma(Float64(b * b), 4.0, -1.0)
        end
        
        code[a_, b_] := N[(N[(b * b), $MachinePrecision] * 4.0 + -1.0), $MachinePrecision]
        
        \begin{array}{l}
        
        \\
        \mathsf{fma}\left(b \cdot b, 4, -1\right)
        \end{array}
        
        Derivation
        1. Initial program 99.9%

          \[\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
        2. Add Preprocessing
        3. Taylor expanded in a around 0

          \[\leadsto \color{blue}{\left(4 \cdot {b}^{2} + {b}^{4}\right) - 1} \]
        4. Step-by-step derivation
          1. sub-negN/A

            \[\leadsto \color{blue}{\left(4 \cdot {b}^{2} + {b}^{4}\right) + \left(\mathsf{neg}\left(1\right)\right)} \]
          2. metadata-evalN/A

            \[\leadsto \left(4 \cdot {b}^{2} + {b}^{\color{blue}{\left(2 \cdot 2\right)}}\right) + \left(\mathsf{neg}\left(1\right)\right) \]
          3. pow-sqrN/A

            \[\leadsto \left(4 \cdot {b}^{2} + \color{blue}{{b}^{2} \cdot {b}^{2}}\right) + \left(\mathsf{neg}\left(1\right)\right) \]
          4. distribute-rgt-outN/A

            \[\leadsto \color{blue}{{b}^{2} \cdot \left(4 + {b}^{2}\right)} + \left(\mathsf{neg}\left(1\right)\right) \]
          5. lower-fma.f64N/A

            \[\leadsto \color{blue}{\mathsf{fma}\left({b}^{2}, 4 + {b}^{2}, \mathsf{neg}\left(1\right)\right)} \]
          6. unpow2N/A

            \[\leadsto \mathsf{fma}\left(\color{blue}{b \cdot b}, 4 + {b}^{2}, \mathsf{neg}\left(1\right)\right) \]
          7. lower-*.f64N/A

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

            \[\leadsto \mathsf{fma}\left(b \cdot b, \color{blue}{{b}^{2} + 4}, \mathsf{neg}\left(1\right)\right) \]
          9. unpow2N/A

            \[\leadsto \mathsf{fma}\left(b \cdot b, \color{blue}{b \cdot b} + 4, \mathsf{neg}\left(1\right)\right) \]
          10. lower-fma.f64N/A

            \[\leadsto \mathsf{fma}\left(b \cdot b, \color{blue}{\mathsf{fma}\left(b, b, 4\right)}, \mathsf{neg}\left(1\right)\right) \]
          11. metadata-eval69.0

            \[\leadsto \mathsf{fma}\left(b \cdot b, \mathsf{fma}\left(b, b, 4\right), \color{blue}{-1}\right) \]
        5. Applied rewrites69.0%

          \[\leadsto \color{blue}{\mathsf{fma}\left(b \cdot b, \mathsf{fma}\left(b, b, 4\right), -1\right)} \]
        6. Taylor expanded in b around 0

          \[\leadsto \mathsf{fma}\left(b \cdot b, 4, -1\right) \]
        7. Step-by-step derivation
          1. Applied rewrites50.4%

            \[\leadsto \mathsf{fma}\left(b \cdot b, 4, -1\right) \]
          2. Add Preprocessing

          Alternative 8: 25.6% accurate, 131.0× speedup?

          \[\begin{array}{l} \\ -1 \end{array} \]
          (FPCore (a b) :precision binary64 -1.0)
          double code(double a, double b) {
          	return -1.0;
          }
          
          real(8) function code(a, b)
              real(8), intent (in) :: a
              real(8), intent (in) :: b
              code = -1.0d0
          end function
          
          public static double code(double a, double b) {
          	return -1.0;
          }
          
          def code(a, b):
          	return -1.0
          
          function code(a, b)
          	return -1.0
          end
          
          function tmp = code(a, b)
          	tmp = -1.0;
          end
          
          code[a_, b_] := -1.0
          
          \begin{array}{l}
          
          \\
          -1
          \end{array}
          
          Derivation
          1. Initial program 99.9%

            \[\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(b \cdot b\right)\right) - 1 \]
          2. Add Preprocessing
          3. Taylor expanded in a around 0

            \[\leadsto \color{blue}{\left(4 \cdot {b}^{2} + {b}^{4}\right) - 1} \]
          4. Step-by-step derivation
            1. sub-negN/A

              \[\leadsto \color{blue}{\left(4 \cdot {b}^{2} + {b}^{4}\right) + \left(\mathsf{neg}\left(1\right)\right)} \]
            2. metadata-evalN/A

              \[\leadsto \left(4 \cdot {b}^{2} + {b}^{\color{blue}{\left(2 \cdot 2\right)}}\right) + \left(\mathsf{neg}\left(1\right)\right) \]
            3. pow-sqrN/A

              \[\leadsto \left(4 \cdot {b}^{2} + \color{blue}{{b}^{2} \cdot {b}^{2}}\right) + \left(\mathsf{neg}\left(1\right)\right) \]
            4. distribute-rgt-outN/A

              \[\leadsto \color{blue}{{b}^{2} \cdot \left(4 + {b}^{2}\right)} + \left(\mathsf{neg}\left(1\right)\right) \]
            5. lower-fma.f64N/A

              \[\leadsto \color{blue}{\mathsf{fma}\left({b}^{2}, 4 + {b}^{2}, \mathsf{neg}\left(1\right)\right)} \]
            6. unpow2N/A

              \[\leadsto \mathsf{fma}\left(\color{blue}{b \cdot b}, 4 + {b}^{2}, \mathsf{neg}\left(1\right)\right) \]
            7. lower-*.f64N/A

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

              \[\leadsto \mathsf{fma}\left(b \cdot b, \color{blue}{{b}^{2} + 4}, \mathsf{neg}\left(1\right)\right) \]
            9. unpow2N/A

              \[\leadsto \mathsf{fma}\left(b \cdot b, \color{blue}{b \cdot b} + 4, \mathsf{neg}\left(1\right)\right) \]
            10. lower-fma.f64N/A

              \[\leadsto \mathsf{fma}\left(b \cdot b, \color{blue}{\mathsf{fma}\left(b, b, 4\right)}, \mathsf{neg}\left(1\right)\right) \]
            11. metadata-eval69.0

              \[\leadsto \mathsf{fma}\left(b \cdot b, \mathsf{fma}\left(b, b, 4\right), \color{blue}{-1}\right) \]
          5. Applied rewrites69.0%

            \[\leadsto \color{blue}{\mathsf{fma}\left(b \cdot b, \mathsf{fma}\left(b, b, 4\right), -1\right)} \]
          6. Taylor expanded in b around 0

            \[\leadsto -1 \]
          7. Step-by-step derivation
            1. Applied rewrites30.9%

              \[\leadsto -1 \]
            2. Add Preprocessing

            Reproduce

            ?
            herbie shell --seed 2024305 
            (FPCore (a b)
              :name "Bouland and Aaronson, Equation (26)"
              :precision binary64
              (- (+ (pow (+ (* a a) (* b b)) 2.0) (* 4.0 (* b b))) 1.0))