Bouland and Aaronson, Equation (24)

Percentage Accurate: 73.7% → 97.7%
Time: 5.0s
Alternatives: 4
Speedup: 1.2×

Specification

?
\[\begin{array}{l} \\ \left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(b \cdot b\right) \cdot \left(3 + a\right)\right)\right) - 1 \end{array} \]
(FPCore (a b)
 :precision binary64
 (-
  (+
   (pow (+ (* a a) (* b b)) 2.0)
   (* 4.0 (+ (* (* a a) (- 1.0 a)) (* (* b b) (+ 3.0 a)))))
  1.0))
double code(double a, double b) {
	return (pow(((a * a) + (b * b)), 2.0) + (4.0 * (((a * a) * (1.0 - a)) + ((b * b) * (3.0 + a))))) - 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 * (((a * a) * (1.0d0 - a)) + ((b * b) * (3.0d0 + a))))) - 1.0d0
end function
public static double code(double a, double b) {
	return (Math.pow(((a * a) + (b * b)), 2.0) + (4.0 * (((a * a) * (1.0 - a)) + ((b * b) * (3.0 + a))))) - 1.0;
}
def code(a, b):
	return (math.pow(((a * a) + (b * b)), 2.0) + (4.0 * (((a * a) * (1.0 - a)) + ((b * b) * (3.0 + a))))) - 1.0
function code(a, b)
	return Float64(Float64((Float64(Float64(a * a) + Float64(b * b)) ^ 2.0) + Float64(4.0 * Float64(Float64(Float64(a * a) * Float64(1.0 - a)) + Float64(Float64(b * b) * Float64(3.0 + a))))) - 1.0)
end
function tmp = code(a, b)
	tmp = ((((a * a) + (b * b)) ^ 2.0) + (4.0 * (((a * a) * (1.0 - a)) + ((b * b) * (3.0 + a))))) - 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[(N[(N[(a * a), $MachinePrecision] * N[(1.0 - a), $MachinePrecision]), $MachinePrecision] + N[(N[(b * b), $MachinePrecision] * N[(3.0 + a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - 1.0), $MachinePrecision]
\begin{array}{l}

\\
\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(b \cdot b\right) \cdot \left(3 + a\right)\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 4 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: 73.7% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(b \cdot b\right) \cdot \left(3 + a\right)\right)\right) - 1 \end{array} \]
(FPCore (a b)
 :precision binary64
 (-
  (+
   (pow (+ (* a a) (* b b)) 2.0)
   (* 4.0 (+ (* (* a a) (- 1.0 a)) (* (* b b) (+ 3.0 a)))))
  1.0))
double code(double a, double b) {
	return (pow(((a * a) + (b * b)), 2.0) + (4.0 * (((a * a) * (1.0 - a)) + ((b * b) * (3.0 + a))))) - 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 * (((a * a) * (1.0d0 - a)) + ((b * b) * (3.0d0 + a))))) - 1.0d0
end function
public static double code(double a, double b) {
	return (Math.pow(((a * a) + (b * b)), 2.0) + (4.0 * (((a * a) * (1.0 - a)) + ((b * b) * (3.0 + a))))) - 1.0;
}
def code(a, b):
	return (math.pow(((a * a) + (b * b)), 2.0) + (4.0 * (((a * a) * (1.0 - a)) + ((b * b) * (3.0 + a))))) - 1.0
function code(a, b)
	return Float64(Float64((Float64(Float64(a * a) + Float64(b * b)) ^ 2.0) + Float64(4.0 * Float64(Float64(Float64(a * a) * Float64(1.0 - a)) + Float64(Float64(b * b) * Float64(3.0 + a))))) - 1.0)
end
function tmp = code(a, b)
	tmp = ((((a * a) + (b * b)) ^ 2.0) + (4.0 * (((a * a) * (1.0 - a)) + ((b * b) * (3.0 + a))))) - 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[(N[(N[(a * a), $MachinePrecision] * N[(1.0 - a), $MachinePrecision]), $MachinePrecision] + N[(N[(b * b), $MachinePrecision] * N[(3.0 + a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - 1.0), $MachinePrecision]
\begin{array}{l}

\\
\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(b \cdot b\right) \cdot \left(3 + a\right)\right)\right) - 1
\end{array}

Alternative 1: 97.7% accurate, 0.4× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \cdot b \leq 10^{-5}:\\ \;\;\;\;{a}^{3} \cdot \left(a + -4\right) + -1\\ \mathbf{else}:\\ \;\;\;\;-1 + \left({b}^{2} \cdot \left(2 \cdot {a}^{2} + 4 \cdot \left(a + 3\right)\right) + {b}^{4}\right)\\ \end{array} \end{array} \]
(FPCore (a b)
 :precision binary64
 (if (<= (* b b) 1e-5)
   (+ (* (pow a 3.0) (+ a -4.0)) -1.0)
   (+
    -1.0
    (+
     (* (pow b 2.0) (+ (* 2.0 (pow a 2.0)) (* 4.0 (+ a 3.0))))
     (pow b 4.0)))))
double code(double a, double b) {
	double tmp;
	if ((b * b) <= 1e-5) {
		tmp = (pow(a, 3.0) * (a + -4.0)) + -1.0;
	} else {
		tmp = -1.0 + ((pow(b, 2.0) * ((2.0 * pow(a, 2.0)) + (4.0 * (a + 3.0)))) + pow(b, 4.0));
	}
	return tmp;
}
real(8) function code(a, b)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8) :: tmp
    if ((b * b) <= 1d-5) then
        tmp = ((a ** 3.0d0) * (a + (-4.0d0))) + (-1.0d0)
    else
        tmp = (-1.0d0) + (((b ** 2.0d0) * ((2.0d0 * (a ** 2.0d0)) + (4.0d0 * (a + 3.0d0)))) + (b ** 4.0d0))
    end if
    code = tmp
end function
public static double code(double a, double b) {
	double tmp;
	if ((b * b) <= 1e-5) {
		tmp = (Math.pow(a, 3.0) * (a + -4.0)) + -1.0;
	} else {
		tmp = -1.0 + ((Math.pow(b, 2.0) * ((2.0 * Math.pow(a, 2.0)) + (4.0 * (a + 3.0)))) + Math.pow(b, 4.0));
	}
	return tmp;
}
def code(a, b):
	tmp = 0
	if (b * b) <= 1e-5:
		tmp = (math.pow(a, 3.0) * (a + -4.0)) + -1.0
	else:
		tmp = -1.0 + ((math.pow(b, 2.0) * ((2.0 * math.pow(a, 2.0)) + (4.0 * (a + 3.0)))) + math.pow(b, 4.0))
	return tmp
function code(a, b)
	tmp = 0.0
	if (Float64(b * b) <= 1e-5)
		tmp = Float64(Float64((a ^ 3.0) * Float64(a + -4.0)) + -1.0);
	else
		tmp = Float64(-1.0 + Float64(Float64((b ^ 2.0) * Float64(Float64(2.0 * (a ^ 2.0)) + Float64(4.0 * Float64(a + 3.0)))) + (b ^ 4.0)));
	end
	return tmp
end
function tmp_2 = code(a, b)
	tmp = 0.0;
	if ((b * b) <= 1e-5)
		tmp = ((a ^ 3.0) * (a + -4.0)) + -1.0;
	else
		tmp = -1.0 + (((b ^ 2.0) * ((2.0 * (a ^ 2.0)) + (4.0 * (a + 3.0)))) + (b ^ 4.0));
	end
	tmp_2 = tmp;
end
code[a_, b_] := If[LessEqual[N[(b * b), $MachinePrecision], 1e-5], N[(N[(N[Power[a, 3.0], $MachinePrecision] * N[(a + -4.0), $MachinePrecision]), $MachinePrecision] + -1.0), $MachinePrecision], N[(-1.0 + N[(N[(N[Power[b, 2.0], $MachinePrecision] * N[(N[(2.0 * N[Power[a, 2.0], $MachinePrecision]), $MachinePrecision] + N[(4.0 * N[(a + 3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[Power[b, 4.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;b \cdot b \leq 10^{-5}:\\
\;\;\;\;{a}^{3} \cdot \left(a + -4\right) + -1\\

\mathbf{else}:\\
\;\;\;\;-1 + \left({b}^{2} \cdot \left(2 \cdot {a}^{2} + 4 \cdot \left(a + 3\right)\right) + {b}^{4}\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (*.f64 b b) < 1.00000000000000008e-5

    1. Initial program 79.7%

      \[\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(b \cdot b\right) \cdot \left(3 + a\right)\right)\right) - 1 \]
    2. Step-by-step derivation
      1. sub-neg79.7%

        \[\leadsto \color{blue}{\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(b \cdot b\right) \cdot \left(3 + a\right)\right)\right) + \left(-1\right)} \]
      2. sqr-neg79.7%

        \[\leadsto \left({\left(a \cdot a + \color{blue}{\left(-b\right) \cdot \left(-b\right)}\right)}^{2} + 4 \cdot \left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(b \cdot b\right) \cdot \left(3 + a\right)\right)\right) + \left(-1\right) \]
      3. +-commutative79.7%

        \[\leadsto \left({\left(a \cdot a + \left(-b\right) \cdot \left(-b\right)\right)}^{2} + 4 \cdot \color{blue}{\left(\left(b \cdot b\right) \cdot \left(3 + a\right) + \left(a \cdot a\right) \cdot \left(1 - a\right)\right)}\right) + \left(-1\right) \]
      4. sqr-neg79.7%

        \[\leadsto \left({\left(a \cdot a + \left(-b\right) \cdot \left(-b\right)\right)}^{2} + 4 \cdot \left(\color{blue}{\left(\left(-b\right) \cdot \left(-b\right)\right)} \cdot \left(3 + a\right) + \left(a \cdot a\right) \cdot \left(1 - a\right)\right)\right) + \left(-1\right) \]
      5. +-commutative79.7%

        \[\leadsto \left({\left(a \cdot a + \left(-b\right) \cdot \left(-b\right)\right)}^{2} + 4 \cdot \color{blue}{\left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(\left(-b\right) \cdot \left(-b\right)\right) \cdot \left(3 + a\right)\right)}\right) + \left(-1\right) \]
    3. Simplified79.7%

      \[\leadsto \color{blue}{\left({\left(\mathsf{fma}\left(a, a, b \cdot b\right)\right)}^{2} + 4 \cdot \mathsf{fma}\left(a \cdot a, 1 - a, \left(b \cdot b\right) \cdot \left(a + 3\right)\right)\right) + -1} \]
    4. Taylor expanded in a around inf 78.5%

      \[\leadsto \color{blue}{\left(-4 \cdot {a}^{3} + {a}^{4}\right)} + -1 \]
    5. Step-by-step derivation
      1. +-commutative78.5%

        \[\leadsto \color{blue}{\left({a}^{4} + -4 \cdot {a}^{3}\right)} + -1 \]
      2. flip-+20.7%

        \[\leadsto \color{blue}{\frac{{a}^{4} \cdot {a}^{4} - \left(-4 \cdot {a}^{3}\right) \cdot \left(-4 \cdot {a}^{3}\right)}{{a}^{4} - -4 \cdot {a}^{3}}} + -1 \]
      3. pow-prod-up20.7%

        \[\leadsto \frac{\color{blue}{{a}^{\left(4 + 4\right)}} - \left(-4 \cdot {a}^{3}\right) \cdot \left(-4 \cdot {a}^{3}\right)}{{a}^{4} - -4 \cdot {a}^{3}} + -1 \]
      4. metadata-eval20.7%

        \[\leadsto \frac{{a}^{\color{blue}{8}} - \left(-4 \cdot {a}^{3}\right) \cdot \left(-4 \cdot {a}^{3}\right)}{{a}^{4} - -4 \cdot {a}^{3}} + -1 \]
      5. *-commutative20.7%

        \[\leadsto \frac{{a}^{8} - \color{blue}{\left({a}^{3} \cdot -4\right)} \cdot \left(-4 \cdot {a}^{3}\right)}{{a}^{4} - -4 \cdot {a}^{3}} + -1 \]
      6. *-commutative20.7%

        \[\leadsto \frac{{a}^{8} - \left({a}^{3} \cdot -4\right) \cdot \color{blue}{\left({a}^{3} \cdot -4\right)}}{{a}^{4} - -4 \cdot {a}^{3}} + -1 \]
      7. swap-sqr20.7%

        \[\leadsto \frac{{a}^{8} - \color{blue}{\left({a}^{3} \cdot {a}^{3}\right) \cdot \left(-4 \cdot -4\right)}}{{a}^{4} - -4 \cdot {a}^{3}} + -1 \]
      8. pow-prod-up20.7%

        \[\leadsto \frac{{a}^{8} - \color{blue}{{a}^{\left(3 + 3\right)}} \cdot \left(-4 \cdot -4\right)}{{a}^{4} - -4 \cdot {a}^{3}} + -1 \]
      9. metadata-eval20.7%

        \[\leadsto \frac{{a}^{8} - {a}^{\color{blue}{6}} \cdot \left(-4 \cdot -4\right)}{{a}^{4} - -4 \cdot {a}^{3}} + -1 \]
      10. metadata-eval20.7%

        \[\leadsto \frac{{a}^{8} - {a}^{6} \cdot \color{blue}{16}}{{a}^{4} - -4 \cdot {a}^{3}} + -1 \]
    6. Applied egg-rr20.7%

      \[\leadsto \color{blue}{\frac{{a}^{8} - {a}^{6} \cdot 16}{{a}^{4} - -4 \cdot {a}^{3}}} + -1 \]
    7. Taylor expanded in a around inf 21.2%

      \[\leadsto \frac{\color{blue}{{a}^{8}}}{{a}^{4} - -4 \cdot {a}^{3}} + -1 \]
    8. Taylor expanded in a around inf 78.5%

      \[\leadsto \color{blue}{\left(-4 \cdot {a}^{3} + {a}^{4}\right)} + -1 \]
    9. Step-by-step derivation
      1. +-commutative78.5%

        \[\leadsto \color{blue}{\left({a}^{4} + -4 \cdot {a}^{3}\right)} + -1 \]
      2. metadata-eval78.5%

        \[\leadsto \left({a}^{\color{blue}{\left(3 + 1\right)}} + -4 \cdot {a}^{3}\right) + -1 \]
      3. pow-plus78.5%

        \[\leadsto \left(\color{blue}{{a}^{3} \cdot a} + -4 \cdot {a}^{3}\right) + -1 \]
      4. *-commutative78.5%

        \[\leadsto \left(\color{blue}{a \cdot {a}^{3}} + -4 \cdot {a}^{3}\right) + -1 \]
      5. distribute-rgt-out98.6%

        \[\leadsto \color{blue}{{a}^{3} \cdot \left(a + -4\right)} + -1 \]
    10. Simplified98.6%

      \[\leadsto \color{blue}{{a}^{3} \cdot \left(a + -4\right)} + -1 \]

    if 1.00000000000000008e-5 < (*.f64 b b)

    1. Initial program 66.7%

      \[\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(b \cdot b\right) \cdot \left(3 + a\right)\right)\right) - 1 \]
    2. Step-by-step derivation
      1. sub-neg66.7%

        \[\leadsto \color{blue}{\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(b \cdot b\right) \cdot \left(3 + a\right)\right)\right) + \left(-1\right)} \]
      2. sqr-neg66.7%

        \[\leadsto \left({\left(a \cdot a + \color{blue}{\left(-b\right) \cdot \left(-b\right)}\right)}^{2} + 4 \cdot \left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(b \cdot b\right) \cdot \left(3 + a\right)\right)\right) + \left(-1\right) \]
      3. +-commutative66.7%

        \[\leadsto \left({\left(a \cdot a + \left(-b\right) \cdot \left(-b\right)\right)}^{2} + 4 \cdot \color{blue}{\left(\left(b \cdot b\right) \cdot \left(3 + a\right) + \left(a \cdot a\right) \cdot \left(1 - a\right)\right)}\right) + \left(-1\right) \]
      4. sqr-neg66.7%

        \[\leadsto \left({\left(a \cdot a + \left(-b\right) \cdot \left(-b\right)\right)}^{2} + 4 \cdot \left(\color{blue}{\left(\left(-b\right) \cdot \left(-b\right)\right)} \cdot \left(3 + a\right) + \left(a \cdot a\right) \cdot \left(1 - a\right)\right)\right) + \left(-1\right) \]
      5. +-commutative66.7%

        \[\leadsto \left({\left(a \cdot a + \left(-b\right) \cdot \left(-b\right)\right)}^{2} + 4 \cdot \color{blue}{\left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(\left(-b\right) \cdot \left(-b\right)\right) \cdot \left(3 + a\right)\right)}\right) + \left(-1\right) \]
    3. Simplified68.9%

      \[\leadsto \color{blue}{\left({\left(\mathsf{fma}\left(a, a, b \cdot b\right)\right)}^{2} + 4 \cdot \mathsf{fma}\left(a \cdot a, 1 - a, \left(b \cdot b\right) \cdot \left(a + 3\right)\right)\right) + -1} \]
    4. Taylor expanded in b around inf 99.3%

      \[\leadsto \color{blue}{\left({b}^{2} \cdot \left(2 \cdot {a}^{2} + 4 \cdot \left(3 + a\right)\right) + {b}^{4}\right)} + -1 \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b \cdot b \leq 10^{-5}:\\ \;\;\;\;{a}^{3} \cdot \left(a + -4\right) + -1\\ \mathbf{else}:\\ \;\;\;\;-1 + \left({b}^{2} \cdot \left(2 \cdot {a}^{2} + 4 \cdot \left(a + 3\right)\right) + {b}^{4}\right)\\ \end{array} \]

Alternative 2: 97.8% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := {\left(b \cdot b + a \cdot a\right)}^{2} + 4 \cdot \left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(b \cdot b\right) \cdot \left(a + 3\right)\right)\\ \mathbf{if}\;t_0 \leq \infty:\\ \;\;\;\;-1 + t_0\\ \mathbf{else}:\\ \;\;\;\;-1 + {a}^{4}\\ \end{array} \end{array} \]
(FPCore (a b)
 :precision binary64
 (let* ((t_0
         (+
          (pow (+ (* b b) (* a a)) 2.0)
          (* 4.0 (+ (* (* a a) (- 1.0 a)) (* (* b b) (+ a 3.0)))))))
   (if (<= t_0 INFINITY) (+ -1.0 t_0) (+ -1.0 (pow a 4.0)))))
double code(double a, double b) {
	double t_0 = pow(((b * b) + (a * a)), 2.0) + (4.0 * (((a * a) * (1.0 - a)) + ((b * b) * (a + 3.0))));
	double tmp;
	if (t_0 <= ((double) INFINITY)) {
		tmp = -1.0 + t_0;
	} else {
		tmp = -1.0 + pow(a, 4.0);
	}
	return tmp;
}
public static double code(double a, double b) {
	double t_0 = Math.pow(((b * b) + (a * a)), 2.0) + (4.0 * (((a * a) * (1.0 - a)) + ((b * b) * (a + 3.0))));
	double tmp;
	if (t_0 <= Double.POSITIVE_INFINITY) {
		tmp = -1.0 + t_0;
	} else {
		tmp = -1.0 + Math.pow(a, 4.0);
	}
	return tmp;
}
def code(a, b):
	t_0 = math.pow(((b * b) + (a * a)), 2.0) + (4.0 * (((a * a) * (1.0 - a)) + ((b * b) * (a + 3.0))))
	tmp = 0
	if t_0 <= math.inf:
		tmp = -1.0 + t_0
	else:
		tmp = -1.0 + math.pow(a, 4.0)
	return tmp
function code(a, b)
	t_0 = Float64((Float64(Float64(b * b) + Float64(a * a)) ^ 2.0) + Float64(4.0 * Float64(Float64(Float64(a * a) * Float64(1.0 - a)) + Float64(Float64(b * b) * Float64(a + 3.0)))))
	tmp = 0.0
	if (t_0 <= Inf)
		tmp = Float64(-1.0 + t_0);
	else
		tmp = Float64(-1.0 + (a ^ 4.0));
	end
	return tmp
end
function tmp_2 = code(a, b)
	t_0 = (((b * b) + (a * a)) ^ 2.0) + (4.0 * (((a * a) * (1.0 - a)) + ((b * b) * (a + 3.0))));
	tmp = 0.0;
	if (t_0 <= Inf)
		tmp = -1.0 + t_0;
	else
		tmp = -1.0 + (a ^ 4.0);
	end
	tmp_2 = tmp;
end
code[a_, b_] := Block[{t$95$0 = N[(N[Power[N[(N[(b * b), $MachinePrecision] + N[(a * a), $MachinePrecision]), $MachinePrecision], 2.0], $MachinePrecision] + N[(4.0 * N[(N[(N[(a * a), $MachinePrecision] * N[(1.0 - a), $MachinePrecision]), $MachinePrecision] + N[(N[(b * b), $MachinePrecision] * N[(a + 3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t$95$0, Infinity], N[(-1.0 + t$95$0), $MachinePrecision], N[(-1.0 + N[Power[a, 4.0], $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := {\left(b \cdot b + a \cdot a\right)}^{2} + 4 \cdot \left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(b \cdot b\right) \cdot \left(a + 3\right)\right)\\
\mathbf{if}\;t_0 \leq \infty:\\
\;\;\;\;-1 + t_0\\

\mathbf{else}:\\
\;\;\;\;-1 + {a}^{4}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (+.f64 (pow.f64 (+.f64 (*.f64 a a) (*.f64 b b)) 2) (*.f64 4 (+.f64 (*.f64 (*.f64 a a) (-.f64 1 a)) (*.f64 (*.f64 b b) (+.f64 3 a))))) < +inf.0

    1. Initial program 99.8%

      \[\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(b \cdot b\right) \cdot \left(3 + a\right)\right)\right) - 1 \]

    if +inf.0 < (+.f64 (pow.f64 (+.f64 (*.f64 a a) (*.f64 b b)) 2) (*.f64 4 (+.f64 (*.f64 (*.f64 a a) (-.f64 1 a)) (*.f64 (*.f64 b b) (+.f64 3 a)))))

    1. Initial program 0.0%

      \[\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(b \cdot b\right) \cdot \left(3 + a\right)\right)\right) - 1 \]
    2. Step-by-step derivation
      1. sub-neg0.0%

        \[\leadsto \color{blue}{\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(b \cdot b\right) \cdot \left(3 + a\right)\right)\right) + \left(-1\right)} \]
      2. sqr-neg0.0%

        \[\leadsto \left({\left(a \cdot a + \color{blue}{\left(-b\right) \cdot \left(-b\right)}\right)}^{2} + 4 \cdot \left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(b \cdot b\right) \cdot \left(3 + a\right)\right)\right) + \left(-1\right) \]
      3. +-commutative0.0%

        \[\leadsto \left({\left(a \cdot a + \left(-b\right) \cdot \left(-b\right)\right)}^{2} + 4 \cdot \color{blue}{\left(\left(b \cdot b\right) \cdot \left(3 + a\right) + \left(a \cdot a\right) \cdot \left(1 - a\right)\right)}\right) + \left(-1\right) \]
      4. sqr-neg0.0%

        \[\leadsto \left({\left(a \cdot a + \left(-b\right) \cdot \left(-b\right)\right)}^{2} + 4 \cdot \left(\color{blue}{\left(\left(-b\right) \cdot \left(-b\right)\right)} \cdot \left(3 + a\right) + \left(a \cdot a\right) \cdot \left(1 - a\right)\right)\right) + \left(-1\right) \]
      5. +-commutative0.0%

        \[\leadsto \left({\left(a \cdot a + \left(-b\right) \cdot \left(-b\right)\right)}^{2} + 4 \cdot \color{blue}{\left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(\left(-b\right) \cdot \left(-b\right)\right) \cdot \left(3 + a\right)\right)}\right) + \left(-1\right) \]
    3. Simplified4.3%

      \[\leadsto \color{blue}{\left({\left(\mathsf{fma}\left(a, a, b \cdot b\right)\right)}^{2} + 4 \cdot \mathsf{fma}\left(a \cdot a, 1 - a, \left(b \cdot b\right) \cdot \left(a + 3\right)\right)\right) + -1} \]
    4. Taylor expanded in a around inf 95.9%

      \[\leadsto \color{blue}{{a}^{4}} + -1 \]
  3. Recombined 2 regimes into one program.
  4. Final simplification98.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;{\left(b \cdot b + a \cdot a\right)}^{2} + 4 \cdot \left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(b \cdot b\right) \cdot \left(a + 3\right)\right) \leq \infty:\\ \;\;\;\;-1 + \left({\left(b \cdot b + a \cdot a\right)}^{2} + 4 \cdot \left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(b \cdot b\right) \cdot \left(a + 3\right)\right)\right)\\ \mathbf{else}:\\ \;\;\;\;-1 + {a}^{4}\\ \end{array} \]

Alternative 3: 92.4% accurate, 1.2× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;a \leq -2.1 \cdot 10^{+20} \lor \neg \left(a \leq 5.6 \cdot 10^{+67}\right):\\ \;\;\;\;-1 + {a}^{4}\\ \mathbf{else}:\\ \;\;\;\;-1 + {b}^{4}\\ \end{array} \end{array} \]
(FPCore (a b)
 :precision binary64
 (if (or (<= a -2.1e+20) (not (<= a 5.6e+67)))
   (+ -1.0 (pow a 4.0))
   (+ -1.0 (pow b 4.0))))
double code(double a, double b) {
	double tmp;
	if ((a <= -2.1e+20) || !(a <= 5.6e+67)) {
		tmp = -1.0 + pow(a, 4.0);
	} else {
		tmp = -1.0 + pow(b, 4.0);
	}
	return tmp;
}
real(8) function code(a, b)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8) :: tmp
    if ((a <= (-2.1d+20)) .or. (.not. (a <= 5.6d+67))) then
        tmp = (-1.0d0) + (a ** 4.0d0)
    else
        tmp = (-1.0d0) + (b ** 4.0d0)
    end if
    code = tmp
end function
public static double code(double a, double b) {
	double tmp;
	if ((a <= -2.1e+20) || !(a <= 5.6e+67)) {
		tmp = -1.0 + Math.pow(a, 4.0);
	} else {
		tmp = -1.0 + Math.pow(b, 4.0);
	}
	return tmp;
}
def code(a, b):
	tmp = 0
	if (a <= -2.1e+20) or not (a <= 5.6e+67):
		tmp = -1.0 + math.pow(a, 4.0)
	else:
		tmp = -1.0 + math.pow(b, 4.0)
	return tmp
function code(a, b)
	tmp = 0.0
	if ((a <= -2.1e+20) || !(a <= 5.6e+67))
		tmp = Float64(-1.0 + (a ^ 4.0));
	else
		tmp = Float64(-1.0 + (b ^ 4.0));
	end
	return tmp
end
function tmp_2 = code(a, b)
	tmp = 0.0;
	if ((a <= -2.1e+20) || ~((a <= 5.6e+67)))
		tmp = -1.0 + (a ^ 4.0);
	else
		tmp = -1.0 + (b ^ 4.0);
	end
	tmp_2 = tmp;
end
code[a_, b_] := If[Or[LessEqual[a, -2.1e+20], N[Not[LessEqual[a, 5.6e+67]], $MachinePrecision]], N[(-1.0 + N[Power[a, 4.0], $MachinePrecision]), $MachinePrecision], N[(-1.0 + N[Power[b, 4.0], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;a \leq -2.1 \cdot 10^{+20} \lor \neg \left(a \leq 5.6 \cdot 10^{+67}\right):\\
\;\;\;\;-1 + {a}^{4}\\

\mathbf{else}:\\
\;\;\;\;-1 + {b}^{4}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if a < -2.1e20 or 5.5999999999999995e67 < a

    1. Initial program 38.7%

      \[\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(b \cdot b\right) \cdot \left(3 + a\right)\right)\right) - 1 \]
    2. Step-by-step derivation
      1. sub-neg38.7%

        \[\leadsto \color{blue}{\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(b \cdot b\right) \cdot \left(3 + a\right)\right)\right) + \left(-1\right)} \]
      2. sqr-neg38.7%

        \[\leadsto \left({\left(a \cdot a + \color{blue}{\left(-b\right) \cdot \left(-b\right)}\right)}^{2} + 4 \cdot \left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(b \cdot b\right) \cdot \left(3 + a\right)\right)\right) + \left(-1\right) \]
      3. +-commutative38.7%

        \[\leadsto \left({\left(a \cdot a + \left(-b\right) \cdot \left(-b\right)\right)}^{2} + 4 \cdot \color{blue}{\left(\left(b \cdot b\right) \cdot \left(3 + a\right) + \left(a \cdot a\right) \cdot \left(1 - a\right)\right)}\right) + \left(-1\right) \]
      4. sqr-neg38.7%

        \[\leadsto \left({\left(a \cdot a + \left(-b\right) \cdot \left(-b\right)\right)}^{2} + 4 \cdot \left(\color{blue}{\left(\left(-b\right) \cdot \left(-b\right)\right)} \cdot \left(3 + a\right) + \left(a \cdot a\right) \cdot \left(1 - a\right)\right)\right) + \left(-1\right) \]
      5. +-commutative38.7%

        \[\leadsto \left({\left(a \cdot a + \left(-b\right) \cdot \left(-b\right)\right)}^{2} + 4 \cdot \color{blue}{\left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(\left(-b\right) \cdot \left(-b\right)\right) \cdot \left(3 + a\right)\right)}\right) + \left(-1\right) \]
    3. Simplified41.4%

      \[\leadsto \color{blue}{\left({\left(\mathsf{fma}\left(a, a, b \cdot b\right)\right)}^{2} + 4 \cdot \mathsf{fma}\left(a \cdot a, 1 - a, \left(b \cdot b\right) \cdot \left(a + 3\right)\right)\right) + -1} \]
    4. Taylor expanded in a around inf 97.5%

      \[\leadsto \color{blue}{{a}^{4}} + -1 \]

    if -2.1e20 < a < 5.5999999999999995e67

    1. Initial program 98.4%

      \[\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(b \cdot b\right) \cdot \left(3 + a\right)\right)\right) - 1 \]
    2. Step-by-step derivation
      1. sub-neg98.4%

        \[\leadsto \color{blue}{\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(b \cdot b\right) \cdot \left(3 + a\right)\right)\right) + \left(-1\right)} \]
      2. sqr-neg98.4%

        \[\leadsto \left({\left(a \cdot a + \color{blue}{\left(-b\right) \cdot \left(-b\right)}\right)}^{2} + 4 \cdot \left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(b \cdot b\right) \cdot \left(3 + a\right)\right)\right) + \left(-1\right) \]
      3. +-commutative98.4%

        \[\leadsto \left({\left(a \cdot a + \left(-b\right) \cdot \left(-b\right)\right)}^{2} + 4 \cdot \color{blue}{\left(\left(b \cdot b\right) \cdot \left(3 + a\right) + \left(a \cdot a\right) \cdot \left(1 - a\right)\right)}\right) + \left(-1\right) \]
      4. sqr-neg98.4%

        \[\leadsto \left({\left(a \cdot a + \left(-b\right) \cdot \left(-b\right)\right)}^{2} + 4 \cdot \left(\color{blue}{\left(\left(-b\right) \cdot \left(-b\right)\right)} \cdot \left(3 + a\right) + \left(a \cdot a\right) \cdot \left(1 - a\right)\right)\right) + \left(-1\right) \]
      5. +-commutative98.4%

        \[\leadsto \left({\left(a \cdot a + \left(-b\right) \cdot \left(-b\right)\right)}^{2} + 4 \cdot \color{blue}{\left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(\left(-b\right) \cdot \left(-b\right)\right) \cdot \left(3 + a\right)\right)}\right) + \left(-1\right) \]
    3. Simplified98.4%

      \[\leadsto \color{blue}{\left({\left(\mathsf{fma}\left(a, a, b \cdot b\right)\right)}^{2} + 4 \cdot \mathsf{fma}\left(a \cdot a, 1 - a, \left(b \cdot b\right) \cdot \left(a + 3\right)\right)\right) + -1} \]
    4. Taylor expanded in b around inf 95.6%

      \[\leadsto \color{blue}{{b}^{4}} + -1 \]
  3. Recombined 2 regimes into one program.
  4. Final simplification96.4%

    \[\leadsto \begin{array}{l} \mathbf{if}\;a \leq -2.1 \cdot 10^{+20} \lor \neg \left(a \leq 5.6 \cdot 10^{+67}\right):\\ \;\;\;\;-1 + {a}^{4}\\ \mathbf{else}:\\ \;\;\;\;-1 + {b}^{4}\\ \end{array} \]

Alternative 4: 68.4% accurate, 1.2× speedup?

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

\\
-1 + {a}^{4}
\end{array}
Derivation
  1. Initial program 72.5%

    \[\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(b \cdot b\right) \cdot \left(3 + a\right)\right)\right) - 1 \]
  2. Step-by-step derivation
    1. sub-neg72.5%

      \[\leadsto \color{blue}{\left({\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(b \cdot b\right) \cdot \left(3 + a\right)\right)\right) + \left(-1\right)} \]
    2. sqr-neg72.5%

      \[\leadsto \left({\left(a \cdot a + \color{blue}{\left(-b\right) \cdot \left(-b\right)}\right)}^{2} + 4 \cdot \left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(b \cdot b\right) \cdot \left(3 + a\right)\right)\right) + \left(-1\right) \]
    3. +-commutative72.5%

      \[\leadsto \left({\left(a \cdot a + \left(-b\right) \cdot \left(-b\right)\right)}^{2} + 4 \cdot \color{blue}{\left(\left(b \cdot b\right) \cdot \left(3 + a\right) + \left(a \cdot a\right) \cdot \left(1 - a\right)\right)}\right) + \left(-1\right) \]
    4. sqr-neg72.5%

      \[\leadsto \left({\left(a \cdot a + \left(-b\right) \cdot \left(-b\right)\right)}^{2} + 4 \cdot \left(\color{blue}{\left(\left(-b\right) \cdot \left(-b\right)\right)} \cdot \left(3 + a\right) + \left(a \cdot a\right) \cdot \left(1 - a\right)\right)\right) + \left(-1\right) \]
    5. +-commutative72.5%

      \[\leadsto \left({\left(a \cdot a + \left(-b\right) \cdot \left(-b\right)\right)}^{2} + 4 \cdot \color{blue}{\left(\left(a \cdot a\right) \cdot \left(1 - a\right) + \left(\left(-b\right) \cdot \left(-b\right)\right) \cdot \left(3 + a\right)\right)}\right) + \left(-1\right) \]
  3. Simplified73.7%

    \[\leadsto \color{blue}{\left({\left(\mathsf{fma}\left(a, a, b \cdot b\right)\right)}^{2} + 4 \cdot \mathsf{fma}\left(a \cdot a, 1 - a, \left(b \cdot b\right) \cdot \left(a + 3\right)\right)\right) + -1} \]
  4. Taylor expanded in a around inf 64.2%

    \[\leadsto \color{blue}{{a}^{4}} + -1 \]
  5. Final simplification64.2%

    \[\leadsto -1 + {a}^{4} \]

Reproduce

?
herbie shell --seed 2023312 
(FPCore (a b)
  :name "Bouland and Aaronson, Equation (24)"
  :precision binary64
  (- (+ (pow (+ (* a a) (* b b)) 2.0) (* 4.0 (+ (* (* a a) (- 1.0 a)) (* (* b b) (+ 3.0 a))))) 1.0))