Bouland and Aaronson, Equation (26)

Percentage Accurate: 99.9% → 100.0%
Time: 5.9s
Alternatives: 6
Speedup: 1.0×

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 6 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, 0.4× speedup?

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

\\
{\left(\mathsf{hypot}\left(a, b\right)\right)}^{4} + \mathsf{fma}\left(b, b \cdot 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. Step-by-step derivation
    1. associate--l+99.9%

      \[\leadsto \color{blue}{{\left(a \cdot a + b \cdot b\right)}^{2} + \left(4 \cdot \left(b \cdot b\right) - 1\right)} \]
    2. +-commutative99.9%

      \[\leadsto {\color{blue}{\left(b \cdot b + a \cdot a\right)}}^{2} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
    3. unpow299.9%

      \[\leadsto \color{blue}{\left(b \cdot b + a \cdot a\right) \cdot \left(b \cdot b + a \cdot a\right)} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
    4. unpow199.9%

      \[\leadsto \left(b \cdot b + a \cdot a\right) \cdot \color{blue}{{\left(b \cdot b + a \cdot a\right)}^{1}} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
    5. sqr-pow99.9%

      \[\leadsto \left(b \cdot b + a \cdot a\right) \cdot \color{blue}{\left({\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)} \cdot {\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)}\right)} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
    6. associate-*r*100.0%

      \[\leadsto \color{blue}{\left(\left(b \cdot b + a \cdot a\right) \cdot {\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)}\right) \cdot {\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)}} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
    7. *-commutative100.0%

      \[\leadsto \color{blue}{\left({\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)} \cdot \left(b \cdot b + a \cdot a\right)\right)} \cdot {\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
  3. Simplified100.0%

    \[\leadsto \color{blue}{{\left(\mathsf{hypot}\left(a, b\right)\right)}^{4} + \mathsf{fma}\left(b, b \cdot 4, -1\right)} \]
  4. Final simplification100.0%

    \[\leadsto {\left(\mathsf{hypot}\left(a, b\right)\right)}^{4} + \mathsf{fma}\left(b, b \cdot 4, -1\right) \]

Alternative 2: 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}
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. Final simplification99.9%

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

Alternative 3: 60.0% accurate, 1.1× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \leq 1.9:\\ \;\;\;\;\mathsf{fma}\left(b, b \cdot 4, -1\right)\\ \mathbf{else}:\\ \;\;\;\;{b}^{4}\\ \end{array} \end{array} \]
(FPCore (a b)
 :precision binary64
 (if (<= b 1.9) (fma b (* b 4.0) -1.0) (pow b 4.0)))
double code(double a, double b) {
	double tmp;
	if (b <= 1.9) {
		tmp = fma(b, (b * 4.0), -1.0);
	} else {
		tmp = pow(b, 4.0);
	}
	return tmp;
}
function code(a, b)
	tmp = 0.0
	if (b <= 1.9)
		tmp = fma(b, Float64(b * 4.0), -1.0);
	else
		tmp = b ^ 4.0;
	end
	return tmp
end
code[a_, b_] := If[LessEqual[b, 1.9], N[(b * N[(b * 4.0), $MachinePrecision] + -1.0), $MachinePrecision], N[Power[b, 4.0], $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;b \leq 1.9:\\
\;\;\;\;\mathsf{fma}\left(b, b \cdot 4, -1\right)\\

\mathbf{else}:\\
\;\;\;\;{b}^{4}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if b < 1.8999999999999999

    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. Step-by-step derivation
      1. associate--l+99.9%

        \[\leadsto \color{blue}{{\left(a \cdot a + b \cdot b\right)}^{2} + \left(4 \cdot \left(b \cdot b\right) - 1\right)} \]
      2. +-commutative99.9%

        \[\leadsto {\color{blue}{\left(b \cdot b + a \cdot a\right)}}^{2} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
      3. unpow299.9%

        \[\leadsto \color{blue}{\left(b \cdot b + a \cdot a\right) \cdot \left(b \cdot b + a \cdot a\right)} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
      4. unpow199.9%

        \[\leadsto \left(b \cdot b + a \cdot a\right) \cdot \color{blue}{{\left(b \cdot b + a \cdot a\right)}^{1}} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
      5. sqr-pow99.9%

        \[\leadsto \left(b \cdot b + a \cdot a\right) \cdot \color{blue}{\left({\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)} \cdot {\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)}\right)} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
      6. associate-*r*99.9%

        \[\leadsto \color{blue}{\left(\left(b \cdot b + a \cdot a\right) \cdot {\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)}\right) \cdot {\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)}} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
      7. *-commutative99.9%

        \[\leadsto \color{blue}{\left({\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)} \cdot \left(b \cdot b + a \cdot a\right)\right)} \cdot {\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
    3. Simplified100.0%

      \[\leadsto \color{blue}{{\left(\mathsf{hypot}\left(a, b\right)\right)}^{4} + \mathsf{fma}\left(b, b \cdot 4, -1\right)} \]
    4. Taylor expanded in a around 0 68.6%

      \[\leadsto \color{blue}{{b}^{4}} + \mathsf{fma}\left(b, b \cdot 4, -1\right) \]
    5. Taylor expanded in b around 0 56.0%

      \[\leadsto \color{blue}{4 \cdot {b}^{2} - 1} \]
    6. Step-by-step derivation
      1. sub-neg56.0%

        \[\leadsto \color{blue}{4 \cdot {b}^{2} + \left(-1\right)} \]
      2. metadata-eval56.0%

        \[\leadsto 4 \cdot {b}^{2} + \color{blue}{-1} \]
      3. *-commutative56.0%

        \[\leadsto \color{blue}{{b}^{2} \cdot 4} + -1 \]
      4. unpow256.0%

        \[\leadsto \color{blue}{\left(b \cdot b\right)} \cdot 4 + -1 \]
      5. associate-*r*56.0%

        \[\leadsto \color{blue}{b \cdot \left(b \cdot 4\right)} + -1 \]
      6. fma-udef56.0%

        \[\leadsto \color{blue}{\mathsf{fma}\left(b, b \cdot 4, -1\right)} \]
      7. *-commutative56.0%

        \[\leadsto \mathsf{fma}\left(b, \color{blue}{4 \cdot b}, -1\right) \]
    7. Applied egg-rr56.0%

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

    if 1.8999999999999999 < b

    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. Step-by-step derivation
      1. associate--l+99.9%

        \[\leadsto \color{blue}{{\left(a \cdot a + b \cdot b\right)}^{2} + \left(4 \cdot \left(b \cdot b\right) - 1\right)} \]
      2. +-commutative99.9%

        \[\leadsto {\color{blue}{\left(b \cdot b + a \cdot a\right)}}^{2} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
      3. unpow299.9%

        \[\leadsto \color{blue}{\left(b \cdot b + a \cdot a\right) \cdot \left(b \cdot b + a \cdot a\right)} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
      4. unpow199.9%

        \[\leadsto \left(b \cdot b + a \cdot a\right) \cdot \color{blue}{{\left(b \cdot b + a \cdot a\right)}^{1}} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
      5. sqr-pow99.9%

        \[\leadsto \left(b \cdot b + a \cdot a\right) \cdot \color{blue}{\left({\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)} \cdot {\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)}\right)} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
      6. associate-*r*100.0%

        \[\leadsto \color{blue}{\left(\left(b \cdot b + a \cdot a\right) \cdot {\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)}\right) \cdot {\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)}} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
      7. *-commutative100.0%

        \[\leadsto \color{blue}{\left({\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)} \cdot \left(b \cdot b + a \cdot a\right)\right)} \cdot {\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
    3. Simplified100.0%

      \[\leadsto \color{blue}{{\left(\mathsf{hypot}\left(a, b\right)\right)}^{4} + \mathsf{fma}\left(b, b \cdot 4, -1\right)} \]
    4. Taylor expanded in a around 0 89.6%

      \[\leadsto \color{blue}{{b}^{4}} + \mathsf{fma}\left(b, b \cdot 4, -1\right) \]
    5. Taylor expanded in b around inf 89.6%

      \[\leadsto \color{blue}{4 \cdot {b}^{2} + {b}^{4}} \]
    6. Taylor expanded in b around inf 89.4%

      \[\leadsto \color{blue}{{b}^{4}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification64.4%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b \leq 1.9:\\ \;\;\;\;\mathsf{fma}\left(b, b \cdot 4, -1\right)\\ \mathbf{else}:\\ \;\;\;\;{b}^{4}\\ \end{array} \]

Alternative 4: 60.0% accurate, 1.1× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;b \leq 1.9:\\ \;\;\;\;\left(1 + b \cdot 2\right) \cdot \left(b \cdot 2 + -1\right)\\ \mathbf{else}:\\ \;\;\;\;{b}^{4}\\ \end{array} \end{array} \]
(FPCore (a b)
 :precision binary64
 (if (<= b 1.9) (* (+ 1.0 (* b 2.0)) (+ (* b 2.0) -1.0)) (pow b 4.0)))
double code(double a, double b) {
	double tmp;
	if (b <= 1.9) {
		tmp = (1.0 + (b * 2.0)) * ((b * 2.0) + -1.0);
	} else {
		tmp = 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 <= 1.9d0) then
        tmp = (1.0d0 + (b * 2.0d0)) * ((b * 2.0d0) + (-1.0d0))
    else
        tmp = b ** 4.0d0
    end if
    code = tmp
end function
public static double code(double a, double b) {
	double tmp;
	if (b <= 1.9) {
		tmp = (1.0 + (b * 2.0)) * ((b * 2.0) + -1.0);
	} else {
		tmp = Math.pow(b, 4.0);
	}
	return tmp;
}
def code(a, b):
	tmp = 0
	if b <= 1.9:
		tmp = (1.0 + (b * 2.0)) * ((b * 2.0) + -1.0)
	else:
		tmp = math.pow(b, 4.0)
	return tmp
function code(a, b)
	tmp = 0.0
	if (b <= 1.9)
		tmp = Float64(Float64(1.0 + Float64(b * 2.0)) * Float64(Float64(b * 2.0) + -1.0));
	else
		tmp = b ^ 4.0;
	end
	return tmp
end
function tmp_2 = code(a, b)
	tmp = 0.0;
	if (b <= 1.9)
		tmp = (1.0 + (b * 2.0)) * ((b * 2.0) + -1.0);
	else
		tmp = b ^ 4.0;
	end
	tmp_2 = tmp;
end
code[a_, b_] := If[LessEqual[b, 1.9], N[(N[(1.0 + N[(b * 2.0), $MachinePrecision]), $MachinePrecision] * N[(N[(b * 2.0), $MachinePrecision] + -1.0), $MachinePrecision]), $MachinePrecision], N[Power[b, 4.0], $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;b \leq 1.9:\\
\;\;\;\;\left(1 + b \cdot 2\right) \cdot \left(b \cdot 2 + -1\right)\\

\mathbf{else}:\\
\;\;\;\;{b}^{4}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if b < 1.8999999999999999

    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. Step-by-step derivation
      1. associate--l+99.9%

        \[\leadsto \color{blue}{{\left(a \cdot a + b \cdot b\right)}^{2} + \left(4 \cdot \left(b \cdot b\right) - 1\right)} \]
      2. +-commutative99.9%

        \[\leadsto {\color{blue}{\left(b \cdot b + a \cdot a\right)}}^{2} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
      3. unpow299.9%

        \[\leadsto \color{blue}{\left(b \cdot b + a \cdot a\right) \cdot \left(b \cdot b + a \cdot a\right)} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
      4. unpow199.9%

        \[\leadsto \left(b \cdot b + a \cdot a\right) \cdot \color{blue}{{\left(b \cdot b + a \cdot a\right)}^{1}} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
      5. sqr-pow99.9%

        \[\leadsto \left(b \cdot b + a \cdot a\right) \cdot \color{blue}{\left({\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)} \cdot {\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)}\right)} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
      6. associate-*r*99.9%

        \[\leadsto \color{blue}{\left(\left(b \cdot b + a \cdot a\right) \cdot {\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)}\right) \cdot {\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)}} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
      7. *-commutative99.9%

        \[\leadsto \color{blue}{\left({\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)} \cdot \left(b \cdot b + a \cdot a\right)\right)} \cdot {\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
    3. Simplified100.0%

      \[\leadsto \color{blue}{{\left(\mathsf{hypot}\left(a, b\right)\right)}^{4} + \mathsf{fma}\left(b, b \cdot 4, -1\right)} \]
    4. Taylor expanded in a around 0 68.6%

      \[\leadsto \color{blue}{{b}^{4}} + \mathsf{fma}\left(b, b \cdot 4, -1\right) \]
    5. Taylor expanded in b around 0 56.0%

      \[\leadsto \color{blue}{4 \cdot {b}^{2} - 1} \]
    6. Step-by-step derivation
      1. add-sqr-sqrt56.0%

        \[\leadsto \color{blue}{\sqrt{4 \cdot {b}^{2}} \cdot \sqrt{4 \cdot {b}^{2}}} - 1 \]
      2. difference-of-sqr-156.0%

        \[\leadsto \color{blue}{\left(\sqrt{4 \cdot {b}^{2}} + 1\right) \cdot \left(\sqrt{4 \cdot {b}^{2}} - 1\right)} \]
      3. +-commutative56.0%

        \[\leadsto \color{blue}{\left(1 + \sqrt{4 \cdot {b}^{2}}\right)} \cdot \left(\sqrt{4 \cdot {b}^{2}} - 1\right) \]
      4. *-commutative56.0%

        \[\leadsto \left(1 + \sqrt{\color{blue}{{b}^{2} \cdot 4}}\right) \cdot \left(\sqrt{4 \cdot {b}^{2}} - 1\right) \]
      5. sqrt-prod56.0%

        \[\leadsto \left(1 + \color{blue}{\sqrt{{b}^{2}} \cdot \sqrt{4}}\right) \cdot \left(\sqrt{4 \cdot {b}^{2}} - 1\right) \]
      6. unpow256.0%

        \[\leadsto \left(1 + \sqrt{\color{blue}{b \cdot b}} \cdot \sqrt{4}\right) \cdot \left(\sqrt{4 \cdot {b}^{2}} - 1\right) \]
      7. sqrt-prod14.2%

        \[\leadsto \left(1 + \color{blue}{\left(\sqrt{b} \cdot \sqrt{b}\right)} \cdot \sqrt{4}\right) \cdot \left(\sqrt{4 \cdot {b}^{2}} - 1\right) \]
      8. add-sqr-sqrt32.9%

        \[\leadsto \left(1 + \color{blue}{b} \cdot \sqrt{4}\right) \cdot \left(\sqrt{4 \cdot {b}^{2}} - 1\right) \]
      9. metadata-eval32.9%

        \[\leadsto \left(1 + b \cdot \color{blue}{2}\right) \cdot \left(\sqrt{4 \cdot {b}^{2}} - 1\right) \]
      10. *-commutative32.9%

        \[\leadsto \left(1 + b \cdot 2\right) \cdot \left(\sqrt{\color{blue}{{b}^{2} \cdot 4}} - 1\right) \]
      11. sqrt-prod32.9%

        \[\leadsto \left(1 + b \cdot 2\right) \cdot \left(\color{blue}{\sqrt{{b}^{2}} \cdot \sqrt{4}} - 1\right) \]
      12. unpow232.9%

        \[\leadsto \left(1 + b \cdot 2\right) \cdot \left(\sqrt{\color{blue}{b \cdot b}} \cdot \sqrt{4} - 1\right) \]
      13. sqrt-prod14.2%

        \[\leadsto \left(1 + b \cdot 2\right) \cdot \left(\color{blue}{\left(\sqrt{b} \cdot \sqrt{b}\right)} \cdot \sqrt{4} - 1\right) \]
      14. add-sqr-sqrt56.0%

        \[\leadsto \left(1 + b \cdot 2\right) \cdot \left(\color{blue}{b} \cdot \sqrt{4} - 1\right) \]
      15. metadata-eval56.0%

        \[\leadsto \left(1 + b \cdot 2\right) \cdot \left(b \cdot \color{blue}{2} - 1\right) \]
    7. Applied egg-rr56.0%

      \[\leadsto \color{blue}{\left(1 + b \cdot 2\right) \cdot \left(b \cdot 2 - 1\right)} \]

    if 1.8999999999999999 < b

    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. Step-by-step derivation
      1. associate--l+99.9%

        \[\leadsto \color{blue}{{\left(a \cdot a + b \cdot b\right)}^{2} + \left(4 \cdot \left(b \cdot b\right) - 1\right)} \]
      2. +-commutative99.9%

        \[\leadsto {\color{blue}{\left(b \cdot b + a \cdot a\right)}}^{2} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
      3. unpow299.9%

        \[\leadsto \color{blue}{\left(b \cdot b + a \cdot a\right) \cdot \left(b \cdot b + a \cdot a\right)} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
      4. unpow199.9%

        \[\leadsto \left(b \cdot b + a \cdot a\right) \cdot \color{blue}{{\left(b \cdot b + a \cdot a\right)}^{1}} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
      5. sqr-pow99.9%

        \[\leadsto \left(b \cdot b + a \cdot a\right) \cdot \color{blue}{\left({\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)} \cdot {\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)}\right)} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
      6. associate-*r*100.0%

        \[\leadsto \color{blue}{\left(\left(b \cdot b + a \cdot a\right) \cdot {\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)}\right) \cdot {\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)}} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
      7. *-commutative100.0%

        \[\leadsto \color{blue}{\left({\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)} \cdot \left(b \cdot b + a \cdot a\right)\right)} \cdot {\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
    3. Simplified100.0%

      \[\leadsto \color{blue}{{\left(\mathsf{hypot}\left(a, b\right)\right)}^{4} + \mathsf{fma}\left(b, b \cdot 4, -1\right)} \]
    4. Taylor expanded in a around 0 89.6%

      \[\leadsto \color{blue}{{b}^{4}} + \mathsf{fma}\left(b, b \cdot 4, -1\right) \]
    5. Taylor expanded in b around inf 89.6%

      \[\leadsto \color{blue}{4 \cdot {b}^{2} + {b}^{4}} \]
    6. Taylor expanded in b around inf 89.4%

      \[\leadsto \color{blue}{{b}^{4}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification64.4%

    \[\leadsto \begin{array}{l} \mathbf{if}\;b \leq 1.9:\\ \;\;\;\;\left(1 + b \cdot 2\right) \cdot \left(b \cdot 2 + -1\right)\\ \mathbf{else}:\\ \;\;\;\;{b}^{4}\\ \end{array} \]

Alternative 5: 50.6% accurate, 10.5× speedup?

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

\\
\left(1 + b \cdot 2\right) \cdot \left(b \cdot 2 + -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. Step-by-step derivation
    1. associate--l+99.9%

      \[\leadsto \color{blue}{{\left(a \cdot a + b \cdot b\right)}^{2} + \left(4 \cdot \left(b \cdot b\right) - 1\right)} \]
    2. +-commutative99.9%

      \[\leadsto {\color{blue}{\left(b \cdot b + a \cdot a\right)}}^{2} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
    3. unpow299.9%

      \[\leadsto \color{blue}{\left(b \cdot b + a \cdot a\right) \cdot \left(b \cdot b + a \cdot a\right)} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
    4. unpow199.9%

      \[\leadsto \left(b \cdot b + a \cdot a\right) \cdot \color{blue}{{\left(b \cdot b + a \cdot a\right)}^{1}} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
    5. sqr-pow99.9%

      \[\leadsto \left(b \cdot b + a \cdot a\right) \cdot \color{blue}{\left({\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)} \cdot {\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)}\right)} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
    6. associate-*r*100.0%

      \[\leadsto \color{blue}{\left(\left(b \cdot b + a \cdot a\right) \cdot {\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)}\right) \cdot {\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)}} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
    7. *-commutative100.0%

      \[\leadsto \color{blue}{\left({\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)} \cdot \left(b \cdot b + a \cdot a\right)\right)} \cdot {\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
  3. Simplified100.0%

    \[\leadsto \color{blue}{{\left(\mathsf{hypot}\left(a, b\right)\right)}^{4} + \mathsf{fma}\left(b, b \cdot 4, -1\right)} \]
  4. Taylor expanded in a around 0 73.9%

    \[\leadsto \color{blue}{{b}^{4}} + \mathsf{fma}\left(b, b \cdot 4, -1\right) \]
  5. Taylor expanded in b around 0 56.0%

    \[\leadsto \color{blue}{4 \cdot {b}^{2} - 1} \]
  6. Step-by-step derivation
    1. add-sqr-sqrt56.0%

      \[\leadsto \color{blue}{\sqrt{4 \cdot {b}^{2}} \cdot \sqrt{4 \cdot {b}^{2}}} - 1 \]
    2. difference-of-sqr-156.0%

      \[\leadsto \color{blue}{\left(\sqrt{4 \cdot {b}^{2}} + 1\right) \cdot \left(\sqrt{4 \cdot {b}^{2}} - 1\right)} \]
    3. +-commutative56.0%

      \[\leadsto \color{blue}{\left(1 + \sqrt{4 \cdot {b}^{2}}\right)} \cdot \left(\sqrt{4 \cdot {b}^{2}} - 1\right) \]
    4. *-commutative56.0%

      \[\leadsto \left(1 + \sqrt{\color{blue}{{b}^{2} \cdot 4}}\right) \cdot \left(\sqrt{4 \cdot {b}^{2}} - 1\right) \]
    5. sqrt-prod56.0%

      \[\leadsto \left(1 + \color{blue}{\sqrt{{b}^{2}} \cdot \sqrt{4}}\right) \cdot \left(\sqrt{4 \cdot {b}^{2}} - 1\right) \]
    6. unpow256.0%

      \[\leadsto \left(1 + \sqrt{\color{blue}{b \cdot b}} \cdot \sqrt{4}\right) \cdot \left(\sqrt{4 \cdot {b}^{2}} - 1\right) \]
    7. sqrt-prod24.6%

      \[\leadsto \left(1 + \color{blue}{\left(\sqrt{b} \cdot \sqrt{b}\right)} \cdot \sqrt{4}\right) \cdot \left(\sqrt{4 \cdot {b}^{2}} - 1\right) \]
    8. add-sqr-sqrt38.6%

      \[\leadsto \left(1 + \color{blue}{b} \cdot \sqrt{4}\right) \cdot \left(\sqrt{4 \cdot {b}^{2}} - 1\right) \]
    9. metadata-eval38.6%

      \[\leadsto \left(1 + b \cdot \color{blue}{2}\right) \cdot \left(\sqrt{4 \cdot {b}^{2}} - 1\right) \]
    10. *-commutative38.6%

      \[\leadsto \left(1 + b \cdot 2\right) \cdot \left(\sqrt{\color{blue}{{b}^{2} \cdot 4}} - 1\right) \]
    11. sqrt-prod38.6%

      \[\leadsto \left(1 + b \cdot 2\right) \cdot \left(\color{blue}{\sqrt{{b}^{2}} \cdot \sqrt{4}} - 1\right) \]
    12. unpow238.6%

      \[\leadsto \left(1 + b \cdot 2\right) \cdot \left(\sqrt{\color{blue}{b \cdot b}} \cdot \sqrt{4} - 1\right) \]
    13. sqrt-prod24.6%

      \[\leadsto \left(1 + b \cdot 2\right) \cdot \left(\color{blue}{\left(\sqrt{b} \cdot \sqrt{b}\right)} \cdot \sqrt{4} - 1\right) \]
    14. add-sqr-sqrt56.0%

      \[\leadsto \left(1 + b \cdot 2\right) \cdot \left(\color{blue}{b} \cdot \sqrt{4} - 1\right) \]
    15. metadata-eval56.0%

      \[\leadsto \left(1 + b \cdot 2\right) \cdot \left(b \cdot \color{blue}{2} - 1\right) \]
  7. Applied egg-rr56.0%

    \[\leadsto \color{blue}{\left(1 + b \cdot 2\right) \cdot \left(b \cdot 2 - 1\right)} \]
  8. Final simplification56.0%

    \[\leadsto \left(1 + b \cdot 2\right) \cdot \left(b \cdot 2 + -1\right) \]

Alternative 6: 24.9% accurate, 116.0× 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. Step-by-step derivation
    1. associate--l+99.9%

      \[\leadsto \color{blue}{{\left(a \cdot a + b \cdot b\right)}^{2} + \left(4 \cdot \left(b \cdot b\right) - 1\right)} \]
    2. +-commutative99.9%

      \[\leadsto {\color{blue}{\left(b \cdot b + a \cdot a\right)}}^{2} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
    3. unpow299.9%

      \[\leadsto \color{blue}{\left(b \cdot b + a \cdot a\right) \cdot \left(b \cdot b + a \cdot a\right)} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
    4. unpow199.9%

      \[\leadsto \left(b \cdot b + a \cdot a\right) \cdot \color{blue}{{\left(b \cdot b + a \cdot a\right)}^{1}} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
    5. sqr-pow99.9%

      \[\leadsto \left(b \cdot b + a \cdot a\right) \cdot \color{blue}{\left({\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)} \cdot {\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)}\right)} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
    6. associate-*r*100.0%

      \[\leadsto \color{blue}{\left(\left(b \cdot b + a \cdot a\right) \cdot {\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)}\right) \cdot {\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)}} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
    7. *-commutative100.0%

      \[\leadsto \color{blue}{\left({\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)} \cdot \left(b \cdot b + a \cdot a\right)\right)} \cdot {\left(b \cdot b + a \cdot a\right)}^{\left(\frac{1}{2}\right)} + \left(4 \cdot \left(b \cdot b\right) - 1\right) \]
  3. Simplified100.0%

    \[\leadsto \color{blue}{{\left(\mathsf{hypot}\left(a, b\right)\right)}^{4} + \mathsf{fma}\left(b, b \cdot 4, -1\right)} \]
  4. Taylor expanded in a around 0 73.9%

    \[\leadsto \color{blue}{{b}^{4}} + \mathsf{fma}\left(b, b \cdot 4, -1\right) \]
  5. Taylor expanded in b around 0 25.0%

    \[\leadsto \color{blue}{-1} \]
  6. Final simplification25.0%

    \[\leadsto -1 \]

Reproduce

?
herbie shell --seed 2023301 
(FPCore (a b)
  :name "Bouland and Aaronson, Equation (26)"
  :precision binary64
  (- (+ (pow (+ (* a a) (* b b)) 2.0) (* 4.0 (* b b))) 1.0))