Bouland and Aaronson, Equation (24)

Percentage Accurate: 72.7% → 98.4%
Time: 7.0s
Alternatives: 9
Speedup: 8.5×

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 9 alternatives:

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

Initial Program: 72.7% 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: 98.4% accurate, 0.2× speedup?

\[\begin{array}{l} b = |b|\\ \\ \begin{array}{l} t_0 := \left(b \cdot b\right) \cdot \left(a + 3\right)\\ \mathbf{if}\;{\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(\left(a \cdot a\right) \cdot \left(1 - a\right) + t_0\right) \leq \infty:\\ \;\;\;\;\mathsf{fma}\left(4, \mathsf{fma}\left(a, a - a \cdot a, t_0\right), {\left(\mathsf{hypot}\left(a, b\right)\right)}^{4} + -1\right)\\ \mathbf{else}:\\ \;\;\;\;-1 + \left(a \cdot \left(a \cdot a\right)\right) \cdot \left(a + -4\right)\\ \end{array} \end{array} \]
NOTE: b should be positive before calling this function
(FPCore (a b)
 :precision binary64
 (let* ((t_0 (* (* b b) (+ a 3.0))))
   (if (<=
        (+ (pow (+ (* a a) (* b b)) 2.0) (* 4.0 (+ (* (* a a) (- 1.0 a)) t_0)))
        INFINITY)
     (fma 4.0 (fma a (- a (* a a)) t_0) (+ (pow (hypot a b) 4.0) -1.0))
     (+ -1.0 (* (* a (* a a)) (+ a -4.0))))))
b = abs(b);
double code(double a, double b) {
	double t_0 = (b * b) * (a + 3.0);
	double tmp;
	if ((pow(((a * a) + (b * b)), 2.0) + (4.0 * (((a * a) * (1.0 - a)) + t_0))) <= ((double) INFINITY)) {
		tmp = fma(4.0, fma(a, (a - (a * a)), t_0), (pow(hypot(a, b), 4.0) + -1.0));
	} else {
		tmp = -1.0 + ((a * (a * a)) * (a + -4.0));
	}
	return tmp;
}
b = abs(b)
function code(a, b)
	t_0 = Float64(Float64(b * b) * Float64(a + 3.0))
	tmp = 0.0
	if (Float64((Float64(Float64(a * a) + Float64(b * b)) ^ 2.0) + Float64(4.0 * Float64(Float64(Float64(a * a) * Float64(1.0 - a)) + t_0))) <= Inf)
		tmp = fma(4.0, fma(a, Float64(a - Float64(a * a)), t_0), Float64((hypot(a, b) ^ 4.0) + -1.0));
	else
		tmp = Float64(-1.0 + Float64(Float64(a * Float64(a * a)) * Float64(a + -4.0)));
	end
	return tmp
end
NOTE: b should be positive before calling this function
code[a_, b_] := Block[{t$95$0 = N[(N[(b * b), $MachinePrecision] * N[(a + 3.0), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[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] + t$95$0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], Infinity], N[(4.0 * N[(a * N[(a - N[(a * a), $MachinePrecision]), $MachinePrecision] + t$95$0), $MachinePrecision] + N[(N[Power[N[Sqrt[a ^ 2 + b ^ 2], $MachinePrecision], 4.0], $MachinePrecision] + -1.0), $MachinePrecision]), $MachinePrecision], N[(-1.0 + N[(N[(a * N[(a * a), $MachinePrecision]), $MachinePrecision] * N[(a + -4.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
b = |b|\\
\\
\begin{array}{l}
t_0 := \left(b \cdot b\right) \cdot \left(a + 3\right)\\
\mathbf{if}\;{\left(a \cdot a + b \cdot b\right)}^{2} + 4 \cdot \left(\left(a \cdot a\right) \cdot \left(1 - a\right) + t_0\right) \leq \infty:\\
\;\;\;\;\mathsf{fma}\left(4, \mathsf{fma}\left(a, a - a \cdot a, t_0\right), {\left(\mathsf{hypot}\left(a, b\right)\right)}^{4} + -1\right)\\

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


\end{array}
\end{array}
Derivation
  1. Initial program 97.8%

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

Alternative 2: 98.3% accurate, 0.5× speedup?

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

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


\end{array}
\end{array}
Derivation
  1. Initial program 97.6%

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

Alternative 3: 93.7% accurate, 1.1× speedup?

\[\begin{array}{l} b = |b|\\ \\ \begin{array}{l} \mathbf{if}\;b \cdot b \leq 0.0002:\\ \;\;\;\;-1 + \left(a + -4\right) \cdot {a}^{3}\\ \mathbf{else}:\\ \;\;\;\;-1 + \left({b}^{4} + b \cdot \left(b \cdot 12\right)\right)\\ \end{array} \end{array} \]
NOTE: b should be positive before calling this function
(FPCore (a b)
 :precision binary64
 (if (<= (* b b) 0.0002)
   (+ -1.0 (* (+ a -4.0) (pow a 3.0)))
   (+ -1.0 (+ (pow b 4.0) (* b (* b 12.0))))))
b = abs(b);
double code(double a, double b) {
	double tmp;
	if ((b * b) <= 0.0002) {
		tmp = -1.0 + ((a + -4.0) * pow(a, 3.0));
	} else {
		tmp = -1.0 + (pow(b, 4.0) + (b * (b * 12.0)));
	}
	return tmp;
}
NOTE: b should be positive before calling this function
real(8) function code(a, b)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8) :: tmp
    if ((b * b) <= 0.0002d0) then
        tmp = (-1.0d0) + ((a + (-4.0d0)) * (a ** 3.0d0))
    else
        tmp = (-1.0d0) + ((b ** 4.0d0) + (b * (b * 12.0d0)))
    end if
    code = tmp
end function
b = Math.abs(b);
public static double code(double a, double b) {
	double tmp;
	if ((b * b) <= 0.0002) {
		tmp = -1.0 + ((a + -4.0) * Math.pow(a, 3.0));
	} else {
		tmp = -1.0 + (Math.pow(b, 4.0) + (b * (b * 12.0)));
	}
	return tmp;
}
b = abs(b)
def code(a, b):
	tmp = 0
	if (b * b) <= 0.0002:
		tmp = -1.0 + ((a + -4.0) * math.pow(a, 3.0))
	else:
		tmp = -1.0 + (math.pow(b, 4.0) + (b * (b * 12.0)))
	return tmp
b = abs(b)
function code(a, b)
	tmp = 0.0
	if (Float64(b * b) <= 0.0002)
		tmp = Float64(-1.0 + Float64(Float64(a + -4.0) * (a ^ 3.0)));
	else
		tmp = Float64(-1.0 + Float64((b ^ 4.0) + Float64(b * Float64(b * 12.0))));
	end
	return tmp
end
b = abs(b)
function tmp_2 = code(a, b)
	tmp = 0.0;
	if ((b * b) <= 0.0002)
		tmp = -1.0 + ((a + -4.0) * (a ^ 3.0));
	else
		tmp = -1.0 + ((b ^ 4.0) + (b * (b * 12.0)));
	end
	tmp_2 = tmp;
end
NOTE: b should be positive before calling this function
code[a_, b_] := If[LessEqual[N[(b * b), $MachinePrecision], 0.0002], N[(-1.0 + N[(N[(a + -4.0), $MachinePrecision] * N[Power[a, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(-1.0 + N[(N[Power[b, 4.0], $MachinePrecision] + N[(b * N[(b * 12.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
b = |b|\\
\\
\begin{array}{l}
\mathbf{if}\;b \cdot b \leq 0.0002:\\
\;\;\;\;-1 + \left(a + -4\right) \cdot {a}^{3}\\

\mathbf{else}:\\
\;\;\;\;-1 + \left({b}^{4} + b \cdot \left(b \cdot 12\right)\right)\\


\end{array}
\end{array}
Derivation
  1. Initial program 95.5%

    \[\begin{array}{l} \mathbf{if}\;b \cdot b \leq 0.0002:\\ \;\;\;\;-1 + \left(a + -4\right) \cdot {a}^{3}\\ \mathbf{else}:\\ \;\;\;\;-1 + \left({b}^{4} + b \cdot \left(b \cdot 12\right)\right)\\ \end{array} \]

Alternative 4: 93.3% accurate, 1.1× speedup?

\[\begin{array}{l} b = |b|\\ \\ \begin{array}{l} \mathbf{if}\;b \cdot b \leq 0.0002:\\ \;\;\;\;-1 + \left(a + -4\right) \cdot {a}^{3}\\ \mathbf{else}:\\ \;\;\;\;-1 + {b}^{4}\\ \end{array} \end{array} \]
NOTE: b should be positive before calling this function
(FPCore (a b)
 :precision binary64
 (if (<= (* b b) 0.0002)
   (+ -1.0 (* (+ a -4.0) (pow a 3.0)))
   (+ -1.0 (pow b 4.0))))
b = abs(b);
double code(double a, double b) {
	double tmp;
	if ((b * b) <= 0.0002) {
		tmp = -1.0 + ((a + -4.0) * pow(a, 3.0));
	} else {
		tmp = -1.0 + pow(b, 4.0);
	}
	return tmp;
}
NOTE: b should be positive before calling this function
real(8) function code(a, b)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8) :: tmp
    if ((b * b) <= 0.0002d0) then
        tmp = (-1.0d0) + ((a + (-4.0d0)) * (a ** 3.0d0))
    else
        tmp = (-1.0d0) + (b ** 4.0d0)
    end if
    code = tmp
end function
b = Math.abs(b);
public static double code(double a, double b) {
	double tmp;
	if ((b * b) <= 0.0002) {
		tmp = -1.0 + ((a + -4.0) * Math.pow(a, 3.0));
	} else {
		tmp = -1.0 + Math.pow(b, 4.0);
	}
	return tmp;
}
b = abs(b)
def code(a, b):
	tmp = 0
	if (b * b) <= 0.0002:
		tmp = -1.0 + ((a + -4.0) * math.pow(a, 3.0))
	else:
		tmp = -1.0 + math.pow(b, 4.0)
	return tmp
b = abs(b)
function code(a, b)
	tmp = 0.0
	if (Float64(b * b) <= 0.0002)
		tmp = Float64(-1.0 + Float64(Float64(a + -4.0) * (a ^ 3.0)));
	else
		tmp = Float64(-1.0 + (b ^ 4.0));
	end
	return tmp
end
b = abs(b)
function tmp_2 = code(a, b)
	tmp = 0.0;
	if ((b * b) <= 0.0002)
		tmp = -1.0 + ((a + -4.0) * (a ^ 3.0));
	else
		tmp = -1.0 + (b ^ 4.0);
	end
	tmp_2 = tmp;
end
NOTE: b should be positive before calling this function
code[a_, b_] := If[LessEqual[N[(b * b), $MachinePrecision], 0.0002], N[(-1.0 + N[(N[(a + -4.0), $MachinePrecision] * N[Power[a, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(-1.0 + N[Power[b, 4.0], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
b = |b|\\
\\
\begin{array}{l}
\mathbf{if}\;b \cdot b \leq 0.0002:\\
\;\;\;\;-1 + \left(a + -4\right) \cdot {a}^{3}\\

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


\end{array}
\end{array}
Derivation
  1. Initial program 95.0%

    \[\begin{array}{l} \mathbf{if}\;b \cdot b \leq 0.0002:\\ \;\;\;\;-1 + \left(a + -4\right) \cdot {a}^{3}\\ \mathbf{else}:\\ \;\;\;\;-1 + {b}^{4}\\ \end{array} \]

Alternative 5: 93.3% accurate, 1.2× speedup?

\[\begin{array}{l} b = |b|\\ \\ \begin{array}{l} \mathbf{if}\;b \cdot b \leq 0.0002:\\ \;\;\;\;-1 + \left(a \cdot \left(a \cdot a\right)\right) \cdot \left(a + -4\right)\\ \mathbf{else}:\\ \;\;\;\;-1 + {b}^{4}\\ \end{array} \end{array} \]
NOTE: b should be positive before calling this function
(FPCore (a b)
 :precision binary64
 (if (<= (* b b) 0.0002)
   (+ -1.0 (* (* a (* a a)) (+ a -4.0)))
   (+ -1.0 (pow b 4.0))))
b = abs(b);
double code(double a, double b) {
	double tmp;
	if ((b * b) <= 0.0002) {
		tmp = -1.0 + ((a * (a * a)) * (a + -4.0));
	} else {
		tmp = -1.0 + pow(b, 4.0);
	}
	return tmp;
}
NOTE: b should be positive before calling this function
real(8) function code(a, b)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8) :: tmp
    if ((b * b) <= 0.0002d0) then
        tmp = (-1.0d0) + ((a * (a * a)) * (a + (-4.0d0)))
    else
        tmp = (-1.0d0) + (b ** 4.0d0)
    end if
    code = tmp
end function
b = Math.abs(b);
public static double code(double a, double b) {
	double tmp;
	if ((b * b) <= 0.0002) {
		tmp = -1.0 + ((a * (a * a)) * (a + -4.0));
	} else {
		tmp = -1.0 + Math.pow(b, 4.0);
	}
	return tmp;
}
b = abs(b)
def code(a, b):
	tmp = 0
	if (b * b) <= 0.0002:
		tmp = -1.0 + ((a * (a * a)) * (a + -4.0))
	else:
		tmp = -1.0 + math.pow(b, 4.0)
	return tmp
b = abs(b)
function code(a, b)
	tmp = 0.0
	if (Float64(b * b) <= 0.0002)
		tmp = Float64(-1.0 + Float64(Float64(a * Float64(a * a)) * Float64(a + -4.0)));
	else
		tmp = Float64(-1.0 + (b ^ 4.0));
	end
	return tmp
end
b = abs(b)
function tmp_2 = code(a, b)
	tmp = 0.0;
	if ((b * b) <= 0.0002)
		tmp = -1.0 + ((a * (a * a)) * (a + -4.0));
	else
		tmp = -1.0 + (b ^ 4.0);
	end
	tmp_2 = tmp;
end
NOTE: b should be positive before calling this function
code[a_, b_] := If[LessEqual[N[(b * b), $MachinePrecision], 0.0002], N[(-1.0 + N[(N[(a * N[(a * a), $MachinePrecision]), $MachinePrecision] * N[(a + -4.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(-1.0 + N[Power[b, 4.0], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
b = |b|\\
\\
\begin{array}{l}
\mathbf{if}\;b \cdot b \leq 0.0002:\\
\;\;\;\;-1 + \left(a \cdot \left(a \cdot a\right)\right) \cdot \left(a + -4\right)\\

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


\end{array}
\end{array}
Derivation
  1. Initial program 94.9%

    \[\begin{array}{l} \mathbf{if}\;b \cdot b \leq 0.0002:\\ \;\;\;\;-1 + \left(a \cdot \left(a \cdot a\right)\right) \cdot \left(a + -4\right)\\ \mathbf{else}:\\ \;\;\;\;-1 + {b}^{4}\\ \end{array} \]

Alternative 6: 83.6% accurate, 8.5× speedup?

\[\begin{array}{l} b = |b|\\ \\ \begin{array}{l} \mathbf{if}\;b \cdot b \leq 4 \cdot 10^{+285}:\\ \;\;\;\;-1 + \left(a \cdot \left(a \cdot a\right)\right) \cdot \left(a + -4\right)\\ \mathbf{else}:\\ \;\;\;\;-1 + b \cdot \left(b \cdot 12\right)\\ \end{array} \end{array} \]
NOTE: b should be positive before calling this function
(FPCore (a b)
 :precision binary64
 (if (<= (* b b) 4e+285)
   (+ -1.0 (* (* a (* a a)) (+ a -4.0)))
   (+ -1.0 (* b (* b 12.0)))))
b = abs(b);
double code(double a, double b) {
	double tmp;
	if ((b * b) <= 4e+285) {
		tmp = -1.0 + ((a * (a * a)) * (a + -4.0));
	} else {
		tmp = -1.0 + (b * (b * 12.0));
	}
	return tmp;
}
NOTE: b should be positive before calling this function
real(8) function code(a, b)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8) :: tmp
    if ((b * b) <= 4d+285) then
        tmp = (-1.0d0) + ((a * (a * a)) * (a + (-4.0d0)))
    else
        tmp = (-1.0d0) + (b * (b * 12.0d0))
    end if
    code = tmp
end function
b = Math.abs(b);
public static double code(double a, double b) {
	double tmp;
	if ((b * b) <= 4e+285) {
		tmp = -1.0 + ((a * (a * a)) * (a + -4.0));
	} else {
		tmp = -1.0 + (b * (b * 12.0));
	}
	return tmp;
}
b = abs(b)
def code(a, b):
	tmp = 0
	if (b * b) <= 4e+285:
		tmp = -1.0 + ((a * (a * a)) * (a + -4.0))
	else:
		tmp = -1.0 + (b * (b * 12.0))
	return tmp
b = abs(b)
function code(a, b)
	tmp = 0.0
	if (Float64(b * b) <= 4e+285)
		tmp = Float64(-1.0 + Float64(Float64(a * Float64(a * a)) * Float64(a + -4.0)));
	else
		tmp = Float64(-1.0 + Float64(b * Float64(b * 12.0)));
	end
	return tmp
end
b = abs(b)
function tmp_2 = code(a, b)
	tmp = 0.0;
	if ((b * b) <= 4e+285)
		tmp = -1.0 + ((a * (a * a)) * (a + -4.0));
	else
		tmp = -1.0 + (b * (b * 12.0));
	end
	tmp_2 = tmp;
end
NOTE: b should be positive before calling this function
code[a_, b_] := If[LessEqual[N[(b * b), $MachinePrecision], 4e+285], N[(-1.0 + N[(N[(a * N[(a * a), $MachinePrecision]), $MachinePrecision] * N[(a + -4.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(-1.0 + N[(b * N[(b * 12.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
b = |b|\\
\\
\begin{array}{l}
\mathbf{if}\;b \cdot b \leq 4 \cdot 10^{+285}:\\
\;\;\;\;-1 + \left(a \cdot \left(a \cdot a\right)\right) \cdot \left(a + -4\right)\\

\mathbf{else}:\\
\;\;\;\;-1 + b \cdot \left(b \cdot 12\right)\\


\end{array}
\end{array}
Derivation
  1. Initial program 85.8%

    \[\begin{array}{l} \mathbf{if}\;b \cdot b \leq 4 \cdot 10^{+285}:\\ \;\;\;\;-1 + \left(a \cdot \left(a \cdot a\right)\right) \cdot \left(a + -4\right)\\ \mathbf{else}:\\ \;\;\;\;-1 + b \cdot \left(b \cdot 12\right)\\ \end{array} \]

Alternative 7: 72.5% accurate, 9.8× speedup?

\[\begin{array}{l} b = |b|\\ \\ \begin{array}{l} \mathbf{if}\;a \leq -5.8 \cdot 10^{+65}:\\ \;\;\;\;-1 + \left(a \cdot a\right) \cdot \left(4 + a \cdot -4\right)\\ \mathbf{elif}\;a \leq 6.2 \cdot 10^{+150}:\\ \;\;\;\;-1 + b \cdot \left(b \cdot 12\right)\\ \mathbf{else}:\\ \;\;\;\;-1 + \left(a \cdot a\right) \cdot 4\\ \end{array} \end{array} \]
NOTE: b should be positive before calling this function
(FPCore (a b)
 :precision binary64
 (if (<= a -5.8e+65)
   (+ -1.0 (* (* a a) (+ 4.0 (* a -4.0))))
   (if (<= a 6.2e+150) (+ -1.0 (* b (* b 12.0))) (+ -1.0 (* (* a a) 4.0)))))
b = abs(b);
double code(double a, double b) {
	double tmp;
	if (a <= -5.8e+65) {
		tmp = -1.0 + ((a * a) * (4.0 + (a * -4.0)));
	} else if (a <= 6.2e+150) {
		tmp = -1.0 + (b * (b * 12.0));
	} else {
		tmp = -1.0 + ((a * a) * 4.0);
	}
	return tmp;
}
NOTE: b should be positive before calling this function
real(8) function code(a, b)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8) :: tmp
    if (a <= (-5.8d+65)) then
        tmp = (-1.0d0) + ((a * a) * (4.0d0 + (a * (-4.0d0))))
    else if (a <= 6.2d+150) then
        tmp = (-1.0d0) + (b * (b * 12.0d0))
    else
        tmp = (-1.0d0) + ((a * a) * 4.0d0)
    end if
    code = tmp
end function
b = Math.abs(b);
public static double code(double a, double b) {
	double tmp;
	if (a <= -5.8e+65) {
		tmp = -1.0 + ((a * a) * (4.0 + (a * -4.0)));
	} else if (a <= 6.2e+150) {
		tmp = -1.0 + (b * (b * 12.0));
	} else {
		tmp = -1.0 + ((a * a) * 4.0);
	}
	return tmp;
}
b = abs(b)
def code(a, b):
	tmp = 0
	if a <= -5.8e+65:
		tmp = -1.0 + ((a * a) * (4.0 + (a * -4.0)))
	elif a <= 6.2e+150:
		tmp = -1.0 + (b * (b * 12.0))
	else:
		tmp = -1.0 + ((a * a) * 4.0)
	return tmp
b = abs(b)
function code(a, b)
	tmp = 0.0
	if (a <= -5.8e+65)
		tmp = Float64(-1.0 + Float64(Float64(a * a) * Float64(4.0 + Float64(a * -4.0))));
	elseif (a <= 6.2e+150)
		tmp = Float64(-1.0 + Float64(b * Float64(b * 12.0)));
	else
		tmp = Float64(-1.0 + Float64(Float64(a * a) * 4.0));
	end
	return tmp
end
b = abs(b)
function tmp_2 = code(a, b)
	tmp = 0.0;
	if (a <= -5.8e+65)
		tmp = -1.0 + ((a * a) * (4.0 + (a * -4.0)));
	elseif (a <= 6.2e+150)
		tmp = -1.0 + (b * (b * 12.0));
	else
		tmp = -1.0 + ((a * a) * 4.0);
	end
	tmp_2 = tmp;
end
NOTE: b should be positive before calling this function
code[a_, b_] := If[LessEqual[a, -5.8e+65], N[(-1.0 + N[(N[(a * a), $MachinePrecision] * N[(4.0 + N[(a * -4.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], If[LessEqual[a, 6.2e+150], N[(-1.0 + N[(b * N[(b * 12.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(-1.0 + N[(N[(a * a), $MachinePrecision] * 4.0), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
b = |b|\\
\\
\begin{array}{l}
\mathbf{if}\;a \leq -5.8 \cdot 10^{+65}:\\
\;\;\;\;-1 + \left(a \cdot a\right) \cdot \left(4 + a \cdot -4\right)\\

\mathbf{elif}\;a \leq 6.2 \cdot 10^{+150}:\\
\;\;\;\;-1 + b \cdot \left(b \cdot 12\right)\\

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


\end{array}
\end{array}
Derivation
  1. Initial program 71.7%

    \[\begin{array}{l} \mathbf{if}\;a \leq -5.8 \cdot 10^{+65}:\\ \;\;\;\;-1 + \left(a \cdot a\right) \cdot \left(4 + a \cdot -4\right)\\ \mathbf{elif}\;a \leq 6.2 \cdot 10^{+150}:\\ \;\;\;\;-1 + b \cdot \left(b \cdot 12\right)\\ \mathbf{else}:\\ \;\;\;\;-1 + \left(a \cdot a\right) \cdot 4\\ \end{array} \]

Alternative 8: 69.4% accurate, 11.6× speedup?

\[\begin{array}{l} b = |b|\\ \\ \begin{array}{l} \mathbf{if}\;b \cdot b \leq 4 \cdot 10^{+285}:\\ \;\;\;\;-1 + \left(a \cdot a\right) \cdot 4\\ \mathbf{else}:\\ \;\;\;\;-1 + b \cdot \left(b \cdot 12\right)\\ \end{array} \end{array} \]
NOTE: b should be positive before calling this function
(FPCore (a b)
 :precision binary64
 (if (<= (* b b) 4e+285) (+ -1.0 (* (* a a) 4.0)) (+ -1.0 (* b (* b 12.0)))))
b = abs(b);
double code(double a, double b) {
	double tmp;
	if ((b * b) <= 4e+285) {
		tmp = -1.0 + ((a * a) * 4.0);
	} else {
		tmp = -1.0 + (b * (b * 12.0));
	}
	return tmp;
}
NOTE: b should be positive before calling this function
real(8) function code(a, b)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8) :: tmp
    if ((b * b) <= 4d+285) then
        tmp = (-1.0d0) + ((a * a) * 4.0d0)
    else
        tmp = (-1.0d0) + (b * (b * 12.0d0))
    end if
    code = tmp
end function
b = Math.abs(b);
public static double code(double a, double b) {
	double tmp;
	if ((b * b) <= 4e+285) {
		tmp = -1.0 + ((a * a) * 4.0);
	} else {
		tmp = -1.0 + (b * (b * 12.0));
	}
	return tmp;
}
b = abs(b)
def code(a, b):
	tmp = 0
	if (b * b) <= 4e+285:
		tmp = -1.0 + ((a * a) * 4.0)
	else:
		tmp = -1.0 + (b * (b * 12.0))
	return tmp
b = abs(b)
function code(a, b)
	tmp = 0.0
	if (Float64(b * b) <= 4e+285)
		tmp = Float64(-1.0 + Float64(Float64(a * a) * 4.0));
	else
		tmp = Float64(-1.0 + Float64(b * Float64(b * 12.0)));
	end
	return tmp
end
b = abs(b)
function tmp_2 = code(a, b)
	tmp = 0.0;
	if ((b * b) <= 4e+285)
		tmp = -1.0 + ((a * a) * 4.0);
	else
		tmp = -1.0 + (b * (b * 12.0));
	end
	tmp_2 = tmp;
end
NOTE: b should be positive before calling this function
code[a_, b_] := If[LessEqual[N[(b * b), $MachinePrecision], 4e+285], N[(-1.0 + N[(N[(a * a), $MachinePrecision] * 4.0), $MachinePrecision]), $MachinePrecision], N[(-1.0 + N[(b * N[(b * 12.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
b = |b|\\
\\
\begin{array}{l}
\mathbf{if}\;b \cdot b \leq 4 \cdot 10^{+285}:\\
\;\;\;\;-1 + \left(a \cdot a\right) \cdot 4\\

\mathbf{else}:\\
\;\;\;\;-1 + b \cdot \left(b \cdot 12\right)\\


\end{array}
\end{array}
Derivation
  1. Initial program 69.5%

    \[\begin{array}{l} \mathbf{if}\;b \cdot b \leq 4 \cdot 10^{+285}:\\ \;\;\;\;-1 + \left(a \cdot a\right) \cdot 4\\ \mathbf{else}:\\ \;\;\;\;-1 + b \cdot \left(b \cdot 12\right)\\ \end{array} \]

Alternative 9: 51.7% accurate, 18.3× speedup?

\[\begin{array}{l} b = |b|\\ \\ -1 + \left(a \cdot a\right) \cdot 4 \end{array} \]
NOTE: b should be positive before calling this function
(FPCore (a b) :precision binary64 (+ -1.0 (* (* a a) 4.0)))
b = abs(b);
double code(double a, double b) {
	return -1.0 + ((a * a) * 4.0);
}
NOTE: b should be positive before calling this function
real(8) function code(a, b)
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    code = (-1.0d0) + ((a * a) * 4.0d0)
end function
b = Math.abs(b);
public static double code(double a, double b) {
	return -1.0 + ((a * a) * 4.0);
}
b = abs(b)
def code(a, b):
	return -1.0 + ((a * a) * 4.0)
b = abs(b)
function code(a, b)
	return Float64(-1.0 + Float64(Float64(a * a) * 4.0))
end
b = abs(b)
function tmp = code(a, b)
	tmp = -1.0 + ((a * a) * 4.0);
end
NOTE: b should be positive before calling this function
code[a_, b_] := N[(-1.0 + N[(N[(a * a), $MachinePrecision] * 4.0), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
b = |b|\\
\\
-1 + \left(a \cdot a\right) \cdot 4
\end{array}
Derivation
  1. Initial program 48.3%

    \[-1 + \left(a \cdot a\right) \cdot 4 \]

Reproduce

?
herbie shell --seed 2023297 
(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))