Main:bigenough3 from C

Percentage Accurate: 53.8% → 99.7%
Time: 11.8s
Alternatives: 7
Speedup: 2.0×

Specification

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

\\
\sqrt{x + 1} - \sqrt{x}
\end{array}

Sampling outcomes in binary64 precision:

Local Percentage Accuracy vs ?

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

Accuracy vs Speed?

Herbie found 7 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: 53.8% accurate, 1.0× speedup?

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

\\
\sqrt{x + 1} - \sqrt{x}
\end{array}

Alternative 1: 99.7% accurate, 1.0× speedup?

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

\\
\frac{1}{\sqrt{1 + x} + \sqrt{x}}
\end{array}
Derivation
  1. Initial program 53.6%

    \[\sqrt{x + 1} - \sqrt{x} \]
  2. Step-by-step derivation
    1. flip--54.5%

      \[\leadsto \color{blue}{\frac{\sqrt{x + 1} \cdot \sqrt{x + 1} - \sqrt{x} \cdot \sqrt{x}}{\sqrt{x + 1} + \sqrt{x}}} \]
    2. div-inv54.5%

      \[\leadsto \color{blue}{\left(\sqrt{x + 1} \cdot \sqrt{x + 1} - \sqrt{x} \cdot \sqrt{x}\right) \cdot \frac{1}{\sqrt{x + 1} + \sqrt{x}}} \]
    3. add-sqr-sqrt54.0%

      \[\leadsto \left(\color{blue}{\left(x + 1\right)} - \sqrt{x} \cdot \sqrt{x}\right) \cdot \frac{1}{\sqrt{x + 1} + \sqrt{x}} \]
    4. add-sqr-sqrt54.5%

      \[\leadsto \left(\left(x + 1\right) - \color{blue}{x}\right) \cdot \frac{1}{\sqrt{x + 1} + \sqrt{x}} \]
  3. Applied egg-rr54.5%

    \[\leadsto \color{blue}{\left(\left(x + 1\right) - x\right) \cdot \frac{1}{\sqrt{x + 1} + \sqrt{x}}} \]
  4. Step-by-step derivation
    1. associate-*r/54.5%

      \[\leadsto \color{blue}{\frac{\left(\left(x + 1\right) - x\right) \cdot 1}{\sqrt{x + 1} + \sqrt{x}}} \]
    2. *-rgt-identity54.5%

      \[\leadsto \frac{\color{blue}{\left(x + 1\right) - x}}{\sqrt{x + 1} + \sqrt{x}} \]
    3. remove-double-neg54.5%

      \[\leadsto \frac{\left(x + 1\right) - x}{\sqrt{x + 1} + \color{blue}{\left(-\left(-\sqrt{x}\right)\right)}} \]
    4. sub-neg54.5%

      \[\leadsto \frac{\left(x + 1\right) - x}{\color{blue}{\sqrt{x + 1} - \left(-\sqrt{x}\right)}} \]
    5. div-sub53.6%

      \[\leadsto \color{blue}{\frac{x + 1}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} - \frac{x}{\sqrt{x + 1} - \left(-\sqrt{x}\right)}} \]
    6. rem-square-sqrt53.5%

      \[\leadsto \frac{x + 1}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} - \frac{\color{blue}{\sqrt{x} \cdot \sqrt{x}}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
    7. sqr-neg53.5%

      \[\leadsto \frac{x + 1}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} - \frac{\color{blue}{\left(-\sqrt{x}\right) \cdot \left(-\sqrt{x}\right)}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
    8. div-sub54.0%

      \[\leadsto \color{blue}{\frac{\left(x + 1\right) - \left(-\sqrt{x}\right) \cdot \left(-\sqrt{x}\right)}{\sqrt{x + 1} - \left(-\sqrt{x}\right)}} \]
    9. +-commutative54.0%

      \[\leadsto \frac{\color{blue}{\left(1 + x\right)} - \left(-\sqrt{x}\right) \cdot \left(-\sqrt{x}\right)}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
    10. sqr-neg54.0%

      \[\leadsto \frac{\left(1 + x\right) - \color{blue}{\sqrt{x} \cdot \sqrt{x}}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
    11. rem-square-sqrt54.5%

      \[\leadsto \frac{\left(1 + x\right) - \color{blue}{x}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
    12. associate--l+99.7%

      \[\leadsto \frac{\color{blue}{1 + \left(x - x\right)}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
    13. +-inverses99.7%

      \[\leadsto \frac{1 + \color{blue}{0}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
    14. metadata-eval99.7%

      \[\leadsto \frac{\color{blue}{1}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
    15. sub-neg99.7%

      \[\leadsto \frac{1}{\color{blue}{\sqrt{x + 1} + \left(-\left(-\sqrt{x}\right)\right)}} \]
    16. remove-double-neg99.7%

      \[\leadsto \frac{1}{\sqrt{x + 1} + \color{blue}{\sqrt{x}}} \]
  5. Simplified99.7%

    \[\leadsto \color{blue}{\frac{1}{\sqrt{1 + x} + \sqrt{x}}} \]
  6. Final simplification99.7%

    \[\leadsto \frac{1}{\sqrt{1 + x} + \sqrt{x}} \]

Alternative 2: 61.6% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \sqrt{1 + x} - \sqrt{x}\\ \mathbf{if}\;t_0 \leq 0:\\ \;\;\;\;\sqrt{\frac{0.5}{x}}\\ \mathbf{else}:\\ \;\;\;\;t_0\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (let* ((t_0 (- (sqrt (+ 1.0 x)) (sqrt x))))
   (if (<= t_0 0.0) (sqrt (/ 0.5 x)) t_0)))
double code(double x) {
	double t_0 = sqrt((1.0 + x)) - sqrt(x);
	double tmp;
	if (t_0 <= 0.0) {
		tmp = sqrt((0.5 / x));
	} else {
		tmp = t_0;
	}
	return tmp;
}
real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: t_0
    real(8) :: tmp
    t_0 = sqrt((1.0d0 + x)) - sqrt(x)
    if (t_0 <= 0.0d0) then
        tmp = sqrt((0.5d0 / x))
    else
        tmp = t_0
    end if
    code = tmp
end function
public static double code(double x) {
	double t_0 = Math.sqrt((1.0 + x)) - Math.sqrt(x);
	double tmp;
	if (t_0 <= 0.0) {
		tmp = Math.sqrt((0.5 / x));
	} else {
		tmp = t_0;
	}
	return tmp;
}
def code(x):
	t_0 = math.sqrt((1.0 + x)) - math.sqrt(x)
	tmp = 0
	if t_0 <= 0.0:
		tmp = math.sqrt((0.5 / x))
	else:
		tmp = t_0
	return tmp
function code(x)
	t_0 = Float64(sqrt(Float64(1.0 + x)) - sqrt(x))
	tmp = 0.0
	if (t_0 <= 0.0)
		tmp = sqrt(Float64(0.5 / x));
	else
		tmp = t_0;
	end
	return tmp
end
function tmp_2 = code(x)
	t_0 = sqrt((1.0 + x)) - sqrt(x);
	tmp = 0.0;
	if (t_0 <= 0.0)
		tmp = sqrt((0.5 / x));
	else
		tmp = t_0;
	end
	tmp_2 = tmp;
end
code[x_] := Block[{t$95$0 = N[(N[Sqrt[N[(1.0 + x), $MachinePrecision]], $MachinePrecision] - N[Sqrt[x], $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t$95$0, 0.0], N[Sqrt[N[(0.5 / x), $MachinePrecision]], $MachinePrecision], t$95$0]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \sqrt{1 + x} - \sqrt{x}\\
\mathbf{if}\;t_0 \leq 0:\\
\;\;\;\;\sqrt{\frac{0.5}{x}}\\

\mathbf{else}:\\
\;\;\;\;t_0\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (-.f64 (sqrt.f64 (+.f64 x 1)) (sqrt.f64 x)) < 0.0

    1. Initial program 3.9%

      \[\sqrt{x + 1} - \sqrt{x} \]
    2. Step-by-step derivation
      1. flip--3.9%

        \[\leadsto \color{blue}{\frac{\sqrt{x + 1} \cdot \sqrt{x + 1} - \sqrt{x} \cdot \sqrt{x}}{\sqrt{x + 1} + \sqrt{x}}} \]
      2. div-inv3.9%

        \[\leadsto \color{blue}{\left(\sqrt{x + 1} \cdot \sqrt{x + 1} - \sqrt{x} \cdot \sqrt{x}\right) \cdot \frac{1}{\sqrt{x + 1} + \sqrt{x}}} \]
      3. add-sqr-sqrt3.8%

        \[\leadsto \left(\color{blue}{\left(x + 1\right)} - \sqrt{x} \cdot \sqrt{x}\right) \cdot \frac{1}{\sqrt{x + 1} + \sqrt{x}} \]
      4. add-sqr-sqrt3.9%

        \[\leadsto \left(\left(x + 1\right) - \color{blue}{x}\right) \cdot \frac{1}{\sqrt{x + 1} + \sqrt{x}} \]
    3. Applied egg-rr3.9%

      \[\leadsto \color{blue}{\left(\left(x + 1\right) - x\right) \cdot \frac{1}{\sqrt{x + 1} + \sqrt{x}}} \]
    4. Step-by-step derivation
      1. associate-*r/3.9%

        \[\leadsto \color{blue}{\frac{\left(\left(x + 1\right) - x\right) \cdot 1}{\sqrt{x + 1} + \sqrt{x}}} \]
      2. *-rgt-identity3.9%

        \[\leadsto \frac{\color{blue}{\left(x + 1\right) - x}}{\sqrt{x + 1} + \sqrt{x}} \]
      3. remove-double-neg3.9%

        \[\leadsto \frac{\left(x + 1\right) - x}{\sqrt{x + 1} + \color{blue}{\left(-\left(-\sqrt{x}\right)\right)}} \]
      4. sub-neg3.9%

        \[\leadsto \frac{\left(x + 1\right) - x}{\color{blue}{\sqrt{x + 1} - \left(-\sqrt{x}\right)}} \]
      5. div-sub3.9%

        \[\leadsto \color{blue}{\frac{x + 1}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} - \frac{x}{\sqrt{x + 1} - \left(-\sqrt{x}\right)}} \]
      6. rem-square-sqrt3.8%

        \[\leadsto \frac{x + 1}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} - \frac{\color{blue}{\sqrt{x} \cdot \sqrt{x}}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      7. sqr-neg3.8%

        \[\leadsto \frac{x + 1}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} - \frac{\color{blue}{\left(-\sqrt{x}\right) \cdot \left(-\sqrt{x}\right)}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      8. div-sub3.8%

        \[\leadsto \color{blue}{\frac{\left(x + 1\right) - \left(-\sqrt{x}\right) \cdot \left(-\sqrt{x}\right)}{\sqrt{x + 1} - \left(-\sqrt{x}\right)}} \]
      9. +-commutative3.8%

        \[\leadsto \frac{\color{blue}{\left(1 + x\right)} - \left(-\sqrt{x}\right) \cdot \left(-\sqrt{x}\right)}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      10. sqr-neg3.8%

        \[\leadsto \frac{\left(1 + x\right) - \color{blue}{\sqrt{x} \cdot \sqrt{x}}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      11. rem-square-sqrt3.9%

        \[\leadsto \frac{\left(1 + x\right) - \color{blue}{x}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      12. associate--l+99.5%

        \[\leadsto \frac{\color{blue}{1 + \left(x - x\right)}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      13. +-inverses99.5%

        \[\leadsto \frac{1 + \color{blue}{0}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      14. metadata-eval99.5%

        \[\leadsto \frac{\color{blue}{1}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      15. sub-neg99.5%

        \[\leadsto \frac{1}{\color{blue}{\sqrt{x + 1} + \left(-\left(-\sqrt{x}\right)\right)}} \]
      16. remove-double-neg99.5%

        \[\leadsto \frac{1}{\sqrt{x + 1} + \color{blue}{\sqrt{x}}} \]
    5. Simplified99.5%

      \[\leadsto \color{blue}{\frac{1}{\sqrt{1 + x} + \sqrt{x}}} \]
    6. Step-by-step derivation
      1. add-sqr-sqrt98.9%

        \[\leadsto \color{blue}{\sqrt{\frac{1}{\sqrt{1 + x} + \sqrt{x}}} \cdot \sqrt{\frac{1}{\sqrt{1 + x} + \sqrt{x}}}} \]
      2. sqrt-unprod99.5%

        \[\leadsto \color{blue}{\sqrt{\frac{1}{\sqrt{1 + x} + \sqrt{x}} \cdot \frac{1}{\sqrt{1 + x} + \sqrt{x}}}} \]
      3. +-commutative99.5%

        \[\leadsto \sqrt{\frac{1}{\sqrt{\color{blue}{x + 1}} + \sqrt{x}} \cdot \frac{1}{\sqrt{1 + x} + \sqrt{x}}} \]
      4. clear-num99.5%

        \[\leadsto \sqrt{\frac{1}{\sqrt{x + 1} + \sqrt{x}} \cdot \color{blue}{\frac{1}{\frac{\sqrt{1 + x} + \sqrt{x}}{1}}}} \]
      5. frac-times99.4%

        \[\leadsto \sqrt{\color{blue}{\frac{1 \cdot 1}{\left(\sqrt{x + 1} + \sqrt{x}\right) \cdot \frac{\sqrt{1 + x} + \sqrt{x}}{1}}}} \]
      6. metadata-eval99.4%

        \[\leadsto \sqrt{\frac{\color{blue}{1}}{\left(\sqrt{x + 1} + \sqrt{x}\right) \cdot \frac{\sqrt{1 + x} + \sqrt{x}}{1}}} \]
      7. +-commutative99.4%

        \[\leadsto \sqrt{\frac{1}{\left(\sqrt{x + 1} + \sqrt{x}\right) \cdot \frac{\sqrt{\color{blue}{x + 1}} + \sqrt{x}}{1}}} \]
      8. /-rgt-identity99.4%

        \[\leadsto \sqrt{\frac{1}{\left(\sqrt{x + 1} + \sqrt{x}\right) \cdot \color{blue}{\left(\sqrt{x + 1} + \sqrt{x}\right)}}} \]
      9. +-commutative99.4%

        \[\leadsto \sqrt{\frac{1}{\left(\sqrt{x + 1} + \sqrt{x}\right) \cdot \color{blue}{\left(\sqrt{x} + \sqrt{x + 1}\right)}}} \]
    7. Applied egg-rr20.3%

      \[\leadsto \color{blue}{\sqrt{\frac{1}{1 + \left(x + x\right)}}} \]
    8. Taylor expanded in x around inf 20.3%

      \[\leadsto \sqrt{\color{blue}{\frac{0.5}{x}}} \]

    if 0.0 < (-.f64 (sqrt.f64 (+.f64 x 1)) (sqrt.f64 x))

    1. Initial program 98.1%

      \[\sqrt{x + 1} - \sqrt{x} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification61.4%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\sqrt{1 + x} - \sqrt{x} \leq 0:\\ \;\;\;\;\sqrt{\frac{0.5}{x}}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{1 + x} - \sqrt{x}\\ \end{array} \]

Alternative 3: 99.3% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \sqrt{1 + x} - \sqrt{x}\\ \mathbf{if}\;t_0 \leq 2 \cdot 10^{-5}:\\ \;\;\;\;\frac{1}{\sqrt{x} + \sqrt{x}}\\ \mathbf{else}:\\ \;\;\;\;t_0\\ \end{array} \end{array} \]
(FPCore (x)
 :precision binary64
 (let* ((t_0 (- (sqrt (+ 1.0 x)) (sqrt x))))
   (if (<= t_0 2e-5) (/ 1.0 (+ (sqrt x) (sqrt x))) t_0)))
double code(double x) {
	double t_0 = sqrt((1.0 + x)) - sqrt(x);
	double tmp;
	if (t_0 <= 2e-5) {
		tmp = 1.0 / (sqrt(x) + sqrt(x));
	} else {
		tmp = t_0;
	}
	return tmp;
}
real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: t_0
    real(8) :: tmp
    t_0 = sqrt((1.0d0 + x)) - sqrt(x)
    if (t_0 <= 2d-5) then
        tmp = 1.0d0 / (sqrt(x) + sqrt(x))
    else
        tmp = t_0
    end if
    code = tmp
end function
public static double code(double x) {
	double t_0 = Math.sqrt((1.0 + x)) - Math.sqrt(x);
	double tmp;
	if (t_0 <= 2e-5) {
		tmp = 1.0 / (Math.sqrt(x) + Math.sqrt(x));
	} else {
		tmp = t_0;
	}
	return tmp;
}
def code(x):
	t_0 = math.sqrt((1.0 + x)) - math.sqrt(x)
	tmp = 0
	if t_0 <= 2e-5:
		tmp = 1.0 / (math.sqrt(x) + math.sqrt(x))
	else:
		tmp = t_0
	return tmp
function code(x)
	t_0 = Float64(sqrt(Float64(1.0 + x)) - sqrt(x))
	tmp = 0.0
	if (t_0 <= 2e-5)
		tmp = Float64(1.0 / Float64(sqrt(x) + sqrt(x)));
	else
		tmp = t_0;
	end
	return tmp
end
function tmp_2 = code(x)
	t_0 = sqrt((1.0 + x)) - sqrt(x);
	tmp = 0.0;
	if (t_0 <= 2e-5)
		tmp = 1.0 / (sqrt(x) + sqrt(x));
	else
		tmp = t_0;
	end
	tmp_2 = tmp;
end
code[x_] := Block[{t$95$0 = N[(N[Sqrt[N[(1.0 + x), $MachinePrecision]], $MachinePrecision] - N[Sqrt[x], $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t$95$0, 2e-5], N[(1.0 / N[(N[Sqrt[x], $MachinePrecision] + N[Sqrt[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], t$95$0]]
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \sqrt{1 + x} - \sqrt{x}\\
\mathbf{if}\;t_0 \leq 2 \cdot 10^{-5}:\\
\;\;\;\;\frac{1}{\sqrt{x} + \sqrt{x}}\\

\mathbf{else}:\\
\;\;\;\;t_0\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (-.f64 (sqrt.f64 (+.f64 x 1)) (sqrt.f64 x)) < 2.00000000000000016e-5

    1. Initial program 5.1%

      \[\sqrt{x + 1} - \sqrt{x} \]
    2. Step-by-step derivation
      1. flip--6.9%

        \[\leadsto \color{blue}{\frac{\sqrt{x + 1} \cdot \sqrt{x + 1} - \sqrt{x} \cdot \sqrt{x}}{\sqrt{x + 1} + \sqrt{x}}} \]
      2. div-inv6.9%

        \[\leadsto \color{blue}{\left(\sqrt{x + 1} \cdot \sqrt{x + 1} - \sqrt{x} \cdot \sqrt{x}\right) \cdot \frac{1}{\sqrt{x + 1} + \sqrt{x}}} \]
      3. add-sqr-sqrt5.8%

        \[\leadsto \left(\color{blue}{\left(x + 1\right)} - \sqrt{x} \cdot \sqrt{x}\right) \cdot \frac{1}{\sqrt{x + 1} + \sqrt{x}} \]
      4. add-sqr-sqrt6.9%

        \[\leadsto \left(\left(x + 1\right) - \color{blue}{x}\right) \cdot \frac{1}{\sqrt{x + 1} + \sqrt{x}} \]
    3. Applied egg-rr6.9%

      \[\leadsto \color{blue}{\left(\left(x + 1\right) - x\right) \cdot \frac{1}{\sqrt{x + 1} + \sqrt{x}}} \]
    4. Step-by-step derivation
      1. associate-*r/6.9%

        \[\leadsto \color{blue}{\frac{\left(\left(x + 1\right) - x\right) \cdot 1}{\sqrt{x + 1} + \sqrt{x}}} \]
      2. *-rgt-identity6.9%

        \[\leadsto \frac{\color{blue}{\left(x + 1\right) - x}}{\sqrt{x + 1} + \sqrt{x}} \]
      3. remove-double-neg6.9%

        \[\leadsto \frac{\left(x + 1\right) - x}{\sqrt{x + 1} + \color{blue}{\left(-\left(-\sqrt{x}\right)\right)}} \]
      4. sub-neg6.9%

        \[\leadsto \frac{\left(x + 1\right) - x}{\color{blue}{\sqrt{x + 1} - \left(-\sqrt{x}\right)}} \]
      5. div-sub5.1%

        \[\leadsto \color{blue}{\frac{x + 1}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} - \frac{x}{\sqrt{x + 1} - \left(-\sqrt{x}\right)}} \]
      6. rem-square-sqrt5.0%

        \[\leadsto \frac{x + 1}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} - \frac{\color{blue}{\sqrt{x} \cdot \sqrt{x}}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      7. sqr-neg5.0%

        \[\leadsto \frac{x + 1}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} - \frac{\color{blue}{\left(-\sqrt{x}\right) \cdot \left(-\sqrt{x}\right)}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      8. div-sub5.8%

        \[\leadsto \color{blue}{\frac{\left(x + 1\right) - \left(-\sqrt{x}\right) \cdot \left(-\sqrt{x}\right)}{\sqrt{x + 1} - \left(-\sqrt{x}\right)}} \]
      9. +-commutative5.8%

        \[\leadsto \frac{\color{blue}{\left(1 + x\right)} - \left(-\sqrt{x}\right) \cdot \left(-\sqrt{x}\right)}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      10. sqr-neg5.8%

        \[\leadsto \frac{\left(1 + x\right) - \color{blue}{\sqrt{x} \cdot \sqrt{x}}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      11. rem-square-sqrt6.9%

        \[\leadsto \frac{\left(1 + x\right) - \color{blue}{x}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      12. associate--l+99.5%

        \[\leadsto \frac{\color{blue}{1 + \left(x - x\right)}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      13. +-inverses99.5%

        \[\leadsto \frac{1 + \color{blue}{0}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      14. metadata-eval99.5%

        \[\leadsto \frac{\color{blue}{1}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      15. sub-neg99.5%

        \[\leadsto \frac{1}{\color{blue}{\sqrt{x + 1} + \left(-\left(-\sqrt{x}\right)\right)}} \]
      16. remove-double-neg99.5%

        \[\leadsto \frac{1}{\sqrt{x + 1} + \color{blue}{\sqrt{x}}} \]
    5. Simplified99.5%

      \[\leadsto \color{blue}{\frac{1}{\sqrt{1 + x} + \sqrt{x}}} \]
    6. Step-by-step derivation
      1. pow1/299.5%

        \[\leadsto \frac{1}{\color{blue}{{\left(1 + x\right)}^{0.5}} + \sqrt{x}} \]
      2. +-commutative99.5%

        \[\leadsto \frac{1}{{\color{blue}{\left(x + 1\right)}}^{0.5} + \sqrt{x}} \]
      3. metadata-eval99.5%

        \[\leadsto \frac{1}{{\left(x + 1\right)}^{\color{blue}{\left(0.25 + 0.25\right)}} + \sqrt{x}} \]
      4. pow-prod-up99.2%

        \[\leadsto \frac{1}{\color{blue}{{\left(x + 1\right)}^{0.25} \cdot {\left(x + 1\right)}^{0.25}} + \sqrt{x}} \]
      5. pow299.2%

        \[\leadsto \frac{1}{\color{blue}{{\left({\left(x + 1\right)}^{0.25}\right)}^{2}} + \sqrt{x}} \]
      6. +-commutative99.2%

        \[\leadsto \frac{1}{{\left({\color{blue}{\left(1 + x\right)}}^{0.25}\right)}^{2} + \sqrt{x}} \]
    7. Applied egg-rr99.2%

      \[\leadsto \frac{1}{\color{blue}{{\left({\left(1 + x\right)}^{0.25}\right)}^{2}} + \sqrt{x}} \]
    8. Taylor expanded in x around inf 99.0%

      \[\leadsto \frac{1}{\color{blue}{\sqrt{x}} + \sqrt{x}} \]

    if 2.00000000000000016e-5 < (-.f64 (sqrt.f64 (+.f64 x 1)) (sqrt.f64 x))

    1. Initial program 99.9%

      \[\sqrt{x + 1} - \sqrt{x} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification99.4%

    \[\leadsto \begin{array}{l} \mathbf{if}\;\sqrt{1 + x} - \sqrt{x} \leq 2 \cdot 10^{-5}:\\ \;\;\;\;\frac{1}{\sqrt{x} + \sqrt{x}}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{1 + x} - \sqrt{x}\\ \end{array} \]

Alternative 4: 58.3% accurate, 2.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;x \leq 0.75:\\ \;\;\;\;1 - x\\ \mathbf{else}:\\ \;\;\;\;\sqrt{\frac{0.5}{x}}\\ \end{array} \end{array} \]
(FPCore (x) :precision binary64 (if (<= x 0.75) (- 1.0 x) (sqrt (/ 0.5 x))))
double code(double x) {
	double tmp;
	if (x <= 0.75) {
		tmp = 1.0 - x;
	} else {
		tmp = sqrt((0.5 / x));
	}
	return tmp;
}
real(8) function code(x)
    real(8), intent (in) :: x
    real(8) :: tmp
    if (x <= 0.75d0) then
        tmp = 1.0d0 - x
    else
        tmp = sqrt((0.5d0 / x))
    end if
    code = tmp
end function
public static double code(double x) {
	double tmp;
	if (x <= 0.75) {
		tmp = 1.0 - x;
	} else {
		tmp = Math.sqrt((0.5 / x));
	}
	return tmp;
}
def code(x):
	tmp = 0
	if x <= 0.75:
		tmp = 1.0 - x
	else:
		tmp = math.sqrt((0.5 / x))
	return tmp
function code(x)
	tmp = 0.0
	if (x <= 0.75)
		tmp = Float64(1.0 - x);
	else
		tmp = sqrt(Float64(0.5 / x));
	end
	return tmp
end
function tmp_2 = code(x)
	tmp = 0.0;
	if (x <= 0.75)
		tmp = 1.0 - x;
	else
		tmp = sqrt((0.5 / x));
	end
	tmp_2 = tmp;
end
code[x_] := If[LessEqual[x, 0.75], N[(1.0 - x), $MachinePrecision], N[Sqrt[N[(0.5 / x), $MachinePrecision]], $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;x \leq 0.75:\\
\;\;\;\;1 - x\\

\mathbf{else}:\\
\;\;\;\;\sqrt{\frac{0.5}{x}}\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if x < 0.75

    1. Initial program 99.9%

      \[\sqrt{x + 1} - \sqrt{x} \]
    2. Step-by-step derivation
      1. flip--99.9%

        \[\leadsto \color{blue}{\frac{\sqrt{x + 1} \cdot \sqrt{x + 1} - \sqrt{x} \cdot \sqrt{x}}{\sqrt{x + 1} + \sqrt{x}}} \]
      2. div-inv99.9%

        \[\leadsto \color{blue}{\left(\sqrt{x + 1} \cdot \sqrt{x + 1} - \sqrt{x} \cdot \sqrt{x}\right) \cdot \frac{1}{\sqrt{x + 1} + \sqrt{x}}} \]
      3. add-sqr-sqrt99.9%

        \[\leadsto \left(\color{blue}{\left(x + 1\right)} - \sqrt{x} \cdot \sqrt{x}\right) \cdot \frac{1}{\sqrt{x + 1} + \sqrt{x}} \]
      4. add-sqr-sqrt99.9%

        \[\leadsto \left(\left(x + 1\right) - \color{blue}{x}\right) \cdot \frac{1}{\sqrt{x + 1} + \sqrt{x}} \]
    3. Applied egg-rr99.9%

      \[\leadsto \color{blue}{\left(\left(x + 1\right) - x\right) \cdot \frac{1}{\sqrt{x + 1} + \sqrt{x}}} \]
    4. Step-by-step derivation
      1. associate-*r/99.9%

        \[\leadsto \color{blue}{\frac{\left(\left(x + 1\right) - x\right) \cdot 1}{\sqrt{x + 1} + \sqrt{x}}} \]
      2. *-rgt-identity99.9%

        \[\leadsto \frac{\color{blue}{\left(x + 1\right) - x}}{\sqrt{x + 1} + \sqrt{x}} \]
      3. remove-double-neg99.9%

        \[\leadsto \frac{\left(x + 1\right) - x}{\sqrt{x + 1} + \color{blue}{\left(-\left(-\sqrt{x}\right)\right)}} \]
      4. sub-neg99.9%

        \[\leadsto \frac{\left(x + 1\right) - x}{\color{blue}{\sqrt{x + 1} - \left(-\sqrt{x}\right)}} \]
      5. div-sub99.9%

        \[\leadsto \color{blue}{\frac{x + 1}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} - \frac{x}{\sqrt{x + 1} - \left(-\sqrt{x}\right)}} \]
      6. rem-square-sqrt99.9%

        \[\leadsto \frac{x + 1}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} - \frac{\color{blue}{\sqrt{x} \cdot \sqrt{x}}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      7. sqr-neg99.9%

        \[\leadsto \frac{x + 1}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} - \frac{\color{blue}{\left(-\sqrt{x}\right) \cdot \left(-\sqrt{x}\right)}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      8. div-sub99.9%

        \[\leadsto \color{blue}{\frac{\left(x + 1\right) - \left(-\sqrt{x}\right) \cdot \left(-\sqrt{x}\right)}{\sqrt{x + 1} - \left(-\sqrt{x}\right)}} \]
      9. +-commutative99.9%

        \[\leadsto \frac{\color{blue}{\left(1 + x\right)} - \left(-\sqrt{x}\right) \cdot \left(-\sqrt{x}\right)}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      10. sqr-neg99.9%

        \[\leadsto \frac{\left(1 + x\right) - \color{blue}{\sqrt{x} \cdot \sqrt{x}}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      11. rem-square-sqrt99.9%

        \[\leadsto \frac{\left(1 + x\right) - \color{blue}{x}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      12. associate--l+99.9%

        \[\leadsto \frac{\color{blue}{1 + \left(x - x\right)}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      13. +-inverses99.9%

        \[\leadsto \frac{1 + \color{blue}{0}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      14. metadata-eval99.9%

        \[\leadsto \frac{\color{blue}{1}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      15. sub-neg99.9%

        \[\leadsto \frac{1}{\color{blue}{\sqrt{x + 1} + \left(-\left(-\sqrt{x}\right)\right)}} \]
      16. remove-double-neg99.9%

        \[\leadsto \frac{1}{\sqrt{x + 1} + \color{blue}{\sqrt{x}}} \]
    5. Simplified99.9%

      \[\leadsto \color{blue}{\frac{1}{\sqrt{1 + x} + \sqrt{x}}} \]
    6. Step-by-step derivation
      1. add-sqr-sqrt99.9%

        \[\leadsto \color{blue}{\sqrt{\frac{1}{\sqrt{1 + x} + \sqrt{x}}} \cdot \sqrt{\frac{1}{\sqrt{1 + x} + \sqrt{x}}}} \]
      2. sqrt-unprod99.9%

        \[\leadsto \color{blue}{\sqrt{\frac{1}{\sqrt{1 + x} + \sqrt{x}} \cdot \frac{1}{\sqrt{1 + x} + \sqrt{x}}}} \]
      3. +-commutative99.9%

        \[\leadsto \sqrt{\frac{1}{\sqrt{\color{blue}{x + 1}} + \sqrt{x}} \cdot \frac{1}{\sqrt{1 + x} + \sqrt{x}}} \]
      4. clear-num99.9%

        \[\leadsto \sqrt{\frac{1}{\sqrt{x + 1} + \sqrt{x}} \cdot \color{blue}{\frac{1}{\frac{\sqrt{1 + x} + \sqrt{x}}{1}}}} \]
      5. frac-times99.9%

        \[\leadsto \sqrt{\color{blue}{\frac{1 \cdot 1}{\left(\sqrt{x + 1} + \sqrt{x}\right) \cdot \frac{\sqrt{1 + x} + \sqrt{x}}{1}}}} \]
      6. metadata-eval99.9%

        \[\leadsto \sqrt{\frac{\color{blue}{1}}{\left(\sqrt{x + 1} + \sqrt{x}\right) \cdot \frac{\sqrt{1 + x} + \sqrt{x}}{1}}} \]
      7. +-commutative99.9%

        \[\leadsto \sqrt{\frac{1}{\left(\sqrt{x + 1} + \sqrt{x}\right) \cdot \frac{\sqrt{\color{blue}{x + 1}} + \sqrt{x}}{1}}} \]
      8. /-rgt-identity99.9%

        \[\leadsto \sqrt{\frac{1}{\left(\sqrt{x + 1} + \sqrt{x}\right) \cdot \color{blue}{\left(\sqrt{x + 1} + \sqrt{x}\right)}}} \]
      9. +-commutative99.9%

        \[\leadsto \sqrt{\frac{1}{\left(\sqrt{x + 1} + \sqrt{x}\right) \cdot \color{blue}{\left(\sqrt{x} + \sqrt{x + 1}\right)}}} \]
    7. Applied egg-rr95.9%

      \[\leadsto \color{blue}{\sqrt{\frac{1}{1 + \left(x + x\right)}}} \]
    8. Taylor expanded in x around 0 95.9%

      \[\leadsto \color{blue}{1 + -1 \cdot x} \]
    9. Step-by-step derivation
      1. mul-1-neg95.9%

        \[\leadsto 1 + \color{blue}{\left(-x\right)} \]
      2. sub-neg95.9%

        \[\leadsto \color{blue}{1 - x} \]
    10. Simplified95.9%

      \[\leadsto \color{blue}{1 - x} \]

    if 0.75 < x

    1. Initial program 5.8%

      \[\sqrt{x + 1} - \sqrt{x} \]
    2. Step-by-step derivation
      1. flip--7.6%

        \[\leadsto \color{blue}{\frac{\sqrt{x + 1} \cdot \sqrt{x + 1} - \sqrt{x} \cdot \sqrt{x}}{\sqrt{x + 1} + \sqrt{x}}} \]
      2. div-inv7.6%

        \[\leadsto \color{blue}{\left(\sqrt{x + 1} \cdot \sqrt{x + 1} - \sqrt{x} \cdot \sqrt{x}\right) \cdot \frac{1}{\sqrt{x + 1} + \sqrt{x}}} \]
      3. add-sqr-sqrt6.6%

        \[\leadsto \left(\color{blue}{\left(x + 1\right)} - \sqrt{x} \cdot \sqrt{x}\right) \cdot \frac{1}{\sqrt{x + 1} + \sqrt{x}} \]
      4. add-sqr-sqrt7.7%

        \[\leadsto \left(\left(x + 1\right) - \color{blue}{x}\right) \cdot \frac{1}{\sqrt{x + 1} + \sqrt{x}} \]
    3. Applied egg-rr7.7%

      \[\leadsto \color{blue}{\left(\left(x + 1\right) - x\right) \cdot \frac{1}{\sqrt{x + 1} + \sqrt{x}}} \]
    4. Step-by-step derivation
      1. associate-*r/7.7%

        \[\leadsto \color{blue}{\frac{\left(\left(x + 1\right) - x\right) \cdot 1}{\sqrt{x + 1} + \sqrt{x}}} \]
      2. *-rgt-identity7.7%

        \[\leadsto \frac{\color{blue}{\left(x + 1\right) - x}}{\sqrt{x + 1} + \sqrt{x}} \]
      3. remove-double-neg7.7%

        \[\leadsto \frac{\left(x + 1\right) - x}{\sqrt{x + 1} + \color{blue}{\left(-\left(-\sqrt{x}\right)\right)}} \]
      4. sub-neg7.7%

        \[\leadsto \frac{\left(x + 1\right) - x}{\color{blue}{\sqrt{x + 1} - \left(-\sqrt{x}\right)}} \]
      5. div-sub5.8%

        \[\leadsto \color{blue}{\frac{x + 1}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} - \frac{x}{\sqrt{x + 1} - \left(-\sqrt{x}\right)}} \]
      6. rem-square-sqrt5.7%

        \[\leadsto \frac{x + 1}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} - \frac{\color{blue}{\sqrt{x} \cdot \sqrt{x}}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      7. sqr-neg5.7%

        \[\leadsto \frac{x + 1}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} - \frac{\color{blue}{\left(-\sqrt{x}\right) \cdot \left(-\sqrt{x}\right)}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      8. div-sub6.6%

        \[\leadsto \color{blue}{\frac{\left(x + 1\right) - \left(-\sqrt{x}\right) \cdot \left(-\sqrt{x}\right)}{\sqrt{x + 1} - \left(-\sqrt{x}\right)}} \]
      9. +-commutative6.6%

        \[\leadsto \frac{\color{blue}{\left(1 + x\right)} - \left(-\sqrt{x}\right) \cdot \left(-\sqrt{x}\right)}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      10. sqr-neg6.6%

        \[\leadsto \frac{\left(1 + x\right) - \color{blue}{\sqrt{x} \cdot \sqrt{x}}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      11. rem-square-sqrt7.7%

        \[\leadsto \frac{\left(1 + x\right) - \color{blue}{x}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      12. associate--l+99.5%

        \[\leadsto \frac{\color{blue}{1 + \left(x - x\right)}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      13. +-inverses99.5%

        \[\leadsto \frac{1 + \color{blue}{0}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      14. metadata-eval99.5%

        \[\leadsto \frac{\color{blue}{1}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
      15. sub-neg99.5%

        \[\leadsto \frac{1}{\color{blue}{\sqrt{x + 1} + \left(-\left(-\sqrt{x}\right)\right)}} \]
      16. remove-double-neg99.5%

        \[\leadsto \frac{1}{\sqrt{x + 1} + \color{blue}{\sqrt{x}}} \]
    5. Simplified99.5%

      \[\leadsto \color{blue}{\frac{1}{\sqrt{1 + x} + \sqrt{x}}} \]
    6. Step-by-step derivation
      1. add-sqr-sqrt98.9%

        \[\leadsto \color{blue}{\sqrt{\frac{1}{\sqrt{1 + x} + \sqrt{x}}} \cdot \sqrt{\frac{1}{\sqrt{1 + x} + \sqrt{x}}}} \]
      2. sqrt-unprod99.5%

        \[\leadsto \color{blue}{\sqrt{\frac{1}{\sqrt{1 + x} + \sqrt{x}} \cdot \frac{1}{\sqrt{1 + x} + \sqrt{x}}}} \]
      3. +-commutative99.5%

        \[\leadsto \sqrt{\frac{1}{\sqrt{\color{blue}{x + 1}} + \sqrt{x}} \cdot \frac{1}{\sqrt{1 + x} + \sqrt{x}}} \]
      4. clear-num99.5%

        \[\leadsto \sqrt{\frac{1}{\sqrt{x + 1} + \sqrt{x}} \cdot \color{blue}{\frac{1}{\frac{\sqrt{1 + x} + \sqrt{x}}{1}}}} \]
      5. frac-times99.4%

        \[\leadsto \sqrt{\color{blue}{\frac{1 \cdot 1}{\left(\sqrt{x + 1} + \sqrt{x}\right) \cdot \frac{\sqrt{1 + x} + \sqrt{x}}{1}}}} \]
      6. metadata-eval99.4%

        \[\leadsto \sqrt{\frac{\color{blue}{1}}{\left(\sqrt{x + 1} + \sqrt{x}\right) \cdot \frac{\sqrt{1 + x} + \sqrt{x}}{1}}} \]
      7. +-commutative99.4%

        \[\leadsto \sqrt{\frac{1}{\left(\sqrt{x + 1} + \sqrt{x}\right) \cdot \frac{\sqrt{\color{blue}{x + 1}} + \sqrt{x}}{1}}} \]
      8. /-rgt-identity99.4%

        \[\leadsto \sqrt{\frac{1}{\left(\sqrt{x + 1} + \sqrt{x}\right) \cdot \color{blue}{\left(\sqrt{x + 1} + \sqrt{x}\right)}}} \]
      9. +-commutative99.4%

        \[\leadsto \sqrt{\frac{1}{\left(\sqrt{x + 1} + \sqrt{x}\right) \cdot \color{blue}{\left(\sqrt{x} + \sqrt{x + 1}\right)}}} \]
    7. Applied egg-rr20.3%

      \[\leadsto \color{blue}{\sqrt{\frac{1}{1 + \left(x + x\right)}}} \]
    8. Taylor expanded in x around inf 20.3%

      \[\leadsto \sqrt{\color{blue}{\frac{0.5}{x}}} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification58.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;x \leq 0.75:\\ \;\;\;\;1 - x\\ \mathbf{else}:\\ \;\;\;\;\sqrt{\frac{0.5}{x}}\\ \end{array} \]

Alternative 5: 58.7% accurate, 2.0× speedup?

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

\\
\frac{1}{1 + \sqrt{x}}
\end{array}
Derivation
  1. Initial program 53.6%

    \[\sqrt{x + 1} - \sqrt{x} \]
  2. Step-by-step derivation
    1. flip--54.5%

      \[\leadsto \color{blue}{\frac{\sqrt{x + 1} \cdot \sqrt{x + 1} - \sqrt{x} \cdot \sqrt{x}}{\sqrt{x + 1} + \sqrt{x}}} \]
    2. div-inv54.5%

      \[\leadsto \color{blue}{\left(\sqrt{x + 1} \cdot \sqrt{x + 1} - \sqrt{x} \cdot \sqrt{x}\right) \cdot \frac{1}{\sqrt{x + 1} + \sqrt{x}}} \]
    3. add-sqr-sqrt54.0%

      \[\leadsto \left(\color{blue}{\left(x + 1\right)} - \sqrt{x} \cdot \sqrt{x}\right) \cdot \frac{1}{\sqrt{x + 1} + \sqrt{x}} \]
    4. add-sqr-sqrt54.5%

      \[\leadsto \left(\left(x + 1\right) - \color{blue}{x}\right) \cdot \frac{1}{\sqrt{x + 1} + \sqrt{x}} \]
  3. Applied egg-rr54.5%

    \[\leadsto \color{blue}{\left(\left(x + 1\right) - x\right) \cdot \frac{1}{\sqrt{x + 1} + \sqrt{x}}} \]
  4. Step-by-step derivation
    1. associate-*r/54.5%

      \[\leadsto \color{blue}{\frac{\left(\left(x + 1\right) - x\right) \cdot 1}{\sqrt{x + 1} + \sqrt{x}}} \]
    2. *-rgt-identity54.5%

      \[\leadsto \frac{\color{blue}{\left(x + 1\right) - x}}{\sqrt{x + 1} + \sqrt{x}} \]
    3. remove-double-neg54.5%

      \[\leadsto \frac{\left(x + 1\right) - x}{\sqrt{x + 1} + \color{blue}{\left(-\left(-\sqrt{x}\right)\right)}} \]
    4. sub-neg54.5%

      \[\leadsto \frac{\left(x + 1\right) - x}{\color{blue}{\sqrt{x + 1} - \left(-\sqrt{x}\right)}} \]
    5. div-sub53.6%

      \[\leadsto \color{blue}{\frac{x + 1}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} - \frac{x}{\sqrt{x + 1} - \left(-\sqrt{x}\right)}} \]
    6. rem-square-sqrt53.5%

      \[\leadsto \frac{x + 1}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} - \frac{\color{blue}{\sqrt{x} \cdot \sqrt{x}}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
    7. sqr-neg53.5%

      \[\leadsto \frac{x + 1}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} - \frac{\color{blue}{\left(-\sqrt{x}\right) \cdot \left(-\sqrt{x}\right)}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
    8. div-sub54.0%

      \[\leadsto \color{blue}{\frac{\left(x + 1\right) - \left(-\sqrt{x}\right) \cdot \left(-\sqrt{x}\right)}{\sqrt{x + 1} - \left(-\sqrt{x}\right)}} \]
    9. +-commutative54.0%

      \[\leadsto \frac{\color{blue}{\left(1 + x\right)} - \left(-\sqrt{x}\right) \cdot \left(-\sqrt{x}\right)}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
    10. sqr-neg54.0%

      \[\leadsto \frac{\left(1 + x\right) - \color{blue}{\sqrt{x} \cdot \sqrt{x}}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
    11. rem-square-sqrt54.5%

      \[\leadsto \frac{\left(1 + x\right) - \color{blue}{x}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
    12. associate--l+99.7%

      \[\leadsto \frac{\color{blue}{1 + \left(x - x\right)}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
    13. +-inverses99.7%

      \[\leadsto \frac{1 + \color{blue}{0}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
    14. metadata-eval99.7%

      \[\leadsto \frac{\color{blue}{1}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
    15. sub-neg99.7%

      \[\leadsto \frac{1}{\color{blue}{\sqrt{x + 1} + \left(-\left(-\sqrt{x}\right)\right)}} \]
    16. remove-double-neg99.7%

      \[\leadsto \frac{1}{\sqrt{x + 1} + \color{blue}{\sqrt{x}}} \]
  5. Simplified99.7%

    \[\leadsto \color{blue}{\frac{1}{\sqrt{1 + x} + \sqrt{x}}} \]
  6. Step-by-step derivation
    1. pow1/299.7%

      \[\leadsto \frac{1}{\color{blue}{{\left(1 + x\right)}^{0.5}} + \sqrt{x}} \]
    2. +-commutative99.7%

      \[\leadsto \frac{1}{{\color{blue}{\left(x + 1\right)}}^{0.5} + \sqrt{x}} \]
    3. metadata-eval99.7%

      \[\leadsto \frac{1}{{\left(x + 1\right)}^{\color{blue}{\left(0.25 + 0.25\right)}} + \sqrt{x}} \]
    4. pow-prod-up99.6%

      \[\leadsto \frac{1}{\color{blue}{{\left(x + 1\right)}^{0.25} \cdot {\left(x + 1\right)}^{0.25}} + \sqrt{x}} \]
    5. pow299.6%

      \[\leadsto \frac{1}{\color{blue}{{\left({\left(x + 1\right)}^{0.25}\right)}^{2}} + \sqrt{x}} \]
    6. +-commutative99.6%

      \[\leadsto \frac{1}{{\left({\color{blue}{\left(1 + x\right)}}^{0.25}\right)}^{2} + \sqrt{x}} \]
  7. Applied egg-rr99.6%

    \[\leadsto \frac{1}{\color{blue}{{\left({\left(1 + x\right)}^{0.25}\right)}^{2}} + \sqrt{x}} \]
  8. Taylor expanded in x around 0 59.2%

    \[\leadsto \frac{1}{\color{blue}{1} + \sqrt{x}} \]
  9. Final simplification59.2%

    \[\leadsto \frac{1}{1 + \sqrt{x}} \]

Alternative 6: 51.7% accurate, 41.0× speedup?

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

\\
\frac{1}{1 + x}
\end{array}
Derivation
  1. Initial program 53.6%

    \[\sqrt{x + 1} - \sqrt{x} \]
  2. Step-by-step derivation
    1. flip--54.5%

      \[\leadsto \color{blue}{\frac{\sqrt{x + 1} \cdot \sqrt{x + 1} - \sqrt{x} \cdot \sqrt{x}}{\sqrt{x + 1} + \sqrt{x}}} \]
    2. div-inv54.5%

      \[\leadsto \color{blue}{\left(\sqrt{x + 1} \cdot \sqrt{x + 1} - \sqrt{x} \cdot \sqrt{x}\right) \cdot \frac{1}{\sqrt{x + 1} + \sqrt{x}}} \]
    3. add-sqr-sqrt54.0%

      \[\leadsto \left(\color{blue}{\left(x + 1\right)} - \sqrt{x} \cdot \sqrt{x}\right) \cdot \frac{1}{\sqrt{x + 1} + \sqrt{x}} \]
    4. add-sqr-sqrt54.5%

      \[\leadsto \left(\left(x + 1\right) - \color{blue}{x}\right) \cdot \frac{1}{\sqrt{x + 1} + \sqrt{x}} \]
  3. Applied egg-rr54.5%

    \[\leadsto \color{blue}{\left(\left(x + 1\right) - x\right) \cdot \frac{1}{\sqrt{x + 1} + \sqrt{x}}} \]
  4. Step-by-step derivation
    1. associate-*r/54.5%

      \[\leadsto \color{blue}{\frac{\left(\left(x + 1\right) - x\right) \cdot 1}{\sqrt{x + 1} + \sqrt{x}}} \]
    2. *-rgt-identity54.5%

      \[\leadsto \frac{\color{blue}{\left(x + 1\right) - x}}{\sqrt{x + 1} + \sqrt{x}} \]
    3. remove-double-neg54.5%

      \[\leadsto \frac{\left(x + 1\right) - x}{\sqrt{x + 1} + \color{blue}{\left(-\left(-\sqrt{x}\right)\right)}} \]
    4. sub-neg54.5%

      \[\leadsto \frac{\left(x + 1\right) - x}{\color{blue}{\sqrt{x + 1} - \left(-\sqrt{x}\right)}} \]
    5. div-sub53.6%

      \[\leadsto \color{blue}{\frac{x + 1}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} - \frac{x}{\sqrt{x + 1} - \left(-\sqrt{x}\right)}} \]
    6. rem-square-sqrt53.5%

      \[\leadsto \frac{x + 1}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} - \frac{\color{blue}{\sqrt{x} \cdot \sqrt{x}}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
    7. sqr-neg53.5%

      \[\leadsto \frac{x + 1}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} - \frac{\color{blue}{\left(-\sqrt{x}\right) \cdot \left(-\sqrt{x}\right)}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
    8. div-sub54.0%

      \[\leadsto \color{blue}{\frac{\left(x + 1\right) - \left(-\sqrt{x}\right) \cdot \left(-\sqrt{x}\right)}{\sqrt{x + 1} - \left(-\sqrt{x}\right)}} \]
    9. +-commutative54.0%

      \[\leadsto \frac{\color{blue}{\left(1 + x\right)} - \left(-\sqrt{x}\right) \cdot \left(-\sqrt{x}\right)}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
    10. sqr-neg54.0%

      \[\leadsto \frac{\left(1 + x\right) - \color{blue}{\sqrt{x} \cdot \sqrt{x}}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
    11. rem-square-sqrt54.5%

      \[\leadsto \frac{\left(1 + x\right) - \color{blue}{x}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
    12. associate--l+99.7%

      \[\leadsto \frac{\color{blue}{1 + \left(x - x\right)}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
    13. +-inverses99.7%

      \[\leadsto \frac{1 + \color{blue}{0}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
    14. metadata-eval99.7%

      \[\leadsto \frac{\color{blue}{1}}{\sqrt{x + 1} - \left(-\sqrt{x}\right)} \]
    15. sub-neg99.7%

      \[\leadsto \frac{1}{\color{blue}{\sqrt{x + 1} + \left(-\left(-\sqrt{x}\right)\right)}} \]
    16. remove-double-neg99.7%

      \[\leadsto \frac{1}{\sqrt{x + 1} + \color{blue}{\sqrt{x}}} \]
  5. Simplified99.7%

    \[\leadsto \color{blue}{\frac{1}{\sqrt{1 + x} + \sqrt{x}}} \]
  6. Step-by-step derivation
    1. expm1-log1p-u99.7%

      \[\leadsto \color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{1}{\sqrt{1 + x} + \sqrt{x}}\right)\right)} \]
    2. expm1-udef54.9%

      \[\leadsto \color{blue}{e^{\mathsf{log1p}\left(\frac{1}{\sqrt{1 + x} + \sqrt{x}}\right)} - 1} \]
  7. Applied egg-rr51.3%

    \[\leadsto \color{blue}{e^{\mathsf{log1p}\left(\frac{1}{\sqrt{1 + \left(x + x\right)}}\right)} - 1} \]
  8. Step-by-step derivation
    1. expm1-def58.7%

      \[\leadsto \color{blue}{\mathsf{expm1}\left(\mathsf{log1p}\left(\frac{1}{\sqrt{1 + \left(x + x\right)}}\right)\right)} \]
    2. expm1-log1p58.7%

      \[\leadsto \color{blue}{\frac{1}{\sqrt{1 + \left(x + x\right)}}} \]
  9. Simplified58.7%

    \[\leadsto \color{blue}{\frac{1}{\sqrt{1 + \left(x + x\right)}}} \]
  10. Taylor expanded in x around 0 52.1%

    \[\leadsto \frac{1}{\color{blue}{1 + x}} \]
  11. Final simplification52.1%

    \[\leadsto \frac{1}{1 + x} \]

Alternative 7: 51.6% accurate, 205.0× speedup?

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

\\
1
\end{array}
Derivation
  1. Initial program 53.6%

    \[\sqrt{x + 1} - \sqrt{x} \]
  2. Taylor expanded in x around 0 52.0%

    \[\leadsto \color{blue}{1} \]
  3. Final simplification52.0%

    \[\leadsto 1 \]

Developer target: 99.7% accurate, 1.0× speedup?

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

\\
\frac{1}{\sqrt{x + 1} + \sqrt{x}}
\end{array}

Reproduce

?
herbie shell --seed 2023285 
(FPCore (x)
  :name "Main:bigenough3 from C"
  :precision binary64

  :herbie-target
  (/ 1.0 (+ (sqrt (+ x 1.0)) (sqrt x)))

  (- (sqrt (+ x 1.0)) (sqrt x)))