
(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:
Herbie found 6 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(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}
(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}
Initial program 60.3%
lift--.f64N/A
flip--N/A
lower-/.f64N/A
lift-sqrt.f64N/A
lift-sqrt.f64N/A
rem-square-sqrtN/A
lift-sqrt.f64N/A
lift-sqrt.f64N/A
rem-square-sqrtN/A
lower--.f64N/A
lift-+.f64N/A
+-commutativeN/A
lower-+.f64N/A
+-commutativeN/A
lower-+.f6460.9
lift-+.f64N/A
+-commutativeN/A
lower-+.f6460.9
Applied rewrites60.9%
Taylor expanded in x around 0
Applied rewrites99.8%
Final simplification99.8%
(FPCore (x) :precision binary64 (if (<= (- (sqrt (+ x 1.0)) (sqrt x)) 0.002) (/ 0.5 (sqrt x)) (fma 0.5 x (- 1.0 (sqrt x)))))
double code(double x) {
double tmp;
if ((sqrt((x + 1.0)) - sqrt(x)) <= 0.002) {
tmp = 0.5 / sqrt(x);
} else {
tmp = fma(0.5, x, (1.0 - sqrt(x)));
}
return tmp;
}
function code(x) tmp = 0.0 if (Float64(sqrt(Float64(x + 1.0)) - sqrt(x)) <= 0.002) tmp = Float64(0.5 / sqrt(x)); else tmp = fma(0.5, x, Float64(1.0 - sqrt(x))); end return tmp end
code[x_] := If[LessEqual[N[(N[Sqrt[N[(x + 1.0), $MachinePrecision]], $MachinePrecision] - N[Sqrt[x], $MachinePrecision]), $MachinePrecision], 0.002], N[(0.5 / N[Sqrt[x], $MachinePrecision]), $MachinePrecision], N[(0.5 * x + N[(1.0 - N[Sqrt[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;\sqrt{x + 1} - \sqrt{x} \leq 0.002:\\
\;\;\;\;\frac{0.5}{\sqrt{x}}\\
\mathbf{else}:\\
\;\;\;\;\mathsf{fma}\left(0.5, x, 1 - \sqrt{x}\right)\\
\end{array}
\end{array}
if (-.f64 (sqrt.f64 (+.f64 x #s(literal 1 binary64))) (sqrt.f64 x)) < 2e-3Initial program 5.8%
Taylor expanded in x around inf
*-commutativeN/A
lower-*.f64N/A
lower-sqrt.f64N/A
lower-/.f6498.5
Applied rewrites98.5%
Applied rewrites98.3%
if 2e-3 < (-.f64 (sqrt.f64 (+.f64 x #s(literal 1 binary64))) (sqrt.f64 x)) Initial program 100.0%
Taylor expanded in x around 0
+-commutativeN/A
associate--l+N/A
lower-fma.f64N/A
lower--.f64N/A
lower-sqrt.f64100.0
Applied rewrites100.0%
(FPCore (x) :precision binary64 (if (<= x 50000000.0) (- (sqrt (+ x 1.0)) (sqrt x)) (* 0.5 (sqrt (/ 1.0 x)))))
double code(double x) {
double tmp;
if (x <= 50000000.0) {
tmp = sqrt((x + 1.0)) - sqrt(x);
} else {
tmp = 0.5 * sqrt((1.0 / x));
}
return tmp;
}
real(8) function code(x)
real(8), intent (in) :: x
real(8) :: tmp
if (x <= 50000000.0d0) then
tmp = sqrt((x + 1.0d0)) - sqrt(x)
else
tmp = 0.5d0 * sqrt((1.0d0 / x))
end if
code = tmp
end function
public static double code(double x) {
double tmp;
if (x <= 50000000.0) {
tmp = Math.sqrt((x + 1.0)) - Math.sqrt(x);
} else {
tmp = 0.5 * Math.sqrt((1.0 / x));
}
return tmp;
}
def code(x): tmp = 0 if x <= 50000000.0: tmp = math.sqrt((x + 1.0)) - math.sqrt(x) else: tmp = 0.5 * math.sqrt((1.0 / x)) return tmp
function code(x) tmp = 0.0 if (x <= 50000000.0) tmp = Float64(sqrt(Float64(x + 1.0)) - sqrt(x)); else tmp = Float64(0.5 * sqrt(Float64(1.0 / x))); end return tmp end
function tmp_2 = code(x) tmp = 0.0; if (x <= 50000000.0) tmp = sqrt((x + 1.0)) - sqrt(x); else tmp = 0.5 * sqrt((1.0 / x)); end tmp_2 = tmp; end
code[x_] := If[LessEqual[x, 50000000.0], N[(N[Sqrt[N[(x + 1.0), $MachinePrecision]], $MachinePrecision] - N[Sqrt[x], $MachinePrecision]), $MachinePrecision], N[(0.5 * N[Sqrt[N[(1.0 / x), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;x \leq 50000000:\\
\;\;\;\;\sqrt{x + 1} - \sqrt{x}\\
\mathbf{else}:\\
\;\;\;\;0.5 \cdot \sqrt{\frac{1}{x}}\\
\end{array}
\end{array}
if x < 5e7Initial program 99.8%
if 5e7 < x Initial program 5.2%
Taylor expanded in x around inf
*-commutativeN/A
lower-*.f64N/A
lower-sqrt.f64N/A
lower-/.f6499.0
Applied rewrites99.0%
Final simplification99.5%
(FPCore (x) :precision binary64 (if (<= x 1.0) (fma 0.5 x (- 1.0 (sqrt x))) (* 0.5 (sqrt (/ 1.0 x)))))
double code(double x) {
double tmp;
if (x <= 1.0) {
tmp = fma(0.5, x, (1.0 - sqrt(x)));
} else {
tmp = 0.5 * sqrt((1.0 / x));
}
return tmp;
}
function code(x) tmp = 0.0 if (x <= 1.0) tmp = fma(0.5, x, Float64(1.0 - sqrt(x))); else tmp = Float64(0.5 * sqrt(Float64(1.0 / x))); end return tmp end
code[x_] := If[LessEqual[x, 1.0], N[(0.5 * x + N[(1.0 - N[Sqrt[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(0.5 * N[Sqrt[N[(1.0 / x), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;x \leq 1:\\
\;\;\;\;\mathsf{fma}\left(0.5, x, 1 - \sqrt{x}\right)\\
\mathbf{else}:\\
\;\;\;\;0.5 \cdot \sqrt{\frac{1}{x}}\\
\end{array}
\end{array}
if x < 1Initial program 100.0%
Taylor expanded in x around 0
+-commutativeN/A
associate--l+N/A
lower-fma.f64N/A
lower--.f64N/A
lower-sqrt.f64100.0
Applied rewrites100.0%
if 1 < x Initial program 5.8%
Taylor expanded in x around inf
*-commutativeN/A
lower-*.f64N/A
lower-sqrt.f64N/A
lower-/.f6498.5
Applied rewrites98.5%
Final simplification99.4%
(FPCore (x) :precision binary64 (fma 0.5 x (- 1.0 (sqrt x))))
double code(double x) {
return fma(0.5, x, (1.0 - sqrt(x)));
}
function code(x) return fma(0.5, x, Float64(1.0 - sqrt(x))) end
code[x_] := N[(0.5 * x + N[(1.0 - N[Sqrt[x], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(0.5, x, 1 - \sqrt{x}\right)
\end{array}
Initial program 60.3%
Taylor expanded in x around 0
+-commutativeN/A
associate--l+N/A
lower-fma.f64N/A
lower--.f64N/A
lower-sqrt.f6459.6
Applied rewrites59.6%
(FPCore (x) :precision binary64 (- 1.0 (sqrt x)))
double code(double x) {
return 1.0 - sqrt(x);
}
real(8) function code(x)
real(8), intent (in) :: x
code = 1.0d0 - sqrt(x)
end function
public static double code(double x) {
return 1.0 - Math.sqrt(x);
}
def code(x): return 1.0 - math.sqrt(x)
function code(x) return Float64(1.0 - sqrt(x)) end
function tmp = code(x) tmp = 1.0 - sqrt(x); end
code[x_] := N[(1.0 - N[Sqrt[x], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
1 - \sqrt{x}
\end{array}
Initial program 60.3%
Taylor expanded in x around 0
Applied rewrites58.2%
(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}
herbie shell --seed 2024277
(FPCore (x)
:name "Main:bigenough3 from C"
:precision binary64
:alt
(! :herbie-platform default (/ 1 (+ (sqrt (+ x 1)) (sqrt x))))
(- (sqrt (+ x 1.0)) (sqrt x)))