
(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 4 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 (+ 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}
Initial program 7.3%
flip--8.8%
div-inv8.8%
add-sqr-sqrt8.1%
add-sqr-sqrt9.5%
associate--l+9.5%
Applied egg-rr9.5%
associate-*r/9.5%
*-rgt-identity9.5%
+-commutative9.5%
associate-+l-99.7%
div-sub99.7%
+-inverses99.7%
div099.7%
--rgt-identity99.7%
+-commutative99.7%
Simplified99.7%
(FPCore (x) :precision binary64 (* 0.5 (pow x -0.5)))
double code(double x) {
return 0.5 * pow(x, -0.5);
}
real(8) function code(x)
real(8), intent (in) :: x
code = 0.5d0 * (x ** (-0.5d0))
end function
public static double code(double x) {
return 0.5 * Math.pow(x, -0.5);
}
def code(x): return 0.5 * math.pow(x, -0.5)
function code(x) return Float64(0.5 * (x ^ -0.5)) end
function tmp = code(x) tmp = 0.5 * (x ^ -0.5); end
code[x_] := N[(0.5 * N[Power[x, -0.5], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
0.5 \cdot {x}^{-0.5}
\end{array}
Initial program 7.3%
flip--8.8%
div-inv8.8%
add-sqr-sqrt8.1%
add-sqr-sqrt9.5%
associate--l+9.5%
Applied egg-rr9.5%
associate-*r/9.5%
*-rgt-identity9.5%
+-commutative9.5%
associate-+l-99.7%
div-sub99.7%
+-inverses99.7%
div099.7%
--rgt-identity99.7%
+-commutative99.7%
Simplified99.7%
Taylor expanded in x around inf 97.4%
rem-exp-log90.4%
exp-neg90.4%
unpow1/290.4%
exp-prod90.4%
distribute-lft-neg-out90.4%
distribute-rgt-neg-in90.4%
metadata-eval90.4%
exp-to-pow97.7%
Simplified97.7%
(FPCore (x) :precision binary64 (sqrt (/ 0.25 x)))
double code(double x) {
return sqrt((0.25 / x));
}
real(8) function code(x)
real(8), intent (in) :: x
code = sqrt((0.25d0 / x))
end function
public static double code(double x) {
return Math.sqrt((0.25 / x));
}
def code(x): return math.sqrt((0.25 / x))
function code(x) return sqrt(Float64(0.25 / x)) end
function tmp = code(x) tmp = sqrt((0.25 / x)); end
code[x_] := N[Sqrt[N[(0.25 / x), $MachinePrecision]], $MachinePrecision]
\begin{array}{l}
\\
\sqrt{\frac{0.25}{x}}
\end{array}
Initial program 7.3%
flip--8.8%
div-inv8.8%
add-sqr-sqrt8.1%
add-sqr-sqrt9.5%
associate--l+9.5%
Applied egg-rr9.5%
associate-*r/9.5%
*-rgt-identity9.5%
+-commutative9.5%
associate-+l-99.7%
div-sub99.7%
+-inverses99.7%
div099.7%
--rgt-identity99.7%
+-commutative99.7%
Simplified99.7%
Taylor expanded in x around inf 97.4%
*-commutative97.4%
Simplified97.4%
add-sqr-sqrt96.8%
sqrt-unprod97.4%
associate-/r*97.4%
pow1/297.4%
pow-flip97.6%
metadata-eval97.6%
associate-/r*97.6%
pow1/297.6%
pow-flip97.7%
metadata-eval97.7%
frac-times97.7%
pow-prod-up97.4%
metadata-eval97.4%
inv-pow97.4%
metadata-eval97.4%
Applied egg-rr97.4%
associate-/l/97.4%
associate-/r*97.4%
metadata-eval97.4%
Simplified97.4%
(FPCore (x) :precision binary64 0.5)
double code(double x) {
return 0.5;
}
real(8) function code(x)
real(8), intent (in) :: x
code = 0.5d0
end function
public static double code(double x) {
return 0.5;
}
def code(x): return 0.5
function code(x) return 0.5 end
function tmp = code(x) tmp = 0.5; end
code[x_] := 0.5
\begin{array}{l}
\\
0.5
\end{array}
Initial program 7.3%
flip--8.8%
div-inv8.8%
add-sqr-sqrt8.1%
add-sqr-sqrt9.5%
associate--l+9.5%
Applied egg-rr9.5%
associate-*r/9.5%
*-rgt-identity9.5%
+-commutative9.5%
associate-+l-99.7%
div-sub99.7%
+-inverses99.7%
div099.7%
--rgt-identity99.7%
+-commutative99.7%
Simplified99.7%
Taylor expanded in x around inf 97.4%
rem-exp-log90.4%
exp-neg90.4%
unpow1/290.4%
exp-prod90.4%
distribute-lft-neg-out90.4%
distribute-rgt-neg-in90.4%
metadata-eval90.4%
exp-to-pow97.7%
Simplified97.7%
metadata-eval97.7%
pow-flip97.4%
pow1/297.4%
add-sqr-sqrt96.8%
associate-/r*96.8%
metadata-eval96.8%
sqrt-div97.1%
pow1/297.1%
pow-flip97.2%
metadata-eval97.2%
sqrt-pow197.1%
metadata-eval97.1%
pow1/297.1%
sqrt-pow197.2%
add-exp-log91.7%
add-sqr-sqrt90.4%
sqrt-unprod91.7%
sqr-neg91.7%
sqrt-unprod0.0%
add-sqr-sqrt7.0%
rec-exp7.0%
add-exp-log7.0%
sqrt-pow17.0%
inv-pow7.0%
Applied egg-rr7.0%
*-inverses7.0%
Simplified7.0%
Final simplification7.0%
(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 2024088
(FPCore (x)
:name "2sqrt (example 3.1)"
:precision binary64
:pre (and (> x 1.0) (< x 1e+308))
:alt
(/ 1.0 (+ (sqrt (+ x 1.0)) (sqrt x)))
(- (sqrt (+ x 1.0)) (sqrt x)))