
(FPCore (a b c) :precision binary64 (/ (+ (- b) (sqrt (- (* b b) (* (* 3.0 a) c)))) (* 3.0 a)))
double code(double a, double b, double c) {
return (-b + sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * a);
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
code = (-b + sqrt(((b * b) - ((3.0d0 * a) * c)))) / (3.0d0 * a)
end function
public static double code(double a, double b, double c) {
return (-b + Math.sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * a);
}
def code(a, b, c): return (-b + math.sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * a)
function code(a, b, c) return Float64(Float64(Float64(-b) + sqrt(Float64(Float64(b * b) - Float64(Float64(3.0 * a) * c)))) / Float64(3.0 * a)) end
function tmp = code(a, b, c) tmp = (-b + sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * a); end
code[a_, b_, c_] := N[(N[((-b) + N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(N[(3.0 * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(3.0 * a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\left(-b\right) + \sqrt{b \cdot b - \left(3 \cdot a\right) \cdot c}}{3 \cdot a}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 6 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (a b c) :precision binary64 (/ (+ (- b) (sqrt (- (* b b) (* (* 3.0 a) c)))) (* 3.0 a)))
double code(double a, double b, double c) {
return (-b + sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * a);
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
code = (-b + sqrt(((b * b) - ((3.0d0 * a) * c)))) / (3.0d0 * a)
end function
public static double code(double a, double b, double c) {
return (-b + Math.sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * a);
}
def code(a, b, c): return (-b + math.sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * a)
function code(a, b, c) return Float64(Float64(Float64(-b) + sqrt(Float64(Float64(b * b) - Float64(Float64(3.0 * a) * c)))) / Float64(3.0 * a)) end
function tmp = code(a, b, c) tmp = (-b + sqrt(((b * b) - ((3.0 * a) * c)))) / (3.0 * a); end
code[a_, b_, c_] := N[(N[((-b) + N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(N[(3.0 * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(3.0 * a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\left(-b\right) + \sqrt{b \cdot b - \left(3 \cdot a\right) \cdot c}}{3 \cdot a}
\end{array}
(FPCore (a b c) :precision binary64 (/ (/ (* c (* a 3.0)) (* a 3.0)) (- (- b) (sqrt (fma b b (* -3.0 (* c a)))))))
double code(double a, double b, double c) {
return ((c * (a * 3.0)) / (a * 3.0)) / (-b - sqrt(fma(b, b, (-3.0 * (c * a)))));
}
function code(a, b, c) return Float64(Float64(Float64(c * Float64(a * 3.0)) / Float64(a * 3.0)) / Float64(Float64(-b) - sqrt(fma(b, b, Float64(-3.0 * Float64(c * a)))))) end
code[a_, b_, c_] := N[(N[(N[(c * N[(a * 3.0), $MachinePrecision]), $MachinePrecision] / N[(a * 3.0), $MachinePrecision]), $MachinePrecision] / N[((-b) - N[Sqrt[N[(b * b + N[(-3.0 * N[(c * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\frac{c \cdot \left(a \cdot 3\right)}{a \cdot 3}}{\left(-b\right) - \sqrt{\mathsf{fma}\left(b, b, -3 \cdot \left(c \cdot a\right)\right)}}
\end{array}
Initial program 57.5%
neg-sub057.5%
sqr-neg57.5%
associate-+l-57.5%
sub0-neg57.5%
sub-neg57.5%
distribute-neg-in57.5%
remove-double-neg57.5%
sqr-neg57.5%
associate-*l*57.5%
Simplified57.5%
add-exp-log57.4%
Applied egg-rr57.4%
flip-+57.7%
pow257.7%
add-sqr-sqrt59.3%
pow259.3%
rem-exp-log59.4%
*-commutative59.4%
pow259.4%
rem-exp-log59.4%
*-commutative59.4%
Applied egg-rr59.4%
associate--r-99.0%
*-commutative99.0%
associate-*r*99.3%
*-commutative99.3%
*-commutative99.3%
*-commutative99.3%
associate-*r*99.3%
*-commutative99.3%
*-commutative99.3%
Simplified99.3%
div-inv99.1%
+-commutative99.1%
*-commutative99.1%
fma-define99.1%
*-commutative99.1%
neg-mul-199.1%
unpow-prod-down99.1%
metadata-eval99.1%
*-un-lft-identity99.1%
*-commutative99.1%
Applied egg-rr99.1%
*-commutative99.1%
times-frac99.3%
*-lft-identity99.3%
associate-/r*99.4%
fma-undefine99.4%
+-inverses99.4%
+-rgt-identity99.4%
Simplified99.4%
(FPCore (a b c) :precision binary64 (if (<= b 1.65) (/ (- (sqrt (fma b b (* a (* c -3.0)))) b) (* a 3.0)) (+ (* -0.5 (/ c b)) (* -0.375 (/ (* a (pow c 2.0)) (pow b 3.0))))))
double code(double a, double b, double c) {
double tmp;
if (b <= 1.65) {
tmp = (sqrt(fma(b, b, (a * (c * -3.0)))) - b) / (a * 3.0);
} else {
tmp = (-0.5 * (c / b)) + (-0.375 * ((a * pow(c, 2.0)) / pow(b, 3.0)));
}
return tmp;
}
function code(a, b, c) tmp = 0.0 if (b <= 1.65) tmp = Float64(Float64(sqrt(fma(b, b, Float64(a * Float64(c * -3.0)))) - b) / Float64(a * 3.0)); else tmp = Float64(Float64(-0.5 * Float64(c / b)) + Float64(-0.375 * Float64(Float64(a * (c ^ 2.0)) / (b ^ 3.0)))); end return tmp end
code[a_, b_, c_] := If[LessEqual[b, 1.65], N[(N[(N[Sqrt[N[(b * b + N[(a * N[(c * -3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(a * 3.0), $MachinePrecision]), $MachinePrecision], N[(N[(-0.5 * N[(c / b), $MachinePrecision]), $MachinePrecision] + N[(-0.375 * N[(N[(a * N[Power[c, 2.0], $MachinePrecision]), $MachinePrecision] / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq 1.65:\\
\;\;\;\;\frac{\sqrt{\mathsf{fma}\left(b, b, a \cdot \left(c \cdot -3\right)\right)} - b}{a \cdot 3}\\
\mathbf{else}:\\
\;\;\;\;-0.5 \cdot \frac{c}{b} + -0.375 \cdot \frac{a \cdot {c}^{2}}{{b}^{3}}\\
\end{array}
\end{array}
if b < 1.6499999999999999Initial program 85.0%
/-rgt-identity85.0%
metadata-eval85.0%
Simplified85.0%
if 1.6499999999999999 < b Initial program 52.4%
neg-sub052.4%
sqr-neg52.4%
associate-+l-52.4%
sub0-neg52.4%
sub-neg52.4%
distribute-neg-in52.4%
remove-double-neg52.4%
sqr-neg52.4%
associate-*l*52.4%
Simplified52.4%
Taylor expanded in a around 0 84.7%
Final simplification84.7%
(FPCore (a b c) :precision binary64 (if (<= b 1.6) (/ (- (sqrt (fma b b (* a (* c -3.0)))) b) (* a 3.0)) (* c (- (* -0.375 (/ (* c a) (pow b 3.0))) (/ 0.5 b)))))
double code(double a, double b, double c) {
double tmp;
if (b <= 1.6) {
tmp = (sqrt(fma(b, b, (a * (c * -3.0)))) - b) / (a * 3.0);
} else {
tmp = c * ((-0.375 * ((c * a) / pow(b, 3.0))) - (0.5 / b));
}
return tmp;
}
function code(a, b, c) tmp = 0.0 if (b <= 1.6) tmp = Float64(Float64(sqrt(fma(b, b, Float64(a * Float64(c * -3.0)))) - b) / Float64(a * 3.0)); else tmp = Float64(c * Float64(Float64(-0.375 * Float64(Float64(c * a) / (b ^ 3.0))) - Float64(0.5 / b))); end return tmp end
code[a_, b_, c_] := If[LessEqual[b, 1.6], N[(N[(N[Sqrt[N[(b * b + N[(a * N[(c * -3.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(a * 3.0), $MachinePrecision]), $MachinePrecision], N[(c * N[(N[(-0.375 * N[(N[(c * a), $MachinePrecision] / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(0.5 / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq 1.6:\\
\;\;\;\;\frac{\sqrt{\mathsf{fma}\left(b, b, a \cdot \left(c \cdot -3\right)\right)} - b}{a \cdot 3}\\
\mathbf{else}:\\
\;\;\;\;c \cdot \left(-0.375 \cdot \frac{c \cdot a}{{b}^{3}} - \frac{0.5}{b}\right)\\
\end{array}
\end{array}
if b < 1.6000000000000001Initial program 85.0%
/-rgt-identity85.0%
metadata-eval85.0%
Simplified85.0%
if 1.6000000000000001 < b Initial program 52.4%
neg-sub052.4%
sqr-neg52.4%
associate-+l-52.4%
sub0-neg52.4%
sub-neg52.4%
distribute-neg-in52.4%
remove-double-neg52.4%
sqr-neg52.4%
associate-*l*52.4%
Simplified52.4%
Taylor expanded in a around 0 84.7%
Taylor expanded in c around 0 84.5%
associate-*r/84.5%
metadata-eval84.5%
Simplified84.5%
Final simplification84.6%
(FPCore (a b c) :precision binary64 (if (<= b 1.65) (/ (- (sqrt (- (* b b) (* 3.0 (* c a)))) b) (* a 3.0)) (* c (- (* -0.375 (/ (* c a) (pow b 3.0))) (/ 0.5 b)))))
double code(double a, double b, double c) {
double tmp;
if (b <= 1.65) {
tmp = (sqrt(((b * b) - (3.0 * (c * a)))) - b) / (a * 3.0);
} else {
tmp = c * ((-0.375 * ((c * a) / pow(b, 3.0))) - (0.5 / b));
}
return tmp;
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
real(8) :: tmp
if (b <= 1.65d0) then
tmp = (sqrt(((b * b) - (3.0d0 * (c * a)))) - b) / (a * 3.0d0)
else
tmp = c * (((-0.375d0) * ((c * a) / (b ** 3.0d0))) - (0.5d0 / b))
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double tmp;
if (b <= 1.65) {
tmp = (Math.sqrt(((b * b) - (3.0 * (c * a)))) - b) / (a * 3.0);
} else {
tmp = c * ((-0.375 * ((c * a) / Math.pow(b, 3.0))) - (0.5 / b));
}
return tmp;
}
def code(a, b, c): tmp = 0 if b <= 1.65: tmp = (math.sqrt(((b * b) - (3.0 * (c * a)))) - b) / (a * 3.0) else: tmp = c * ((-0.375 * ((c * a) / math.pow(b, 3.0))) - (0.5 / b)) return tmp
function code(a, b, c) tmp = 0.0 if (b <= 1.65) tmp = Float64(Float64(sqrt(Float64(Float64(b * b) - Float64(3.0 * Float64(c * a)))) - b) / Float64(a * 3.0)); else tmp = Float64(c * Float64(Float64(-0.375 * Float64(Float64(c * a) / (b ^ 3.0))) - Float64(0.5 / b))); end return tmp end
function tmp_2 = code(a, b, c) tmp = 0.0; if (b <= 1.65) tmp = (sqrt(((b * b) - (3.0 * (c * a)))) - b) / (a * 3.0); else tmp = c * ((-0.375 * ((c * a) / (b ^ 3.0))) - (0.5 / b)); end tmp_2 = tmp; end
code[a_, b_, c_] := If[LessEqual[b, 1.65], N[(N[(N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(3.0 * N[(c * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b), $MachinePrecision] / N[(a * 3.0), $MachinePrecision]), $MachinePrecision], N[(c * N[(N[(-0.375 * N[(N[(c * a), $MachinePrecision] / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(0.5 / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq 1.65:\\
\;\;\;\;\frac{\sqrt{b \cdot b - 3 \cdot \left(c \cdot a\right)} - b}{a \cdot 3}\\
\mathbf{else}:\\
\;\;\;\;c \cdot \left(-0.375 \cdot \frac{c \cdot a}{{b}^{3}} - \frac{0.5}{b}\right)\\
\end{array}
\end{array}
if b < 1.6499999999999999Initial program 85.0%
neg-sub085.0%
sqr-neg85.0%
associate-+l-85.0%
sub0-neg85.0%
sub-neg85.0%
distribute-neg-in85.0%
remove-double-neg85.0%
sqr-neg85.0%
associate-*l*85.0%
Simplified85.0%
if 1.6499999999999999 < b Initial program 52.4%
neg-sub052.4%
sqr-neg52.4%
associate-+l-52.4%
sub0-neg52.4%
sub-neg52.4%
distribute-neg-in52.4%
remove-double-neg52.4%
sqr-neg52.4%
associate-*l*52.4%
Simplified52.4%
Taylor expanded in a around 0 84.7%
Taylor expanded in c around 0 84.5%
associate-*r/84.5%
metadata-eval84.5%
Simplified84.5%
Final simplification84.6%
(FPCore (a b c) :precision binary64 (* c (- (* -0.375 (/ (* c a) (pow b 3.0))) (/ 0.5 b))))
double code(double a, double b, double c) {
return c * ((-0.375 * ((c * a) / pow(b, 3.0))) - (0.5 / b));
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
code = c * (((-0.375d0) * ((c * a) / (b ** 3.0d0))) - (0.5d0 / b))
end function
public static double code(double a, double b, double c) {
return c * ((-0.375 * ((c * a) / Math.pow(b, 3.0))) - (0.5 / b));
}
def code(a, b, c): return c * ((-0.375 * ((c * a) / math.pow(b, 3.0))) - (0.5 / b))
function code(a, b, c) return Float64(c * Float64(Float64(-0.375 * Float64(Float64(c * a) / (b ^ 3.0))) - Float64(0.5 / b))) end
function tmp = code(a, b, c) tmp = c * ((-0.375 * ((c * a) / (b ^ 3.0))) - (0.5 / b)); end
code[a_, b_, c_] := N[(c * N[(N[(-0.375 * N[(N[(c * a), $MachinePrecision] / N[Power[b, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] - N[(0.5 / b), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
c \cdot \left(-0.375 \cdot \frac{c \cdot a}{{b}^{3}} - \frac{0.5}{b}\right)
\end{array}
Initial program 57.5%
neg-sub057.5%
sqr-neg57.5%
associate-+l-57.5%
sub0-neg57.5%
sub-neg57.5%
distribute-neg-in57.5%
remove-double-neg57.5%
sqr-neg57.5%
associate-*l*57.5%
Simplified57.5%
Taylor expanded in a around 0 79.9%
Taylor expanded in c around 0 79.8%
associate-*r/79.8%
metadata-eval79.8%
Simplified79.8%
Final simplification79.8%
(FPCore (a b c) :precision binary64 (/ (* c -0.5) b))
double code(double a, double b, double c) {
return (c * -0.5) / b;
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
code = (c * (-0.5d0)) / b
end function
public static double code(double a, double b, double c) {
return (c * -0.5) / b;
}
def code(a, b, c): return (c * -0.5) / b
function code(a, b, c) return Float64(Float64(c * -0.5) / b) end
function tmp = code(a, b, c) tmp = (c * -0.5) / b; end
code[a_, b_, c_] := N[(N[(c * -0.5), $MachinePrecision] / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{c \cdot -0.5}{b}
\end{array}
Initial program 57.5%
neg-sub057.5%
sqr-neg57.5%
associate-+l-57.5%
sub0-neg57.5%
sub-neg57.5%
distribute-neg-in57.5%
remove-double-neg57.5%
sqr-neg57.5%
associate-*l*57.5%
Simplified57.5%
Taylor expanded in b around inf 62.5%
associate-*r/62.5%
*-commutative62.5%
Simplified62.5%
herbie shell --seed 2024094
(FPCore (a b c)
:name "Cubic critical, narrow range"
:precision binary64
:pre (and (and (and (< 1.0536712127723509e-8 a) (< a 94906265.62425156)) (and (< 1.0536712127723509e-8 b) (< b 94906265.62425156))) (and (< 1.0536712127723509e-8 c) (< c 94906265.62425156)))
(/ (+ (- b) (sqrt (- (* b b) (* (* 3.0 a) c)))) (* 3.0 a)))