
(FPCore (a b c) :precision binary64 (/ (+ (- b) (sqrt (- (* b b) (* (* 4.0 a) c)))) (* 2.0 a)))
double code(double a, double b, double c) {
return (-b + sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * 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) - ((4.0d0 * a) * c)))) / (2.0d0 * a)
end function
public static double code(double a, double b, double c) {
return (-b + Math.sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a);
}
def code(a, b, c): return (-b + math.sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a)
function code(a, b, c) return Float64(Float64(Float64(-b) + sqrt(Float64(Float64(b * b) - Float64(Float64(4.0 * a) * c)))) / Float64(2.0 * a)) end
function tmp = code(a, b, c) tmp = (-b + sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a); end
code[a_, b_, c_] := N[(N[((-b) + N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(N[(4.0 * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \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) (* (* 4.0 a) c)))) (* 2.0 a)))
double code(double a, double b, double c) {
return (-b + sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * 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) - ((4.0d0 * a) * c)))) / (2.0d0 * a)
end function
public static double code(double a, double b, double c) {
return (-b + Math.sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a);
}
def code(a, b, c): return (-b + math.sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a)
function code(a, b, c) return Float64(Float64(Float64(-b) + sqrt(Float64(Float64(b * b) - Float64(Float64(4.0 * a) * c)))) / Float64(2.0 * a)) end
function tmp = code(a, b, c) tmp = (-b + sqrt(((b * b) - ((4.0 * a) * c)))) / (2.0 * a); end
code[a_, b_, c_] := N[(N[((-b) + N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(N[(4.0 * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\left(-b\right) + \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}}{2 \cdot a}
\end{array}
(FPCore (a b c)
:precision binary64
(if (<= b -5e+153)
(- (/ c b) (/ b a))
(if (<= b 3.3e-84)
(/ (+ (- b) (sqrt (fma (* c a) -4.0 (* b b)))) (* 2.0 a))
(/ (- c) b))))
double code(double a, double b, double c) {
double tmp;
if (b <= -5e+153) {
tmp = (c / b) - (b / a);
} else if (b <= 3.3e-84) {
tmp = (-b + sqrt(fma((c * a), -4.0, (b * b)))) / (2.0 * a);
} else {
tmp = -c / b;
}
return tmp;
}
function code(a, b, c) tmp = 0.0 if (b <= -5e+153) tmp = Float64(Float64(c / b) - Float64(b / a)); elseif (b <= 3.3e-84) tmp = Float64(Float64(Float64(-b) + sqrt(fma(Float64(c * a), -4.0, Float64(b * b)))) / Float64(2.0 * a)); else tmp = Float64(Float64(-c) / b); end return tmp end
code[a_, b_, c_] := If[LessEqual[b, -5e+153], N[(N[(c / b), $MachinePrecision] - N[(b / a), $MachinePrecision]), $MachinePrecision], If[LessEqual[b, 3.3e-84], N[(N[((-b) + N[Sqrt[N[(N[(c * a), $MachinePrecision] * -4.0 + N[(b * b), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision], N[((-c) / b), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -5 \cdot 10^{+153}:\\
\;\;\;\;\frac{c}{b} - \frac{b}{a}\\
\mathbf{elif}\;b \leq 3.3 \cdot 10^{-84}:\\
\;\;\;\;\frac{\left(-b\right) + \sqrt{\mathsf{fma}\left(c \cdot a, -4, b \cdot b\right)}}{2 \cdot a}\\
\mathbf{else}:\\
\;\;\;\;\frac{-c}{b}\\
\end{array}
\end{array}
if b < -5.00000000000000018e153Initial program 39.3%
Taylor expanded in b around -inf
mul-1-negN/A
lower-neg.f64N/A
distribute-rgt-inN/A
associate-*l/N/A
*-lft-identityN/A
lower-fma.f64N/A
associate-*r/N/A
mul-1-negN/A
lower-/.f64N/A
lower-neg.f64N/A
unpow2N/A
lower-*.f64N/A
lower-/.f6499.2
Applied rewrites99.2%
Taylor expanded in c around 0
Applied rewrites100.0%
if -5.00000000000000018e153 < b < 3.29999999999999984e-84Initial program 82.4%
lift--.f64N/A
lift-*.f64N/A
fp-cancel-sub-sign-invN/A
+-commutativeN/A
lift-*.f64N/A
distribute-lft-neg-inN/A
associate-*r*N/A
*-commutativeN/A
lower-fma.f64N/A
*-commutativeN/A
lower-*.f64N/A
metadata-eval82.4
Applied rewrites82.4%
if 3.29999999999999984e-84 < b Initial program 11.1%
Taylor expanded in a around 0
associate-*r/N/A
mul-1-negN/A
lower-/.f64N/A
lower-neg.f6489.4
Applied rewrites89.4%
(FPCore (a b c)
:precision binary64
(if (<= b -6e-59)
(- (/ c b) (/ b a))
(if (<= b 1.82e-90)
(/ (+ (- b) (sqrt (* (* c a) -4.0))) (* 2.0 a))
(/ (- c) b))))
double code(double a, double b, double c) {
double tmp;
if (b <= -6e-59) {
tmp = (c / b) - (b / a);
} else if (b <= 1.82e-90) {
tmp = (-b + sqrt(((c * a) * -4.0))) / (2.0 * a);
} else {
tmp = -c / 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 <= (-6d-59)) then
tmp = (c / b) - (b / a)
else if (b <= 1.82d-90) then
tmp = (-b + sqrt(((c * a) * (-4.0d0)))) / (2.0d0 * a)
else
tmp = -c / b
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double tmp;
if (b <= -6e-59) {
tmp = (c / b) - (b / a);
} else if (b <= 1.82e-90) {
tmp = (-b + Math.sqrt(((c * a) * -4.0))) / (2.0 * a);
} else {
tmp = -c / b;
}
return tmp;
}
def code(a, b, c): tmp = 0 if b <= -6e-59: tmp = (c / b) - (b / a) elif b <= 1.82e-90: tmp = (-b + math.sqrt(((c * a) * -4.0))) / (2.0 * a) else: tmp = -c / b return tmp
function code(a, b, c) tmp = 0.0 if (b <= -6e-59) tmp = Float64(Float64(c / b) - Float64(b / a)); elseif (b <= 1.82e-90) tmp = Float64(Float64(Float64(-b) + sqrt(Float64(Float64(c * a) * -4.0))) / Float64(2.0 * a)); else tmp = Float64(Float64(-c) / b); end return tmp end
function tmp_2 = code(a, b, c) tmp = 0.0; if (b <= -6e-59) tmp = (c / b) - (b / a); elseif (b <= 1.82e-90) tmp = (-b + sqrt(((c * a) * -4.0))) / (2.0 * a); else tmp = -c / b; end tmp_2 = tmp; end
code[a_, b_, c_] := If[LessEqual[b, -6e-59], N[(N[(c / b), $MachinePrecision] - N[(b / a), $MachinePrecision]), $MachinePrecision], If[LessEqual[b, 1.82e-90], N[(N[((-b) + N[Sqrt[N[(N[(c * a), $MachinePrecision] * -4.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision], N[((-c) / b), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -6 \cdot 10^{-59}:\\
\;\;\;\;\frac{c}{b} - \frac{b}{a}\\
\mathbf{elif}\;b \leq 1.82 \cdot 10^{-90}:\\
\;\;\;\;\frac{\left(-b\right) + \sqrt{\left(c \cdot a\right) \cdot -4}}{2 \cdot a}\\
\mathbf{else}:\\
\;\;\;\;\frac{-c}{b}\\
\end{array}
\end{array}
if b < -6.0000000000000002e-59Initial program 68.5%
Taylor expanded in b around -inf
mul-1-negN/A
lower-neg.f64N/A
distribute-rgt-inN/A
associate-*l/N/A
*-lft-identityN/A
lower-fma.f64N/A
associate-*r/N/A
mul-1-negN/A
lower-/.f64N/A
lower-neg.f64N/A
unpow2N/A
lower-*.f64N/A
lower-/.f6487.8
Applied rewrites87.8%
Taylor expanded in c around 0
Applied rewrites88.2%
if -6.0000000000000002e-59 < b < 1.8199999999999999e-90Initial program 77.8%
Taylor expanded in a around inf
*-commutativeN/A
lower-*.f64N/A
*-commutativeN/A
lower-*.f6473.8
Applied rewrites73.8%
if 1.8199999999999999e-90 < b Initial program 11.1%
Taylor expanded in a around 0
associate-*r/N/A
mul-1-negN/A
lower-/.f64N/A
lower-neg.f6489.4
Applied rewrites89.4%
(FPCore (a b c) :precision binary64 (if (<= b -4e-310) (- (/ c b) (/ b a)) (/ (- c) b)))
double code(double a, double b, double c) {
double tmp;
if (b <= -4e-310) {
tmp = (c / b) - (b / a);
} else {
tmp = -c / 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 <= (-4d-310)) then
tmp = (c / b) - (b / a)
else
tmp = -c / b
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double tmp;
if (b <= -4e-310) {
tmp = (c / b) - (b / a);
} else {
tmp = -c / b;
}
return tmp;
}
def code(a, b, c): tmp = 0 if b <= -4e-310: tmp = (c / b) - (b / a) else: tmp = -c / b return tmp
function code(a, b, c) tmp = 0.0 if (b <= -4e-310) tmp = Float64(Float64(c / b) - Float64(b / a)); else tmp = Float64(Float64(-c) / b); end return tmp end
function tmp_2 = code(a, b, c) tmp = 0.0; if (b <= -4e-310) tmp = (c / b) - (b / a); else tmp = -c / b; end tmp_2 = tmp; end
code[a_, b_, c_] := If[LessEqual[b, -4e-310], N[(N[(c / b), $MachinePrecision] - N[(b / a), $MachinePrecision]), $MachinePrecision], N[((-c) / b), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -4 \cdot 10^{-310}:\\
\;\;\;\;\frac{c}{b} - \frac{b}{a}\\
\mathbf{else}:\\
\;\;\;\;\frac{-c}{b}\\
\end{array}
\end{array}
if b < -3.999999999999988e-310Initial program 74.2%
Taylor expanded in b around -inf
mul-1-negN/A
lower-neg.f64N/A
distribute-rgt-inN/A
associate-*l/N/A
*-lft-identityN/A
lower-fma.f64N/A
associate-*r/N/A
mul-1-negN/A
lower-/.f64N/A
lower-neg.f64N/A
unpow2N/A
lower-*.f64N/A
lower-/.f6466.4
Applied rewrites66.4%
Taylor expanded in c around 0
Applied rewrites67.7%
if -3.999999999999988e-310 < b Initial program 26.3%
Taylor expanded in a around 0
associate-*r/N/A
mul-1-negN/A
lower-/.f64N/A
lower-neg.f6470.1
Applied rewrites70.1%
(FPCore (a b c) :precision binary64 (if (<= b -4e-310) (/ (- b) a) (/ (- c) b)))
double code(double a, double b, double c) {
double tmp;
if (b <= -4e-310) {
tmp = -b / a;
} else {
tmp = -c / 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 <= (-4d-310)) then
tmp = -b / a
else
tmp = -c / b
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double tmp;
if (b <= -4e-310) {
tmp = -b / a;
} else {
tmp = -c / b;
}
return tmp;
}
def code(a, b, c): tmp = 0 if b <= -4e-310: tmp = -b / a else: tmp = -c / b return tmp
function code(a, b, c) tmp = 0.0 if (b <= -4e-310) tmp = Float64(Float64(-b) / a); else tmp = Float64(Float64(-c) / b); end return tmp end
function tmp_2 = code(a, b, c) tmp = 0.0; if (b <= -4e-310) tmp = -b / a; else tmp = -c / b; end tmp_2 = tmp; end
code[a_, b_, c_] := If[LessEqual[b, -4e-310], N[((-b) / a), $MachinePrecision], N[((-c) / b), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -4 \cdot 10^{-310}:\\
\;\;\;\;\frac{-b}{a}\\
\mathbf{else}:\\
\;\;\;\;\frac{-c}{b}\\
\end{array}
\end{array}
if b < -3.999999999999988e-310Initial program 74.2%
Taylor expanded in b around -inf
associate-*r/N/A
lower-/.f64N/A
mul-1-negN/A
lower-neg.f6467.4
Applied rewrites67.4%
if -3.999999999999988e-310 < b Initial program 26.3%
Taylor expanded in a around 0
associate-*r/N/A
mul-1-negN/A
lower-/.f64N/A
lower-neg.f6470.1
Applied rewrites70.1%
(FPCore (a b c) :precision binary64 (if (<= b 2.05e-29) (/ (- b) a) (/ c b)))
double code(double a, double b, double c) {
double tmp;
if (b <= 2.05e-29) {
tmp = -b / a;
} else {
tmp = c / 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 <= 2.05d-29) then
tmp = -b / a
else
tmp = c / b
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double tmp;
if (b <= 2.05e-29) {
tmp = -b / a;
} else {
tmp = c / b;
}
return tmp;
}
def code(a, b, c): tmp = 0 if b <= 2.05e-29: tmp = -b / a else: tmp = c / b return tmp
function code(a, b, c) tmp = 0.0 if (b <= 2.05e-29) tmp = Float64(Float64(-b) / a); else tmp = Float64(c / b); end return tmp end
function tmp_2 = code(a, b, c) tmp = 0.0; if (b <= 2.05e-29) tmp = -b / a; else tmp = c / b; end tmp_2 = tmp; end
code[a_, b_, c_] := If[LessEqual[b, 2.05e-29], N[((-b) / a), $MachinePrecision], N[(c / b), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq 2.05 \cdot 10^{-29}:\\
\;\;\;\;\frac{-b}{a}\\
\mathbf{else}:\\
\;\;\;\;\frac{c}{b}\\
\end{array}
\end{array}
if b < 2.0499999999999999e-29Initial program 70.4%
Taylor expanded in b around -inf
associate-*r/N/A
lower-/.f64N/A
mul-1-negN/A
lower-neg.f6448.7
Applied rewrites48.7%
if 2.0499999999999999e-29 < b Initial program 10.7%
Taylor expanded in b around -inf
mul-1-negN/A
lower-neg.f64N/A
distribute-rgt-inN/A
associate-*l/N/A
*-lft-identityN/A
lower-fma.f64N/A
associate-*r/N/A
mul-1-negN/A
lower-/.f64N/A
lower-neg.f64N/A
unpow2N/A
lower-*.f64N/A
lower-/.f642.5
Applied rewrites2.5%
Taylor expanded in a around inf
Applied rewrites29.5%
(FPCore (a b c) :precision binary64 (/ c b))
double code(double a, double b, double c) {
return c / 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 / b
end function
public static double code(double a, double b, double c) {
return c / b;
}
def code(a, b, c): return c / b
function code(a, b, c) return Float64(c / b) end
function tmp = code(a, b, c) tmp = c / b; end
code[a_, b_, c_] := N[(c / b), $MachinePrecision]
\begin{array}{l}
\\
\frac{c}{b}
\end{array}
Initial program 47.0%
Taylor expanded in b around -inf
mul-1-negN/A
lower-neg.f64N/A
distribute-rgt-inN/A
associate-*l/N/A
*-lft-identityN/A
lower-fma.f64N/A
associate-*r/N/A
mul-1-negN/A
lower-/.f64N/A
lower-neg.f64N/A
unpow2N/A
lower-*.f64N/A
lower-/.f6430.0
Applied rewrites30.0%
Taylor expanded in a around inf
Applied rewrites13.3%
(FPCore (a b c)
:precision binary64
(let* ((t_0 (sqrt (- (* b b) (* (* 4.0 a) c)))))
(if (< b 0.0)
(/ (+ (- b) t_0) (* 2.0 a))
(/ c (* a (/ (- (- b) t_0) (* 2.0 a)))))))
double code(double a, double b, double c) {
double t_0 = sqrt(((b * b) - ((4.0 * a) * c)));
double tmp;
if (b < 0.0) {
tmp = (-b + t_0) / (2.0 * a);
} else {
tmp = c / (a * ((-b - t_0) / (2.0 * a)));
}
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) :: t_0
real(8) :: tmp
t_0 = sqrt(((b * b) - ((4.0d0 * a) * c)))
if (b < 0.0d0) then
tmp = (-b + t_0) / (2.0d0 * a)
else
tmp = c / (a * ((-b - t_0) / (2.0d0 * a)))
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double t_0 = Math.sqrt(((b * b) - ((4.0 * a) * c)));
double tmp;
if (b < 0.0) {
tmp = (-b + t_0) / (2.0 * a);
} else {
tmp = c / (a * ((-b - t_0) / (2.0 * a)));
}
return tmp;
}
def code(a, b, c): t_0 = math.sqrt(((b * b) - ((4.0 * a) * c))) tmp = 0 if b < 0.0: tmp = (-b + t_0) / (2.0 * a) else: tmp = c / (a * ((-b - t_0) / (2.0 * a))) return tmp
function code(a, b, c) t_0 = sqrt(Float64(Float64(b * b) - Float64(Float64(4.0 * a) * c))) tmp = 0.0 if (b < 0.0) tmp = Float64(Float64(Float64(-b) + t_0) / Float64(2.0 * a)); else tmp = Float64(c / Float64(a * Float64(Float64(Float64(-b) - t_0) / Float64(2.0 * a)))); end return tmp end
function tmp_2 = code(a, b, c) t_0 = sqrt(((b * b) - ((4.0 * a) * c))); tmp = 0.0; if (b < 0.0) tmp = (-b + t_0) / (2.0 * a); else tmp = c / (a * ((-b - t_0) / (2.0 * a))); end tmp_2 = tmp; end
code[a_, b_, c_] := Block[{t$95$0 = N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(N[(4.0 * a), $MachinePrecision] * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]}, If[Less[b, 0.0], N[(N[((-b) + t$95$0), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision], N[(c / N[(a * N[(N[((-b) - t$95$0), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt{b \cdot b - \left(4 \cdot a\right) \cdot c}\\
\mathbf{if}\;b < 0:\\
\;\;\;\;\frac{\left(-b\right) + t\_0}{2 \cdot a}\\
\mathbf{else}:\\
\;\;\;\;\frac{c}{a \cdot \frac{\left(-b\right) - t\_0}{2 \cdot a}}\\
\end{array}
\end{array}
herbie shell --seed 2024337
(FPCore (a b c)
:name "The quadratic formula (r1)"
:precision binary64
:alt
(! :herbie-platform default (let ((d (- (* b b) (* (* 4 a) c)))) (let ((r1 (/ (+ (- b) (sqrt d)) (* 2 a)))) (let ((r2 (/ (- (- b) (sqrt d)) (* 2 a)))) (if (< b 0) r1 (/ c (* a r2)))))))
(/ (+ (- b) (sqrt (- (* b b) (* (* 4.0 a) c)))) (* 2.0 a)))