
(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(4.0 * Float64(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[(4.0 * N[(a * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 4 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(4.0 * Float64(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[(4.0 * N[(a * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}}{2 \cdot a}
\end{array}
(FPCore (a b c)
:precision binary64
(if (<= b -2.6e-58)
(/ (- c) b)
(if (<= b 2e+97)
(/ (- (- b) (sqrt (- (* b b) (* 4.0 (* c a))))) (* a 2.0))
(- (/ c b) (/ b a)))))
double code(double a, double b, double c) {
double tmp;
if (b <= -2.6e-58) {
tmp = -c / b;
} else if (b <= 2e+97) {
tmp = (-b - sqrt(((b * b) - (4.0 * (c * a))))) / (a * 2.0);
} else {
tmp = (c / b) - (b / 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) :: tmp
if (b <= (-2.6d-58)) then
tmp = -c / b
else if (b <= 2d+97) then
tmp = (-b - sqrt(((b * b) - (4.0d0 * (c * a))))) / (a * 2.0d0)
else
tmp = (c / b) - (b / a)
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double tmp;
if (b <= -2.6e-58) {
tmp = -c / b;
} else if (b <= 2e+97) {
tmp = (-b - Math.sqrt(((b * b) - (4.0 * (c * a))))) / (a * 2.0);
} else {
tmp = (c / b) - (b / a);
}
return tmp;
}
def code(a, b, c): tmp = 0 if b <= -2.6e-58: tmp = -c / b elif b <= 2e+97: tmp = (-b - math.sqrt(((b * b) - (4.0 * (c * a))))) / (a * 2.0) else: tmp = (c / b) - (b / a) return tmp
function code(a, b, c) tmp = 0.0 if (b <= -2.6e-58) tmp = Float64(Float64(-c) / b); elseif (b <= 2e+97) tmp = Float64(Float64(Float64(-b) - sqrt(Float64(Float64(b * b) - Float64(4.0 * Float64(c * a))))) / Float64(a * 2.0)); else tmp = Float64(Float64(c / b) - Float64(b / a)); end return tmp end
function tmp_2 = code(a, b, c) tmp = 0.0; if (b <= -2.6e-58) tmp = -c / b; elseif (b <= 2e+97) tmp = (-b - sqrt(((b * b) - (4.0 * (c * a))))) / (a * 2.0); else tmp = (c / b) - (b / a); end tmp_2 = tmp; end
code[a_, b_, c_] := If[LessEqual[b, -2.6e-58], N[((-c) / b), $MachinePrecision], If[LessEqual[b, 2e+97], N[(N[((-b) - N[Sqrt[N[(N[(b * b), $MachinePrecision] - N[(4.0 * N[(c * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(a * 2.0), $MachinePrecision]), $MachinePrecision], N[(N[(c / b), $MachinePrecision] - N[(b / a), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -2.6 \cdot 10^{-58}:\\
\;\;\;\;\frac{-c}{b}\\
\mathbf{elif}\;b \leq 2 \cdot 10^{+97}:\\
\;\;\;\;\frac{\left(-b\right) - \sqrt{b \cdot b - 4 \cdot \left(c \cdot a\right)}}{a \cdot 2}\\
\mathbf{else}:\\
\;\;\;\;\frac{c}{b} - \frac{b}{a}\\
\end{array}
\end{array}
if b < -2.60000000000000007e-58Initial program 9.4%
Simplified9.4%
Taylor expanded in b around -inf 94.2%
associate-*r/94.2%
neg-mul-194.2%
Simplified94.2%
if -2.60000000000000007e-58 < b < 2.0000000000000001e97Initial program 81.4%
if 2.0000000000000001e97 < b Initial program 53.7%
Simplified53.9%
Taylor expanded in b around inf 98.4%
mul-1-neg98.4%
unsub-neg98.4%
Simplified98.4%
Final simplification89.5%
(FPCore (a b c)
:precision binary64
(if (<= b -3.15e-56)
(/ (- c) b)
(if (<= b 1.2e-41)
(/ (- (- b) (sqrt (* c (* a -4.0)))) (* a 2.0))
(- (/ b a)))))
double code(double a, double b, double c) {
double tmp;
if (b <= -3.15e-56) {
tmp = -c / b;
} else if (b <= 1.2e-41) {
tmp = (-b - sqrt((c * (a * -4.0)))) / (a * 2.0);
} else {
tmp = -(b / 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) :: tmp
if (b <= (-3.15d-56)) then
tmp = -c / b
else if (b <= 1.2d-41) then
tmp = (-b - sqrt((c * (a * (-4.0d0))))) / (a * 2.0d0)
else
tmp = -(b / a)
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double tmp;
if (b <= -3.15e-56) {
tmp = -c / b;
} else if (b <= 1.2e-41) {
tmp = (-b - Math.sqrt((c * (a * -4.0)))) / (a * 2.0);
} else {
tmp = -(b / a);
}
return tmp;
}
def code(a, b, c): tmp = 0 if b <= -3.15e-56: tmp = -c / b elif b <= 1.2e-41: tmp = (-b - math.sqrt((c * (a * -4.0)))) / (a * 2.0) else: tmp = -(b / a) return tmp
function code(a, b, c) tmp = 0.0 if (b <= -3.15e-56) tmp = Float64(Float64(-c) / b); elseif (b <= 1.2e-41) tmp = Float64(Float64(Float64(-b) - sqrt(Float64(c * Float64(a * -4.0)))) / Float64(a * 2.0)); else tmp = Float64(-Float64(b / a)); end return tmp end
function tmp_2 = code(a, b, c) tmp = 0.0; if (b <= -3.15e-56) tmp = -c / b; elseif (b <= 1.2e-41) tmp = (-b - sqrt((c * (a * -4.0)))) / (a * 2.0); else tmp = -(b / a); end tmp_2 = tmp; end
code[a_, b_, c_] := If[LessEqual[b, -3.15e-56], N[((-c) / b), $MachinePrecision], If[LessEqual[b, 1.2e-41], N[(N[((-b) - N[Sqrt[N[(c * N[(a * -4.0), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / N[(a * 2.0), $MachinePrecision]), $MachinePrecision], (-N[(b / a), $MachinePrecision])]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -3.15 \cdot 10^{-56}:\\
\;\;\;\;\frac{-c}{b}\\
\mathbf{elif}\;b \leq 1.2 \cdot 10^{-41}:\\
\;\;\;\;\frac{\left(-b\right) - \sqrt{c \cdot \left(a \cdot -4\right)}}{a \cdot 2}\\
\mathbf{else}:\\
\;\;\;\;-\frac{b}{a}\\
\end{array}
\end{array}
if b < -3.1499999999999999e-56Initial program 9.4%
Simplified9.4%
Taylor expanded in b around -inf 94.2%
associate-*r/94.2%
neg-mul-194.2%
Simplified94.2%
if -3.1499999999999999e-56 < b < 1.20000000000000011e-41Initial program 77.7%
Taylor expanded in b around 0 72.0%
*-commutative72.0%
associate-*l*72.0%
Simplified72.0%
if 1.20000000000000011e-41 < b Initial program 66.1%
Simplified66.2%
Taylor expanded in b around inf 89.4%
associate-*r/89.4%
mul-1-neg89.4%
Simplified89.4%
Final simplification85.1%
(FPCore (a b c) :precision binary64 (if (<= b -2e-310) (/ (- c) b) (- (/ b a))))
double code(double a, double b, double c) {
double tmp;
if (b <= -2e-310) {
tmp = -c / b;
} else {
tmp = -(b / 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) :: tmp
if (b <= (-2d-310)) then
tmp = -c / b
else
tmp = -(b / a)
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double tmp;
if (b <= -2e-310) {
tmp = -c / b;
} else {
tmp = -(b / a);
}
return tmp;
}
def code(a, b, c): tmp = 0 if b <= -2e-310: tmp = -c / b else: tmp = -(b / a) return tmp
function code(a, b, c) tmp = 0.0 if (b <= -2e-310) tmp = Float64(Float64(-c) / b); else tmp = Float64(-Float64(b / a)); end return tmp end
function tmp_2 = code(a, b, c) tmp = 0.0; if (b <= -2e-310) tmp = -c / b; else tmp = -(b / a); end tmp_2 = tmp; end
code[a_, b_, c_] := If[LessEqual[b, -2e-310], N[((-c) / b), $MachinePrecision], (-N[(b / a), $MachinePrecision])]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -2 \cdot 10^{-310}:\\
\;\;\;\;\frac{-c}{b}\\
\mathbf{else}:\\
\;\;\;\;-\frac{b}{a}\\
\end{array}
\end{array}
if b < -1.999999999999994e-310Initial program 30.6%
Simplified30.7%
Taylor expanded in b around -inf 67.1%
associate-*r/67.1%
neg-mul-167.1%
Simplified67.1%
if -1.999999999999994e-310 < b Initial program 73.1%
Simplified73.2%
Taylor expanded in b around inf 69.0%
associate-*r/69.0%
mul-1-neg69.0%
Simplified69.0%
Final simplification68.1%
(FPCore (a b c) :precision binary64 (- (/ b a)))
double code(double a, double b, double c) {
return -(b / 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 / a)
end function
public static double code(double a, double b, double c) {
return -(b / a);
}
def code(a, b, c): return -(b / a)
function code(a, b, c) return Float64(-Float64(b / a)) end
function tmp = code(a, b, c) tmp = -(b / a); end
code[a_, b_, c_] := (-N[(b / a), $MachinePrecision])
\begin{array}{l}
\\
-\frac{b}{a}
\end{array}
Initial program 51.9%
Simplified51.9%
Taylor expanded in b around inf 35.8%
associate-*r/35.8%
mul-1-neg35.8%
Simplified35.8%
Final simplification35.8%
(FPCore (a b c)
:precision binary64
(let* ((t_0 (sqrt (- (* b b) (* 4.0 (* a c))))))
(if (< b 0.0)
(/ c (* a (/ (+ (- b) t_0) (* 2.0 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 = c / (a * ((-b + t_0) / (2.0 * a)));
} else {
tmp = (-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 = c / (a * ((-b + t_0) / (2.0d0 * a)))
else
tmp = (-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 = c / (a * ((-b + t_0) / (2.0 * a)));
} else {
tmp = (-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 = c / (a * ((-b + t_0) / (2.0 * a))) else: tmp = (-b - t_0) / (2.0 * a) return tmp
function code(a, b, c) t_0 = sqrt(Float64(Float64(b * b) - Float64(4.0 * Float64(a * c)))) tmp = 0.0 if (b < 0.0) tmp = Float64(c / Float64(a * Float64(Float64(Float64(-b) + t_0) / Float64(2.0 * a)))); else tmp = 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 = c / (a * ((-b + t_0) / (2.0 * a))); else tmp = (-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[(4.0 * N[(a * c), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]}, If[Less[b, 0.0], N[(c / N[(a * N[(N[((-b) + t$95$0), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[((-b) - t$95$0), $MachinePrecision] / N[(2.0 * a), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt{b \cdot b - 4 \cdot \left(a \cdot c\right)}\\
\mathbf{if}\;b < 0:\\
\;\;\;\;\frac{c}{a \cdot \frac{\left(-b\right) + t_0}{2 \cdot a}}\\
\mathbf{else}:\\
\;\;\;\;\frac{\left(-b\right) - t_0}{2 \cdot a}\\
\end{array}
\end{array}
herbie shell --seed 2023252
(FPCore (a b c)
:name "The quadratic formula (r2)"
:precision binary64
:herbie-target
(if (< b 0.0) (/ c (* a (/ (+ (- b) (sqrt (- (* b b) (* 4.0 (* a c))))) (* 2.0 a)))) (/ (- (- b) (sqrt (- (* b b) (* 4.0 (* a c))))) (* 2.0 a)))
(/ (- (- b) (sqrt (- (* b b) (* 4.0 (* a c))))) (* 2.0 a)))