
(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 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(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 -1.26e-73)
(/ c (- b))
(if (<= b 4.4e+107)
(/ (- (- b) (sqrt (fma a (* c -4.0) (* b b)))) (* a 2.0))
(- (/ c b) (/ b a)))))
double code(double a, double b, double c) {
double tmp;
if (b <= -1.26e-73) {
tmp = c / -b;
} else if (b <= 4.4e+107) {
tmp = (-b - sqrt(fma(a, (c * -4.0), (b * b)))) / (a * 2.0);
} else {
tmp = (c / b) - (b / a);
}
return tmp;
}
function code(a, b, c) tmp = 0.0 if (b <= -1.26e-73) tmp = Float64(c / Float64(-b)); elseif (b <= 4.4e+107) tmp = Float64(Float64(Float64(-b) - sqrt(fma(a, Float64(c * -4.0), Float64(b * b)))) / Float64(a * 2.0)); else tmp = Float64(Float64(c / b) - Float64(b / a)); end return tmp end
code[a_, b_, c_] := If[LessEqual[b, -1.26e-73], N[(c / (-b)), $MachinePrecision], If[LessEqual[b, 4.4e+107], N[(N[((-b) - N[Sqrt[N[(a * N[(c * -4.0), $MachinePrecision] + N[(b * b), $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 -1.26 \cdot 10^{-73}:\\
\;\;\;\;\frac{c}{-b}\\
\mathbf{elif}\;b \leq 4.4 \cdot 10^{+107}:\\
\;\;\;\;\frac{\left(-b\right) - \sqrt{\mathsf{fma}\left(a, c \cdot -4, b \cdot b\right)}}{a \cdot 2}\\
\mathbf{else}:\\
\;\;\;\;\frac{c}{b} - \frac{b}{a}\\
\end{array}
\end{array}
if b < -1.26000000000000001e-73Initial program 21.0%
Taylor expanded in b around -inf
mul-1-negN/A
distribute-neg-frac2N/A
mul-1-negN/A
lower-/.f64N/A
mul-1-negN/A
lower-neg.f6484.8
Simplified84.8%
if -1.26000000000000001e-73 < b < 4.4e107Initial program 82.5%
Taylor expanded in b around 0
cancel-sign-sub-invN/A
metadata-evalN/A
+-commutativeN/A
*-commutativeN/A
associate-*l*N/A
*-commutativeN/A
lower-fma.f64N/A
*-commutativeN/A
lower-*.f64N/A
unpow2N/A
lower-*.f6482.5
Simplified82.5%
if 4.4e107 < b Initial program 57.9%
Taylor expanded in c around 0
+-commutativeN/A
mul-1-negN/A
unsub-negN/A
lower--.f64N/A
lower-/.f64N/A
lower-/.f6494.6
Simplified94.6%
Final simplification85.7%
(FPCore (a b c)
:precision binary64
(if (<= b -1.26e-73)
(/ c (- b))
(if (<= b 1.1e-37)
(/ (- (- b) (sqrt (* a (* c -4.0)))) (* a 2.0))
(- (/ c b) (/ b a)))))
double code(double a, double b, double c) {
double tmp;
if (b <= -1.26e-73) {
tmp = c / -b;
} else if (b <= 1.1e-37) {
tmp = (-b - sqrt((a * (c * -4.0)))) / (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 <= (-1.26d-73)) then
tmp = c / -b
else if (b <= 1.1d-37) then
tmp = (-b - sqrt((a * (c * (-4.0d0))))) / (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 <= -1.26e-73) {
tmp = c / -b;
} else if (b <= 1.1e-37) {
tmp = (-b - Math.sqrt((a * (c * -4.0)))) / (a * 2.0);
} else {
tmp = (c / b) - (b / a);
}
return tmp;
}
def code(a, b, c): tmp = 0 if b <= -1.26e-73: tmp = c / -b elif b <= 1.1e-37: tmp = (-b - math.sqrt((a * (c * -4.0)))) / (a * 2.0) else: tmp = (c / b) - (b / a) return tmp
function code(a, b, c) tmp = 0.0 if (b <= -1.26e-73) tmp = Float64(c / Float64(-b)); elseif (b <= 1.1e-37) tmp = Float64(Float64(Float64(-b) - sqrt(Float64(a * Float64(c * -4.0)))) / 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 <= -1.26e-73) tmp = c / -b; elseif (b <= 1.1e-37) tmp = (-b - sqrt((a * (c * -4.0)))) / (a * 2.0); else tmp = (c / b) - (b / a); end tmp_2 = tmp; end
code[a_, b_, c_] := If[LessEqual[b, -1.26e-73], N[(c / (-b)), $MachinePrecision], If[LessEqual[b, 1.1e-37], N[(N[((-b) - N[Sqrt[N[(a * N[(c * -4.0), $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 -1.26 \cdot 10^{-73}:\\
\;\;\;\;\frac{c}{-b}\\
\mathbf{elif}\;b \leq 1.1 \cdot 10^{-37}:\\
\;\;\;\;\frac{\left(-b\right) - \sqrt{a \cdot \left(c \cdot -4\right)}}{a \cdot 2}\\
\mathbf{else}:\\
\;\;\;\;\frac{c}{b} - \frac{b}{a}\\
\end{array}
\end{array}
if b < -1.26000000000000001e-73Initial program 21.0%
Taylor expanded in b around -inf
mul-1-negN/A
distribute-neg-frac2N/A
mul-1-negN/A
lower-/.f64N/A
mul-1-negN/A
lower-neg.f6484.8
Simplified84.8%
if -1.26000000000000001e-73 < b < 1.10000000000000001e-37Initial program 79.7%
Taylor expanded in b around 0
cancel-sign-sub-invN/A
metadata-evalN/A
+-commutativeN/A
*-commutativeN/A
associate-*l*N/A
*-commutativeN/A
lower-fma.f64N/A
*-commutativeN/A
lower-*.f64N/A
unpow2N/A
lower-*.f6479.7
Simplified79.7%
Taylor expanded in a around inf
*-commutativeN/A
associate-*r*N/A
*-commutativeN/A
lower-*.f64N/A
*-commutativeN/A
lower-*.f6474.7
Simplified74.7%
if 1.10000000000000001e-37 < b Initial program 71.7%
Taylor expanded in c around 0
+-commutativeN/A
mul-1-negN/A
unsub-negN/A
lower--.f64N/A
lower-/.f64N/A
lower-/.f6486.4
Simplified86.4%
Final simplification82.3%
(FPCore (a b c) :precision binary64 (if (<= b -2e-311) (/ c (- b)) (- (/ c b) (/ b a))))
double code(double a, double b, double c) {
double tmp;
if (b <= -2e-311) {
tmp = c / -b;
} 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 <= (-2d-311)) then
tmp = c / -b
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 <= -2e-311) {
tmp = c / -b;
} else {
tmp = (c / b) - (b / a);
}
return tmp;
}
def code(a, b, c): tmp = 0 if b <= -2e-311: tmp = c / -b else: tmp = (c / b) - (b / a) return tmp
function code(a, b, c) tmp = 0.0 if (b <= -2e-311) tmp = Float64(c / Float64(-b)); 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 <= -2e-311) tmp = c / -b; else tmp = (c / b) - (b / a); end tmp_2 = tmp; end
code[a_, b_, c_] := If[LessEqual[b, -2e-311], N[(c / (-b)), $MachinePrecision], N[(N[(c / b), $MachinePrecision] - N[(b / a), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -2 \cdot 10^{-311}:\\
\;\;\;\;\frac{c}{-b}\\
\mathbf{else}:\\
\;\;\;\;\frac{c}{b} - \frac{b}{a}\\
\end{array}
\end{array}
if b < -1.9999999999999e-311Initial program 40.0%
Taylor expanded in b around -inf
mul-1-negN/A
distribute-neg-frac2N/A
mul-1-negN/A
lower-/.f64N/A
mul-1-negN/A
lower-neg.f6458.2
Simplified58.2%
if -1.9999999999999e-311 < b Initial program 75.4%
Taylor expanded in c around 0
+-commutativeN/A
mul-1-negN/A
unsub-negN/A
lower--.f64N/A
lower-/.f64N/A
lower-/.f6468.7
Simplified68.7%
(FPCore (a b c) :precision binary64 (if (<= b -2e-311) (/ c (- b)) (/ b (- a))))
double code(double a, double b, double c) {
double tmp;
if (b <= -2e-311) {
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-311)) 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-311) {
tmp = c / -b;
} else {
tmp = b / -a;
}
return tmp;
}
def code(a, b, c): tmp = 0 if b <= -2e-311: tmp = c / -b else: tmp = b / -a return tmp
function code(a, b, c) tmp = 0.0 if (b <= -2e-311) tmp = Float64(c / Float64(-b)); else tmp = Float64(b / Float64(-a)); end return tmp end
function tmp_2 = code(a, b, c) tmp = 0.0; if (b <= -2e-311) tmp = c / -b; else tmp = b / -a; end tmp_2 = tmp; end
code[a_, b_, c_] := If[LessEqual[b, -2e-311], N[(c / (-b)), $MachinePrecision], N[(b / (-a)), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -2 \cdot 10^{-311}:\\
\;\;\;\;\frac{c}{-b}\\
\mathbf{else}:\\
\;\;\;\;\frac{b}{-a}\\
\end{array}
\end{array}
if b < -1.9999999999999e-311Initial program 40.0%
Taylor expanded in b around -inf
mul-1-negN/A
distribute-neg-frac2N/A
mul-1-negN/A
lower-/.f64N/A
mul-1-negN/A
lower-neg.f6458.2
Simplified58.2%
if -1.9999999999999e-311 < b Initial program 75.4%
Taylor expanded in b around inf
mul-1-negN/A
distribute-neg-frac2N/A
mul-1-negN/A
lower-/.f64N/A
mul-1-negN/A
lower-neg.f6468.3
Simplified68.3%
(FPCore (a b c) :precision binary64 (if (<= b 3.7e-299) 0.0 (/ b (- a))))
double code(double a, double b, double c) {
double tmp;
if (b <= 3.7e-299) {
tmp = 0.0;
} 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 <= 3.7d-299) then
tmp = 0.0d0
else
tmp = b / -a
end if
code = tmp
end function
public static double code(double a, double b, double c) {
double tmp;
if (b <= 3.7e-299) {
tmp = 0.0;
} else {
tmp = b / -a;
}
return tmp;
}
def code(a, b, c): tmp = 0 if b <= 3.7e-299: tmp = 0.0 else: tmp = b / -a return tmp
function code(a, b, c) tmp = 0.0 if (b <= 3.7e-299) tmp = 0.0; else tmp = Float64(b / Float64(-a)); end return tmp end
function tmp_2 = code(a, b, c) tmp = 0.0; if (b <= 3.7e-299) tmp = 0.0; else tmp = b / -a; end tmp_2 = tmp; end
code[a_, b_, c_] := If[LessEqual[b, 3.7e-299], 0.0, N[(b / (-a)), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq 3.7 \cdot 10^{-299}:\\
\;\;\;\;0\\
\mathbf{else}:\\
\;\;\;\;\frac{b}{-a}\\
\end{array}
\end{array}
if b < 3.70000000000000014e-299Initial program 40.5%
Taylor expanded in b around -inf
mul-1-negN/A
lower-neg.f6413.2
Simplified13.2%
Taylor expanded in b around 0
Simplified13.2%
if 3.70000000000000014e-299 < b Initial program 75.2%
Taylor expanded in b around inf
mul-1-negN/A
distribute-neg-frac2N/A
mul-1-negN/A
lower-/.f64N/A
mul-1-negN/A
lower-neg.f6468.8
Simplified68.8%
(FPCore (a b c) :precision binary64 0.0)
double code(double a, double b, double c) {
return 0.0;
}
real(8) function code(a, b, c)
real(8), intent (in) :: a
real(8), intent (in) :: b
real(8), intent (in) :: c
code = 0.0d0
end function
public static double code(double a, double b, double c) {
return 0.0;
}
def code(a, b, c): return 0.0
function code(a, b, c) return 0.0 end
function tmp = code(a, b, c) tmp = 0.0; end
code[a_, b_, c_] := 0.0
\begin{array}{l}
\\
0
\end{array}
Initial program 58.5%
Taylor expanded in b around -inf
mul-1-negN/A
lower-neg.f647.8
Simplified7.8%
Taylor expanded in b around 0
Simplified7.8%
(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 2024215
(FPCore (a b c)
:name "The quadratic formula (r2)"
:precision binary64
:alt
(! :herbie-platform default (let ((d (sqrt (- (* b b) (* 4 (* a c)))))) (let ((r1 (/ (+ (- b) d) (* 2 a)))) (let ((r2 (/ (- (- b) d) (* 2 a)))) (if (< b 0) (/ c (* a r1)) r2)))))
(/ (- (- b) (sqrt (- (* b b) (* 4.0 (* a c))))) (* 2.0 a)))