
(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 5 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 -2.3e-147)
(/ c (- b))
(if (<= b 7e+114)
(/ (- (- 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 <= -2.3e-147) {
tmp = c / -b;
} else if (b <= 7e+114) {
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 <= (-2.3d-147)) then
tmp = c / -b
else if (b <= 7d+114) 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 <= -2.3e-147) {
tmp = c / -b;
} else if (b <= 7e+114) {
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 <= -2.3e-147: tmp = c / -b elif b <= 7e+114: 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 <= -2.3e-147) tmp = Float64(c / Float64(-b)); elseif (b <= 7e+114) 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 <= -2.3e-147) tmp = c / -b; elseif (b <= 7e+114) 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, -2.3e-147], N[(c / (-b)), $MachinePrecision], If[LessEqual[b, 7e+114], 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 -2.3 \cdot 10^{-147}:\\
\;\;\;\;\frac{c}{-b}\\
\mathbf{elif}\;b \leq 7 \cdot 10^{+114}:\\
\;\;\;\;\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 < -2.2999999999999999e-147Initial program 24.5%
div-sub21.3%
sub-neg21.3%
neg-mul-121.3%
*-commutative21.3%
associate-/l*20.2%
distribute-neg-frac20.2%
neg-mul-120.2%
*-commutative20.2%
associate-/l*21.3%
distribute-rgt-out24.4%
associate-/r*24.4%
metadata-eval24.4%
sub-neg24.4%
+-commutative24.4%
Simplified24.4%
Taylor expanded in b around -inf 80.7%
mul-1-neg80.7%
distribute-neg-frac280.7%
Simplified80.7%
if -2.2999999999999999e-147 < b < 7.0000000000000001e114Initial program 87.2%
if 7.0000000000000001e114 < b Initial program 49.2%
div-sub49.2%
sub-neg49.2%
neg-mul-149.2%
*-commutative49.2%
associate-/l*49.2%
distribute-neg-frac49.2%
neg-mul-149.2%
*-commutative49.2%
associate-/l*49.2%
distribute-rgt-out49.2%
associate-/r*49.2%
metadata-eval49.2%
sub-neg49.2%
+-commutative49.2%
Simplified49.2%
Taylor expanded in c around 0 96.9%
+-commutative96.9%
mul-1-neg96.9%
unsub-neg96.9%
Simplified96.9%
Final simplification87.0%
(FPCore (a b c) :precision binary64 (if (<= b -2e-310) (/ c (- b)) (- (/ c b) (/ b a))))
double code(double a, double b, double c) {
double tmp;
if (b <= -2e-310) {
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-310)) 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-310) {
tmp = c / -b;
} else {
tmp = (c / b) - (b / a);
}
return tmp;
}
def code(a, b, c): tmp = 0 if b <= -2e-310: tmp = c / -b else: tmp = (c / b) - (b / a) return tmp
function code(a, b, c) tmp = 0.0 if (b <= -2e-310) 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-310) tmp = c / -b; else tmp = (c / b) - (b / a); end tmp_2 = tmp; end
code[a_, b_, c_] := If[LessEqual[b, -2e-310], 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^{-310}:\\
\;\;\;\;\frac{c}{-b}\\
\mathbf{else}:\\
\;\;\;\;\frac{c}{b} - \frac{b}{a}\\
\end{array}
\end{array}
if b < -1.999999999999994e-310Initial program 32.3%
div-sub29.7%
sub-neg29.7%
neg-mul-129.7%
*-commutative29.7%
associate-/l*28.7%
distribute-neg-frac28.7%
neg-mul-128.7%
*-commutative28.7%
associate-/l*29.6%
distribute-rgt-out32.2%
associate-/r*32.2%
metadata-eval32.2%
sub-neg32.2%
+-commutative32.2%
Simplified32.2%
Taylor expanded in b around -inf 69.5%
mul-1-neg69.5%
distribute-neg-frac269.5%
Simplified69.5%
if -1.999999999999994e-310 < b Initial program 73.0%
div-sub73.1%
sub-neg73.1%
neg-mul-173.1%
*-commutative73.1%
associate-/l*73.0%
distribute-neg-frac73.0%
neg-mul-173.0%
*-commutative73.0%
associate-/l*72.9%
distribute-rgt-out72.9%
associate-/r*72.9%
metadata-eval72.9%
sub-neg72.9%
+-commutative72.9%
Simplified72.9%
Taylor expanded in c around 0 72.1%
+-commutative72.1%
mul-1-neg72.1%
unsub-neg72.1%
Simplified72.1%
(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(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-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 32.3%
div-sub29.7%
sub-neg29.7%
neg-mul-129.7%
*-commutative29.7%
associate-/l*28.7%
distribute-neg-frac28.7%
neg-mul-128.7%
*-commutative28.7%
associate-/l*29.6%
distribute-rgt-out32.2%
associate-/r*32.2%
metadata-eval32.2%
sub-neg32.2%
+-commutative32.2%
Simplified32.2%
Taylor expanded in b around -inf 69.5%
mul-1-neg69.5%
distribute-neg-frac269.5%
Simplified69.5%
if -1.999999999999994e-310 < b Initial program 73.0%
div-sub73.1%
sub-neg73.1%
neg-mul-173.1%
*-commutative73.1%
associate-/l*73.0%
distribute-neg-frac73.0%
neg-mul-173.0%
*-commutative73.0%
associate-/l*72.9%
distribute-rgt-out72.9%
associate-/r*72.9%
metadata-eval72.9%
sub-neg72.9%
+-commutative72.9%
Simplified72.9%
Taylor expanded in a around 0 71.4%
associate-*r/71.4%
mul-1-neg71.4%
Simplified71.4%
Final simplification70.5%
(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 / Float64(-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 54.3%
div-sub53.1%
sub-neg53.1%
neg-mul-153.1%
*-commutative53.1%
associate-/l*52.6%
distribute-neg-frac52.6%
neg-mul-152.6%
*-commutative52.6%
associate-/l*53.0%
distribute-rgt-out54.2%
associate-/r*54.2%
metadata-eval54.2%
sub-neg54.2%
+-commutative54.2%
Simplified54.2%
Taylor expanded in b around -inf 33.2%
mul-1-neg33.2%
distribute-neg-frac233.2%
Simplified33.2%
(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 54.3%
div-sub53.1%
sub-neg53.1%
neg-mul-153.1%
*-commutative53.1%
associate-/l*52.6%
distribute-neg-frac52.6%
neg-mul-152.6%
*-commutative52.6%
associate-/l*53.0%
distribute-rgt-out54.2%
associate-/r*54.2%
metadata-eval54.2%
sub-neg54.2%
+-commutative54.2%
Simplified54.2%
Taylor expanded in a around 0 39.1%
Taylor expanded in a around inf 8.8%
(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 2024111
(FPCore (a b c)
:name "The quadratic formula (r2)"
:precision binary64
:alt
(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)))