
(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 -5.8e-56)
(/ c (- b))
(if (<= b 2.5e+87)
(/ (- (- 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 <= -5.8e-56) {
tmp = c / -b;
} else if (b <= 2.5e+87) {
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 <= (-5.8d-56)) then
tmp = c / -b
else if (b <= 2.5d+87) 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 <= -5.8e-56) {
tmp = c / -b;
} else if (b <= 2.5e+87) {
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 <= -5.8e-56: tmp = c / -b elif b <= 2.5e+87: 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 <= -5.8e-56) tmp = Float64(c / Float64(-b)); elseif (b <= 2.5e+87) 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 <= -5.8e-56) tmp = c / -b; elseif (b <= 2.5e+87) 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, -5.8e-56], N[(c / (-b)), $MachinePrecision], If[LessEqual[b, 2.5e+87], 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 -5.8 \cdot 10^{-56}:\\
\;\;\;\;\frac{c}{-b}\\
\mathbf{elif}\;b \leq 2.5 \cdot 10^{+87}:\\
\;\;\;\;\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 < -5.79999999999999982e-56Initial program 16.3%
div-sub14.9%
sub-neg14.9%
neg-mul-114.9%
*-commutative14.9%
associate-/l*13.7%
distribute-neg-frac13.7%
neg-mul-113.7%
*-commutative13.7%
associate-/l*14.9%
distribute-rgt-out16.3%
associate-/r*16.3%
metadata-eval16.3%
sub-neg16.3%
+-commutative16.3%
Simplified16.3%
Taylor expanded in b around -inf 86.2%
mul-1-neg86.2%
distribute-neg-frac286.2%
Simplified86.2%
if -5.79999999999999982e-56 < b < 2.4999999999999999e87Initial program 79.9%
if 2.4999999999999999e87 < b Initial program 44.5%
div-sub44.5%
sub-neg44.5%
neg-mul-144.5%
*-commutative44.5%
associate-/l*44.5%
distribute-neg-frac44.5%
neg-mul-144.5%
*-commutative44.5%
associate-/l*44.4%
distribute-rgt-out44.4%
associate-/r*44.4%
metadata-eval44.4%
sub-neg44.4%
+-commutative44.4%
Simplified44.4%
Taylor expanded in c around 0 96.0%
+-commutative96.0%
mul-1-neg96.0%
unsub-neg96.0%
Simplified96.0%
Final simplification86.3%
(FPCore (a b c) :precision binary64 (if (<= b -5e-310) (/ c (- b)) (- (/ c b) (/ b a))))
double code(double a, double b, double c) {
double tmp;
if (b <= -5e-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 <= (-5d-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 <= -5e-310) {
tmp = c / -b;
} else {
tmp = (c / b) - (b / a);
}
return tmp;
}
def code(a, b, c): tmp = 0 if b <= -5e-310: tmp = c / -b else: tmp = (c / b) - (b / a) return tmp
function code(a, b, c) tmp = 0.0 if (b <= -5e-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 <= -5e-310) tmp = c / -b; else tmp = (c / b) - (b / a); end tmp_2 = tmp; end
code[a_, b_, c_] := If[LessEqual[b, -5e-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 -5 \cdot 10^{-310}:\\
\;\;\;\;\frac{c}{-b}\\
\mathbf{else}:\\
\;\;\;\;\frac{c}{b} - \frac{b}{a}\\
\end{array}
\end{array}
if b < -4.999999999999985e-310Initial program 35.4%
div-sub34.4%
sub-neg34.4%
neg-mul-134.4%
*-commutative34.4%
associate-/l*33.6%
distribute-neg-frac33.6%
neg-mul-133.6%
*-commutative33.6%
associate-/l*34.4%
distribute-rgt-out35.4%
associate-/r*35.4%
metadata-eval35.4%
sub-neg35.4%
+-commutative35.4%
Simplified35.4%
Taylor expanded in b around -inf 64.2%
mul-1-neg64.2%
distribute-neg-frac264.2%
Simplified64.2%
if -4.999999999999985e-310 < b Initial program 60.7%
div-sub60.7%
sub-neg60.7%
neg-mul-160.7%
*-commutative60.7%
associate-/l*60.6%
distribute-neg-frac60.6%
neg-mul-160.6%
*-commutative60.6%
associate-/l*60.6%
distribute-rgt-out60.6%
associate-/r*60.6%
metadata-eval60.6%
sub-neg60.6%
+-commutative60.6%
Simplified60.6%
Taylor expanded in c around 0 71.6%
+-commutative71.6%
mul-1-neg71.6%
unsub-neg71.6%
Simplified71.6%
(FPCore (a b c) :precision binary64 (if (<= b -2.6e-305) (/ c (- b)) (/ b (- a))))
double code(double a, double b, double c) {
double tmp;
if (b <= -2.6e-305) {
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 <= (-2.6d-305)) 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 <= -2.6e-305) {
tmp = c / -b;
} else {
tmp = b / -a;
}
return tmp;
}
def code(a, b, c): tmp = 0 if b <= -2.6e-305: tmp = c / -b else: tmp = b / -a return tmp
function code(a, b, c) tmp = 0.0 if (b <= -2.6e-305) 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 <= -2.6e-305) tmp = c / -b; else tmp = b / -a; end tmp_2 = tmp; end
code[a_, b_, c_] := If[LessEqual[b, -2.6e-305], N[(c / (-b)), $MachinePrecision], N[(b / (-a)), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b \leq -2.6 \cdot 10^{-305}:\\
\;\;\;\;\frac{c}{-b}\\
\mathbf{else}:\\
\;\;\;\;\frac{b}{-a}\\
\end{array}
\end{array}
if b < -2.6000000000000002e-305Initial program 34.9%
div-sub33.9%
sub-neg33.9%
neg-mul-133.9%
*-commutative33.9%
associate-/l*33.1%
distribute-neg-frac33.1%
neg-mul-133.1%
*-commutative33.1%
associate-/l*33.9%
distribute-rgt-out34.9%
associate-/r*34.9%
metadata-eval34.9%
sub-neg34.9%
+-commutative34.9%
Simplified34.9%
Taylor expanded in b around -inf 64.7%
mul-1-neg64.7%
distribute-neg-frac264.7%
Simplified64.7%
if -2.6000000000000002e-305 < b Initial program 61.0%
div-sub61.0%
sub-neg61.0%
neg-mul-161.0%
*-commutative61.0%
associate-/l*60.9%
distribute-neg-frac60.9%
neg-mul-160.9%
*-commutative60.9%
associate-/l*60.9%
distribute-rgt-out60.9%
associate-/r*60.9%
metadata-eval60.9%
sub-neg60.9%
+-commutative60.9%
Simplified60.9%
Taylor expanded in a around 0 70.8%
associate-*r/70.8%
mul-1-neg70.8%
Simplified70.8%
Final simplification67.6%
(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 47.5%
div-sub47.0%
sub-neg47.0%
neg-mul-147.0%
*-commutative47.0%
associate-/l*46.6%
distribute-neg-frac46.6%
neg-mul-146.6%
*-commutative46.6%
associate-/l*47.0%
distribute-rgt-out47.5%
associate-/r*47.5%
metadata-eval47.5%
sub-neg47.5%
+-commutative47.5%
Simplified47.5%
Taylor expanded in b around -inf 34.4%
mul-1-neg34.4%
distribute-neg-frac234.4%
Simplified34.4%
(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 47.5%
div-sub47.0%
sub-neg47.0%
neg-mul-147.0%
*-commutative47.0%
associate-/l*46.6%
distribute-neg-frac46.6%
neg-mul-146.6%
*-commutative46.6%
associate-/l*47.0%
distribute-rgt-out47.5%
associate-/r*47.5%
metadata-eval47.5%
sub-neg47.5%
+-commutative47.5%
Simplified47.5%
Applied egg-rr30.7%
Taylor expanded in a around 0 11.4%
(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(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 47.5%
div-sub47.0%
sub-neg47.0%
neg-mul-147.0%
*-commutative47.0%
associate-/l*46.6%
distribute-neg-frac46.6%
neg-mul-146.6%
*-commutative46.6%
associate-/l*47.0%
distribute-rgt-out47.5%
associate-/r*47.5%
metadata-eval47.5%
sub-neg47.5%
+-commutative47.5%
Simplified47.5%
Applied egg-rr30.7%
Taylor expanded in b around -inf 2.7%
(FPCore (a b c)
:precision binary64
(let* ((t_0 (fabs (/ b 2.0)))
(t_1 (* (sqrt (fabs a)) (sqrt (fabs c))))
(t_2
(if (== (copysign a c) a)
(* (sqrt (- t_0 t_1)) (sqrt (+ t_0 t_1)))
(hypot (/ b 2.0) t_1))))
(if (< b 0.0) (/ c (- t_2 (/ b 2.0))) (/ (+ (/ b 2.0) t_2) (- a)))))
double code(double a, double b, double c) {
double t_0 = fabs((b / 2.0));
double t_1 = sqrt(fabs(a)) * sqrt(fabs(c));
double tmp;
if (copysign(a, c) == a) {
tmp = sqrt((t_0 - t_1)) * sqrt((t_0 + t_1));
} else {
tmp = hypot((b / 2.0), t_1);
}
double t_2 = tmp;
double tmp_1;
if (b < 0.0) {
tmp_1 = c / (t_2 - (b / 2.0));
} else {
tmp_1 = ((b / 2.0) + t_2) / -a;
}
return tmp_1;
}
public static double code(double a, double b, double c) {
double t_0 = Math.abs((b / 2.0));
double t_1 = Math.sqrt(Math.abs(a)) * Math.sqrt(Math.abs(c));
double tmp;
if (Math.copySign(a, c) == a) {
tmp = Math.sqrt((t_0 - t_1)) * Math.sqrt((t_0 + t_1));
} else {
tmp = Math.hypot((b / 2.0), t_1);
}
double t_2 = tmp;
double tmp_1;
if (b < 0.0) {
tmp_1 = c / (t_2 - (b / 2.0));
} else {
tmp_1 = ((b / 2.0) + t_2) / -a;
}
return tmp_1;
}
def code(a, b, c): t_0 = math.fabs((b / 2.0)) t_1 = math.sqrt(math.fabs(a)) * math.sqrt(math.fabs(c)) tmp = 0 if math.copysign(a, c) == a: tmp = math.sqrt((t_0 - t_1)) * math.sqrt((t_0 + t_1)) else: tmp = math.hypot((b / 2.0), t_1) t_2 = tmp tmp_1 = 0 if b < 0.0: tmp_1 = c / (t_2 - (b / 2.0)) else: tmp_1 = ((b / 2.0) + t_2) / -a return tmp_1
function code(a, b, c) t_0 = abs(Float64(b / 2.0)) t_1 = Float64(sqrt(abs(a)) * sqrt(abs(c))) tmp = 0.0 if (copysign(a, c) == a) tmp = Float64(sqrt(Float64(t_0 - t_1)) * sqrt(Float64(t_0 + t_1))); else tmp = hypot(Float64(b / 2.0), t_1); end t_2 = tmp tmp_1 = 0.0 if (b < 0.0) tmp_1 = Float64(c / Float64(t_2 - Float64(b / 2.0))); else tmp_1 = Float64(Float64(Float64(b / 2.0) + t_2) / Float64(-a)); end return tmp_1 end
function tmp_3 = code(a, b, c) t_0 = abs((b / 2.0)); t_1 = sqrt(abs(a)) * sqrt(abs(c)); tmp = 0.0; if ((sign(c) * abs(a)) == a) tmp = sqrt((t_0 - t_1)) * sqrt((t_0 + t_1)); else tmp = hypot((b / 2.0), t_1); end t_2 = tmp; tmp_2 = 0.0; if (b < 0.0) tmp_2 = c / (t_2 - (b / 2.0)); else tmp_2 = ((b / 2.0) + t_2) / -a; end tmp_3 = tmp_2; end
code[a_, b_, c_] := Block[{t$95$0 = N[Abs[N[(b / 2.0), $MachinePrecision]], $MachinePrecision]}, Block[{t$95$1 = N[(N[Sqrt[N[Abs[a], $MachinePrecision]], $MachinePrecision] * N[Sqrt[N[Abs[c], $MachinePrecision]], $MachinePrecision]), $MachinePrecision]}, Block[{t$95$2 = If[Equal[N[With[{TMP1 = Abs[a], TMP2 = Sign[c]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision], a], N[(N[Sqrt[N[(t$95$0 - t$95$1), $MachinePrecision]], $MachinePrecision] * N[Sqrt[N[(t$95$0 + t$95$1), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[Sqrt[N[(b / 2.0), $MachinePrecision] ^ 2 + t$95$1 ^ 2], $MachinePrecision]]}, If[Less[b, 0.0], N[(c / N[(t$95$2 - N[(b / 2.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(N[(N[(b / 2.0), $MachinePrecision] + t$95$2), $MachinePrecision] / (-a)), $MachinePrecision]]]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \left|\frac{b}{2}\right|\\
t_1 := \sqrt{\left|a\right|} \cdot \sqrt{\left|c\right|}\\
t_2 := \begin{array}{l}
\mathbf{if}\;\mathsf{copysign}\left(a, c\right) = a:\\
\;\;\;\;\sqrt{t\_0 - t\_1} \cdot \sqrt{t\_0 + t\_1}\\
\mathbf{else}:\\
\;\;\;\;\mathsf{hypot}\left(\frac{b}{2}, t\_1\right)\\
\end{array}\\
\mathbf{if}\;b < 0:\\
\;\;\;\;\frac{c}{t\_2 - \frac{b}{2}}\\
\mathbf{else}:\\
\;\;\;\;\frac{\frac{b}{2} + t\_2}{-a}\\
\end{array}
\end{array}
herbie shell --seed 2024139
(FPCore (a b c)
:name "quadm (p42, negative)"
:precision binary64
:herbie-expected 10
:alt
(! :herbie-platform default (let ((sqtD (let ((x (* (sqrt (fabs a)) (sqrt (fabs c))))) (if (== (copysign a c) a) (* (sqrt (- (fabs (/ b 2)) x)) (sqrt (+ (fabs (/ b 2)) x))) (hypot (/ b 2) x))))) (if (< b 0) (/ c (- sqtD (/ b 2))) (/ (+ (/ b 2) sqtD) (- a)))))
(/ (- (- b) (sqrt (- (* b b) (* 4.0 (* a c))))) (* 2.0 a)))