
(FPCore (a b_2 c) :precision binary64 (/ (+ (- b_2) (sqrt (- (* b_2 b_2) (* a c)))) a))
double code(double a, double b_2, double c) {
return (-b_2 + sqrt(((b_2 * b_2) - (a * c)))) / a;
}
real(8) function code(a, b_2, c)
real(8), intent (in) :: a
real(8), intent (in) :: b_2
real(8), intent (in) :: c
code = (-b_2 + sqrt(((b_2 * b_2) - (a * c)))) / a
end function
public static double code(double a, double b_2, double c) {
return (-b_2 + Math.sqrt(((b_2 * b_2) - (a * c)))) / a;
}
def code(a, b_2, c): return (-b_2 + math.sqrt(((b_2 * b_2) - (a * c)))) / a
function code(a, b_2, c) return Float64(Float64(Float64(-b_2) + sqrt(Float64(Float64(b_2 * b_2) - Float64(a * c)))) / a) end
function tmp = code(a, b_2, c) tmp = (-b_2 + sqrt(((b_2 * b_2) - (a * c)))) / a; end
code[a_, b$95$2_, c_] := N[(N[((-b$95$2) + N[Sqrt[N[(N[(b$95$2 * b$95$2), $MachinePrecision] - N[(a * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / a), $MachinePrecision]
\begin{array}{l}
\\
\frac{\left(-b\_2\right) + \sqrt{b\_2 \cdot b\_2 - a \cdot c}}{a}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 5 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (a b_2 c) :precision binary64 (/ (+ (- b_2) (sqrt (- (* b_2 b_2) (* a c)))) a))
double code(double a, double b_2, double c) {
return (-b_2 + sqrt(((b_2 * b_2) - (a * c)))) / a;
}
real(8) function code(a, b_2, c)
real(8), intent (in) :: a
real(8), intent (in) :: b_2
real(8), intent (in) :: c
code = (-b_2 + sqrt(((b_2 * b_2) - (a * c)))) / a
end function
public static double code(double a, double b_2, double c) {
return (-b_2 + Math.sqrt(((b_2 * b_2) - (a * c)))) / a;
}
def code(a, b_2, c): return (-b_2 + math.sqrt(((b_2 * b_2) - (a * c)))) / a
function code(a, b_2, c) return Float64(Float64(Float64(-b_2) + sqrt(Float64(Float64(b_2 * b_2) - Float64(a * c)))) / a) end
function tmp = code(a, b_2, c) tmp = (-b_2 + sqrt(((b_2 * b_2) - (a * c)))) / a; end
code[a_, b$95$2_, c_] := N[(N[((-b$95$2) + N[Sqrt[N[(N[(b$95$2 * b$95$2), $MachinePrecision] - N[(a * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] / a), $MachinePrecision]
\begin{array}{l}
\\
\frac{\left(-b\_2\right) + \sqrt{b\_2 \cdot b\_2 - a \cdot c}}{a}
\end{array}
(FPCore (a b_2 c)
:precision binary64
(if (<= b_2 -1.82e+177)
(* -2.0 (/ b_2 a))
(if (<= b_2 5.4e-109)
(/ (- (sqrt (- (* b_2 b_2) (* a c))) b_2) a)
(* -0.5 (/ c b_2)))))
double code(double a, double b_2, double c) {
double tmp;
if (b_2 <= -1.82e+177) {
tmp = -2.0 * (b_2 / a);
} else if (b_2 <= 5.4e-109) {
tmp = (sqrt(((b_2 * b_2) - (a * c))) - b_2) / a;
} else {
tmp = -0.5 * (c / b_2);
}
return tmp;
}
real(8) function code(a, b_2, c)
real(8), intent (in) :: a
real(8), intent (in) :: b_2
real(8), intent (in) :: c
real(8) :: tmp
if (b_2 <= (-1.82d+177)) then
tmp = (-2.0d0) * (b_2 / a)
else if (b_2 <= 5.4d-109) then
tmp = (sqrt(((b_2 * b_2) - (a * c))) - b_2) / a
else
tmp = (-0.5d0) * (c / b_2)
end if
code = tmp
end function
public static double code(double a, double b_2, double c) {
double tmp;
if (b_2 <= -1.82e+177) {
tmp = -2.0 * (b_2 / a);
} else if (b_2 <= 5.4e-109) {
tmp = (Math.sqrt(((b_2 * b_2) - (a * c))) - b_2) / a;
} else {
tmp = -0.5 * (c / b_2);
}
return tmp;
}
def code(a, b_2, c): tmp = 0 if b_2 <= -1.82e+177: tmp = -2.0 * (b_2 / a) elif b_2 <= 5.4e-109: tmp = (math.sqrt(((b_2 * b_2) - (a * c))) - b_2) / a else: tmp = -0.5 * (c / b_2) return tmp
function code(a, b_2, c) tmp = 0.0 if (b_2 <= -1.82e+177) tmp = Float64(-2.0 * Float64(b_2 / a)); elseif (b_2 <= 5.4e-109) tmp = Float64(Float64(sqrt(Float64(Float64(b_2 * b_2) - Float64(a * c))) - b_2) / a); else tmp = Float64(-0.5 * Float64(c / b_2)); end return tmp end
function tmp_2 = code(a, b_2, c) tmp = 0.0; if (b_2 <= -1.82e+177) tmp = -2.0 * (b_2 / a); elseif (b_2 <= 5.4e-109) tmp = (sqrt(((b_2 * b_2) - (a * c))) - b_2) / a; else tmp = -0.5 * (c / b_2); end tmp_2 = tmp; end
code[a_, b$95$2_, c_] := If[LessEqual[b$95$2, -1.82e+177], N[(-2.0 * N[(b$95$2 / a), $MachinePrecision]), $MachinePrecision], If[LessEqual[b$95$2, 5.4e-109], N[(N[(N[Sqrt[N[(N[(b$95$2 * b$95$2), $MachinePrecision] - N[(a * c), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] - b$95$2), $MachinePrecision] / a), $MachinePrecision], N[(-0.5 * N[(c / b$95$2), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b\_2 \leq -1.82 \cdot 10^{+177}:\\
\;\;\;\;-2 \cdot \frac{b\_2}{a}\\
\mathbf{elif}\;b\_2 \leq 5.4 \cdot 10^{-109}:\\
\;\;\;\;\frac{\sqrt{b\_2 \cdot b\_2 - a \cdot c} - b\_2}{a}\\
\mathbf{else}:\\
\;\;\;\;-0.5 \cdot \frac{c}{b\_2}\\
\end{array}
\end{array}
if b_2 < -1.82e177Initial program 43.3%
Taylor expanded in b_2 around -inf 100.0%
if -1.82e177 < b_2 < 5.4000000000000001e-109Initial program 86.7%
if 5.4000000000000001e-109 < b_2 Initial program 17.0%
Taylor expanded in b_2 around inf 84.1%
Final simplification87.2%
(FPCore (a b_2 c) :precision binary64 (if (<= b_2 -4.3e-83) (* -2.0 (/ b_2 a)) (if (<= b_2 2e-110) (/ (- (sqrt (* a (- c))) b_2) a) (* -0.5 (/ c b_2)))))
double code(double a, double b_2, double c) {
double tmp;
if (b_2 <= -4.3e-83) {
tmp = -2.0 * (b_2 / a);
} else if (b_2 <= 2e-110) {
tmp = (sqrt((a * -c)) - b_2) / a;
} else {
tmp = -0.5 * (c / b_2);
}
return tmp;
}
real(8) function code(a, b_2, c)
real(8), intent (in) :: a
real(8), intent (in) :: b_2
real(8), intent (in) :: c
real(8) :: tmp
if (b_2 <= (-4.3d-83)) then
tmp = (-2.0d0) * (b_2 / a)
else if (b_2 <= 2d-110) then
tmp = (sqrt((a * -c)) - b_2) / a
else
tmp = (-0.5d0) * (c / b_2)
end if
code = tmp
end function
public static double code(double a, double b_2, double c) {
double tmp;
if (b_2 <= -4.3e-83) {
tmp = -2.0 * (b_2 / a);
} else if (b_2 <= 2e-110) {
tmp = (Math.sqrt((a * -c)) - b_2) / a;
} else {
tmp = -0.5 * (c / b_2);
}
return tmp;
}
def code(a, b_2, c): tmp = 0 if b_2 <= -4.3e-83: tmp = -2.0 * (b_2 / a) elif b_2 <= 2e-110: tmp = (math.sqrt((a * -c)) - b_2) / a else: tmp = -0.5 * (c / b_2) return tmp
function code(a, b_2, c) tmp = 0.0 if (b_2 <= -4.3e-83) tmp = Float64(-2.0 * Float64(b_2 / a)); elseif (b_2 <= 2e-110) tmp = Float64(Float64(sqrt(Float64(a * Float64(-c))) - b_2) / a); else tmp = Float64(-0.5 * Float64(c / b_2)); end return tmp end
function tmp_2 = code(a, b_2, c) tmp = 0.0; if (b_2 <= -4.3e-83) tmp = -2.0 * (b_2 / a); elseif (b_2 <= 2e-110) tmp = (sqrt((a * -c)) - b_2) / a; else tmp = -0.5 * (c / b_2); end tmp_2 = tmp; end
code[a_, b$95$2_, c_] := If[LessEqual[b$95$2, -4.3e-83], N[(-2.0 * N[(b$95$2 / a), $MachinePrecision]), $MachinePrecision], If[LessEqual[b$95$2, 2e-110], N[(N[(N[Sqrt[N[(a * (-c)), $MachinePrecision]], $MachinePrecision] - b$95$2), $MachinePrecision] / a), $MachinePrecision], N[(-0.5 * N[(c / b$95$2), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b\_2 \leq -4.3 \cdot 10^{-83}:\\
\;\;\;\;-2 \cdot \frac{b\_2}{a}\\
\mathbf{elif}\;b\_2 \leq 2 \cdot 10^{-110}:\\
\;\;\;\;\frac{\sqrt{a \cdot \left(-c\right)} - b\_2}{a}\\
\mathbf{else}:\\
\;\;\;\;-0.5 \cdot \frac{c}{b\_2}\\
\end{array}
\end{array}
if b_2 < -4.30000000000000033e-83Initial program 77.2%
Taylor expanded in b_2 around -inf 86.7%
if -4.30000000000000033e-83 < b_2 < 2.0000000000000001e-110Initial program 81.6%
Taylor expanded in b_2 around 0 76.4%
mul-1-neg76.4%
Simplified76.4%
if 2.0000000000000001e-110 < b_2 Initial program 17.0%
Taylor expanded in b_2 around inf 84.1%
Final simplification82.6%
(FPCore (a b_2 c) :precision binary64 (if (<= b_2 5e-310) (* -2.0 (/ b_2 a)) (* -0.5 (/ c b_2))))
double code(double a, double b_2, double c) {
double tmp;
if (b_2 <= 5e-310) {
tmp = -2.0 * (b_2 / a);
} else {
tmp = -0.5 * (c / b_2);
}
return tmp;
}
real(8) function code(a, b_2, c)
real(8), intent (in) :: a
real(8), intent (in) :: b_2
real(8), intent (in) :: c
real(8) :: tmp
if (b_2 <= 5d-310) then
tmp = (-2.0d0) * (b_2 / a)
else
tmp = (-0.5d0) * (c / b_2)
end if
code = tmp
end function
public static double code(double a, double b_2, double c) {
double tmp;
if (b_2 <= 5e-310) {
tmp = -2.0 * (b_2 / a);
} else {
tmp = -0.5 * (c / b_2);
}
return tmp;
}
def code(a, b_2, c): tmp = 0 if b_2 <= 5e-310: tmp = -2.0 * (b_2 / a) else: tmp = -0.5 * (c / b_2) return tmp
function code(a, b_2, c) tmp = 0.0 if (b_2 <= 5e-310) tmp = Float64(-2.0 * Float64(b_2 / a)); else tmp = Float64(-0.5 * Float64(c / b_2)); end return tmp end
function tmp_2 = code(a, b_2, c) tmp = 0.0; if (b_2 <= 5e-310) tmp = -2.0 * (b_2 / a); else tmp = -0.5 * (c / b_2); end tmp_2 = tmp; end
code[a_, b$95$2_, c_] := If[LessEqual[b$95$2, 5e-310], N[(-2.0 * N[(b$95$2 / a), $MachinePrecision]), $MachinePrecision], N[(-0.5 * N[(c / b$95$2), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;b\_2 \leq 5 \cdot 10^{-310}:\\
\;\;\;\;-2 \cdot \frac{b\_2}{a}\\
\mathbf{else}:\\
\;\;\;\;-0.5 \cdot \frac{c}{b\_2}\\
\end{array}
\end{array}
if b_2 < 4.999999999999985e-310Initial program 79.1%
Taylor expanded in b_2 around -inf 59.4%
if 4.999999999999985e-310 < b_2 Initial program 31.9%
Taylor expanded in b_2 around inf 66.0%
(FPCore (a b_2 c) :precision binary64 (* -2.0 (/ b_2 a)))
double code(double a, double b_2, double c) {
return -2.0 * (b_2 / a);
}
real(8) function code(a, b_2, c)
real(8), intent (in) :: a
real(8), intent (in) :: b_2
real(8), intent (in) :: c
code = (-2.0d0) * (b_2 / a)
end function
public static double code(double a, double b_2, double c) {
return -2.0 * (b_2 / a);
}
def code(a, b_2, c): return -2.0 * (b_2 / a)
function code(a, b_2, c) return Float64(-2.0 * Float64(b_2 / a)) end
function tmp = code(a, b_2, c) tmp = -2.0 * (b_2 / a); end
code[a_, b$95$2_, c_] := N[(-2.0 * N[(b$95$2 / a), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
-2 \cdot \frac{b\_2}{a}
\end{array}
Initial program 55.7%
Taylor expanded in b_2 around -inf 31.3%
(FPCore (a b_2 c) :precision binary64 (/ b_2 (- a)))
double code(double a, double b_2, double c) {
return b_2 / -a;
}
real(8) function code(a, b_2, c)
real(8), intent (in) :: a
real(8), intent (in) :: b_2
real(8), intent (in) :: c
code = b_2 / -a
end function
public static double code(double a, double b_2, double c) {
return b_2 / -a;
}
def code(a, b_2, c): return b_2 / -a
function code(a, b_2, c) return Float64(b_2 / Float64(-a)) end
function tmp = code(a, b_2, c) tmp = b_2 / -a; end
code[a_, b$95$2_, c_] := N[(b$95$2 / (-a)), $MachinePrecision]
\begin{array}{l}
\\
\frac{b\_2}{-a}
\end{array}
Initial program 55.7%
Taylor expanded in b_2 around 0 35.0%
mul-1-neg35.0%
Simplified35.0%
Taylor expanded in b_2 around inf 13.0%
mul-1-neg13.0%
distribute-frac-neg213.0%
Simplified13.0%
(FPCore (a b_2 c)
:precision binary64
(let* ((t_0 (* (sqrt (fabs a)) (sqrt (fabs c))))
(t_1
(if (== (copysign a c) a)
(* (sqrt (- (fabs b_2) t_0)) (sqrt (+ (fabs b_2) t_0)))
(hypot b_2 t_0))))
(if (< b_2 0.0) (/ (- t_1 b_2) a) (/ (- c) (+ b_2 t_1)))))
double code(double a, double b_2, double c) {
double t_0 = sqrt(fabs(a)) * sqrt(fabs(c));
double tmp;
if (copysign(a, c) == a) {
tmp = sqrt((fabs(b_2) - t_0)) * sqrt((fabs(b_2) + t_0));
} else {
tmp = hypot(b_2, t_0);
}
double t_1 = tmp;
double tmp_1;
if (b_2 < 0.0) {
tmp_1 = (t_1 - b_2) / a;
} else {
tmp_1 = -c / (b_2 + t_1);
}
return tmp_1;
}
public static double code(double a, double b_2, double c) {
double t_0 = Math.sqrt(Math.abs(a)) * Math.sqrt(Math.abs(c));
double tmp;
if (Math.copySign(a, c) == a) {
tmp = Math.sqrt((Math.abs(b_2) - t_0)) * Math.sqrt((Math.abs(b_2) + t_0));
} else {
tmp = Math.hypot(b_2, t_0);
}
double t_1 = tmp;
double tmp_1;
if (b_2 < 0.0) {
tmp_1 = (t_1 - b_2) / a;
} else {
tmp_1 = -c / (b_2 + t_1);
}
return tmp_1;
}
def code(a, b_2, c): t_0 = math.sqrt(math.fabs(a)) * math.sqrt(math.fabs(c)) tmp = 0 if math.copysign(a, c) == a: tmp = math.sqrt((math.fabs(b_2) - t_0)) * math.sqrt((math.fabs(b_2) + t_0)) else: tmp = math.hypot(b_2, t_0) t_1 = tmp tmp_1 = 0 if b_2 < 0.0: tmp_1 = (t_1 - b_2) / a else: tmp_1 = -c / (b_2 + t_1) return tmp_1
function code(a, b_2, c) t_0 = Float64(sqrt(abs(a)) * sqrt(abs(c))) tmp = 0.0 if (copysign(a, c) == a) tmp = Float64(sqrt(Float64(abs(b_2) - t_0)) * sqrt(Float64(abs(b_2) + t_0))); else tmp = hypot(b_2, t_0); end t_1 = tmp tmp_1 = 0.0 if (b_2 < 0.0) tmp_1 = Float64(Float64(t_1 - b_2) / a); else tmp_1 = Float64(Float64(-c) / Float64(b_2 + t_1)); end return tmp_1 end
function tmp_3 = code(a, b_2, c) t_0 = sqrt(abs(a)) * sqrt(abs(c)); tmp = 0.0; if ((sign(c) * abs(a)) == a) tmp = sqrt((abs(b_2) - t_0)) * sqrt((abs(b_2) + t_0)); else tmp = hypot(b_2, t_0); end t_1 = tmp; tmp_2 = 0.0; if (b_2 < 0.0) tmp_2 = (t_1 - b_2) / a; else tmp_2 = -c / (b_2 + t_1); end tmp_3 = tmp_2; end
code[a_, b$95$2_, c_] := Block[{t$95$0 = N[(N[Sqrt[N[Abs[a], $MachinePrecision]], $MachinePrecision] * N[Sqrt[N[Abs[c], $MachinePrecision]], $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = If[Equal[N[With[{TMP1 = Abs[a], TMP2 = Sign[c]}, TMP1 * If[TMP2 == 0, 1, TMP2]], $MachinePrecision], a], N[(N[Sqrt[N[(N[Abs[b$95$2], $MachinePrecision] - t$95$0), $MachinePrecision]], $MachinePrecision] * N[Sqrt[N[(N[Abs[b$95$2], $MachinePrecision] + t$95$0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision], N[Sqrt[b$95$2 ^ 2 + t$95$0 ^ 2], $MachinePrecision]]}, If[Less[b$95$2, 0.0], N[(N[(t$95$1 - b$95$2), $MachinePrecision] / a), $MachinePrecision], N[((-c) / N[(b$95$2 + t$95$1), $MachinePrecision]), $MachinePrecision]]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \sqrt{\left|a\right|} \cdot \sqrt{\left|c\right|}\\
t_1 := \begin{array}{l}
\mathbf{if}\;\mathsf{copysign}\left(a, c\right) = a:\\
\;\;\;\;\sqrt{\left|b\_2\right| - t\_0} \cdot \sqrt{\left|b\_2\right| + t\_0}\\
\mathbf{else}:\\
\;\;\;\;\mathsf{hypot}\left(b\_2, t\_0\right)\\
\end{array}\\
\mathbf{if}\;b\_2 < 0:\\
\;\;\;\;\frac{t\_1 - b\_2}{a}\\
\mathbf{else}:\\
\;\;\;\;\frac{-c}{b\_2 + t\_1}\\
\end{array}
\end{array}
herbie shell --seed 2024096
(FPCore (a b_2 c)
:name "quad2p (problem 3.2.1, positive)"
:precision binary64
:herbie-expected 10
:alt
(if (< b_2 0.0) (/ (- (if (== (copysign a c) a) (* (sqrt (- (fabs b_2) (* (sqrt (fabs a)) (sqrt (fabs c))))) (sqrt (+ (fabs b_2) (* (sqrt (fabs a)) (sqrt (fabs c)))))) (hypot b_2 (* (sqrt (fabs a)) (sqrt (fabs c))))) b_2) a) (/ (- c) (+ b_2 (if (== (copysign a c) a) (* (sqrt (- (fabs b_2) (* (sqrt (fabs a)) (sqrt (fabs c))))) (sqrt (+ (fabs b_2) (* (sqrt (fabs a)) (sqrt (fabs c)))))) (hypot b_2 (* (sqrt (fabs a)) (sqrt (fabs c))))))))
(/ (+ (- b_2) (sqrt (- (* b_2 b_2) (* a c)))) a))