
(FPCore (f n) :precision binary64 (/ (- (+ f n)) (- f n)))
double code(double f, double n) {
return -(f + n) / (f - n);
}
real(8) function code(f, n)
real(8), intent (in) :: f
real(8), intent (in) :: n
code = -(f + n) / (f - n)
end function
public static double code(double f, double n) {
return -(f + n) / (f - n);
}
def code(f, n): return -(f + n) / (f - n)
function code(f, n) return Float64(Float64(-Float64(f + n)) / Float64(f - n)) end
function tmp = code(f, n) tmp = -(f + n) / (f - n); end
code[f_, n_] := N[((-N[(f + n), $MachinePrecision]) / N[(f - n), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{-\left(f + n\right)}{f - n}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 5 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (f n) :precision binary64 (/ (- (+ f n)) (- f n)))
double code(double f, double n) {
return -(f + n) / (f - n);
}
real(8) function code(f, n)
real(8), intent (in) :: f
real(8), intent (in) :: n
code = -(f + n) / (f - n)
end function
public static double code(double f, double n) {
return -(f + n) / (f - n);
}
def code(f, n): return -(f + n) / (f - n)
function code(f, n) return Float64(Float64(-Float64(f + n)) / Float64(f - n)) end
function tmp = code(f, n) tmp = -(f + n) / (f - n); end
code[f_, n_] := N[((-N[(f + n), $MachinePrecision]) / N[(f - n), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{-\left(f + n\right)}{f - n}
\end{array}
(FPCore (f n) :precision binary64 (let* ((t_0 (/ f (- n f))) (t_1 (/ n (- n f)))) (/ (- (* t_0 t_0) (* t_1 t_1)) (- t_0 t_1))))
double code(double f, double n) {
double t_0 = f / (n - f);
double t_1 = n / (n - f);
return ((t_0 * t_0) - (t_1 * t_1)) / (t_0 - t_1);
}
real(8) function code(f, n)
real(8), intent (in) :: f
real(8), intent (in) :: n
real(8) :: t_0
real(8) :: t_1
t_0 = f / (n - f)
t_1 = n / (n - f)
code = ((t_0 * t_0) - (t_1 * t_1)) / (t_0 - t_1)
end function
public static double code(double f, double n) {
double t_0 = f / (n - f);
double t_1 = n / (n - f);
return ((t_0 * t_0) - (t_1 * t_1)) / (t_0 - t_1);
}
def code(f, n): t_0 = f / (n - f) t_1 = n / (n - f) return ((t_0 * t_0) - (t_1 * t_1)) / (t_0 - t_1)
function code(f, n) t_0 = Float64(f / Float64(n - f)) t_1 = Float64(n / Float64(n - f)) return Float64(Float64(Float64(t_0 * t_0) - Float64(t_1 * t_1)) / Float64(t_0 - t_1)) end
function tmp = code(f, n) t_0 = f / (n - f); t_1 = n / (n - f); tmp = ((t_0 * t_0) - (t_1 * t_1)) / (t_0 - t_1); end
code[f_, n_] := Block[{t$95$0 = N[(f / N[(n - f), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$1 = N[(n / N[(n - f), $MachinePrecision]), $MachinePrecision]}, N[(N[(N[(t$95$0 * t$95$0), $MachinePrecision] - N[(t$95$1 * t$95$1), $MachinePrecision]), $MachinePrecision] / N[(t$95$0 - t$95$1), $MachinePrecision]), $MachinePrecision]]]
\begin{array}{l}
\\
\begin{array}{l}
t_0 := \frac{f}{n - f}\\
t_1 := \frac{n}{n - f}\\
\frac{t_0 \cdot t_0 - t_1 \cdot t_1}{t_0 - t_1}
\end{array}
\end{array}
Initial program 99.9%
neg-mul-199.9%
*-commutative99.9%
associate-/l*99.9%
div-sub99.9%
metadata-eval99.9%
metadata-eval99.9%
associate-/l*99.9%
*-commutative99.9%
neg-mul-199.9%
metadata-eval99.9%
metadata-eval99.9%
associate-/l*99.9%
*-commutative99.9%
neg-mul-199.9%
div-sub99.9%
unsub-neg99.9%
remove-double-neg99.9%
+-commutative99.9%
sub-neg99.9%
metadata-eval99.9%
/-rgt-identity99.9%
Simplified99.9%
log1p-expm1-u99.9%
Applied egg-rr99.9%
log1p-expm1-u99.9%
*-un-lft-identity99.9%
associate-*l/99.7%
distribute-rgt-in99.7%
flip-+99.7%
un-div-inv99.8%
un-div-inv99.7%
un-div-inv99.9%
un-div-inv99.7%
un-div-inv99.8%
un-div-inv100.0%
Applied egg-rr100.0%
Final simplification100.0%
(FPCore (f n) :precision binary64 (if (or (<= f -4.6e-7) (not (<= f 4.9e+58))) (+ (* -2.0 (/ n f)) -1.0) 1.0))
double code(double f, double n) {
double tmp;
if ((f <= -4.6e-7) || !(f <= 4.9e+58)) {
tmp = (-2.0 * (n / f)) + -1.0;
} else {
tmp = 1.0;
}
return tmp;
}
real(8) function code(f, n)
real(8), intent (in) :: f
real(8), intent (in) :: n
real(8) :: tmp
if ((f <= (-4.6d-7)) .or. (.not. (f <= 4.9d+58))) then
tmp = ((-2.0d0) * (n / f)) + (-1.0d0)
else
tmp = 1.0d0
end if
code = tmp
end function
public static double code(double f, double n) {
double tmp;
if ((f <= -4.6e-7) || !(f <= 4.9e+58)) {
tmp = (-2.0 * (n / f)) + -1.0;
} else {
tmp = 1.0;
}
return tmp;
}
def code(f, n): tmp = 0 if (f <= -4.6e-7) or not (f <= 4.9e+58): tmp = (-2.0 * (n / f)) + -1.0 else: tmp = 1.0 return tmp
function code(f, n) tmp = 0.0 if ((f <= -4.6e-7) || !(f <= 4.9e+58)) tmp = Float64(Float64(-2.0 * Float64(n / f)) + -1.0); else tmp = 1.0; end return tmp end
function tmp_2 = code(f, n) tmp = 0.0; if ((f <= -4.6e-7) || ~((f <= 4.9e+58))) tmp = (-2.0 * (n / f)) + -1.0; else tmp = 1.0; end tmp_2 = tmp; end
code[f_, n_] := If[Or[LessEqual[f, -4.6e-7], N[Not[LessEqual[f, 4.9e+58]], $MachinePrecision]], N[(N[(-2.0 * N[(n / f), $MachinePrecision]), $MachinePrecision] + -1.0), $MachinePrecision], 1.0]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;f \leq -4.6 \cdot 10^{-7} \lor \neg \left(f \leq 4.9 \cdot 10^{+58}\right):\\
\;\;\;\;-2 \cdot \frac{n}{f} + -1\\
\mathbf{else}:\\
\;\;\;\;1\\
\end{array}
\end{array}
if f < -4.5999999999999999e-7 or 4.90000000000000018e58 < f Initial program 99.9%
neg-mul-199.9%
*-commutative99.9%
associate-/l*99.9%
div-sub99.9%
metadata-eval99.9%
metadata-eval99.9%
associate-/l*99.9%
*-commutative99.9%
neg-mul-199.9%
metadata-eval99.9%
metadata-eval99.9%
associate-/l*99.9%
*-commutative99.9%
neg-mul-199.9%
div-sub99.9%
unsub-neg99.9%
remove-double-neg99.9%
+-commutative99.9%
sub-neg99.9%
metadata-eval99.9%
/-rgt-identity99.9%
Simplified99.9%
Taylor expanded in n around 0 78.9%
if -4.5999999999999999e-7 < f < 4.90000000000000018e58Initial program 99.9%
neg-mul-199.9%
*-commutative99.9%
associate-/l*99.9%
div-sub99.9%
metadata-eval99.9%
metadata-eval99.9%
associate-/l*99.9%
*-commutative99.9%
neg-mul-199.9%
metadata-eval99.9%
metadata-eval99.9%
associate-/l*99.9%
*-commutative99.9%
neg-mul-199.9%
div-sub99.9%
unsub-neg99.9%
remove-double-neg99.9%
+-commutative99.9%
sub-neg99.9%
metadata-eval99.9%
/-rgt-identity99.9%
Simplified99.9%
Taylor expanded in f around 0 75.6%
Final simplification76.9%
(FPCore (f n) :precision binary64 (/ (+ f n) (- n f)))
double code(double f, double n) {
return (f + n) / (n - f);
}
real(8) function code(f, n)
real(8), intent (in) :: f
real(8), intent (in) :: n
code = (f + n) / (n - f)
end function
public static double code(double f, double n) {
return (f + n) / (n - f);
}
def code(f, n): return (f + n) / (n - f)
function code(f, n) return Float64(Float64(f + n) / Float64(n - f)) end
function tmp = code(f, n) tmp = (f + n) / (n - f); end
code[f_, n_] := N[(N[(f + n), $MachinePrecision] / N[(n - f), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{f + n}{n - f}
\end{array}
Initial program 99.9%
neg-mul-199.9%
*-commutative99.9%
associate-/l*99.9%
div-sub99.9%
metadata-eval99.9%
metadata-eval99.9%
associate-/l*99.9%
*-commutative99.9%
neg-mul-199.9%
metadata-eval99.9%
metadata-eval99.9%
associate-/l*99.9%
*-commutative99.9%
neg-mul-199.9%
div-sub99.9%
unsub-neg99.9%
remove-double-neg99.9%
+-commutative99.9%
sub-neg99.9%
metadata-eval99.9%
/-rgt-identity99.9%
Simplified99.9%
Final simplification99.9%
(FPCore (f n) :precision binary64 (if (<= f -5e+33) -1.0 (if (<= f 1.4e+59) 1.0 -1.0)))
double code(double f, double n) {
double tmp;
if (f <= -5e+33) {
tmp = -1.0;
} else if (f <= 1.4e+59) {
tmp = 1.0;
} else {
tmp = -1.0;
}
return tmp;
}
real(8) function code(f, n)
real(8), intent (in) :: f
real(8), intent (in) :: n
real(8) :: tmp
if (f <= (-5d+33)) then
tmp = -1.0d0
else if (f <= 1.4d+59) then
tmp = 1.0d0
else
tmp = -1.0d0
end if
code = tmp
end function
public static double code(double f, double n) {
double tmp;
if (f <= -5e+33) {
tmp = -1.0;
} else if (f <= 1.4e+59) {
tmp = 1.0;
} else {
tmp = -1.0;
}
return tmp;
}
def code(f, n): tmp = 0 if f <= -5e+33: tmp = -1.0 elif f <= 1.4e+59: tmp = 1.0 else: tmp = -1.0 return tmp
function code(f, n) tmp = 0.0 if (f <= -5e+33) tmp = -1.0; elseif (f <= 1.4e+59) tmp = 1.0; else tmp = -1.0; end return tmp end
function tmp_2 = code(f, n) tmp = 0.0; if (f <= -5e+33) tmp = -1.0; elseif (f <= 1.4e+59) tmp = 1.0; else tmp = -1.0; end tmp_2 = tmp; end
code[f_, n_] := If[LessEqual[f, -5e+33], -1.0, If[LessEqual[f, 1.4e+59], 1.0, -1.0]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;f \leq -5 \cdot 10^{+33}:\\
\;\;\;\;-1\\
\mathbf{elif}\;f \leq 1.4 \cdot 10^{+59}:\\
\;\;\;\;1\\
\mathbf{else}:\\
\;\;\;\;-1\\
\end{array}
\end{array}
if f < -4.99999999999999973e33 or 1.3999999999999999e59 < f Initial program 99.9%
neg-mul-199.9%
*-commutative99.9%
associate-/l*99.9%
div-sub99.9%
metadata-eval99.9%
metadata-eval99.9%
associate-/l*99.9%
*-commutative99.9%
neg-mul-199.9%
metadata-eval99.9%
metadata-eval99.9%
associate-/l*99.9%
*-commutative99.9%
neg-mul-199.9%
div-sub99.9%
unsub-neg99.9%
remove-double-neg99.9%
+-commutative99.9%
sub-neg99.9%
metadata-eval99.9%
/-rgt-identity99.9%
Simplified99.9%
Taylor expanded in f around inf 80.1%
if -4.99999999999999973e33 < f < 1.3999999999999999e59Initial program 99.9%
neg-mul-199.9%
*-commutative99.9%
associate-/l*99.9%
div-sub99.9%
metadata-eval99.9%
metadata-eval99.9%
associate-/l*99.9%
*-commutative99.9%
neg-mul-199.9%
metadata-eval99.9%
metadata-eval99.9%
associate-/l*99.9%
*-commutative99.9%
neg-mul-199.9%
div-sub99.9%
unsub-neg99.9%
remove-double-neg99.9%
+-commutative99.9%
sub-neg99.9%
metadata-eval99.9%
/-rgt-identity99.9%
Simplified99.9%
Taylor expanded in f around 0 74.3%
Final simplification76.5%
(FPCore (f n) :precision binary64 -1.0)
double code(double f, double n) {
return -1.0;
}
real(8) function code(f, n)
real(8), intent (in) :: f
real(8), intent (in) :: n
code = -1.0d0
end function
public static double code(double f, double n) {
return -1.0;
}
def code(f, n): return -1.0
function code(f, n) return -1.0 end
function tmp = code(f, n) tmp = -1.0; end
code[f_, n_] := -1.0
\begin{array}{l}
\\
-1
\end{array}
Initial program 99.9%
neg-mul-199.9%
*-commutative99.9%
associate-/l*99.9%
div-sub99.9%
metadata-eval99.9%
metadata-eval99.9%
associate-/l*99.9%
*-commutative99.9%
neg-mul-199.9%
metadata-eval99.9%
metadata-eval99.9%
associate-/l*99.9%
*-commutative99.9%
neg-mul-199.9%
div-sub99.9%
unsub-neg99.9%
remove-double-neg99.9%
+-commutative99.9%
sub-neg99.9%
metadata-eval99.9%
/-rgt-identity99.9%
Simplified99.9%
Taylor expanded in f around inf 45.5%
Final simplification45.5%
herbie shell --seed 2023238
(FPCore (f n)
:name "subtraction fraction"
:precision binary64
(/ (- (+ f n)) (- f n)))