
(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 (/ (+ 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 (or (<= n -9.5e-26)
(and (not (<= n 2.05e-235))
(or (<= n 1.2e-196) (not (<= n 3.9e-110)))))
(+ (* 2.0 (/ f n)) 1.0)
-1.0))
double code(double f, double n) {
double tmp;
if ((n <= -9.5e-26) || (!(n <= 2.05e-235) && ((n <= 1.2e-196) || !(n <= 3.9e-110)))) {
tmp = (2.0 * (f / n)) + 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 ((n <= (-9.5d-26)) .or. (.not. (n <= 2.05d-235)) .and. (n <= 1.2d-196) .or. (.not. (n <= 3.9d-110))) then
tmp = (2.0d0 * (f / n)) + 1.0d0
else
tmp = -1.0d0
end if
code = tmp
end function
public static double code(double f, double n) {
double tmp;
if ((n <= -9.5e-26) || (!(n <= 2.05e-235) && ((n <= 1.2e-196) || !(n <= 3.9e-110)))) {
tmp = (2.0 * (f / n)) + 1.0;
} else {
tmp = -1.0;
}
return tmp;
}
def code(f, n): tmp = 0 if (n <= -9.5e-26) or (not (n <= 2.05e-235) and ((n <= 1.2e-196) or not (n <= 3.9e-110))): tmp = (2.0 * (f / n)) + 1.0 else: tmp = -1.0 return tmp
function code(f, n) tmp = 0.0 if ((n <= -9.5e-26) || (!(n <= 2.05e-235) && ((n <= 1.2e-196) || !(n <= 3.9e-110)))) tmp = Float64(Float64(2.0 * Float64(f / n)) + 1.0); else tmp = -1.0; end return tmp end
function tmp_2 = code(f, n) tmp = 0.0; if ((n <= -9.5e-26) || (~((n <= 2.05e-235)) && ((n <= 1.2e-196) || ~((n <= 3.9e-110))))) tmp = (2.0 * (f / n)) + 1.0; else tmp = -1.0; end tmp_2 = tmp; end
code[f_, n_] := If[Or[LessEqual[n, -9.5e-26], And[N[Not[LessEqual[n, 2.05e-235]], $MachinePrecision], Or[LessEqual[n, 1.2e-196], N[Not[LessEqual[n, 3.9e-110]], $MachinePrecision]]]], N[(N[(2.0 * N[(f / n), $MachinePrecision]), $MachinePrecision] + 1.0), $MachinePrecision], -1.0]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;n \leq -9.5 \cdot 10^{-26} \lor \neg \left(n \leq 2.05 \cdot 10^{-235}\right) \land \left(n \leq 1.2 \cdot 10^{-196} \lor \neg \left(n \leq 3.9 \cdot 10^{-110}\right)\right):\\
\;\;\;\;2 \cdot \frac{f}{n} + 1\\
\mathbf{else}:\\
\;\;\;\;-1\\
\end{array}
\end{array}
if n < -9.4999999999999995e-26 or 2.04999999999999998e-235 < n < 1.2000000000000001e-196 or 3.9e-110 < n 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 0 77.8%
if -9.4999999999999995e-26 < n < 2.04999999999999998e-235 or 1.2000000000000001e-196 < n < 3.9e-110Initial program 100.0%
neg-mul-1100.0%
*-commutative100.0%
associate-/l*100.0%
div-sub100.0%
metadata-eval100.0%
metadata-eval100.0%
associate-/l*100.0%
*-commutative100.0%
neg-mul-1100.0%
metadata-eval100.0%
metadata-eval100.0%
associate-/l*100.0%
*-commutative100.0%
neg-mul-1100.0%
div-sub100.0%
unsub-neg100.0%
remove-double-neg100.0%
+-commutative100.0%
sub-neg100.0%
metadata-eval100.0%
/-rgt-identity100.0%
Simplified100.0%
Taylor expanded in f around inf 87.6%
Final simplification81.2%
(FPCore (f n) :precision binary64 (if (or (<= n -8.2e-26) (not (<= n 4.2e-71))) (+ (* 2.0 (/ f n)) 1.0) (+ (* -2.0 (/ n f)) -1.0)))
double code(double f, double n) {
double tmp;
if ((n <= -8.2e-26) || !(n <= 4.2e-71)) {
tmp = (2.0 * (f / n)) + 1.0;
} else {
tmp = (-2.0 * (n / f)) + -1.0;
}
return tmp;
}
real(8) function code(f, n)
real(8), intent (in) :: f
real(8), intent (in) :: n
real(8) :: tmp
if ((n <= (-8.2d-26)) .or. (.not. (n <= 4.2d-71))) then
tmp = (2.0d0 * (f / n)) + 1.0d0
else
tmp = ((-2.0d0) * (n / f)) + (-1.0d0)
end if
code = tmp
end function
public static double code(double f, double n) {
double tmp;
if ((n <= -8.2e-26) || !(n <= 4.2e-71)) {
tmp = (2.0 * (f / n)) + 1.0;
} else {
tmp = (-2.0 * (n / f)) + -1.0;
}
return tmp;
}
def code(f, n): tmp = 0 if (n <= -8.2e-26) or not (n <= 4.2e-71): tmp = (2.0 * (f / n)) + 1.0 else: tmp = (-2.0 * (n / f)) + -1.0 return tmp
function code(f, n) tmp = 0.0 if ((n <= -8.2e-26) || !(n <= 4.2e-71)) tmp = Float64(Float64(2.0 * Float64(f / n)) + 1.0); else tmp = Float64(Float64(-2.0 * Float64(n / f)) + -1.0); end return tmp end
function tmp_2 = code(f, n) tmp = 0.0; if ((n <= -8.2e-26) || ~((n <= 4.2e-71))) tmp = (2.0 * (f / n)) + 1.0; else tmp = (-2.0 * (n / f)) + -1.0; end tmp_2 = tmp; end
code[f_, n_] := If[Or[LessEqual[n, -8.2e-26], N[Not[LessEqual[n, 4.2e-71]], $MachinePrecision]], N[(N[(2.0 * N[(f / n), $MachinePrecision]), $MachinePrecision] + 1.0), $MachinePrecision], N[(N[(-2.0 * N[(n / f), $MachinePrecision]), $MachinePrecision] + -1.0), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;n \leq -8.2 \cdot 10^{-26} \lor \neg \left(n \leq 4.2 \cdot 10^{-71}\right):\\
\;\;\;\;2 \cdot \frac{f}{n} + 1\\
\mathbf{else}:\\
\;\;\;\;-2 \cdot \frac{n}{f} + -1\\
\end{array}
\end{array}
if n < -8.1999999999999997e-26 or 4.2000000000000002e-71 < n 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 0 77.8%
if -8.1999999999999997e-26 < n < 4.2000000000000002e-71Initial program 100.0%
neg-mul-1100.0%
*-commutative100.0%
associate-/l*100.0%
div-sub100.0%
metadata-eval100.0%
metadata-eval100.0%
associate-/l*100.0%
*-commutative100.0%
neg-mul-1100.0%
metadata-eval100.0%
metadata-eval100.0%
associate-/l*100.0%
*-commutative100.0%
neg-mul-1100.0%
div-sub100.0%
unsub-neg100.0%
remove-double-neg100.0%
+-commutative100.0%
sub-neg100.0%
metadata-eval100.0%
/-rgt-identity100.0%
Simplified100.0%
Taylor expanded in n around 0 83.5%
Final simplification80.0%
(FPCore (f n) :precision binary64 (if (<= n -1.5e-29) 1.0 (if (<= n 3.2e-110) -1.0 1.0)))
double code(double f, double n) {
double tmp;
if (n <= -1.5e-29) {
tmp = 1.0;
} else if (n <= 3.2e-110) {
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 (n <= (-1.5d-29)) then
tmp = 1.0d0
else if (n <= 3.2d-110) 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 (n <= -1.5e-29) {
tmp = 1.0;
} else if (n <= 3.2e-110) {
tmp = -1.0;
} else {
tmp = 1.0;
}
return tmp;
}
def code(f, n): tmp = 0 if n <= -1.5e-29: tmp = 1.0 elif n <= 3.2e-110: tmp = -1.0 else: tmp = 1.0 return tmp
function code(f, n) tmp = 0.0 if (n <= -1.5e-29) tmp = 1.0; elseif (n <= 3.2e-110) tmp = -1.0; else tmp = 1.0; end return tmp end
function tmp_2 = code(f, n) tmp = 0.0; if (n <= -1.5e-29) tmp = 1.0; elseif (n <= 3.2e-110) tmp = -1.0; else tmp = 1.0; end tmp_2 = tmp; end
code[f_, n_] := If[LessEqual[n, -1.5e-29], 1.0, If[LessEqual[n, 3.2e-110], -1.0, 1.0]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;n \leq -1.5 \cdot 10^{-29}:\\
\;\;\;\;1\\
\mathbf{elif}\;n \leq 3.2 \cdot 10^{-110}:\\
\;\;\;\;-1\\
\mathbf{else}:\\
\;\;\;\;1\\
\end{array}
\end{array}
if n < -1.5000000000000001e-29 or 3.20000000000000028e-110 < n 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 0 76.2%
if -1.5000000000000001e-29 < n < 3.20000000000000028e-110Initial program 100.0%
neg-mul-1100.0%
*-commutative100.0%
associate-/l*100.0%
div-sub100.0%
metadata-eval100.0%
metadata-eval100.0%
associate-/l*100.0%
*-commutative100.0%
neg-mul-1100.0%
metadata-eval100.0%
metadata-eval100.0%
associate-/l*100.0%
*-commutative100.0%
neg-mul-1100.0%
div-sub100.0%
unsub-neg100.0%
remove-double-neg100.0%
+-commutative100.0%
sub-neg100.0%
metadata-eval100.0%
/-rgt-identity100.0%
Simplified100.0%
Taylor expanded in f around inf 83.9%
Final simplification79.1%
(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 45.1%
Final simplification45.1%
herbie shell --seed 2023196
(FPCore (f n)
:name "subtraction fraction"
:precision binary64
(/ (- (+ f n)) (- f n)))