
(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 4 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 100.0%
sub-neg100.0%
remove-double-neg100.0%
distribute-neg-in100.0%
neg-mul-1100.0%
associate-/r*100.0%
neg-mul-1100.0%
*-commutative100.0%
associate-/l*100.0%
metadata-eval100.0%
/-rgt-identity100.0%
+-commutative100.0%
sub-neg100.0%
Simplified100.0%
Final simplification100.0%
(FPCore (f n) :precision binary64 (if (<= n -4.2e+16) 1.0 (if (<= n 9e-20) (+ (* -2.0 (/ n f)) -1.0) 1.0)))
double code(double f, double n) {
double tmp;
if (n <= -4.2e+16) {
tmp = 1.0;
} else if (n <= 9e-20) {
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 (n <= (-4.2d+16)) then
tmp = 1.0d0
else if (n <= 9d-20) 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 (n <= -4.2e+16) {
tmp = 1.0;
} else if (n <= 9e-20) {
tmp = (-2.0 * (n / f)) + -1.0;
} else {
tmp = 1.0;
}
return tmp;
}
def code(f, n): tmp = 0 if n <= -4.2e+16: tmp = 1.0 elif n <= 9e-20: tmp = (-2.0 * (n / f)) + -1.0 else: tmp = 1.0 return tmp
function code(f, n) tmp = 0.0 if (n <= -4.2e+16) tmp = 1.0; elseif (n <= 9e-20) 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 (n <= -4.2e+16) tmp = 1.0; elseif (n <= 9e-20) tmp = (-2.0 * (n / f)) + -1.0; else tmp = 1.0; end tmp_2 = tmp; end
code[f_, n_] := If[LessEqual[n, -4.2e+16], 1.0, If[LessEqual[n, 9e-20], N[(N[(-2.0 * N[(n / f), $MachinePrecision]), $MachinePrecision] + -1.0), $MachinePrecision], 1.0]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;n \leq -4.2 \cdot 10^{+16}:\\
\;\;\;\;1\\
\mathbf{elif}\;n \leq 9 \cdot 10^{-20}:\\
\;\;\;\;-2 \cdot \frac{n}{f} + -1\\
\mathbf{else}:\\
\;\;\;\;1\\
\end{array}
\end{array}
if n < -4.2e16 or 9.0000000000000003e-20 < n Initial program 100.0%
sub-neg100.0%
remove-double-neg100.0%
distribute-neg-in100.0%
neg-mul-1100.0%
associate-/r*100.0%
neg-mul-1100.0%
*-commutative100.0%
associate-/l*100.0%
metadata-eval100.0%
/-rgt-identity100.0%
+-commutative100.0%
sub-neg100.0%
Simplified100.0%
Taylor expanded in f around 0 78.1%
if -4.2e16 < n < 9.0000000000000003e-20Initial program 100.0%
sub-neg100.0%
remove-double-neg100.0%
distribute-neg-in100.0%
neg-mul-1100.0%
associate-/r*100.0%
neg-mul-1100.0%
*-commutative100.0%
associate-/l*100.0%
metadata-eval100.0%
/-rgt-identity100.0%
+-commutative100.0%
sub-neg100.0%
Simplified100.0%
Taylor expanded in n around 0 81.6%
Final simplification79.9%
(FPCore (f n) :precision binary64 (if (<= n -1.2e+17) 1.0 (if (<= n 3.8e-41) -1.0 1.0)))
double code(double f, double n) {
double tmp;
if (n <= -1.2e+17) {
tmp = 1.0;
} else if (n <= 3.8e-41) {
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 <= (-1.2d+17)) then
tmp = 1.0d0
else if (n <= 3.8d-41) 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 <= -1.2e+17) {
tmp = 1.0;
} else if (n <= 3.8e-41) {
tmp = -1.0;
} else {
tmp = 1.0;
}
return tmp;
}
def code(f, n): tmp = 0 if n <= -1.2e+17: tmp = 1.0 elif n <= 3.8e-41: tmp = -1.0 else: tmp = 1.0 return tmp
function code(f, n) tmp = 0.0 if (n <= -1.2e+17) tmp = 1.0; elseif (n <= 3.8e-41) tmp = -1.0; else tmp = 1.0; end return tmp end
function tmp_2 = code(f, n) tmp = 0.0; if (n <= -1.2e+17) tmp = 1.0; elseif (n <= 3.8e-41) tmp = -1.0; else tmp = 1.0; end tmp_2 = tmp; end
code[f_, n_] := If[LessEqual[n, -1.2e+17], 1.0, If[LessEqual[n, 3.8e-41], -1.0, 1.0]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;n \leq -1.2 \cdot 10^{+17}:\\
\;\;\;\;1\\
\mathbf{elif}\;n \leq 3.8 \cdot 10^{-41}:\\
\;\;\;\;-1\\
\mathbf{else}:\\
\;\;\;\;1\\
\end{array}
\end{array}
if n < -1.2e17 or 3.79999999999999979e-41 < n Initial program 100.0%
sub-neg100.0%
remove-double-neg100.0%
distribute-neg-in100.0%
neg-mul-1100.0%
associate-/r*100.0%
neg-mul-1100.0%
*-commutative100.0%
associate-/l*100.0%
metadata-eval100.0%
/-rgt-identity100.0%
+-commutative100.0%
sub-neg100.0%
Simplified100.0%
Taylor expanded in f around 0 76.8%
if -1.2e17 < n < 3.79999999999999979e-41Initial program 100.0%
sub-neg100.0%
remove-double-neg100.0%
distribute-neg-in100.0%
neg-mul-1100.0%
associate-/r*100.0%
neg-mul-1100.0%
*-commutative100.0%
associate-/l*100.0%
metadata-eval100.0%
/-rgt-identity100.0%
+-commutative100.0%
sub-neg100.0%
Simplified100.0%
Taylor expanded in f around inf 82.0%
Final simplification79.4%
(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 100.0%
sub-neg100.0%
remove-double-neg100.0%
distribute-neg-in100.0%
neg-mul-1100.0%
associate-/r*100.0%
neg-mul-1100.0%
*-commutative100.0%
associate-/l*100.0%
metadata-eval100.0%
/-rgt-identity100.0%
+-commutative100.0%
sub-neg100.0%
Simplified100.0%
Taylor expanded in f around inf 52.4%
Final simplification52.4%
herbie shell --seed 2023293
(FPCore (f n)
:name "subtraction fraction"
:precision binary64
(/ (- (+ f n)) (- f n)))