
(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%
neg-mul-1100.0%
remove-double-neg100.0%
unsub-neg100.0%
distribute-neg-in100.0%
neg-mul-1100.0%
times-frac100.0%
metadata-eval100.0%
+-commutative100.0%
+-commutative100.0%
sub-neg100.0%
*-lft-identity100.0%
+-commutative100.0%
Simplified100.0%
Final simplification100.0%
(FPCore (f n) :precision binary64 (if (or (<= f -16500000.0) (not (<= f 1.3e-85))) (+ (* -2.0 (/ n f)) -1.0) 1.0))
double code(double f, double n) {
double tmp;
if ((f <= -16500000.0) || !(f <= 1.3e-85)) {
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 <= (-16500000.0d0)) .or. (.not. (f <= 1.3d-85))) 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 <= -16500000.0) || !(f <= 1.3e-85)) {
tmp = (-2.0 * (n / f)) + -1.0;
} else {
tmp = 1.0;
}
return tmp;
}
def code(f, n): tmp = 0 if (f <= -16500000.0) or not (f <= 1.3e-85): tmp = (-2.0 * (n / f)) + -1.0 else: tmp = 1.0 return tmp
function code(f, n) tmp = 0.0 if ((f <= -16500000.0) || !(f <= 1.3e-85)) 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 <= -16500000.0) || ~((f <= 1.3e-85))) tmp = (-2.0 * (n / f)) + -1.0; else tmp = 1.0; end tmp_2 = tmp; end
code[f_, n_] := If[Or[LessEqual[f, -16500000.0], N[Not[LessEqual[f, 1.3e-85]], $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 -16500000 \lor \neg \left(f \leq 1.3 \cdot 10^{-85}\right):\\
\;\;\;\;-2 \cdot \frac{n}{f} + -1\\
\mathbf{else}:\\
\;\;\;\;1\\
\end{array}
\end{array}
if f < -1.65e7 or 1.30000000000000006e-85 < f Initial program 100.0%
neg-mul-1100.0%
remove-double-neg100.0%
unsub-neg100.0%
distribute-neg-in100.0%
neg-mul-1100.0%
times-frac100.0%
metadata-eval100.0%
+-commutative100.0%
+-commutative100.0%
sub-neg100.0%
*-lft-identity100.0%
+-commutative100.0%
Simplified100.0%
Taylor expanded in n around 0 78.9%
if -1.65e7 < f < 1.30000000000000006e-85Initial program 100.0%
neg-mul-1100.0%
remove-double-neg100.0%
unsub-neg100.0%
distribute-neg-in100.0%
neg-mul-1100.0%
times-frac100.0%
metadata-eval100.0%
+-commutative100.0%
+-commutative100.0%
sub-neg100.0%
*-lft-identity100.0%
+-commutative100.0%
Simplified100.0%
Taylor expanded in f around 0 82.4%
Final simplification80.5%
(FPCore (f n) :precision binary64 (if (<= f -15000000.0) -1.0 (if (<= f 1e-87) 1.0 -1.0)))
double code(double f, double n) {
double tmp;
if (f <= -15000000.0) {
tmp = -1.0;
} else if (f <= 1e-87) {
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 <= (-15000000.0d0)) then
tmp = -1.0d0
else if (f <= 1d-87) 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 <= -15000000.0) {
tmp = -1.0;
} else if (f <= 1e-87) {
tmp = 1.0;
} else {
tmp = -1.0;
}
return tmp;
}
def code(f, n): tmp = 0 if f <= -15000000.0: tmp = -1.0 elif f <= 1e-87: tmp = 1.0 else: tmp = -1.0 return tmp
function code(f, n) tmp = 0.0 if (f <= -15000000.0) tmp = -1.0; elseif (f <= 1e-87) tmp = 1.0; else tmp = -1.0; end return tmp end
function tmp_2 = code(f, n) tmp = 0.0; if (f <= -15000000.0) tmp = -1.0; elseif (f <= 1e-87) tmp = 1.0; else tmp = -1.0; end tmp_2 = tmp; end
code[f_, n_] := If[LessEqual[f, -15000000.0], -1.0, If[LessEqual[f, 1e-87], 1.0, -1.0]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;f \leq -15000000:\\
\;\;\;\;-1\\
\mathbf{elif}\;f \leq 10^{-87}:\\
\;\;\;\;1\\
\mathbf{else}:\\
\;\;\;\;-1\\
\end{array}
\end{array}
if f < -1.5e7 or 1.00000000000000002e-87 < f Initial program 100.0%
neg-mul-1100.0%
remove-double-neg100.0%
unsub-neg100.0%
distribute-neg-in100.0%
neg-mul-1100.0%
times-frac100.0%
metadata-eval100.0%
+-commutative100.0%
+-commutative100.0%
sub-neg100.0%
*-lft-identity100.0%
+-commutative100.0%
Simplified100.0%
Taylor expanded in f around inf 77.4%
if -1.5e7 < f < 1.00000000000000002e-87Initial program 100.0%
neg-mul-1100.0%
remove-double-neg100.0%
unsub-neg100.0%
distribute-neg-in100.0%
neg-mul-1100.0%
times-frac100.0%
metadata-eval100.0%
+-commutative100.0%
+-commutative100.0%
sub-neg100.0%
*-lft-identity100.0%
+-commutative100.0%
Simplified100.0%
Taylor expanded in f around 0 82.4%
Final simplification79.7%
(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%
neg-mul-1100.0%
remove-double-neg100.0%
unsub-neg100.0%
distribute-neg-in100.0%
neg-mul-1100.0%
times-frac100.0%
metadata-eval100.0%
+-commutative100.0%
+-commutative100.0%
sub-neg100.0%
*-lft-identity100.0%
+-commutative100.0%
Simplified100.0%
Taylor expanded in f around inf 50.2%
Final simplification50.2%
herbie shell --seed 2023331
(FPCore (f n)
:name "subtraction fraction"
:precision binary64
(/ (- (+ f n)) (- f n)))