
(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 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%
Final simplification100.0%
(FPCore (f n) :precision binary64 (if (or (<= n -2.45e-13) (not (<= n 9.6e-15))) (+ (* 2.0 (/ f n)) 1.0) -1.0))
double code(double f, double n) {
double tmp;
if ((n <= -2.45e-13) || !(n <= 9.6e-15)) {
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 <= (-2.45d-13)) .or. (.not. (n <= 9.6d-15))) 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 <= -2.45e-13) || !(n <= 9.6e-15)) {
tmp = (2.0 * (f / n)) + 1.0;
} else {
tmp = -1.0;
}
return tmp;
}
def code(f, n): tmp = 0 if (n <= -2.45e-13) or not (n <= 9.6e-15): tmp = (2.0 * (f / n)) + 1.0 else: tmp = -1.0 return tmp
function code(f, n) tmp = 0.0 if ((n <= -2.45e-13) || !(n <= 9.6e-15)) 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 <= -2.45e-13) || ~((n <= 9.6e-15))) tmp = (2.0 * (f / n)) + 1.0; else tmp = -1.0; end tmp_2 = tmp; end
code[f_, n_] := If[Or[LessEqual[n, -2.45e-13], N[Not[LessEqual[n, 9.6e-15]], $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 -2.45 \cdot 10^{-13} \lor \neg \left(n \leq 9.6 \cdot 10^{-15}\right):\\
\;\;\;\;2 \cdot \frac{f}{n} + 1\\
\mathbf{else}:\\
\;\;\;\;-1\\
\end{array}
\end{array}
if n < -2.45000000000000016e-13 or 9.5999999999999998e-15 < n Initial 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 0 75.9%
if -2.45000000000000016e-13 < n < 9.5999999999999998e-15Initial 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 78.3%
Final simplification77.1%
(FPCore (f n) :precision binary64 (if (or (<= n -1.75e-11) (not (<= n 9.2e-13))) (+ (* 2.0 (/ f n)) 1.0) (+ (* -2.0 (/ n f)) -1.0)))
double code(double f, double n) {
double tmp;
if ((n <= -1.75e-11) || !(n <= 9.2e-13)) {
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 <= (-1.75d-11)) .or. (.not. (n <= 9.2d-13))) 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 <= -1.75e-11) || !(n <= 9.2e-13)) {
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 <= -1.75e-11) or not (n <= 9.2e-13): 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 <= -1.75e-11) || !(n <= 9.2e-13)) 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 <= -1.75e-11) || ~((n <= 9.2e-13))) 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, -1.75e-11], N[Not[LessEqual[n, 9.2e-13]], $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 -1.75 \cdot 10^{-11} \lor \neg \left(n \leq 9.2 \cdot 10^{-13}\right):\\
\;\;\;\;2 \cdot \frac{f}{n} + 1\\
\mathbf{else}:\\
\;\;\;\;-2 \cdot \frac{n}{f} + -1\\
\end{array}
\end{array}
if n < -1.7500000000000001e-11 or 9.19999999999999917e-13 < n Initial 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 0 75.9%
if -1.7500000000000001e-11 < n < 9.19999999999999917e-13Initial 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 79.5%
Final simplification77.8%
(FPCore (f n) :precision binary64 (if (<= n -6.5e-16) 1.0 (if (<= n 1.35e-5) -1.0 1.0)))
double code(double f, double n) {
double tmp;
if (n <= -6.5e-16) {
tmp = 1.0;
} else if (n <= 1.35e-5) {
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 <= (-6.5d-16)) then
tmp = 1.0d0
else if (n <= 1.35d-5) 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 <= -6.5e-16) {
tmp = 1.0;
} else if (n <= 1.35e-5) {
tmp = -1.0;
} else {
tmp = 1.0;
}
return tmp;
}
def code(f, n): tmp = 0 if n <= -6.5e-16: tmp = 1.0 elif n <= 1.35e-5: tmp = -1.0 else: tmp = 1.0 return tmp
function code(f, n) tmp = 0.0 if (n <= -6.5e-16) tmp = 1.0; elseif (n <= 1.35e-5) tmp = -1.0; else tmp = 1.0; end return tmp end
function tmp_2 = code(f, n) tmp = 0.0; if (n <= -6.5e-16) tmp = 1.0; elseif (n <= 1.35e-5) tmp = -1.0; else tmp = 1.0; end tmp_2 = tmp; end
code[f_, n_] := If[LessEqual[n, -6.5e-16], 1.0, If[LessEqual[n, 1.35e-5], -1.0, 1.0]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;n \leq -6.5 \cdot 10^{-16}:\\
\;\;\;\;1\\
\mathbf{elif}\;n \leq 1.35 \cdot 10^{-5}:\\
\;\;\;\;-1\\
\mathbf{else}:\\
\;\;\;\;1\\
\end{array}
\end{array}
if n < -6.50000000000000011e-16 or 1.3499999999999999e-5 < n Initial 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 0 74.9%
if -6.50000000000000011e-16 < n < 1.3499999999999999e-5Initial 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 78.3%
Final simplification76.7%
(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%
*-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 53.3%
Final simplification53.3%
herbie shell --seed 2023230
(FPCore (f n)
:name "subtraction fraction"
:precision binary64
(/ (- (+ f n)) (- f n)))