
(FPCore (N) :precision binary64 (- (log (+ N 1.0)) (log N)))
double code(double N) {
return log((N + 1.0)) - log(N);
}
real(8) function code(n)
real(8), intent (in) :: n
code = log((n + 1.0d0)) - log(n)
end function
public static double code(double N) {
return Math.log((N + 1.0)) - Math.log(N);
}
def code(N): return math.log((N + 1.0)) - math.log(N)
function code(N) return Float64(log(Float64(N + 1.0)) - log(N)) end
function tmp = code(N) tmp = log((N + 1.0)) - log(N); end
code[N_] := N[(N[Log[N[(N + 1.0), $MachinePrecision]], $MachinePrecision] - N[Log[N], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\log \left(N + 1\right) - \log N
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 6 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (N) :precision binary64 (- (log (+ N 1.0)) (log N)))
double code(double N) {
return log((N + 1.0)) - log(N);
}
real(8) function code(n)
real(8), intent (in) :: n
code = log((n + 1.0d0)) - log(n)
end function
public static double code(double N) {
return Math.log((N + 1.0)) - Math.log(N);
}
def code(N): return math.log((N + 1.0)) - math.log(N)
function code(N) return Float64(log(Float64(N + 1.0)) - log(N)) end
function tmp = code(N) tmp = log((N + 1.0)) - log(N); end
code[N_] := N[(N[Log[N[(N + 1.0), $MachinePrecision]], $MachinePrecision] - N[Log[N], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\log \left(N + 1\right) - \log N
\end{array}
(FPCore (N) :precision binary64 (if (<= (- (log (+ 1.0 N)) (log N)) 0.0005) (/ (- (/ (- -0.5 (/ (fma -0.3333333333333333 N 0.25) (* N N))) N) -1.0) N) (log (/ (+ 1.0 N) N))))
double code(double N) {
double tmp;
if ((log((1.0 + N)) - log(N)) <= 0.0005) {
tmp = (((-0.5 - (fma(-0.3333333333333333, N, 0.25) / (N * N))) / N) - -1.0) / N;
} else {
tmp = log(((1.0 + N) / N));
}
return tmp;
}
function code(N) tmp = 0.0 if (Float64(log(Float64(1.0 + N)) - log(N)) <= 0.0005) tmp = Float64(Float64(Float64(Float64(-0.5 - Float64(fma(-0.3333333333333333, N, 0.25) / Float64(N * N))) / N) - -1.0) / N); else tmp = log(Float64(Float64(1.0 + N) / N)); end return tmp end
code[N_] := If[LessEqual[N[(N[Log[N[(1.0 + N), $MachinePrecision]], $MachinePrecision] - N[Log[N], $MachinePrecision]), $MachinePrecision], 0.0005], N[(N[(N[(N[(-0.5 - N[(N[(-0.3333333333333333 * N + 0.25), $MachinePrecision] / N[(N * N), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N), $MachinePrecision] - -1.0), $MachinePrecision] / N), $MachinePrecision], N[Log[N[(N[(1.0 + N), $MachinePrecision] / N), $MachinePrecision]], $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;\log \left(1 + N\right) - \log N \leq 0.0005:\\
\;\;\;\;\frac{\frac{-0.5 - \frac{\mathsf{fma}\left(-0.3333333333333333, N, 0.25\right)}{N \cdot N}}{N} - -1}{N}\\
\mathbf{else}:\\
\;\;\;\;\log \left(\frac{1 + N}{N}\right)\\
\end{array}
\end{array}
if (-.f64 (log.f64 (+.f64 N #s(literal 1 binary64))) (log.f64 N)) < 5.0000000000000001e-4Initial program 18.6%
Taylor expanded in N around inf
Applied rewrites99.8%
Taylor expanded in N around 0
Applied rewrites99.8%
if 5.0000000000000001e-4 < (-.f64 (log.f64 (+.f64 N #s(literal 1 binary64))) (log.f64 N)) Initial program 92.9%
lift--.f64N/A
lift-log.f64N/A
lift-log.f64N/A
diff-logN/A
lower-log.f64N/A
lower-/.f6495.3
lift-+.f64N/A
+-commutativeN/A
lower-+.f6495.3
Applied rewrites95.3%
Final simplification99.5%
(FPCore (N) :precision binary64 (/ (- (/ (- -0.5 (/ (fma -0.3333333333333333 N 0.25) (* N N))) N) -1.0) N))
double code(double N) {
return (((-0.5 - (fma(-0.3333333333333333, N, 0.25) / (N * N))) / N) - -1.0) / N;
}
function code(N) return Float64(Float64(Float64(Float64(-0.5 - Float64(fma(-0.3333333333333333, N, 0.25) / Float64(N * N))) / N) - -1.0) / N) end
code[N_] := N[(N[(N[(N[(-0.5 - N[(N[(-0.3333333333333333 * N + 0.25), $MachinePrecision] / N[(N * N), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] / N), $MachinePrecision] - -1.0), $MachinePrecision] / N), $MachinePrecision]
\begin{array}{l}
\\
\frac{\frac{-0.5 - \frac{\mathsf{fma}\left(-0.3333333333333333, N, 0.25\right)}{N \cdot N}}{N} - -1}{N}
\end{array}
Initial program 23.5%
Taylor expanded in N around inf
Applied rewrites96.6%
Taylor expanded in N around 0
Applied rewrites96.6%
(FPCore (N) :precision binary64 (/ (- (/ (- (/ 0.3333333333333333 N) 0.5) N) -1.0) N))
double code(double N) {
return ((((0.3333333333333333 / N) - 0.5) / N) - -1.0) / N;
}
real(8) function code(n)
real(8), intent (in) :: n
code = ((((0.3333333333333333d0 / n) - 0.5d0) / n) - (-1.0d0)) / n
end function
public static double code(double N) {
return ((((0.3333333333333333 / N) - 0.5) / N) - -1.0) / N;
}
def code(N): return ((((0.3333333333333333 / N) - 0.5) / N) - -1.0) / N
function code(N) return Float64(Float64(Float64(Float64(Float64(0.3333333333333333 / N) - 0.5) / N) - -1.0) / N) end
function tmp = code(N) tmp = ((((0.3333333333333333 / N) - 0.5) / N) - -1.0) / N; end
code[N_] := N[(N[(N[(N[(N[(0.3333333333333333 / N), $MachinePrecision] - 0.5), $MachinePrecision] / N), $MachinePrecision] - -1.0), $MachinePrecision] / N), $MachinePrecision]
\begin{array}{l}
\\
\frac{\frac{\frac{0.3333333333333333}{N} - 0.5}{N} - -1}{N}
\end{array}
Initial program 23.5%
Taylor expanded in N around inf
lower-/.f64N/A
associate--l+N/A
+-commutativeN/A
unpow2N/A
associate-/r*N/A
metadata-evalN/A
associate-*r/N/A
associate-*r/N/A
metadata-evalN/A
div-subN/A
metadata-evalN/A
sub-negN/A
lower--.f64N/A
lower-/.f64N/A
lower--.f64N/A
associate-*r/N/A
metadata-evalN/A
lower-/.f6495.3
Applied rewrites95.3%
(FPCore (N) :precision binary64 (/ 1.0 (/ N (- (/ -0.5 N) -1.0))))
double code(double N) {
return 1.0 / (N / ((-0.5 / N) - -1.0));
}
real(8) function code(n)
real(8), intent (in) :: n
code = 1.0d0 / (n / (((-0.5d0) / n) - (-1.0d0)))
end function
public static double code(double N) {
return 1.0 / (N / ((-0.5 / N) - -1.0));
}
def code(N): return 1.0 / (N / ((-0.5 / N) - -1.0))
function code(N) return Float64(1.0 / Float64(N / Float64(Float64(-0.5 / N) - -1.0))) end
function tmp = code(N) tmp = 1.0 / (N / ((-0.5 / N) - -1.0)); end
code[N_] := N[(1.0 / N[(N / N[(N[(-0.5 / N), $MachinePrecision] - -1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\frac{1}{\frac{N}{\frac{-0.5}{N} - -1}}
\end{array}
Initial program 23.5%
Taylor expanded in N around inf
Applied rewrites96.6%
Taylor expanded in N around inf
Applied rewrites92.4%
Applied rewrites92.4%
(FPCore (N) :precision binary64 (/ (- 1.0 (/ 0.5 N)) N))
double code(double N) {
return (1.0 - (0.5 / N)) / N;
}
real(8) function code(n)
real(8), intent (in) :: n
code = (1.0d0 - (0.5d0 / n)) / n
end function
public static double code(double N) {
return (1.0 - (0.5 / N)) / N;
}
def code(N): return (1.0 - (0.5 / N)) / N
function code(N) return Float64(Float64(1.0 - Float64(0.5 / N)) / N) end
function tmp = code(N) tmp = (1.0 - (0.5 / N)) / N; end
code[N_] := N[(N[(1.0 - N[(0.5 / N), $MachinePrecision]), $MachinePrecision] / N), $MachinePrecision]
\begin{array}{l}
\\
\frac{1 - \frac{0.5}{N}}{N}
\end{array}
Initial program 23.5%
Taylor expanded in N around inf
lower-/.f64N/A
lower--.f64N/A
associate-*r/N/A
metadata-evalN/A
lower-/.f6492.4
Applied rewrites92.4%
(FPCore (N) :precision binary64 (/ 1.0 N))
double code(double N) {
return 1.0 / N;
}
real(8) function code(n)
real(8), intent (in) :: n
code = 1.0d0 / n
end function
public static double code(double N) {
return 1.0 / N;
}
def code(N): return 1.0 / N
function code(N) return Float64(1.0 / N) end
function tmp = code(N) tmp = 1.0 / N; end
code[N_] := N[(1.0 / N), $MachinePrecision]
\begin{array}{l}
\\
\frac{1}{N}
\end{array}
Initial program 23.5%
Taylor expanded in N around inf
lower-/.f6484.7
Applied rewrites84.7%
(FPCore (N) :precision binary64 (+ (+ (+ (/ 1.0 N) (/ -1.0 (* 2.0 (pow N 2.0)))) (/ 1.0 (* 3.0 (pow N 3.0)))) (/ -1.0 (* 4.0 (pow N 4.0)))))
double code(double N) {
return (((1.0 / N) + (-1.0 / (2.0 * pow(N, 2.0)))) + (1.0 / (3.0 * pow(N, 3.0)))) + (-1.0 / (4.0 * pow(N, 4.0)));
}
real(8) function code(n)
real(8), intent (in) :: n
code = (((1.0d0 / n) + ((-1.0d0) / (2.0d0 * (n ** 2.0d0)))) + (1.0d0 / (3.0d0 * (n ** 3.0d0)))) + ((-1.0d0) / (4.0d0 * (n ** 4.0d0)))
end function
public static double code(double N) {
return (((1.0 / N) + (-1.0 / (2.0 * Math.pow(N, 2.0)))) + (1.0 / (3.0 * Math.pow(N, 3.0)))) + (-1.0 / (4.0 * Math.pow(N, 4.0)));
}
def code(N): return (((1.0 / N) + (-1.0 / (2.0 * math.pow(N, 2.0)))) + (1.0 / (3.0 * math.pow(N, 3.0)))) + (-1.0 / (4.0 * math.pow(N, 4.0)))
function code(N) return Float64(Float64(Float64(Float64(1.0 / N) + Float64(-1.0 / Float64(2.0 * (N ^ 2.0)))) + Float64(1.0 / Float64(3.0 * (N ^ 3.0)))) + Float64(-1.0 / Float64(4.0 * (N ^ 4.0)))) end
function tmp = code(N) tmp = (((1.0 / N) + (-1.0 / (2.0 * (N ^ 2.0)))) + (1.0 / (3.0 * (N ^ 3.0)))) + (-1.0 / (4.0 * (N ^ 4.0))); end
code[N_] := N[(N[(N[(N[(1.0 / N), $MachinePrecision] + N[(-1.0 / N[(2.0 * N[Power[N, 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(1.0 / N[(3.0 * N[Power[N, 3.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + N[(-1.0 / N[(4.0 * N[Power[N, 4.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\left(\left(\frac{1}{N} + \frac{-1}{2 \cdot {N}^{2}}\right) + \frac{1}{3 \cdot {N}^{3}}\right) + \frac{-1}{4 \cdot {N}^{4}}
\end{array}
herbie shell --seed 2024250
(FPCore (N)
:name "2log (problem 3.3.6)"
:precision binary64
:pre (and (> N 1.0) (< N 1e+40))
:alt
(! :herbie-platform default (+ (/ 1 N) (/ -1 (* 2 (pow N 2))) (/ 1 (* 3 (pow N 3))) (/ -1 (* 4 (pow N 4)))))
(- (log (+ N 1.0)) (log N)))