
(FPCore (x y) :precision binary64 (+ x (/ (- x y) 2.0)))
double code(double x, double y) {
return x + ((x - y) / 2.0);
}
real(8) function code(x, y)
real(8), intent (in) :: x
real(8), intent (in) :: y
code = x + ((x - y) / 2.0d0)
end function
public static double code(double x, double y) {
return x + ((x - y) / 2.0);
}
def code(x, y): return x + ((x - y) / 2.0)
function code(x, y) return Float64(x + Float64(Float64(x - y) / 2.0)) end
function tmp = code(x, y) tmp = x + ((x - y) / 2.0); end
code[x_, y_] := N[(x + N[(N[(x - y), $MachinePrecision] / 2.0), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
x + \frac{x - y}{2}
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 4 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (x y) :precision binary64 (+ x (/ (- x y) 2.0)))
double code(double x, double y) {
return x + ((x - y) / 2.0);
}
real(8) function code(x, y)
real(8), intent (in) :: x
real(8), intent (in) :: y
code = x + ((x - y) / 2.0d0)
end function
public static double code(double x, double y) {
return x + ((x - y) / 2.0);
}
def code(x, y): return x + ((x - y) / 2.0)
function code(x, y) return Float64(x + Float64(Float64(x - y) / 2.0)) end
function tmp = code(x, y) tmp = x + ((x - y) / 2.0); end
code[x_, y_] := N[(x + N[(N[(x - y), $MachinePrecision] / 2.0), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
x + \frac{x - y}{2}
\end{array}
(FPCore (x y) :precision binary64 (fma x 1.5 (* y -0.5)))
double code(double x, double y) {
return fma(x, 1.5, (y * -0.5));
}
function code(x, y) return fma(x, 1.5, Float64(y * -0.5)) end
code[x_, y_] := N[(x * 1.5 + N[(y * -0.5), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\mathsf{fma}\left(x, 1.5, y \cdot -0.5\right)
\end{array}
Initial program 99.9%
div-sub99.9%
associate-+r-99.9%
remove-double-neg99.9%
distribute-frac-neg99.9%
sub-neg99.9%
neg-mul-199.9%
*-commutative99.9%
associate-/l*99.9%
*-rgt-identity99.9%
metadata-eval99.9%
distribute-lft-out--99.9%
fma-neg100.0%
metadata-eval100.0%
metadata-eval100.0%
metadata-eval100.0%
distribute-frac-neg100.0%
neg-mul-1100.0%
*-commutative100.0%
associate-/l*100.0%
metadata-eval100.0%
Simplified100.0%
(FPCore (x y)
:precision binary64
(if (or (<= y -1.12e+61)
(and (not (<= y 2.9e-73)) (or (<= y 1.7e-21) (not (<= y 1.9e+74)))))
(* y -0.5)
(* x 1.5)))
double code(double x, double y) {
double tmp;
if ((y <= -1.12e+61) || (!(y <= 2.9e-73) && ((y <= 1.7e-21) || !(y <= 1.9e+74)))) {
tmp = y * -0.5;
} else {
tmp = x * 1.5;
}
return tmp;
}
real(8) function code(x, y)
real(8), intent (in) :: x
real(8), intent (in) :: y
real(8) :: tmp
if ((y <= (-1.12d+61)) .or. (.not. (y <= 2.9d-73)) .and. (y <= 1.7d-21) .or. (.not. (y <= 1.9d+74))) then
tmp = y * (-0.5d0)
else
tmp = x * 1.5d0
end if
code = tmp
end function
public static double code(double x, double y) {
double tmp;
if ((y <= -1.12e+61) || (!(y <= 2.9e-73) && ((y <= 1.7e-21) || !(y <= 1.9e+74)))) {
tmp = y * -0.5;
} else {
tmp = x * 1.5;
}
return tmp;
}
def code(x, y): tmp = 0 if (y <= -1.12e+61) or (not (y <= 2.9e-73) and ((y <= 1.7e-21) or not (y <= 1.9e+74))): tmp = y * -0.5 else: tmp = x * 1.5 return tmp
function code(x, y) tmp = 0.0 if ((y <= -1.12e+61) || (!(y <= 2.9e-73) && ((y <= 1.7e-21) || !(y <= 1.9e+74)))) tmp = Float64(y * -0.5); else tmp = Float64(x * 1.5); end return tmp end
function tmp_2 = code(x, y) tmp = 0.0; if ((y <= -1.12e+61) || (~((y <= 2.9e-73)) && ((y <= 1.7e-21) || ~((y <= 1.9e+74))))) tmp = y * -0.5; else tmp = x * 1.5; end tmp_2 = tmp; end
code[x_, y_] := If[Or[LessEqual[y, -1.12e+61], And[N[Not[LessEqual[y, 2.9e-73]], $MachinePrecision], Or[LessEqual[y, 1.7e-21], N[Not[LessEqual[y, 1.9e+74]], $MachinePrecision]]]], N[(y * -0.5), $MachinePrecision], N[(x * 1.5), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;y \leq -1.12 \cdot 10^{+61} \lor \neg \left(y \leq 2.9 \cdot 10^{-73}\right) \land \left(y \leq 1.7 \cdot 10^{-21} \lor \neg \left(y \leq 1.9 \cdot 10^{+74}\right)\right):\\
\;\;\;\;y \cdot -0.5\\
\mathbf{else}:\\
\;\;\;\;x \cdot 1.5\\
\end{array}
\end{array}
if y < -1.12e61 or 2.9e-73 < y < 1.7e-21 or 1.8999999999999999e74 < y Initial program 100.0%
Taylor expanded in x around 0 87.5%
if -1.12e61 < y < 2.9e-73 or 1.7e-21 < y < 1.8999999999999999e74Initial program 99.8%
Taylor expanded in x around inf 78.0%
Final simplification82.3%
(FPCore (x y) :precision binary64 (+ x (/ (- x y) 2.0)))
double code(double x, double y) {
return x + ((x - y) / 2.0);
}
real(8) function code(x, y)
real(8), intent (in) :: x
real(8), intent (in) :: y
code = x + ((x - y) / 2.0d0)
end function
public static double code(double x, double y) {
return x + ((x - y) / 2.0);
}
def code(x, y): return x + ((x - y) / 2.0)
function code(x, y) return Float64(x + Float64(Float64(x - y) / 2.0)) end
function tmp = code(x, y) tmp = x + ((x - y) / 2.0); end
code[x_, y_] := N[(x + N[(N[(x - y), $MachinePrecision] / 2.0), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
x + \frac{x - y}{2}
\end{array}
Initial program 99.9%
(FPCore (x y) :precision binary64 (* y -0.5))
double code(double x, double y) {
return y * -0.5;
}
real(8) function code(x, y)
real(8), intent (in) :: x
real(8), intent (in) :: y
code = y * (-0.5d0)
end function
public static double code(double x, double y) {
return y * -0.5;
}
def code(x, y): return y * -0.5
function code(x, y) return Float64(y * -0.5) end
function tmp = code(x, y) tmp = y * -0.5; end
code[x_, y_] := N[(y * -0.5), $MachinePrecision]
\begin{array}{l}
\\
y \cdot -0.5
\end{array}
Initial program 99.9%
Taylor expanded in x around 0 51.6%
Final simplification51.6%
(FPCore (x y) :precision binary64 (- (* 1.5 x) (* 0.5 y)))
double code(double x, double y) {
return (1.5 * x) - (0.5 * y);
}
real(8) function code(x, y)
real(8), intent (in) :: x
real(8), intent (in) :: y
code = (1.5d0 * x) - (0.5d0 * y)
end function
public static double code(double x, double y) {
return (1.5 * x) - (0.5 * y);
}
def code(x, y): return (1.5 * x) - (0.5 * y)
function code(x, y) return Float64(Float64(1.5 * x) - Float64(0.5 * y)) end
function tmp = code(x, y) tmp = (1.5 * x) - (0.5 * y); end
code[x_, y_] := N[(N[(1.5 * x), $MachinePrecision] - N[(0.5 * y), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
1.5 \cdot x - 0.5 \cdot y
\end{array}
herbie shell --seed 2024087
(FPCore (x y)
:name "Graphics.Rendering.Chart.Axis.Types:hBufferRect from Chart-1.5.3"
:precision binary64
:alt
(- (* 1.5 x) (* 0.5 y))
(+ x (/ (- x y) 2.0)))