
(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 -3.15e+80)
(and (not (<= y -7.2e-53))
(or (<= y -2.8e-77)
(and (not (<= y -1e-125))
(or (<= y -4.1e-144) (not (<= y 85000000.0)))))))
(* y -0.5)
(* x 1.5)))
double code(double x, double y) {
double tmp;
if ((y <= -3.15e+80) || (!(y <= -7.2e-53) && ((y <= -2.8e-77) || (!(y <= -1e-125) && ((y <= -4.1e-144) || !(y <= 85000000.0)))))) {
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 <= (-3.15d+80)) .or. (.not. (y <= (-7.2d-53))) .and. (y <= (-2.8d-77)) .or. (.not. (y <= (-1d-125))) .and. (y <= (-4.1d-144)) .or. (.not. (y <= 85000000.0d0))) 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 <= -3.15e+80) || (!(y <= -7.2e-53) && ((y <= -2.8e-77) || (!(y <= -1e-125) && ((y <= -4.1e-144) || !(y <= 85000000.0)))))) {
tmp = y * -0.5;
} else {
tmp = x * 1.5;
}
return tmp;
}
def code(x, y): tmp = 0 if (y <= -3.15e+80) or (not (y <= -7.2e-53) and ((y <= -2.8e-77) or (not (y <= -1e-125) and ((y <= -4.1e-144) or not (y <= 85000000.0))))): tmp = y * -0.5 else: tmp = x * 1.5 return tmp
function code(x, y) tmp = 0.0 if ((y <= -3.15e+80) || (!(y <= -7.2e-53) && ((y <= -2.8e-77) || (!(y <= -1e-125) && ((y <= -4.1e-144) || !(y <= 85000000.0)))))) 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 <= -3.15e+80) || (~((y <= -7.2e-53)) && ((y <= -2.8e-77) || (~((y <= -1e-125)) && ((y <= -4.1e-144) || ~((y <= 85000000.0))))))) tmp = y * -0.5; else tmp = x * 1.5; end tmp_2 = tmp; end
code[x_, y_] := If[Or[LessEqual[y, -3.15e+80], And[N[Not[LessEqual[y, -7.2e-53]], $MachinePrecision], Or[LessEqual[y, -2.8e-77], And[N[Not[LessEqual[y, -1e-125]], $MachinePrecision], Or[LessEqual[y, -4.1e-144], N[Not[LessEqual[y, 85000000.0]], $MachinePrecision]]]]]], N[(y * -0.5), $MachinePrecision], N[(x * 1.5), $MachinePrecision]]
\begin{array}{l}
\\
\begin{array}{l}
\mathbf{if}\;y \leq -3.15 \cdot 10^{+80} \lor \neg \left(y \leq -7.2 \cdot 10^{-53}\right) \land \left(y \leq -2.8 \cdot 10^{-77} \lor \neg \left(y \leq -1 \cdot 10^{-125}\right) \land \left(y \leq -4.1 \cdot 10^{-144} \lor \neg \left(y \leq 85000000\right)\right)\right):\\
\;\;\;\;y \cdot -0.5\\
\mathbf{else}:\\
\;\;\;\;x \cdot 1.5\\
\end{array}
\end{array}
if y < -3.14999999999999989e80 or -7.1999999999999998e-53 < y < -2.7999999999999999e-77 or -1.00000000000000001e-125 < y < -4.1e-144 or 8.5e7 < y Initial program 99.9%
Taylor expanded in x around 0 83.1%
if -3.14999999999999989e80 < y < -7.1999999999999998e-53 or -2.7999999999999999e-77 < y < -1.00000000000000001e-125 or -4.1e-144 < y < 8.5e7Initial program 99.8%
Taylor expanded in x around inf 81.9%
Final simplification82.5%
(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 53.3%
Final simplification53.3%
(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 2024091
(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)))