
(FPCore (a b) :precision binary64 (- (* a a) (* b b)))
double code(double a, double b) {
return (a * a) - (b * b);
}
real(8) function code(a, b)
real(8), intent (in) :: a
real(8), intent (in) :: b
code = (a * a) - (b * b)
end function
public static double code(double a, double b) {
return (a * a) - (b * b);
}
def code(a, b): return (a * a) - (b * b)
function code(a, b) return Float64(Float64(a * a) - Float64(b * b)) end
function tmp = code(a, b) tmp = (a * a) - (b * b); end
code[a_, b_] := N[(N[(a * a), $MachinePrecision] - N[(b * b), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
a \cdot a - b \cdot b
\end{array}
Sampling outcomes in binary64 precision:
Herbie found 5 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (a b) :precision binary64 (- (* a a) (* b b)))
double code(double a, double b) {
return (a * a) - (b * b);
}
real(8) function code(a, b)
real(8), intent (in) :: a
real(8), intent (in) :: b
code = (a * a) - (b * b)
end function
public static double code(double a, double b) {
return (a * a) - (b * b);
}
def code(a, b): return (a * a) - (b * b)
function code(a, b) return Float64(Float64(a * a) - Float64(b * b)) end
function tmp = code(a, b) tmp = (a * a) - (b * b); end
code[a_, b_] := N[(N[(a * a), $MachinePrecision] - N[(b * b), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
a \cdot a - b \cdot b
\end{array}
a_m = (fabs.f64 a) (FPCore (a_m b) :precision binary64 (if (<= a_m 1.35e+218) (fma a_m a_m (* b (- b))) (* a_m (+ a_m b))))
a_m = fabs(a);
double code(double a_m, double b) {
double tmp;
if (a_m <= 1.35e+218) {
tmp = fma(a_m, a_m, (b * -b));
} else {
tmp = a_m * (a_m + b);
}
return tmp;
}
a_m = abs(a) function code(a_m, b) tmp = 0.0 if (a_m <= 1.35e+218) tmp = fma(a_m, a_m, Float64(b * Float64(-b))); else tmp = Float64(a_m * Float64(a_m + b)); end return tmp end
a_m = N[Abs[a], $MachinePrecision] code[a$95$m_, b_] := If[LessEqual[a$95$m, 1.35e+218], N[(a$95$m * a$95$m + N[(b * (-b)), $MachinePrecision]), $MachinePrecision], N[(a$95$m * N[(a$95$m + b), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}
a_m = \left|a\right|
\\
\begin{array}{l}
\mathbf{if}\;a\_m \leq 1.35 \cdot 10^{+218}:\\
\;\;\;\;\mathsf{fma}\left(a\_m, a\_m, b \cdot \left(-b\right)\right)\\
\mathbf{else}:\\
\;\;\;\;a\_m \cdot \left(a\_m + b\right)\\
\end{array}
\end{array}
if a < 1.35000000000000006e218Initial program 94.3%
sqr-neg94.3%
cancel-sign-sub94.3%
fma-define98.4%
Simplified98.4%
if 1.35000000000000006e218 < a Initial program 72.7%
difference-of-squares100.0%
sub-neg100.0%
add-sqr-sqrt36.4%
sqrt-unprod100.0%
sqr-neg100.0%
sqrt-prod63.6%
add-sqr-sqrt100.0%
Applied egg-rr100.0%
Taylor expanded in a around inf 100.0%
Final simplification98.4%
a_m = (fabs.f64 a) (FPCore (a_m b) :precision binary64 (if (<= (* b b) 2e+301) (- (* a_m a_m) (* b b)) (* b (- b))))
a_m = fabs(a);
double code(double a_m, double b) {
double tmp;
if ((b * b) <= 2e+301) {
tmp = (a_m * a_m) - (b * b);
} else {
tmp = b * -b;
}
return tmp;
}
a_m = abs(a)
real(8) function code(a_m, b)
real(8), intent (in) :: a_m
real(8), intent (in) :: b
real(8) :: tmp
if ((b * b) <= 2d+301) then
tmp = (a_m * a_m) - (b * b)
else
tmp = b * -b
end if
code = tmp
end function
a_m = Math.abs(a);
public static double code(double a_m, double b) {
double tmp;
if ((b * b) <= 2e+301) {
tmp = (a_m * a_m) - (b * b);
} else {
tmp = b * -b;
}
return tmp;
}
a_m = math.fabs(a) def code(a_m, b): tmp = 0 if (b * b) <= 2e+301: tmp = (a_m * a_m) - (b * b) else: tmp = b * -b return tmp
a_m = abs(a) function code(a_m, b) tmp = 0.0 if (Float64(b * b) <= 2e+301) tmp = Float64(Float64(a_m * a_m) - Float64(b * b)); else tmp = Float64(b * Float64(-b)); end return tmp end
a_m = abs(a); function tmp_2 = code(a_m, b) tmp = 0.0; if ((b * b) <= 2e+301) tmp = (a_m * a_m) - (b * b); else tmp = b * -b; end tmp_2 = tmp; end
a_m = N[Abs[a], $MachinePrecision] code[a$95$m_, b_] := If[LessEqual[N[(b * b), $MachinePrecision], 2e+301], N[(N[(a$95$m * a$95$m), $MachinePrecision] - N[(b * b), $MachinePrecision]), $MachinePrecision], N[(b * (-b)), $MachinePrecision]]
\begin{array}{l}
a_m = \left|a\right|
\\
\begin{array}{l}
\mathbf{if}\;b \cdot b \leq 2 \cdot 10^{+301}:\\
\;\;\;\;a\_m \cdot a\_m - b \cdot b\\
\mathbf{else}:\\
\;\;\;\;b \cdot \left(-b\right)\\
\end{array}
\end{array}
if (*.f64 b b) < 2.00000000000000011e301Initial program 100.0%
if 2.00000000000000011e301 < (*.f64 b b) Initial program 74.6%
Taylor expanded in a around 0 89.6%
neg-mul-189.6%
Simplified89.6%
unpow289.6%
distribute-lft-neg-in89.6%
Applied egg-rr89.6%
Final simplification97.3%
a_m = (fabs.f64 a) (FPCore (a_m b) :precision binary64 (if (<= (* b b) 2e-23) (* a_m (+ a_m b)) (* b (- b))))
a_m = fabs(a);
double code(double a_m, double b) {
double tmp;
if ((b * b) <= 2e-23) {
tmp = a_m * (a_m + b);
} else {
tmp = b * -b;
}
return tmp;
}
a_m = abs(a)
real(8) function code(a_m, b)
real(8), intent (in) :: a_m
real(8), intent (in) :: b
real(8) :: tmp
if ((b * b) <= 2d-23) then
tmp = a_m * (a_m + b)
else
tmp = b * -b
end if
code = tmp
end function
a_m = Math.abs(a);
public static double code(double a_m, double b) {
double tmp;
if ((b * b) <= 2e-23) {
tmp = a_m * (a_m + b);
} else {
tmp = b * -b;
}
return tmp;
}
a_m = math.fabs(a) def code(a_m, b): tmp = 0 if (b * b) <= 2e-23: tmp = a_m * (a_m + b) else: tmp = b * -b return tmp
a_m = abs(a) function code(a_m, b) tmp = 0.0 if (Float64(b * b) <= 2e-23) tmp = Float64(a_m * Float64(a_m + b)); else tmp = Float64(b * Float64(-b)); end return tmp end
a_m = abs(a); function tmp_2 = code(a_m, b) tmp = 0.0; if ((b * b) <= 2e-23) tmp = a_m * (a_m + b); else tmp = b * -b; end tmp_2 = tmp; end
a_m = N[Abs[a], $MachinePrecision] code[a$95$m_, b_] := If[LessEqual[N[(b * b), $MachinePrecision], 2e-23], N[(a$95$m * N[(a$95$m + b), $MachinePrecision]), $MachinePrecision], N[(b * (-b)), $MachinePrecision]]
\begin{array}{l}
a_m = \left|a\right|
\\
\begin{array}{l}
\mathbf{if}\;b \cdot b \leq 2 \cdot 10^{-23}:\\
\;\;\;\;a\_m \cdot \left(a\_m + b\right)\\
\mathbf{else}:\\
\;\;\;\;b \cdot \left(-b\right)\\
\end{array}
\end{array}
if (*.f64 b b) < 1.99999999999999992e-23Initial program 100.0%
difference-of-squares100.0%
sub-neg100.0%
add-sqr-sqrt50.4%
sqrt-unprod92.7%
sqr-neg92.7%
sqrt-prod42.3%
add-sqr-sqrt84.7%
Applied egg-rr84.7%
Taylor expanded in a around inf 85.1%
if 1.99999999999999992e-23 < (*.f64 b b) Initial program 87.4%
Taylor expanded in a around 0 80.4%
neg-mul-180.4%
Simplified80.4%
unpow280.4%
distribute-lft-neg-in80.4%
Applied egg-rr80.4%
Final simplification82.6%
a_m = (fabs.f64 a) (FPCore (a_m b) :precision binary64 (if (<= a_m 7.8e+217) (* b (- b)) (* a_m b)))
a_m = fabs(a);
double code(double a_m, double b) {
double tmp;
if (a_m <= 7.8e+217) {
tmp = b * -b;
} else {
tmp = a_m * b;
}
return tmp;
}
a_m = abs(a)
real(8) function code(a_m, b)
real(8), intent (in) :: a_m
real(8), intent (in) :: b
real(8) :: tmp
if (a_m <= 7.8d+217) then
tmp = b * -b
else
tmp = a_m * b
end if
code = tmp
end function
a_m = Math.abs(a);
public static double code(double a_m, double b) {
double tmp;
if (a_m <= 7.8e+217) {
tmp = b * -b;
} else {
tmp = a_m * b;
}
return tmp;
}
a_m = math.fabs(a) def code(a_m, b): tmp = 0 if a_m <= 7.8e+217: tmp = b * -b else: tmp = a_m * b return tmp
a_m = abs(a) function code(a_m, b) tmp = 0.0 if (a_m <= 7.8e+217) tmp = Float64(b * Float64(-b)); else tmp = Float64(a_m * b); end return tmp end
a_m = abs(a); function tmp_2 = code(a_m, b) tmp = 0.0; if (a_m <= 7.8e+217) tmp = b * -b; else tmp = a_m * b; end tmp_2 = tmp; end
a_m = N[Abs[a], $MachinePrecision] code[a$95$m_, b_] := If[LessEqual[a$95$m, 7.8e+217], N[(b * (-b)), $MachinePrecision], N[(a$95$m * b), $MachinePrecision]]
\begin{array}{l}
a_m = \left|a\right|
\\
\begin{array}{l}
\mathbf{if}\;a\_m \leq 7.8 \cdot 10^{+217}:\\
\;\;\;\;b \cdot \left(-b\right)\\
\mathbf{else}:\\
\;\;\;\;a\_m \cdot b\\
\end{array}
\end{array}
if a < 7.79999999999999986e217Initial program 94.3%
Taylor expanded in a around 0 58.6%
neg-mul-158.6%
Simplified58.6%
unpow258.6%
distribute-lft-neg-in58.6%
Applied egg-rr58.6%
if 7.79999999999999986e217 < a Initial program 72.7%
difference-of-squares100.0%
sub-neg100.0%
add-sqr-sqrt36.4%
sqrt-unprod100.0%
sqr-neg100.0%
sqrt-prod63.6%
add-sqr-sqrt100.0%
Applied egg-rr100.0%
Taylor expanded in a around inf 100.0%
Taylor expanded in a around 0 29.0%
Final simplification57.3%
a_m = (fabs.f64 a) (FPCore (a_m b) :precision binary64 (* a_m b))
a_m = fabs(a);
double code(double a_m, double b) {
return a_m * b;
}
a_m = abs(a)
real(8) function code(a_m, b)
real(8), intent (in) :: a_m
real(8), intent (in) :: b
code = a_m * b
end function
a_m = Math.abs(a);
public static double code(double a_m, double b) {
return a_m * b;
}
a_m = math.fabs(a) def code(a_m, b): return a_m * b
a_m = abs(a) function code(a_m, b) return Float64(a_m * b) end
a_m = abs(a); function tmp = code(a_m, b) tmp = a_m * b; end
a_m = N[Abs[a], $MachinePrecision] code[a$95$m_, b_] := N[(a$95$m * b), $MachinePrecision]
\begin{array}{l}
a_m = \left|a\right|
\\
a\_m \cdot b
\end{array}
Initial program 93.4%
difference-of-squares100.0%
sub-neg100.0%
add-sqr-sqrt49.1%
sqrt-unprod73.6%
sqr-neg73.6%
sqrt-prod25.9%
add-sqr-sqrt50.3%
Applied egg-rr50.3%
Taylor expanded in a around inf 54.4%
Taylor expanded in a around 0 14.2%
(FPCore (a b) :precision binary64 (* (+ a b) (- a b)))
double code(double a, double b) {
return (a + b) * (a - b);
}
real(8) function code(a, b)
real(8), intent (in) :: a
real(8), intent (in) :: b
code = (a + b) * (a - b)
end function
public static double code(double a, double b) {
return (a + b) * (a - b);
}
def code(a, b): return (a + b) * (a - b)
function code(a, b) return Float64(Float64(a + b) * Float64(a - b)) end
function tmp = code(a, b) tmp = (a + b) * (a - b); end
code[a_, b_] := N[(N[(a + b), $MachinePrecision] * N[(a - b), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
\\
\left(a + b\right) \cdot \left(a - b\right)
\end{array}
herbie shell --seed 2024111
(FPCore (a b)
:name "Difference of squares"
:precision binary64
:alt
(* (+ a b) (- a b))
(- (* a a) (* b b)))