Codec.Picture.Jpg.FastDct:referenceDct from JuicyPixels-3.2.6.1

Percentage Accurate: 28.0% → 31.4%
Time: 19.9s
Alternatives: 3
Speedup: 225.0×

Specification

?
\[\begin{array}{l} \\ \left(x \cdot \cos \left(\frac{\left(\left(y \cdot 2 + 1\right) \cdot z\right) \cdot t}{16}\right)\right) \cdot \cos \left(\frac{\left(\left(a \cdot 2 + 1\right) \cdot b\right) \cdot t}{16}\right) \end{array} \]
(FPCore (x y z t a b)
 :precision binary64
 (*
  (* x (cos (/ (* (* (+ (* y 2.0) 1.0) z) t) 16.0)))
  (cos (/ (* (* (+ (* a 2.0) 1.0) b) t) 16.0))))
double code(double x, double y, double z, double t, double a, double b) {
	return (x * cos((((((y * 2.0) + 1.0) * z) * t) / 16.0))) * cos((((((a * 2.0) + 1.0) * b) * t) / 16.0));
}
real(8) function code(x, y, z, t, a, b)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    code = (x * cos((((((y * 2.0d0) + 1.0d0) * z) * t) / 16.0d0))) * cos((((((a * 2.0d0) + 1.0d0) * b) * t) / 16.0d0))
end function
public static double code(double x, double y, double z, double t, double a, double b) {
	return (x * Math.cos((((((y * 2.0) + 1.0) * z) * t) / 16.0))) * Math.cos((((((a * 2.0) + 1.0) * b) * t) / 16.0));
}
def code(x, y, z, t, a, b):
	return (x * math.cos((((((y * 2.0) + 1.0) * z) * t) / 16.0))) * math.cos((((((a * 2.0) + 1.0) * b) * t) / 16.0))
function code(x, y, z, t, a, b)
	return Float64(Float64(x * cos(Float64(Float64(Float64(Float64(Float64(y * 2.0) + 1.0) * z) * t) / 16.0))) * cos(Float64(Float64(Float64(Float64(Float64(a * 2.0) + 1.0) * b) * t) / 16.0)))
end
function tmp = code(x, y, z, t, a, b)
	tmp = (x * cos((((((y * 2.0) + 1.0) * z) * t) / 16.0))) * cos((((((a * 2.0) + 1.0) * b) * t) / 16.0));
end
code[x_, y_, z_, t_, a_, b_] := N[(N[(x * N[Cos[N[(N[(N[(N[(N[(y * 2.0), $MachinePrecision] + 1.0), $MachinePrecision] * z), $MachinePrecision] * t), $MachinePrecision] / 16.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * N[Cos[N[(N[(N[(N[(N[(a * 2.0), $MachinePrecision] + 1.0), $MachinePrecision] * b), $MachinePrecision] * t), $MachinePrecision] / 16.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\left(x \cdot \cos \left(\frac{\left(\left(y \cdot 2 + 1\right) \cdot z\right) \cdot t}{16}\right)\right) \cdot \cos \left(\frac{\left(\left(a \cdot 2 + 1\right) \cdot b\right) \cdot t}{16}\right)
\end{array}

Sampling outcomes in binary64 precision:

Local Percentage Accuracy vs ?

The average percentage accuracy by input value. Horizontal axis shows value of an input variable; the variable is choosen in the title. Vertical axis is accuracy; higher is better. Red represent the original program, while blue represents Herbie's suggestion. These can be toggled with buttons below the plot. The line is an average while dots represent individual samples.

Accuracy vs Speed?

Herbie found 3 alternatives:

AlternativeAccuracySpeedup
The accuracy (vertical axis) and speed (horizontal axis) of each alternatives. Up and to the right is better. The red square shows the initial program, and each blue circle shows an alternative.The line shows the best available speed-accuracy tradeoffs.

Initial Program: 28.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \left(x \cdot \cos \left(\frac{\left(\left(y \cdot 2 + 1\right) \cdot z\right) \cdot t}{16}\right)\right) \cdot \cos \left(\frac{\left(\left(a \cdot 2 + 1\right) \cdot b\right) \cdot t}{16}\right) \end{array} \]
(FPCore (x y z t a b)
 :precision binary64
 (*
  (* x (cos (/ (* (* (+ (* y 2.0) 1.0) z) t) 16.0)))
  (cos (/ (* (* (+ (* a 2.0) 1.0) b) t) 16.0))))
double code(double x, double y, double z, double t, double a, double b) {
	return (x * cos((((((y * 2.0) + 1.0) * z) * t) / 16.0))) * cos((((((a * 2.0) + 1.0) * b) * t) / 16.0));
}
real(8) function code(x, y, z, t, a, b)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    code = (x * cos((((((y * 2.0d0) + 1.0d0) * z) * t) / 16.0d0))) * cos((((((a * 2.0d0) + 1.0d0) * b) * t) / 16.0d0))
end function
public static double code(double x, double y, double z, double t, double a, double b) {
	return (x * Math.cos((((((y * 2.0) + 1.0) * z) * t) / 16.0))) * Math.cos((((((a * 2.0) + 1.0) * b) * t) / 16.0));
}
def code(x, y, z, t, a, b):
	return (x * math.cos((((((y * 2.0) + 1.0) * z) * t) / 16.0))) * math.cos((((((a * 2.0) + 1.0) * b) * t) / 16.0))
function code(x, y, z, t, a, b)
	return Float64(Float64(x * cos(Float64(Float64(Float64(Float64(Float64(y * 2.0) + 1.0) * z) * t) / 16.0))) * cos(Float64(Float64(Float64(Float64(Float64(a * 2.0) + 1.0) * b) * t) / 16.0)))
end
function tmp = code(x, y, z, t, a, b)
	tmp = (x * cos((((((y * 2.0) + 1.0) * z) * t) / 16.0))) * cos((((((a * 2.0) + 1.0) * b) * t) / 16.0));
end
code[x_, y_, z_, t_, a_, b_] := N[(N[(x * N[Cos[N[(N[(N[(N[(N[(y * 2.0), $MachinePrecision] + 1.0), $MachinePrecision] * z), $MachinePrecision] * t), $MachinePrecision] / 16.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * N[Cos[N[(N[(N[(N[(N[(a * 2.0), $MachinePrecision] + 1.0), $MachinePrecision] * b), $MachinePrecision] * t), $MachinePrecision] / 16.0), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\left(x \cdot \cos \left(\frac{\left(\left(y \cdot 2 + 1\right) \cdot z\right) \cdot t}{16}\right)\right) \cdot \cos \left(\frac{\left(\left(a \cdot 2 + 1\right) \cdot b\right) \cdot t}{16}\right)
\end{array}

Alternative 1: 31.4% accurate, 1.0× speedup?

\[\begin{array}{l} t_m = \left|t\right| \\ \begin{array}{l} \mathbf{if}\;t\_m \leq 1.75 \cdot 10^{+40}:\\ \;\;\;\;x \cdot \left(\cos \left(0.0625 \cdot \left(b \cdot \left(t\_m \cdot \left(-2 \cdot a + -1\right)\right)\right)\right) \cdot \cos \left(0.0625 \cdot \left(t\_m \cdot z\right)\right)\right)\\ \mathbf{else}:\\ \;\;\;\;x\\ \end{array} \end{array} \]
t_m = (fabs.f64 t)
(FPCore (x y z t_m a b)
 :precision binary64
 (if (<= t_m 1.75e+40)
   (*
    x
    (*
     (cos (* 0.0625 (* b (* t_m (+ (* -2.0 a) -1.0)))))
     (cos (* 0.0625 (* t_m z)))))
   x))
t_m = fabs(t);
double code(double x, double y, double z, double t_m, double a, double b) {
	double tmp;
	if (t_m <= 1.75e+40) {
		tmp = x * (cos((0.0625 * (b * (t_m * ((-2.0 * a) + -1.0))))) * cos((0.0625 * (t_m * z))));
	} else {
		tmp = x;
	}
	return tmp;
}
t_m = abs(t)
real(8) function code(x, y, z, t_m, a, b)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t_m
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    real(8) :: tmp
    if (t_m <= 1.75d+40) then
        tmp = x * (cos((0.0625d0 * (b * (t_m * (((-2.0d0) * a) + (-1.0d0)))))) * cos((0.0625d0 * (t_m * z))))
    else
        tmp = x
    end if
    code = tmp
end function
t_m = Math.abs(t);
public static double code(double x, double y, double z, double t_m, double a, double b) {
	double tmp;
	if (t_m <= 1.75e+40) {
		tmp = x * (Math.cos((0.0625 * (b * (t_m * ((-2.0 * a) + -1.0))))) * Math.cos((0.0625 * (t_m * z))));
	} else {
		tmp = x;
	}
	return tmp;
}
t_m = math.fabs(t)
def code(x, y, z, t_m, a, b):
	tmp = 0
	if t_m <= 1.75e+40:
		tmp = x * (math.cos((0.0625 * (b * (t_m * ((-2.0 * a) + -1.0))))) * math.cos((0.0625 * (t_m * z))))
	else:
		tmp = x
	return tmp
t_m = abs(t)
function code(x, y, z, t_m, a, b)
	tmp = 0.0
	if (t_m <= 1.75e+40)
		tmp = Float64(x * Float64(cos(Float64(0.0625 * Float64(b * Float64(t_m * Float64(Float64(-2.0 * a) + -1.0))))) * cos(Float64(0.0625 * Float64(t_m * z)))));
	else
		tmp = x;
	end
	return tmp
end
t_m = abs(t);
function tmp_2 = code(x, y, z, t_m, a, b)
	tmp = 0.0;
	if (t_m <= 1.75e+40)
		tmp = x * (cos((0.0625 * (b * (t_m * ((-2.0 * a) + -1.0))))) * cos((0.0625 * (t_m * z))));
	else
		tmp = x;
	end
	tmp_2 = tmp;
end
t_m = N[Abs[t], $MachinePrecision]
code[x_, y_, z_, t$95$m_, a_, b_] := If[LessEqual[t$95$m, 1.75e+40], N[(x * N[(N[Cos[N[(0.0625 * N[(b * N[(t$95$m * N[(N[(-2.0 * a), $MachinePrecision] + -1.0), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * N[Cos[N[(0.0625 * N[(t$95$m * z), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision], x]
\begin{array}{l}
t_m = \left|t\right|

\\
\begin{array}{l}
\mathbf{if}\;t\_m \leq 1.75 \cdot 10^{+40}:\\
\;\;\;\;x \cdot \left(\cos \left(0.0625 \cdot \left(b \cdot \left(t\_m \cdot \left(-2 \cdot a + -1\right)\right)\right)\right) \cdot \cos \left(0.0625 \cdot \left(t\_m \cdot z\right)\right)\right)\\

\mathbf{else}:\\
\;\;\;\;x\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if t < 1.75e40

    1. Initial program 29.7%

      \[\left(x \cdot \cos \left(\frac{\left(\left(y \cdot 2 + 1\right) \cdot z\right) \cdot t}{16}\right)\right) \cdot \cos \left(\frac{\left(\left(a \cdot 2 + 1\right) \cdot b\right) \cdot t}{16}\right) \]
    2. Simplified30.8%

      \[\leadsto \color{blue}{\cos \left(\mathsf{fma}\left(y, 2, 1\right) \cdot \left(z \cdot \left(t \cdot 0.0625\right)\right)\right) \cdot \left(x \cdot \cos \left(\left(b \cdot 0.0625\right) \cdot \left(t \cdot \mathsf{fma}\left(a, -2, -1\right)\right)\right)\right)} \]
    3. Add Preprocessing
    4. Taylor expanded in y around 0 31.5%

      \[\leadsto \color{blue}{x \cdot \left(\cos \left(0.0625 \cdot \left(b \cdot \left(t \cdot \left(-2 \cdot a - 1\right)\right)\right)\right) \cdot \cos \left(0.0625 \cdot \left(t \cdot z\right)\right)\right)} \]

    if 1.75e40 < t

    1. Initial program 12.4%

      \[\left(x \cdot \cos \left(\frac{\left(\left(y \cdot 2 + 1\right) \cdot z\right) \cdot t}{16}\right)\right) \cdot \cos \left(\frac{\left(\left(a \cdot 2 + 1\right) \cdot b\right) \cdot t}{16}\right) \]
    2. Simplified12.4%

      \[\leadsto \color{blue}{x \cdot \left(\cos \left(\left(\mathsf{fma}\left(y, 2, 1\right) \cdot z\right) \cdot \frac{t}{16}\right) \cdot \cos \left(\left(\mathsf{fma}\left(a, 2, 1\right) \cdot b\right) \cdot \frac{t}{16}\right)\right)} \]
    3. Add Preprocessing
    4. Taylor expanded in t around 0 15.8%

      \[\leadsto \color{blue}{x} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification28.2%

    \[\leadsto \begin{array}{l} \mathbf{if}\;t \leq 1.75 \cdot 10^{+40}:\\ \;\;\;\;x \cdot \left(\cos \left(0.0625 \cdot \left(b \cdot \left(t \cdot \left(-2 \cdot a + -1\right)\right)\right)\right) \cdot \cos \left(0.0625 \cdot \left(t \cdot z\right)\right)\right)\\ \mathbf{else}:\\ \;\;\;\;x\\ \end{array} \]
  5. Add Preprocessing

Alternative 2: 30.2% accurate, 2.1× speedup?

\[\begin{array}{l} t_m = \left|t\right| \\ x \cdot \cos \left(z \cdot \left(t\_m \cdot 0.0625\right)\right) \end{array} \]
t_m = (fabs.f64 t)
(FPCore (x y z t_m a b) :precision binary64 (* x (cos (* z (* t_m 0.0625)))))
t_m = fabs(t);
double code(double x, double y, double z, double t_m, double a, double b) {
	return x * cos((z * (t_m * 0.0625)));
}
t_m = abs(t)
real(8) function code(x, y, z, t_m, a, b)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t_m
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    code = x * cos((z * (t_m * 0.0625d0)))
end function
t_m = Math.abs(t);
public static double code(double x, double y, double z, double t_m, double a, double b) {
	return x * Math.cos((z * (t_m * 0.0625)));
}
t_m = math.fabs(t)
def code(x, y, z, t_m, a, b):
	return x * math.cos((z * (t_m * 0.0625)))
t_m = abs(t)
function code(x, y, z, t_m, a, b)
	return Float64(x * cos(Float64(z * Float64(t_m * 0.0625))))
end
t_m = abs(t);
function tmp = code(x, y, z, t_m, a, b)
	tmp = x * cos((z * (t_m * 0.0625)));
end
t_m = N[Abs[t], $MachinePrecision]
code[x_, y_, z_, t$95$m_, a_, b_] := N[(x * N[Cos[N[(z * N[(t$95$m * 0.0625), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}
t_m = \left|t\right|

\\
x \cdot \cos \left(z \cdot \left(t\_m \cdot 0.0625\right)\right)
\end{array}
Derivation
  1. Initial program 26.0%

    \[\left(x \cdot \cos \left(\frac{\left(\left(y \cdot 2 + 1\right) \cdot z\right) \cdot t}{16}\right)\right) \cdot \cos \left(\frac{\left(\left(a \cdot 2 + 1\right) \cdot b\right) \cdot t}{16}\right) \]
  2. Simplified26.0%

    \[\leadsto \color{blue}{x \cdot \left(\cos \left(\left(\mathsf{fma}\left(y, 2, 1\right) \cdot z\right) \cdot \frac{t}{16}\right) \cdot \cos \left(\left(\mathsf{fma}\left(a, 2, 1\right) \cdot b\right) \cdot \frac{t}{16}\right)\right)} \]
  3. Add Preprocessing
  4. Step-by-step derivation
    1. fma-define26.0%

      \[\leadsto x \cdot \left(\cos \left(\left(\color{blue}{\left(y \cdot 2 + 1\right)} \cdot z\right) \cdot \frac{t}{16}\right) \cdot \cos \left(\left(\mathsf{fma}\left(a, 2, 1\right) \cdot b\right) \cdot \frac{t}{16}\right)\right) \]
    2. associate-/l*26.0%

      \[\leadsto x \cdot \left(\cos \color{blue}{\left(\frac{\left(\left(y \cdot 2 + 1\right) \cdot z\right) \cdot t}{16}\right)} \cdot \cos \left(\left(\mathsf{fma}\left(a, 2, 1\right) \cdot b\right) \cdot \frac{t}{16}\right)\right) \]
    3. clear-num26.0%

      \[\leadsto x \cdot \left(\cos \color{blue}{\left(\frac{1}{\frac{16}{\left(\left(y \cdot 2 + 1\right) \cdot z\right) \cdot t}}\right)} \cdot \cos \left(\left(\mathsf{fma}\left(a, 2, 1\right) \cdot b\right) \cdot \frac{t}{16}\right)\right) \]
    4. fma-define26.0%

      \[\leadsto x \cdot \left(\cos \left(\frac{1}{\frac{16}{\left(\color{blue}{\mathsf{fma}\left(y, 2, 1\right)} \cdot z\right) \cdot t}}\right) \cdot \cos \left(\left(\mathsf{fma}\left(a, 2, 1\right) \cdot b\right) \cdot \frac{t}{16}\right)\right) \]
    5. associate-*l*26.7%

      \[\leadsto x \cdot \left(\cos \left(\frac{1}{\frac{16}{\color{blue}{\mathsf{fma}\left(y, 2, 1\right) \cdot \left(z \cdot t\right)}}}\right) \cdot \cos \left(\left(\mathsf{fma}\left(a, 2, 1\right) \cdot b\right) \cdot \frac{t}{16}\right)\right) \]
  5. Applied egg-rr26.7%

    \[\leadsto x \cdot \left(\cos \color{blue}{\left(\frac{1}{\frac{16}{\mathsf{fma}\left(y, 2, 1\right) \cdot \left(z \cdot t\right)}}\right)} \cdot \cos \left(\left(\mathsf{fma}\left(a, 2, 1\right) \cdot b\right) \cdot \frac{t}{16}\right)\right) \]
  6. Taylor expanded in a around 0 26.9%

    \[\leadsto x \cdot \left(\cos \left(\frac{1}{\frac{16}{\mathsf{fma}\left(y, 2, 1\right) \cdot \left(z \cdot t\right)}}\right) \cdot \color{blue}{\cos \left(0.0625 \cdot \left(b \cdot t\right)\right)}\right) \]
  7. Step-by-step derivation
    1. associate-*r*26.9%

      \[\leadsto x \cdot \left(\cos \left(\frac{1}{\frac{16}{\mathsf{fma}\left(y, 2, 1\right) \cdot \left(z \cdot t\right)}}\right) \cdot \cos \color{blue}{\left(\left(0.0625 \cdot b\right) \cdot t\right)}\right) \]
  8. Simplified26.9%

    \[\leadsto x \cdot \left(\cos \left(\frac{1}{\frac{16}{\mathsf{fma}\left(y, 2, 1\right) \cdot \left(z \cdot t\right)}}\right) \cdot \color{blue}{\cos \left(\left(0.0625 \cdot b\right) \cdot t\right)}\right) \]
  9. Taylor expanded in y around 0 28.0%

    \[\leadsto x \cdot \left(\cos \left(\frac{1}{\color{blue}{\frac{16}{t \cdot z}}}\right) \cdot \cos \left(\left(0.0625 \cdot b\right) \cdot t\right)\right) \]
  10. Taylor expanded in b around 0 28.5%

    \[\leadsto \color{blue}{x \cdot \cos \left(0.0625 \cdot \left(t \cdot z\right)\right)} \]
  11. Step-by-step derivation
    1. associate-*r*28.5%

      \[\leadsto x \cdot \cos \color{blue}{\left(\left(0.0625 \cdot t\right) \cdot z\right)} \]
    2. *-commutative28.5%

      \[\leadsto x \cdot \cos \color{blue}{\left(z \cdot \left(0.0625 \cdot t\right)\right)} \]
  12. Simplified28.5%

    \[\leadsto \color{blue}{x \cdot \cos \left(z \cdot \left(0.0625 \cdot t\right)\right)} \]
  13. Final simplification28.5%

    \[\leadsto x \cdot \cos \left(z \cdot \left(t \cdot 0.0625\right)\right) \]
  14. Add Preprocessing

Alternative 3: 31.0% accurate, 225.0× speedup?

\[\begin{array}{l} t_m = \left|t\right| \\ x \end{array} \]
t_m = (fabs.f64 t)
(FPCore (x y z t_m a b) :precision binary64 x)
t_m = fabs(t);
double code(double x, double y, double z, double t_m, double a, double b) {
	return x;
}
t_m = abs(t)
real(8) function code(x, y, z, t_m, a, b)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t_m
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    code = x
end function
t_m = Math.abs(t);
public static double code(double x, double y, double z, double t_m, double a, double b) {
	return x;
}
t_m = math.fabs(t)
def code(x, y, z, t_m, a, b):
	return x
t_m = abs(t)
function code(x, y, z, t_m, a, b)
	return x
end
t_m = abs(t);
function tmp = code(x, y, z, t_m, a, b)
	tmp = x;
end
t_m = N[Abs[t], $MachinePrecision]
code[x_, y_, z_, t$95$m_, a_, b_] := x
\begin{array}{l}
t_m = \left|t\right|

\\
x
\end{array}
Derivation
  1. Initial program 26.0%

    \[\left(x \cdot \cos \left(\frac{\left(\left(y \cdot 2 + 1\right) \cdot z\right) \cdot t}{16}\right)\right) \cdot \cos \left(\frac{\left(\left(a \cdot 2 + 1\right) \cdot b\right) \cdot t}{16}\right) \]
  2. Simplified26.0%

    \[\leadsto \color{blue}{x \cdot \left(\cos \left(\left(\mathsf{fma}\left(y, 2, 1\right) \cdot z\right) \cdot \frac{t}{16}\right) \cdot \cos \left(\left(\mathsf{fma}\left(a, 2, 1\right) \cdot b\right) \cdot \frac{t}{16}\right)\right)} \]
  3. Add Preprocessing
  4. Taylor expanded in t around 0 28.2%

    \[\leadsto \color{blue}{x} \]
  5. Add Preprocessing

Developer Target 1: 30.6% accurate, 1.0× speedup?

\[\begin{array}{l} \\ x \cdot \cos \left(\frac{b}{16} \cdot \frac{t}{\left(1 - a \cdot 2\right) + {\left(a \cdot 2\right)}^{2}}\right) \end{array} \]
(FPCore (x y z t a b)
 :precision binary64
 (* x (cos (* (/ b 16.0) (/ t (+ (- 1.0 (* a 2.0)) (pow (* a 2.0) 2.0)))))))
double code(double x, double y, double z, double t, double a, double b) {
	return x * cos(((b / 16.0) * (t / ((1.0 - (a * 2.0)) + pow((a * 2.0), 2.0)))));
}
real(8) function code(x, y, z, t, a, b)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t
    real(8), intent (in) :: a
    real(8), intent (in) :: b
    code = x * cos(((b / 16.0d0) * (t / ((1.0d0 - (a * 2.0d0)) + ((a * 2.0d0) ** 2.0d0)))))
end function
public static double code(double x, double y, double z, double t, double a, double b) {
	return x * Math.cos(((b / 16.0) * (t / ((1.0 - (a * 2.0)) + Math.pow((a * 2.0), 2.0)))));
}
def code(x, y, z, t, a, b):
	return x * math.cos(((b / 16.0) * (t / ((1.0 - (a * 2.0)) + math.pow((a * 2.0), 2.0)))))
function code(x, y, z, t, a, b)
	return Float64(x * cos(Float64(Float64(b / 16.0) * Float64(t / Float64(Float64(1.0 - Float64(a * 2.0)) + (Float64(a * 2.0) ^ 2.0))))))
end
function tmp = code(x, y, z, t, a, b)
	tmp = x * cos(((b / 16.0) * (t / ((1.0 - (a * 2.0)) + ((a * 2.0) ^ 2.0)))));
end
code[x_, y_, z_, t_, a_, b_] := N[(x * N[Cos[N[(N[(b / 16.0), $MachinePrecision] * N[(t / N[(N[(1.0 - N[(a * 2.0), $MachinePrecision]), $MachinePrecision] + N[Power[N[(a * 2.0), $MachinePrecision], 2.0], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
x \cdot \cos \left(\frac{b}{16} \cdot \frac{t}{\left(1 - a \cdot 2\right) + {\left(a \cdot 2\right)}^{2}}\right)
\end{array}

Reproduce

?
herbie shell --seed 2024177 
(FPCore (x y z t a b)
  :name "Codec.Picture.Jpg.FastDct:referenceDct from JuicyPixels-3.2.6.1"
  :precision binary64

  :alt
  (! :herbie-platform default (* x (cos (* (/ b 16) (/ t (+ (- 1 (* a 2)) (pow (* a 2) 2)))))))

  (* (* x (cos (/ (* (* (+ (* y 2.0) 1.0) z) t) 16.0))) (cos (/ (* (* (+ (* a 2.0) 1.0) b) t) 16.0))))