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

Percentage Accurate: 26.8% → 29.4%
Time: 11.8s
Alternatives: 3
Speedup: 2.3×

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: 26.8% 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: 29.4% accurate, 2.3× speedup?

\[\begin{array}{l} \\ \cos \left(0.0625 \cdot \left(b \cdot t\right)\right) \cdot x \end{array} \]
(FPCore (x y z t a b) :precision binary64 (* (cos (* 0.0625 (* b t))) x))
double code(double x, double y, double z, double t, double a, double b) {
	return cos((0.0625 * (b * t))) * x;
}
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 = cos((0.0625d0 * (b * t))) * x
end function
public static double code(double x, double y, double z, double t, double a, double b) {
	return Math.cos((0.0625 * (b * t))) * x;
}
def code(x, y, z, t, a, b):
	return math.cos((0.0625 * (b * t))) * x
function code(x, y, z, t, a, b)
	return Float64(cos(Float64(0.0625 * Float64(b * t))) * x)
end
function tmp = code(x, y, z, t, a, b)
	tmp = cos((0.0625 * (b * t))) * x;
end
code[x_, y_, z_, t_, a_, b_] := N[(N[Cos[N[(0.0625 * N[(b * t), $MachinePrecision]), $MachinePrecision]], $MachinePrecision] * x), $MachinePrecision]
\begin{array}{l}

\\
\cos \left(0.0625 \cdot \left(b \cdot t\right)\right) \cdot x
\end{array}
Derivation
  1. Initial program 28.0%

    \[\left(x \cdot \cos \left(\frac{\left(\left(y \cdot 2 + 1\right) \cdot z\right) \cdot t}{16}\right)\right) \cdot \cos \left(\frac{\left(\left(a \cdot 2 + 1\right) \cdot b\right) \cdot t}{16}\right) \]
  2. Add Preprocessing
  3. Taylor expanded in y around 0

    \[\leadsto \left(x \cdot \cos \color{blue}{\left(\frac{1}{16} \cdot \left(t \cdot z\right)\right)}\right) \cdot \cos \left(\frac{\left(\left(a \cdot 2 + 1\right) \cdot b\right) \cdot t}{16}\right) \]
  4. Step-by-step derivation
    1. *-commutativeN/A

      \[\leadsto \left(x \cdot \cos \color{blue}{\left(\left(t \cdot z\right) \cdot \frac{1}{16}\right)}\right) \cdot \cos \left(\frac{\left(\left(a \cdot 2 + 1\right) \cdot b\right) \cdot t}{16}\right) \]
    2. lower-*.f64N/A

      \[\leadsto \left(x \cdot \cos \color{blue}{\left(\left(t \cdot z\right) \cdot \frac{1}{16}\right)}\right) \cdot \cos \left(\frac{\left(\left(a \cdot 2 + 1\right) \cdot b\right) \cdot t}{16}\right) \]
    3. lower-*.f6429.0

      \[\leadsto \left(x \cdot \cos \left(\color{blue}{\left(t \cdot z\right)} \cdot 0.0625\right)\right) \cdot \cos \left(\frac{\left(\left(a \cdot 2 + 1\right) \cdot b\right) \cdot t}{16}\right) \]
  5. Applied rewrites29.0%

    \[\leadsto \left(x \cdot \cos \color{blue}{\left(\left(t \cdot z\right) \cdot 0.0625\right)}\right) \cdot \cos \left(\frac{\left(\left(a \cdot 2 + 1\right) \cdot b\right) \cdot t}{16}\right) \]
  6. Taylor expanded in z around 0

    \[\leadsto \color{blue}{x \cdot \cos \left(\frac{1}{16} \cdot \left(b \cdot \left(t \cdot \left(1 + 2 \cdot a\right)\right)\right)\right)} \]
  7. Step-by-step derivation
    1. *-commutativeN/A

      \[\leadsto \color{blue}{\cos \left(\frac{1}{16} \cdot \left(b \cdot \left(t \cdot \left(1 + 2 \cdot a\right)\right)\right)\right) \cdot x} \]
    2. lower-*.f64N/A

      \[\leadsto \color{blue}{\cos \left(\frac{1}{16} \cdot \left(b \cdot \left(t \cdot \left(1 + 2 \cdot a\right)\right)\right)\right) \cdot x} \]
    3. lower-cos.f64N/A

      \[\leadsto \color{blue}{\cos \left(\frac{1}{16} \cdot \left(b \cdot \left(t \cdot \left(1 + 2 \cdot a\right)\right)\right)\right)} \cdot x \]
    4. *-commutativeN/A

      \[\leadsto \cos \color{blue}{\left(\left(b \cdot \left(t \cdot \left(1 + 2 \cdot a\right)\right)\right) \cdot \frac{1}{16}\right)} \cdot x \]
    5. lower-*.f64N/A

      \[\leadsto \cos \color{blue}{\left(\left(b \cdot \left(t \cdot \left(1 + 2 \cdot a\right)\right)\right) \cdot \frac{1}{16}\right)} \cdot x \]
    6. *-commutativeN/A

      \[\leadsto \cos \left(\color{blue}{\left(\left(t \cdot \left(1 + 2 \cdot a\right)\right) \cdot b\right)} \cdot \frac{1}{16}\right) \cdot x \]
    7. lower-*.f64N/A

      \[\leadsto \cos \left(\color{blue}{\left(\left(t \cdot \left(1 + 2 \cdot a\right)\right) \cdot b\right)} \cdot \frac{1}{16}\right) \cdot x \]
    8. *-commutativeN/A

      \[\leadsto \cos \left(\left(\color{blue}{\left(\left(1 + 2 \cdot a\right) \cdot t\right)} \cdot b\right) \cdot \frac{1}{16}\right) \cdot x \]
    9. lower-*.f64N/A

      \[\leadsto \cos \left(\left(\color{blue}{\left(\left(1 + 2 \cdot a\right) \cdot t\right)} \cdot b\right) \cdot \frac{1}{16}\right) \cdot x \]
    10. +-commutativeN/A

      \[\leadsto \cos \left(\left(\left(\color{blue}{\left(2 \cdot a + 1\right)} \cdot t\right) \cdot b\right) \cdot \frac{1}{16}\right) \cdot x \]
    11. lower-fma.f6430.2

      \[\leadsto \cos \left(\left(\left(\color{blue}{\mathsf{fma}\left(2, a, 1\right)} \cdot t\right) \cdot b\right) \cdot 0.0625\right) \cdot x \]
  8. Applied rewrites30.2%

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

    \[\leadsto \cos \left(\left(b \cdot t\right) \cdot \frac{1}{16}\right) \cdot x \]
  10. Step-by-step derivation
    1. Applied rewrites31.2%

      \[\leadsto \cos \left(\left(b \cdot t\right) \cdot 0.0625\right) \cdot x \]
    2. Final simplification31.2%

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

    Alternative 2: 23.6% accurate, 8.2× speedup?

    \[\begin{array}{l} \\ \mathsf{fma}\left(\mathsf{fma}\left(-0.0078125, a, -0.001953125\right) \cdot \left(t \cdot t\right), b \cdot b, 1\right) \cdot x \end{array} \]
    (FPCore (x y z t a b)
     :precision binary64
     (* (fma (* (fma -0.0078125 a -0.001953125) (* t t)) (* b b) 1.0) x))
    double code(double x, double y, double z, double t, double a, double b) {
    	return fma((fma(-0.0078125, a, -0.001953125) * (t * t)), (b * b), 1.0) * x;
    }
    
    function code(x, y, z, t, a, b)
    	return Float64(fma(Float64(fma(-0.0078125, a, -0.001953125) * Float64(t * t)), Float64(b * b), 1.0) * x)
    end
    
    code[x_, y_, z_, t_, a_, b_] := N[(N[(N[(N[(-0.0078125 * a + -0.001953125), $MachinePrecision] * N[(t * t), $MachinePrecision]), $MachinePrecision] * N[(b * b), $MachinePrecision] + 1.0), $MachinePrecision] * x), $MachinePrecision]
    
    \begin{array}{l}
    
    \\
    \mathsf{fma}\left(\mathsf{fma}\left(-0.0078125, a, -0.001953125\right) \cdot \left(t \cdot t\right), b \cdot b, 1\right) \cdot x
    \end{array}
    
    Derivation
    1. Initial program 28.0%

      \[\left(x \cdot \cos \left(\frac{\left(\left(y \cdot 2 + 1\right) \cdot z\right) \cdot t}{16}\right)\right) \cdot \cos \left(\frac{\left(\left(a \cdot 2 + 1\right) \cdot b\right) \cdot t}{16}\right) \]
    2. Add Preprocessing
    3. Taylor expanded in y around 0

      \[\leadsto \left(x \cdot \cos \color{blue}{\left(\frac{1}{16} \cdot \left(t \cdot z\right)\right)}\right) \cdot \cos \left(\frac{\left(\left(a \cdot 2 + 1\right) \cdot b\right) \cdot t}{16}\right) \]
    4. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \left(x \cdot \cos \color{blue}{\left(\left(t \cdot z\right) \cdot \frac{1}{16}\right)}\right) \cdot \cos \left(\frac{\left(\left(a \cdot 2 + 1\right) \cdot b\right) \cdot t}{16}\right) \]
      2. lower-*.f64N/A

        \[\leadsto \left(x \cdot \cos \color{blue}{\left(\left(t \cdot z\right) \cdot \frac{1}{16}\right)}\right) \cdot \cos \left(\frac{\left(\left(a \cdot 2 + 1\right) \cdot b\right) \cdot t}{16}\right) \]
      3. lower-*.f6429.0

        \[\leadsto \left(x \cdot \cos \left(\color{blue}{\left(t \cdot z\right)} \cdot 0.0625\right)\right) \cdot \cos \left(\frac{\left(\left(a \cdot 2 + 1\right) \cdot b\right) \cdot t}{16}\right) \]
    5. Applied rewrites29.0%

      \[\leadsto \left(x \cdot \cos \color{blue}{\left(\left(t \cdot z\right) \cdot 0.0625\right)}\right) \cdot \cos \left(\frac{\left(\left(a \cdot 2 + 1\right) \cdot b\right) \cdot t}{16}\right) \]
    6. Taylor expanded in z around 0

      \[\leadsto \color{blue}{x \cdot \cos \left(\frac{1}{16} \cdot \left(b \cdot \left(t \cdot \left(1 + 2 \cdot a\right)\right)\right)\right)} \]
    7. Step-by-step derivation
      1. *-commutativeN/A

        \[\leadsto \color{blue}{\cos \left(\frac{1}{16} \cdot \left(b \cdot \left(t \cdot \left(1 + 2 \cdot a\right)\right)\right)\right) \cdot x} \]
      2. lower-*.f64N/A

        \[\leadsto \color{blue}{\cos \left(\frac{1}{16} \cdot \left(b \cdot \left(t \cdot \left(1 + 2 \cdot a\right)\right)\right)\right) \cdot x} \]
      3. lower-cos.f64N/A

        \[\leadsto \color{blue}{\cos \left(\frac{1}{16} \cdot \left(b \cdot \left(t \cdot \left(1 + 2 \cdot a\right)\right)\right)\right)} \cdot x \]
      4. *-commutativeN/A

        \[\leadsto \cos \color{blue}{\left(\left(b \cdot \left(t \cdot \left(1 + 2 \cdot a\right)\right)\right) \cdot \frac{1}{16}\right)} \cdot x \]
      5. lower-*.f64N/A

        \[\leadsto \cos \color{blue}{\left(\left(b \cdot \left(t \cdot \left(1 + 2 \cdot a\right)\right)\right) \cdot \frac{1}{16}\right)} \cdot x \]
      6. *-commutativeN/A

        \[\leadsto \cos \left(\color{blue}{\left(\left(t \cdot \left(1 + 2 \cdot a\right)\right) \cdot b\right)} \cdot \frac{1}{16}\right) \cdot x \]
      7. lower-*.f64N/A

        \[\leadsto \cos \left(\color{blue}{\left(\left(t \cdot \left(1 + 2 \cdot a\right)\right) \cdot b\right)} \cdot \frac{1}{16}\right) \cdot x \]
      8. *-commutativeN/A

        \[\leadsto \cos \left(\left(\color{blue}{\left(\left(1 + 2 \cdot a\right) \cdot t\right)} \cdot b\right) \cdot \frac{1}{16}\right) \cdot x \]
      9. lower-*.f64N/A

        \[\leadsto \cos \left(\left(\color{blue}{\left(\left(1 + 2 \cdot a\right) \cdot t\right)} \cdot b\right) \cdot \frac{1}{16}\right) \cdot x \]
      10. +-commutativeN/A

        \[\leadsto \cos \left(\left(\left(\color{blue}{\left(2 \cdot a + 1\right)} \cdot t\right) \cdot b\right) \cdot \frac{1}{16}\right) \cdot x \]
      11. lower-fma.f6430.2

        \[\leadsto \cos \left(\left(\left(\color{blue}{\mathsf{fma}\left(2, a, 1\right)} \cdot t\right) \cdot b\right) \cdot 0.0625\right) \cdot x \]
    8. Applied rewrites30.2%

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

      \[\leadsto \left(\cos \left(\frac{1}{16} \cdot \left(b \cdot t\right)\right) + \frac{-1}{8} \cdot \left(a \cdot \left(b \cdot \left(t \cdot \sin \left(\frac{1}{16} \cdot \left(b \cdot t\right)\right)\right)\right)\right)\right) \cdot x \]
    10. Step-by-step derivation
      1. Applied rewrites29.2%

        \[\leadsto \mathsf{fma}\left(-0.125 \cdot a, \left(b \cdot t\right) \cdot \sin \left(\left(b \cdot t\right) \cdot 0.0625\right), \cos \left(\left(b \cdot t\right) \cdot 0.0625\right)\right) \cdot x \]
      2. Taylor expanded in b around 0

        \[\leadsto \left(1 + {b}^{2} \cdot \left(\frac{-1}{128} \cdot \left(a \cdot {t}^{2}\right) + \frac{-1}{512} \cdot {t}^{2}\right)\right) \cdot x \]
      3. Step-by-step derivation
        1. Applied rewrites26.0%

          \[\leadsto \mathsf{fma}\left(\left(t \cdot t\right) \cdot \mathsf{fma}\left(-0.0078125, a, -0.001953125\right), b \cdot b, 1\right) \cdot x \]
        2. Final simplification26.0%

          \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(-0.0078125, a, -0.001953125\right) \cdot \left(t \cdot t\right), b \cdot b, 1\right) \cdot x \]
        3. Add Preprocessing

        Alternative 3: 23.4% accurate, 8.2× speedup?

        \[\begin{array}{l} \\ \mathsf{fma}\left(\left(b \cdot b\right) \cdot \mathsf{fma}\left(-0.0078125, a, -0.001953125\right), t \cdot t, 1\right) \cdot x \end{array} \]
        (FPCore (x y z t a b)
         :precision binary64
         (* (fma (* (* b b) (fma -0.0078125 a -0.001953125)) (* t t) 1.0) x))
        double code(double x, double y, double z, double t, double a, double b) {
        	return fma(((b * b) * fma(-0.0078125, a, -0.001953125)), (t * t), 1.0) * x;
        }
        
        function code(x, y, z, t, a, b)
        	return Float64(fma(Float64(Float64(b * b) * fma(-0.0078125, a, -0.001953125)), Float64(t * t), 1.0) * x)
        end
        
        code[x_, y_, z_, t_, a_, b_] := N[(N[(N[(N[(b * b), $MachinePrecision] * N[(-0.0078125 * a + -0.001953125), $MachinePrecision]), $MachinePrecision] * N[(t * t), $MachinePrecision] + 1.0), $MachinePrecision] * x), $MachinePrecision]
        
        \begin{array}{l}
        
        \\
        \mathsf{fma}\left(\left(b \cdot b\right) \cdot \mathsf{fma}\left(-0.0078125, a, -0.001953125\right), t \cdot t, 1\right) \cdot x
        \end{array}
        
        Derivation
        1. Initial program 28.0%

          \[\left(x \cdot \cos \left(\frac{\left(\left(y \cdot 2 + 1\right) \cdot z\right) \cdot t}{16}\right)\right) \cdot \cos \left(\frac{\left(\left(a \cdot 2 + 1\right) \cdot b\right) \cdot t}{16}\right) \]
        2. Add Preprocessing
        3. Taylor expanded in y around 0

          \[\leadsto \left(x \cdot \cos \color{blue}{\left(\frac{1}{16} \cdot \left(t \cdot z\right)\right)}\right) \cdot \cos \left(\frac{\left(\left(a \cdot 2 + 1\right) \cdot b\right) \cdot t}{16}\right) \]
        4. Step-by-step derivation
          1. *-commutativeN/A

            \[\leadsto \left(x \cdot \cos \color{blue}{\left(\left(t \cdot z\right) \cdot \frac{1}{16}\right)}\right) \cdot \cos \left(\frac{\left(\left(a \cdot 2 + 1\right) \cdot b\right) \cdot t}{16}\right) \]
          2. lower-*.f64N/A

            \[\leadsto \left(x \cdot \cos \color{blue}{\left(\left(t \cdot z\right) \cdot \frac{1}{16}\right)}\right) \cdot \cos \left(\frac{\left(\left(a \cdot 2 + 1\right) \cdot b\right) \cdot t}{16}\right) \]
          3. lower-*.f6429.0

            \[\leadsto \left(x \cdot \cos \left(\color{blue}{\left(t \cdot z\right)} \cdot 0.0625\right)\right) \cdot \cos \left(\frac{\left(\left(a \cdot 2 + 1\right) \cdot b\right) \cdot t}{16}\right) \]
        5. Applied rewrites29.0%

          \[\leadsto \left(x \cdot \cos \color{blue}{\left(\left(t \cdot z\right) \cdot 0.0625\right)}\right) \cdot \cos \left(\frac{\left(\left(a \cdot 2 + 1\right) \cdot b\right) \cdot t}{16}\right) \]
        6. Taylor expanded in z around 0

          \[\leadsto \color{blue}{x \cdot \cos \left(\frac{1}{16} \cdot \left(b \cdot \left(t \cdot \left(1 + 2 \cdot a\right)\right)\right)\right)} \]
        7. Step-by-step derivation
          1. *-commutativeN/A

            \[\leadsto \color{blue}{\cos \left(\frac{1}{16} \cdot \left(b \cdot \left(t \cdot \left(1 + 2 \cdot a\right)\right)\right)\right) \cdot x} \]
          2. lower-*.f64N/A

            \[\leadsto \color{blue}{\cos \left(\frac{1}{16} \cdot \left(b \cdot \left(t \cdot \left(1 + 2 \cdot a\right)\right)\right)\right) \cdot x} \]
          3. lower-cos.f64N/A

            \[\leadsto \color{blue}{\cos \left(\frac{1}{16} \cdot \left(b \cdot \left(t \cdot \left(1 + 2 \cdot a\right)\right)\right)\right)} \cdot x \]
          4. *-commutativeN/A

            \[\leadsto \cos \color{blue}{\left(\left(b \cdot \left(t \cdot \left(1 + 2 \cdot a\right)\right)\right) \cdot \frac{1}{16}\right)} \cdot x \]
          5. lower-*.f64N/A

            \[\leadsto \cos \color{blue}{\left(\left(b \cdot \left(t \cdot \left(1 + 2 \cdot a\right)\right)\right) \cdot \frac{1}{16}\right)} \cdot x \]
          6. *-commutativeN/A

            \[\leadsto \cos \left(\color{blue}{\left(\left(t \cdot \left(1 + 2 \cdot a\right)\right) \cdot b\right)} \cdot \frac{1}{16}\right) \cdot x \]
          7. lower-*.f64N/A

            \[\leadsto \cos \left(\color{blue}{\left(\left(t \cdot \left(1 + 2 \cdot a\right)\right) \cdot b\right)} \cdot \frac{1}{16}\right) \cdot x \]
          8. *-commutativeN/A

            \[\leadsto \cos \left(\left(\color{blue}{\left(\left(1 + 2 \cdot a\right) \cdot t\right)} \cdot b\right) \cdot \frac{1}{16}\right) \cdot x \]
          9. lower-*.f64N/A

            \[\leadsto \cos \left(\left(\color{blue}{\left(\left(1 + 2 \cdot a\right) \cdot t\right)} \cdot b\right) \cdot \frac{1}{16}\right) \cdot x \]
          10. +-commutativeN/A

            \[\leadsto \cos \left(\left(\left(\color{blue}{\left(2 \cdot a + 1\right)} \cdot t\right) \cdot b\right) \cdot \frac{1}{16}\right) \cdot x \]
          11. lower-fma.f6430.2

            \[\leadsto \cos \left(\left(\left(\color{blue}{\mathsf{fma}\left(2, a, 1\right)} \cdot t\right) \cdot b\right) \cdot 0.0625\right) \cdot x \]
        8. Applied rewrites30.2%

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

          \[\leadsto \left(\cos \left(\frac{1}{16} \cdot \left(b \cdot t\right)\right) + \frac{-1}{8} \cdot \left(a \cdot \left(b \cdot \left(t \cdot \sin \left(\frac{1}{16} \cdot \left(b \cdot t\right)\right)\right)\right)\right)\right) \cdot x \]
        10. Step-by-step derivation
          1. Applied rewrites29.2%

            \[\leadsto \mathsf{fma}\left(-0.125 \cdot a, \left(b \cdot t\right) \cdot \sin \left(\left(b \cdot t\right) \cdot 0.0625\right), \cos \left(\left(b \cdot t\right) \cdot 0.0625\right)\right) \cdot x \]
          2. Taylor expanded in t around 0

            \[\leadsto \left(1 + {t}^{2} \cdot \left(\frac{-1}{128} \cdot \left(a \cdot {b}^{2}\right) + \frac{-1}{512} \cdot {b}^{2}\right)\right) \cdot x \]
          3. Step-by-step derivation
            1. Applied rewrites25.4%

              \[\leadsto \mathsf{fma}\left(\left(b \cdot b\right) \cdot \mathsf{fma}\left(-0.0078125, a, -0.001953125\right), t \cdot t, 1\right) \cdot x \]
            2. Add Preprocessing

            Developer Target 1: 30.1% accurate, 1.1× 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 2024294 
            (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))))