Numeric.Signal.Multichannel:$cput from hsignal-0.2.7.1

Percentage Accurate: 97.0% → 97.0%
Time: 8.9s
Alternatives: 17
Speedup: 1.0×

Specification

?
\[\begin{array}{l} \\ \frac{x - y}{z - y} \cdot t \end{array} \]
(FPCore (x y z t) :precision binary64 (* (/ (- x y) (- z y)) t))
double code(double x, double y, double z, double t) {
	return ((x - y) / (z - y)) * t;
}
real(8) function code(x, y, z, t)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t
    code = ((x - y) / (z - y)) * t
end function
public static double code(double x, double y, double z, double t) {
	return ((x - y) / (z - y)) * t;
}
def code(x, y, z, t):
	return ((x - y) / (z - y)) * t
function code(x, y, z, t)
	return Float64(Float64(Float64(x - y) / Float64(z - y)) * t)
end
function tmp = code(x, y, z, t)
	tmp = ((x - y) / (z - y)) * t;
end
code[x_, y_, z_, t_] := N[(N[(N[(x - y), $MachinePrecision] / N[(z - y), $MachinePrecision]), $MachinePrecision] * t), $MachinePrecision]
\begin{array}{l}

\\
\frac{x - y}{z - y} \cdot t
\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 17 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: 97.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{x - y}{z - y} \cdot t \end{array} \]
(FPCore (x y z t) :precision binary64 (* (/ (- x y) (- z y)) t))
double code(double x, double y, double z, double t) {
	return ((x - y) / (z - y)) * t;
}
real(8) function code(x, y, z, t)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t
    code = ((x - y) / (z - y)) * t
end function
public static double code(double x, double y, double z, double t) {
	return ((x - y) / (z - y)) * t;
}
def code(x, y, z, t):
	return ((x - y) / (z - y)) * t
function code(x, y, z, t)
	return Float64(Float64(Float64(x - y) / Float64(z - y)) * t)
end
function tmp = code(x, y, z, t)
	tmp = ((x - y) / (z - y)) * t;
end
code[x_, y_, z_, t_] := N[(N[(N[(x - y), $MachinePrecision] / N[(z - y), $MachinePrecision]), $MachinePrecision] * t), $MachinePrecision]
\begin{array}{l}

\\
\frac{x - y}{z - y} \cdot t
\end{array}

Alternative 1: 97.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ t \cdot \frac{x - y}{z - y} \end{array} \]
(FPCore (x y z t) :precision binary64 (* t (/ (- x y) (- z y))))
double code(double x, double y, double z, double t) {
	return t * ((x - y) / (z - y));
}
real(8) function code(x, y, z, t)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t
    code = t * ((x - y) / (z - y))
end function
public static double code(double x, double y, double z, double t) {
	return t * ((x - y) / (z - y));
}
def code(x, y, z, t):
	return t * ((x - y) / (z - y))
function code(x, y, z, t)
	return Float64(t * Float64(Float64(x - y) / Float64(z - y)))
end
function tmp = code(x, y, z, t)
	tmp = t * ((x - y) / (z - y));
end
code[x_, y_, z_, t_] := N[(t * N[(N[(x - y), $MachinePrecision] / N[(z - y), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
t \cdot \frac{x - y}{z - y}
\end{array}
Derivation
  1. Initial program 95.6%

    \[\frac{x - y}{z - y} \cdot t \]
  2. Add Preprocessing
  3. Final simplification95.6%

    \[\leadsto t \cdot \frac{x - y}{z - y} \]
  4. Add Preprocessing

Alternative 2: 95.3% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_1 := \frac{x - y}{z - y}\\ t_2 := \frac{x}{z - y} \cdot t\\ \mathbf{if}\;t\_1 \leq -1000000:\\ \;\;\;\;t\_2\\ \mathbf{elif}\;t\_1 \leq 5 \cdot 10^{-5}:\\ \;\;\;\;\frac{x - y}{z} \cdot t\\ \mathbf{elif}\;t\_1 \leq 200000:\\ \;\;\;\;\mathsf{fma}\left(t, \frac{z - x}{y}, t\right)\\ \mathbf{else}:\\ \;\;\;\;t\_2\\ \end{array} \end{array} \]
(FPCore (x y z t)
 :precision binary64
 (let* ((t_1 (/ (- x y) (- z y))) (t_2 (* (/ x (- z y)) t)))
   (if (<= t_1 -1000000.0)
     t_2
     (if (<= t_1 5e-5)
       (* (/ (- x y) z) t)
       (if (<= t_1 200000.0) (fma t (/ (- z x) y) t) t_2)))))
double code(double x, double y, double z, double t) {
	double t_1 = (x - y) / (z - y);
	double t_2 = (x / (z - y)) * t;
	double tmp;
	if (t_1 <= -1000000.0) {
		tmp = t_2;
	} else if (t_1 <= 5e-5) {
		tmp = ((x - y) / z) * t;
	} else if (t_1 <= 200000.0) {
		tmp = fma(t, ((z - x) / y), t);
	} else {
		tmp = t_2;
	}
	return tmp;
}
function code(x, y, z, t)
	t_1 = Float64(Float64(x - y) / Float64(z - y))
	t_2 = Float64(Float64(x / Float64(z - y)) * t)
	tmp = 0.0
	if (t_1 <= -1000000.0)
		tmp = t_2;
	elseif (t_1 <= 5e-5)
		tmp = Float64(Float64(Float64(x - y) / z) * t);
	elseif (t_1 <= 200000.0)
		tmp = fma(t, Float64(Float64(z - x) / y), t);
	else
		tmp = t_2;
	end
	return tmp
end
code[x_, y_, z_, t_] := Block[{t$95$1 = N[(N[(x - y), $MachinePrecision] / N[(z - y), $MachinePrecision]), $MachinePrecision]}, Block[{t$95$2 = N[(N[(x / N[(z - y), $MachinePrecision]), $MachinePrecision] * t), $MachinePrecision]}, If[LessEqual[t$95$1, -1000000.0], t$95$2, If[LessEqual[t$95$1, 5e-5], N[(N[(N[(x - y), $MachinePrecision] / z), $MachinePrecision] * t), $MachinePrecision], If[LessEqual[t$95$1, 200000.0], N[(t * N[(N[(z - x), $MachinePrecision] / y), $MachinePrecision] + t), $MachinePrecision], t$95$2]]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_1 := \frac{x - y}{z - y}\\
t_2 := \frac{x}{z - y} \cdot t\\
\mathbf{if}\;t\_1 \leq -1000000:\\
\;\;\;\;t\_2\\

\mathbf{elif}\;t\_1 \leq 5 \cdot 10^{-5}:\\
\;\;\;\;\frac{x - y}{z} \cdot t\\

\mathbf{elif}\;t\_1 \leq 200000:\\
\;\;\;\;\mathsf{fma}\left(t, \frac{z - x}{y}, t\right)\\

\mathbf{else}:\\
\;\;\;\;t\_2\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if (/.f64 (-.f64 x y) (-.f64 z y)) < -1e6 or 2e5 < (/.f64 (-.f64 x y) (-.f64 z y))

    1. Initial program 95.1%

      \[\frac{x - y}{z - y} \cdot t \]
    2. Add Preprocessing
    3. Taylor expanded in x around inf

      \[\leadsto \color{blue}{\frac{x}{z - y}} \cdot t \]
    4. Step-by-step derivation
      1. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{x}{z - y}} \cdot t \]
      2. lower--.f6494.6

        \[\leadsto \frac{x}{\color{blue}{z - y}} \cdot t \]
    5. Applied rewrites94.6%

      \[\leadsto \color{blue}{\frac{x}{z - y}} \cdot t \]

    if -1e6 < (/.f64 (-.f64 x y) (-.f64 z y)) < 5.00000000000000024e-5

    1. Initial program 95.9%

      \[\frac{x - y}{z - y} \cdot t \]
    2. Add Preprocessing
    3. Taylor expanded in z around inf

      \[\leadsto \color{blue}{\frac{x - y}{z}} \cdot t \]
    4. Step-by-step derivation
      1. lower-/.f64N/A

        \[\leadsto \color{blue}{\frac{x - y}{z}} \cdot t \]
      2. lower--.f6493.8

        \[\leadsto \frac{\color{blue}{x - y}}{z} \cdot t \]
    5. Applied rewrites93.8%

      \[\leadsto \color{blue}{\frac{x - y}{z}} \cdot t \]

    if 5.00000000000000024e-5 < (/.f64 (-.f64 x y) (-.f64 z y)) < 2e5

    1. Initial program 99.9%

      \[\frac{x - y}{z - y} \cdot t \]
    2. Add Preprocessing
    3. Taylor expanded in y around inf

      \[\leadsto \color{blue}{\left(t + -1 \cdot \frac{t \cdot x}{y}\right) - -1 \cdot \frac{t \cdot z}{y}} \]
    4. Step-by-step derivation
      1. associate--l+N/A

        \[\leadsto \color{blue}{t + \left(-1 \cdot \frac{t \cdot x}{y} - -1 \cdot \frac{t \cdot z}{y}\right)} \]
      2. distribute-lft-out--N/A

        \[\leadsto t + \color{blue}{-1 \cdot \left(\frac{t \cdot x}{y} - \frac{t \cdot z}{y}\right)} \]
      3. div-subN/A

        \[\leadsto t + -1 \cdot \color{blue}{\frac{t \cdot x - t \cdot z}{y}} \]
      4. +-commutativeN/A

        \[\leadsto \color{blue}{-1 \cdot \frac{t \cdot x - t \cdot z}{y} + t} \]
      5. mul-1-negN/A

        \[\leadsto \color{blue}{\left(\mathsf{neg}\left(\frac{t \cdot x - t \cdot z}{y}\right)\right)} + t \]
      6. distribute-lft-out--N/A

        \[\leadsto \left(\mathsf{neg}\left(\frac{\color{blue}{t \cdot \left(x - z\right)}}{y}\right)\right) + t \]
      7. associate-/l*N/A

        \[\leadsto \left(\mathsf{neg}\left(\color{blue}{t \cdot \frac{x - z}{y}}\right)\right) + t \]
      8. distribute-rgt-neg-inN/A

        \[\leadsto \color{blue}{t \cdot \left(\mathsf{neg}\left(\frac{x - z}{y}\right)\right)} + t \]
      9. mul-1-negN/A

        \[\leadsto t \cdot \color{blue}{\left(-1 \cdot \frac{x - z}{y}\right)} + t \]
      10. lower-fma.f64N/A

        \[\leadsto \color{blue}{\mathsf{fma}\left(t, -1 \cdot \frac{x - z}{y}, t\right)} \]
    5. Applied rewrites97.6%

      \[\leadsto \color{blue}{\mathsf{fma}\left(t, \frac{z - x}{y}, t\right)} \]
  3. Recombined 3 regimes into one program.
  4. Add Preprocessing

Developer Target 1: 97.0% accurate, 0.8× speedup?

\[\begin{array}{l} \\ \frac{t}{\frac{z - y}{x - y}} \end{array} \]
(FPCore (x y z t) :precision binary64 (/ t (/ (- z y) (- x y))))
double code(double x, double y, double z, double t) {
	return t / ((z - y) / (x - y));
}
real(8) function code(x, y, z, t)
    real(8), intent (in) :: x
    real(8), intent (in) :: y
    real(8), intent (in) :: z
    real(8), intent (in) :: t
    code = t / ((z - y) / (x - y))
end function
public static double code(double x, double y, double z, double t) {
	return t / ((z - y) / (x - y));
}
def code(x, y, z, t):
	return t / ((z - y) / (x - y))
function code(x, y, z, t)
	return Float64(t / Float64(Float64(z - y) / Float64(x - y)))
end
function tmp = code(x, y, z, t)
	tmp = t / ((z - y) / (x - y));
end
code[x_, y_, z_, t_] := N[(t / N[(N[(z - y), $MachinePrecision] / N[(x - y), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
\frac{t}{\frac{z - y}{x - y}}
\end{array}

Reproduce

?
herbie shell --seed 2024230 
(FPCore (x y z t)
  :name "Numeric.Signal.Multichannel:$cput from hsignal-0.2.7.1"
  :precision binary64

  :alt
  (! :herbie-platform default (/ t (/ (- z y) (- x y))))

  (* (/ (- x y) (- z y)) t))