SynthBasics:moogVCF from YampaSynth-0.2

Percentage Accurate: 93.6% → 98.6%
Time: 10.2s
Alternatives: 7
Speedup: 0.7×

Specification

?
\[\begin{array}{l} \\ x + \left(y \cdot z\right) \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right) \end{array} \]
(FPCore (x y z t)
 :precision binary64
 (+ x (* (* y z) (- (tanh (/ t y)) (tanh (/ x y))))))
double code(double x, double y, double z, double t) {
	return x + ((y * z) * (tanh((t / y)) - tanh((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 = x + ((y * z) * (tanh((t / y)) - tanh((x / y))))
end function
public static double code(double x, double y, double z, double t) {
	return x + ((y * z) * (Math.tanh((t / y)) - Math.tanh((x / y))));
}
def code(x, y, z, t):
	return x + ((y * z) * (math.tanh((t / y)) - math.tanh((x / y))))
function code(x, y, z, t)
	return Float64(x + Float64(Float64(y * z) * Float64(tanh(Float64(t / y)) - tanh(Float64(x / y)))))
end
function tmp = code(x, y, z, t)
	tmp = x + ((y * z) * (tanh((t / y)) - tanh((x / y))));
end
code[x_, y_, z_, t_] := N[(x + N[(N[(y * z), $MachinePrecision] * N[(N[Tanh[N[(t / y), $MachinePrecision]], $MachinePrecision] - N[Tanh[N[(x / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
x + \left(y \cdot z\right) \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\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 7 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: 93.6% accurate, 1.0× speedup?

\[\begin{array}{l} \\ x + \left(y \cdot z\right) \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right) \end{array} \]
(FPCore (x y z t)
 :precision binary64
 (+ x (* (* y z) (- (tanh (/ t y)) (tanh (/ x y))))))
double code(double x, double y, double z, double t) {
	return x + ((y * z) * (tanh((t / y)) - tanh((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 = x + ((y * z) * (tanh((t / y)) - tanh((x / y))))
end function
public static double code(double x, double y, double z, double t) {
	return x + ((y * z) * (Math.tanh((t / y)) - Math.tanh((x / y))));
}
def code(x, y, z, t):
	return x + ((y * z) * (math.tanh((t / y)) - math.tanh((x / y))))
function code(x, y, z, t)
	return Float64(x + Float64(Float64(y * z) * Float64(tanh(Float64(t / y)) - tanh(Float64(x / y)))))
end
function tmp = code(x, y, z, t)
	tmp = x + ((y * z) * (tanh((t / y)) - tanh((x / y))));
end
code[x_, y_, z_, t_] := N[(x + N[(N[(y * z), $MachinePrecision] * N[(N[Tanh[N[(t / y), $MachinePrecision]], $MachinePrecision] - N[Tanh[N[(x / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
x + \left(y \cdot z\right) \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right)
\end{array}

Alternative 1: 98.6% accurate, 0.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_1 := x + \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right) \cdot \left(y \cdot z\right)\\ \mathbf{if}\;t_1 \leq -\infty:\\ \;\;\;\;x + z \cdot \left(t - x\right)\\ \mathbf{elif}\;t_1 \leq 4 \cdot 10^{+306}:\\ \;\;\;\;t_1\\ \mathbf{else}:\\ \;\;\;\;x + \left(z \cdot t - z \cdot x\right)\\ \end{array} \end{array} \]
(FPCore (x y z t)
 :precision binary64
 (let* ((t_1 (+ x (* (- (tanh (/ t y)) (tanh (/ x y))) (* y z)))))
   (if (<= t_1 (- INFINITY))
     (+ x (* z (- t x)))
     (if (<= t_1 4e+306) t_1 (+ x (- (* z t) (* z x)))))))
double code(double x, double y, double z, double t) {
	double t_1 = x + ((tanh((t / y)) - tanh((x / y))) * (y * z));
	double tmp;
	if (t_1 <= -((double) INFINITY)) {
		tmp = x + (z * (t - x));
	} else if (t_1 <= 4e+306) {
		tmp = t_1;
	} else {
		tmp = x + ((z * t) - (z * x));
	}
	return tmp;
}
public static double code(double x, double y, double z, double t) {
	double t_1 = x + ((Math.tanh((t / y)) - Math.tanh((x / y))) * (y * z));
	double tmp;
	if (t_1 <= -Double.POSITIVE_INFINITY) {
		tmp = x + (z * (t - x));
	} else if (t_1 <= 4e+306) {
		tmp = t_1;
	} else {
		tmp = x + ((z * t) - (z * x));
	}
	return tmp;
}
def code(x, y, z, t):
	t_1 = x + ((math.tanh((t / y)) - math.tanh((x / y))) * (y * z))
	tmp = 0
	if t_1 <= -math.inf:
		tmp = x + (z * (t - x))
	elif t_1 <= 4e+306:
		tmp = t_1
	else:
		tmp = x + ((z * t) - (z * x))
	return tmp
function code(x, y, z, t)
	t_1 = Float64(x + Float64(Float64(tanh(Float64(t / y)) - tanh(Float64(x / y))) * Float64(y * z)))
	tmp = 0.0
	if (t_1 <= Float64(-Inf))
		tmp = Float64(x + Float64(z * Float64(t - x)));
	elseif (t_1 <= 4e+306)
		tmp = t_1;
	else
		tmp = Float64(x + Float64(Float64(z * t) - Float64(z * x)));
	end
	return tmp
end
function tmp_2 = code(x, y, z, t)
	t_1 = x + ((tanh((t / y)) - tanh((x / y))) * (y * z));
	tmp = 0.0;
	if (t_1 <= -Inf)
		tmp = x + (z * (t - x));
	elseif (t_1 <= 4e+306)
		tmp = t_1;
	else
		tmp = x + ((z * t) - (z * x));
	end
	tmp_2 = tmp;
end
code[x_, y_, z_, t_] := Block[{t$95$1 = N[(x + N[(N[(N[Tanh[N[(t / y), $MachinePrecision]], $MachinePrecision] - N[Tanh[N[(x / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision] * N[(y * z), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]}, If[LessEqual[t$95$1, (-Infinity)], N[(x + N[(z * N[(t - x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], If[LessEqual[t$95$1, 4e+306], t$95$1, N[(x + N[(N[(z * t), $MachinePrecision] - N[(z * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]]]
\begin{array}{l}

\\
\begin{array}{l}
t_1 := x + \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right) \cdot \left(y \cdot z\right)\\
\mathbf{if}\;t_1 \leq -\infty:\\
\;\;\;\;x + z \cdot \left(t - x\right)\\

\mathbf{elif}\;t_1 \leq 4 \cdot 10^{+306}:\\
\;\;\;\;t_1\\

\mathbf{else}:\\
\;\;\;\;x + \left(z \cdot t - z \cdot x\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 3 regimes
  2. if (+.f64 x (*.f64 (*.f64 y z) (-.f64 (tanh.f64 (/.f64 t y)) (tanh.f64 (/.f64 x y))))) < -inf.0

    1. Initial program 55.3%

      \[x + \left(y \cdot z\right) \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right) \]
    2. Taylor expanded in y around inf 100.0%

      \[\leadsto x + \color{blue}{z \cdot \left(t - x\right)} \]

    if -inf.0 < (+.f64 x (*.f64 (*.f64 y z) (-.f64 (tanh.f64 (/.f64 t y)) (tanh.f64 (/.f64 x y))))) < 4.00000000000000007e306

    1. Initial program 99.5%

      \[x + \left(y \cdot z\right) \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right) \]

    if 4.00000000000000007e306 < (+.f64 x (*.f64 (*.f64 y z) (-.f64 (tanh.f64 (/.f64 t y)) (tanh.f64 (/.f64 x y)))))

    1. Initial program 37.6%

      \[x + \left(y \cdot z\right) \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right) \]
    2. Taylor expanded in y around inf 99.8%

      \[\leadsto x + \color{blue}{z \cdot \left(t - x\right)} \]
    3. Step-by-step derivation
      1. sub-neg99.8%

        \[\leadsto x + z \cdot \color{blue}{\left(t + \left(-x\right)\right)} \]
      2. distribute-rgt-in99.9%

        \[\leadsto x + \color{blue}{\left(t \cdot z + \left(-x\right) \cdot z\right)} \]
      3. +-commutative99.9%

        \[\leadsto x + \color{blue}{\left(\left(-x\right) \cdot z + t \cdot z\right)} \]
    4. Applied egg-rr99.9%

      \[\leadsto x + \color{blue}{\left(\left(-x\right) \cdot z + t \cdot z\right)} \]
    5. Step-by-step derivation
      1. +-commutative99.9%

        \[\leadsto x + \color{blue}{\left(t \cdot z + \left(-x\right) \cdot z\right)} \]
      2. *-commutative99.9%

        \[\leadsto x + \left(\color{blue}{z \cdot t} + \left(-x\right) \cdot z\right) \]
      3. distribute-lft-neg-out99.9%

        \[\leadsto x + \left(z \cdot t + \color{blue}{\left(-x \cdot z\right)}\right) \]
      4. unsub-neg99.9%

        \[\leadsto x + \color{blue}{\left(z \cdot t - x \cdot z\right)} \]
    6. Applied egg-rr99.9%

      \[\leadsto x + \color{blue}{\left(z \cdot t - x \cdot z\right)} \]
  3. Recombined 3 regimes into one program.
  4. Final simplification99.6%

    \[\leadsto \begin{array}{l} \mathbf{if}\;x + \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right) \cdot \left(y \cdot z\right) \leq -\infty:\\ \;\;\;\;x + z \cdot \left(t - x\right)\\ \mathbf{elif}\;x + \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right) \cdot \left(y \cdot z\right) \leq 4 \cdot 10^{+306}:\\ \;\;\;\;x + \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right) \cdot \left(y \cdot z\right)\\ \mathbf{else}:\\ \;\;\;\;x + \left(z \cdot t - z \cdot x\right)\\ \end{array} \]

Alternative 2: 97.6% accurate, 0.7× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq 9.5 \cdot 10^{+232}:\\ \;\;\;\;\mathsf{fma}\left(y, z \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right), x\right)\\ \mathbf{else}:\\ \;\;\;\;x + z \cdot \left(t - x\right)\\ \end{array} \end{array} \]
(FPCore (x y z t)
 :precision binary64
 (if (<= y 9.5e+232)
   (fma y (* z (- (tanh (/ t y)) (tanh (/ x y)))) x)
   (+ x (* z (- t x)))))
double code(double x, double y, double z, double t) {
	double tmp;
	if (y <= 9.5e+232) {
		tmp = fma(y, (z * (tanh((t / y)) - tanh((x / y)))), x);
	} else {
		tmp = x + (z * (t - x));
	}
	return tmp;
}
function code(x, y, z, t)
	tmp = 0.0
	if (y <= 9.5e+232)
		tmp = fma(y, Float64(z * Float64(tanh(Float64(t / y)) - tanh(Float64(x / y)))), x);
	else
		tmp = Float64(x + Float64(z * Float64(t - x)));
	end
	return tmp
end
code[x_, y_, z_, t_] := If[LessEqual[y, 9.5e+232], N[(y * N[(z * N[(N[Tanh[N[(t / y), $MachinePrecision]], $MachinePrecision] - N[Tanh[N[(x / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision] + x), $MachinePrecision], N[(x + N[(z * N[(t - x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq 9.5 \cdot 10^{+232}:\\
\;\;\;\;\mathsf{fma}\left(y, z \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right), x\right)\\

\mathbf{else}:\\
\;\;\;\;x + z \cdot \left(t - x\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if y < 9.4999999999999996e232

    1. Initial program 94.7%

      \[x + \left(y \cdot z\right) \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right) \]
    2. Step-by-step derivation
      1. +-commutative94.7%

        \[\leadsto \color{blue}{\left(y \cdot z\right) \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right) + x} \]
      2. associate-*l*97.8%

        \[\leadsto \color{blue}{y \cdot \left(z \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right)\right)} + x \]
      3. fma-def97.8%

        \[\leadsto \color{blue}{\mathsf{fma}\left(y, z \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right), x\right)} \]
    3. Simplified97.8%

      \[\leadsto \color{blue}{\mathsf{fma}\left(y, z \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right), x\right)} \]

    if 9.4999999999999996e232 < y

    1. Initial program 66.1%

      \[x + \left(y \cdot z\right) \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right) \]
    2. Taylor expanded in y around inf 96.8%

      \[\leadsto x + \color{blue}{z \cdot \left(t - x\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification97.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq 9.5 \cdot 10^{+232}:\\ \;\;\;\;\mathsf{fma}\left(y, z \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right), x\right)\\ \mathbf{else}:\\ \;\;\;\;x + z \cdot \left(t - x\right)\\ \end{array} \]

Alternative 3: 82.6% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq 1.4 \cdot 10^{+182}:\\ \;\;\;\;x + y \cdot \left(z \cdot \tanh \left(\frac{t}{y}\right)\right)\\ \mathbf{else}:\\ \;\;\;\;x + z \cdot \left(t - x\right)\\ \end{array} \end{array} \]
(FPCore (x y z t)
 :precision binary64
 (if (<= y 1.4e+182) (+ x (* y (* z (tanh (/ t y))))) (+ x (* z (- t x)))))
double code(double x, double y, double z, double t) {
	double tmp;
	if (y <= 1.4e+182) {
		tmp = x + (y * (z * tanh((t / y))));
	} else {
		tmp = x + (z * (t - x));
	}
	return tmp;
}
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
    real(8) :: tmp
    if (y <= 1.4d+182) then
        tmp = x + (y * (z * tanh((t / y))))
    else
        tmp = x + (z * (t - x))
    end if
    code = tmp
end function
public static double code(double x, double y, double z, double t) {
	double tmp;
	if (y <= 1.4e+182) {
		tmp = x + (y * (z * Math.tanh((t / y))));
	} else {
		tmp = x + (z * (t - x));
	}
	return tmp;
}
def code(x, y, z, t):
	tmp = 0
	if y <= 1.4e+182:
		tmp = x + (y * (z * math.tanh((t / y))))
	else:
		tmp = x + (z * (t - x))
	return tmp
function code(x, y, z, t)
	tmp = 0.0
	if (y <= 1.4e+182)
		tmp = Float64(x + Float64(y * Float64(z * tanh(Float64(t / y)))));
	else
		tmp = Float64(x + Float64(z * Float64(t - x)));
	end
	return tmp
end
function tmp_2 = code(x, y, z, t)
	tmp = 0.0;
	if (y <= 1.4e+182)
		tmp = x + (y * (z * tanh((t / y))));
	else
		tmp = x + (z * (t - x));
	end
	tmp_2 = tmp;
end
code[x_, y_, z_, t_] := If[LessEqual[y, 1.4e+182], N[(x + N[(y * N[(z * N[Tanh[N[(t / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision], N[(x + N[(z * N[(t - x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq 1.4 \cdot 10^{+182}:\\
\;\;\;\;x + y \cdot \left(z \cdot \tanh \left(\frac{t}{y}\right)\right)\\

\mathbf{else}:\\
\;\;\;\;x + z \cdot \left(t - x\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if y < 1.40000000000000003e182

    1. Initial program 94.9%

      \[x + \left(y \cdot z\right) \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right) \]
    2. Taylor expanded in x around 0 24.0%

      \[\leadsto x + \color{blue}{y \cdot \left(z \cdot \left(\frac{e^{\frac{t}{y}}}{e^{\frac{t}{y}} + \frac{1}{e^{\frac{t}{y}}}} - \frac{1}{e^{\frac{t}{y}} \cdot \left(e^{\frac{t}{y}} + \frac{1}{e^{\frac{t}{y}}}\right)}\right)\right)} \]
    3. Step-by-step derivation
      1. associate-*r*23.8%

        \[\leadsto x + \color{blue}{\left(y \cdot z\right) \cdot \left(\frac{e^{\frac{t}{y}}}{e^{\frac{t}{y}} + \frac{1}{e^{\frac{t}{y}}}} - \frac{1}{e^{\frac{t}{y}} \cdot \left(e^{\frac{t}{y}} + \frac{1}{e^{\frac{t}{y}}}\right)}\right)} \]
      2. associate-/r*23.8%

        \[\leadsto x + \left(y \cdot z\right) \cdot \left(\frac{e^{\frac{t}{y}}}{e^{\frac{t}{y}} + \frac{1}{e^{\frac{t}{y}}}} - \color{blue}{\frac{\frac{1}{e^{\frac{t}{y}}}}{e^{\frac{t}{y}} + \frac{1}{e^{\frac{t}{y}}}}}\right) \]
      3. div-sub23.8%

        \[\leadsto x + \left(y \cdot z\right) \cdot \color{blue}{\frac{e^{\frac{t}{y}} - \frac{1}{e^{\frac{t}{y}}}}{e^{\frac{t}{y}} + \frac{1}{e^{\frac{t}{y}}}}} \]
      4. rec-exp23.8%

        \[\leadsto x + \left(y \cdot z\right) \cdot \frac{e^{\frac{t}{y}} - \color{blue}{e^{-\frac{t}{y}}}}{e^{\frac{t}{y}} + \frac{1}{e^{\frac{t}{y}}}} \]
      5. rec-exp23.8%

        \[\leadsto x + \left(y \cdot z\right) \cdot \frac{e^{\frac{t}{y}} - e^{-\frac{t}{y}}}{e^{\frac{t}{y}} + \color{blue}{e^{-\frac{t}{y}}}} \]
      6. tanh-def-a79.4%

        \[\leadsto x + \left(y \cdot z\right) \cdot \color{blue}{\tanh \left(\frac{t}{y}\right)} \]
      7. associate-*r*81.0%

        \[\leadsto x + \color{blue}{y \cdot \left(z \cdot \tanh \left(\frac{t}{y}\right)\right)} \]
    4. Simplified81.0%

      \[\leadsto x + \color{blue}{y \cdot \left(z \cdot \tanh \left(\frac{t}{y}\right)\right)} \]

    if 1.40000000000000003e182 < y

    1. Initial program 74.3%

      \[x + \left(y \cdot z\right) \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right) \]
    2. Taylor expanded in y around inf 97.8%

      \[\leadsto x + \color{blue}{z \cdot \left(t - x\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification83.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq 1.4 \cdot 10^{+182}:\\ \;\;\;\;x + y \cdot \left(z \cdot \tanh \left(\frac{t}{y}\right)\right)\\ \mathbf{else}:\\ \;\;\;\;x + z \cdot \left(t - x\right)\\ \end{array} \]

Alternative 4: 68.6% accurate, 19.3× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq 6.4 \cdot 10^{-16}:\\ \;\;\;\;x\\ \mathbf{else}:\\ \;\;\;\;x + \left(z \cdot t - z \cdot x\right)\\ \end{array} \end{array} \]
(FPCore (x y z t)
 :precision binary64
 (if (<= y 6.4e-16) x (+ x (- (* z t) (* z x)))))
double code(double x, double y, double z, double t) {
	double tmp;
	if (y <= 6.4e-16) {
		tmp = x;
	} else {
		tmp = x + ((z * t) - (z * x));
	}
	return tmp;
}
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
    real(8) :: tmp
    if (y <= 6.4d-16) then
        tmp = x
    else
        tmp = x + ((z * t) - (z * x))
    end if
    code = tmp
end function
public static double code(double x, double y, double z, double t) {
	double tmp;
	if (y <= 6.4e-16) {
		tmp = x;
	} else {
		tmp = x + ((z * t) - (z * x));
	}
	return tmp;
}
def code(x, y, z, t):
	tmp = 0
	if y <= 6.4e-16:
		tmp = x
	else:
		tmp = x + ((z * t) - (z * x))
	return tmp
function code(x, y, z, t)
	tmp = 0.0
	if (y <= 6.4e-16)
		tmp = x;
	else
		tmp = Float64(x + Float64(Float64(z * t) - Float64(z * x)));
	end
	return tmp
end
function tmp_2 = code(x, y, z, t)
	tmp = 0.0;
	if (y <= 6.4e-16)
		tmp = x;
	else
		tmp = x + ((z * t) - (z * x));
	end
	tmp_2 = tmp;
end
code[x_, y_, z_, t_] := If[LessEqual[y, 6.4e-16], x, N[(x + N[(N[(z * t), $MachinePrecision] - N[(z * x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq 6.4 \cdot 10^{-16}:\\
\;\;\;\;x\\

\mathbf{else}:\\
\;\;\;\;x + \left(z \cdot t - z \cdot x\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if y < 6.40000000000000046e-16

    1. Initial program 95.1%

      \[x + \left(y \cdot z\right) \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right) \]
    2. Step-by-step derivation
      1. +-commutative95.1%

        \[\leadsto \color{blue}{\left(y \cdot z\right) \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right) + x} \]
      2. associate-*l*97.4%

        \[\leadsto \color{blue}{y \cdot \left(z \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right)\right)} + x \]
      3. fma-def97.4%

        \[\leadsto \color{blue}{\mathsf{fma}\left(y, z \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right), x\right)} \]
    3. Simplified97.4%

      \[\leadsto \color{blue}{\mathsf{fma}\left(y, z \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right), x\right)} \]
    4. Taylor expanded in y around 0 66.6%

      \[\leadsto \color{blue}{x} \]

    if 6.40000000000000046e-16 < y

    1. Initial program 83.6%

      \[x + \left(y \cdot z\right) \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right) \]
    2. Taylor expanded in y around inf 86.4%

      \[\leadsto x + \color{blue}{z \cdot \left(t - x\right)} \]
    3. Step-by-step derivation
      1. sub-neg86.4%

        \[\leadsto x + z \cdot \color{blue}{\left(t + \left(-x\right)\right)} \]
      2. distribute-rgt-in86.4%

        \[\leadsto x + \color{blue}{\left(t \cdot z + \left(-x\right) \cdot z\right)} \]
      3. +-commutative86.4%

        \[\leadsto x + \color{blue}{\left(\left(-x\right) \cdot z + t \cdot z\right)} \]
    4. Applied egg-rr86.4%

      \[\leadsto x + \color{blue}{\left(\left(-x\right) \cdot z + t \cdot z\right)} \]
    5. Step-by-step derivation
      1. +-commutative86.4%

        \[\leadsto x + \color{blue}{\left(t \cdot z + \left(-x\right) \cdot z\right)} \]
      2. *-commutative86.4%

        \[\leadsto x + \left(\color{blue}{z \cdot t} + \left(-x\right) \cdot z\right) \]
      3. distribute-lft-neg-out86.4%

        \[\leadsto x + \left(z \cdot t + \color{blue}{\left(-x \cdot z\right)}\right) \]
      4. unsub-neg86.4%

        \[\leadsto x + \color{blue}{\left(z \cdot t - x \cdot z\right)} \]
    6. Applied egg-rr86.4%

      \[\leadsto x + \color{blue}{\left(z \cdot t - x \cdot z\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification71.2%

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq 6.4 \cdot 10^{-16}:\\ \;\;\;\;x\\ \mathbf{else}:\\ \;\;\;\;x + \left(z \cdot t - z \cdot x\right)\\ \end{array} \]

Alternative 5: 68.9% accurate, 23.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq 8.4 \cdot 10^{-16}:\\ \;\;\;\;x\\ \mathbf{else}:\\ \;\;\;\;x + z \cdot \left(t - x\right)\\ \end{array} \end{array} \]
(FPCore (x y z t)
 :precision binary64
 (if (<= y 8.4e-16) x (+ x (* z (- t x)))))
double code(double x, double y, double z, double t) {
	double tmp;
	if (y <= 8.4e-16) {
		tmp = x;
	} else {
		tmp = x + (z * (t - x));
	}
	return tmp;
}
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
    real(8) :: tmp
    if (y <= 8.4d-16) then
        tmp = x
    else
        tmp = x + (z * (t - x))
    end if
    code = tmp
end function
public static double code(double x, double y, double z, double t) {
	double tmp;
	if (y <= 8.4e-16) {
		tmp = x;
	} else {
		tmp = x + (z * (t - x));
	}
	return tmp;
}
def code(x, y, z, t):
	tmp = 0
	if y <= 8.4e-16:
		tmp = x
	else:
		tmp = x + (z * (t - x))
	return tmp
function code(x, y, z, t)
	tmp = 0.0
	if (y <= 8.4e-16)
		tmp = x;
	else
		tmp = Float64(x + Float64(z * Float64(t - x)));
	end
	return tmp
end
function tmp_2 = code(x, y, z, t)
	tmp = 0.0;
	if (y <= 8.4e-16)
		tmp = x;
	else
		tmp = x + (z * (t - x));
	end
	tmp_2 = tmp;
end
code[x_, y_, z_, t_] := If[LessEqual[y, 8.4e-16], x, N[(x + N[(z * N[(t - x), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq 8.4 \cdot 10^{-16}:\\
\;\;\;\;x\\

\mathbf{else}:\\
\;\;\;\;x + z \cdot \left(t - x\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if y < 8.4000000000000004e-16

    1. Initial program 95.1%

      \[x + \left(y \cdot z\right) \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right) \]
    2. Step-by-step derivation
      1. +-commutative95.1%

        \[\leadsto \color{blue}{\left(y \cdot z\right) \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right) + x} \]
      2. associate-*l*97.4%

        \[\leadsto \color{blue}{y \cdot \left(z \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right)\right)} + x \]
      3. fma-def97.4%

        \[\leadsto \color{blue}{\mathsf{fma}\left(y, z \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right), x\right)} \]
    3. Simplified97.4%

      \[\leadsto \color{blue}{\mathsf{fma}\left(y, z \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right), x\right)} \]
    4. Taylor expanded in y around 0 66.6%

      \[\leadsto \color{blue}{x} \]

    if 8.4000000000000004e-16 < y

    1. Initial program 83.6%

      \[x + \left(y \cdot z\right) \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right) \]
    2. Taylor expanded in y around inf 86.4%

      \[\leadsto x + \color{blue}{z \cdot \left(t - x\right)} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification71.2%

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq 8.4 \cdot 10^{-16}:\\ \;\;\;\;x\\ \mathbf{else}:\\ \;\;\;\;x + z \cdot \left(t - x\right)\\ \end{array} \]

Alternative 6: 65.3% accurate, 30.2× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;y \leq 2.15 \cdot 10^{-10}:\\ \;\;\;\;x\\ \mathbf{else}:\\ \;\;\;\;x + z \cdot t\\ \end{array} \end{array} \]
(FPCore (x y z t) :precision binary64 (if (<= y 2.15e-10) x (+ x (* z t))))
double code(double x, double y, double z, double t) {
	double tmp;
	if (y <= 2.15e-10) {
		tmp = x;
	} else {
		tmp = x + (z * t);
	}
	return tmp;
}
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
    real(8) :: tmp
    if (y <= 2.15d-10) then
        tmp = x
    else
        tmp = x + (z * t)
    end if
    code = tmp
end function
public static double code(double x, double y, double z, double t) {
	double tmp;
	if (y <= 2.15e-10) {
		tmp = x;
	} else {
		tmp = x + (z * t);
	}
	return tmp;
}
def code(x, y, z, t):
	tmp = 0
	if y <= 2.15e-10:
		tmp = x
	else:
		tmp = x + (z * t)
	return tmp
function code(x, y, z, t)
	tmp = 0.0
	if (y <= 2.15e-10)
		tmp = x;
	else
		tmp = Float64(x + Float64(z * t));
	end
	return tmp
end
function tmp_2 = code(x, y, z, t)
	tmp = 0.0;
	if (y <= 2.15e-10)
		tmp = x;
	else
		tmp = x + (z * t);
	end
	tmp_2 = tmp;
end
code[x_, y_, z_, t_] := If[LessEqual[y, 2.15e-10], x, N[(x + N[(z * t), $MachinePrecision]), $MachinePrecision]]
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;y \leq 2.15 \cdot 10^{-10}:\\
\;\;\;\;x\\

\mathbf{else}:\\
\;\;\;\;x + z \cdot t\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if y < 2.15000000000000007e-10

    1. Initial program 95.1%

      \[x + \left(y \cdot z\right) \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right) \]
    2. Step-by-step derivation
      1. +-commutative95.1%

        \[\leadsto \color{blue}{\left(y \cdot z\right) \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right) + x} \]
      2. associate-*l*97.4%

        \[\leadsto \color{blue}{y \cdot \left(z \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right)\right)} + x \]
      3. fma-def97.4%

        \[\leadsto \color{blue}{\mathsf{fma}\left(y, z \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right), x\right)} \]
    3. Simplified97.4%

      \[\leadsto \color{blue}{\mathsf{fma}\left(y, z \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right), x\right)} \]
    4. Taylor expanded in y around 0 66.6%

      \[\leadsto \color{blue}{x} \]

    if 2.15000000000000007e-10 < y

    1. Initial program 83.6%

      \[x + \left(y \cdot z\right) \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right) \]
    2. Taylor expanded in x around 0 30.3%

      \[\leadsto x + \color{blue}{y \cdot \left(z \cdot \left(\frac{e^{\frac{t}{y}}}{e^{\frac{t}{y}} + \frac{1}{e^{\frac{t}{y}}}} - \frac{1}{e^{\frac{t}{y}} \cdot \left(e^{\frac{t}{y}} + \frac{1}{e^{\frac{t}{y}}}\right)}\right)\right)} \]
    3. Step-by-step derivation
      1. associate-*r*29.5%

        \[\leadsto x + \color{blue}{\left(y \cdot z\right) \cdot \left(\frac{e^{\frac{t}{y}}}{e^{\frac{t}{y}} + \frac{1}{e^{\frac{t}{y}}}} - \frac{1}{e^{\frac{t}{y}} \cdot \left(e^{\frac{t}{y}} + \frac{1}{e^{\frac{t}{y}}}\right)}\right)} \]
      2. associate-/r*29.5%

        \[\leadsto x + \left(y \cdot z\right) \cdot \left(\frac{e^{\frac{t}{y}}}{e^{\frac{t}{y}} + \frac{1}{e^{\frac{t}{y}}}} - \color{blue}{\frac{\frac{1}{e^{\frac{t}{y}}}}{e^{\frac{t}{y}} + \frac{1}{e^{\frac{t}{y}}}}}\right) \]
      3. div-sub29.5%

        \[\leadsto x + \left(y \cdot z\right) \cdot \color{blue}{\frac{e^{\frac{t}{y}} - \frac{1}{e^{\frac{t}{y}}}}{e^{\frac{t}{y}} + \frac{1}{e^{\frac{t}{y}}}}} \]
      4. rec-exp29.5%

        \[\leadsto x + \left(y \cdot z\right) \cdot \frac{e^{\frac{t}{y}} - \color{blue}{e^{-\frac{t}{y}}}}{e^{\frac{t}{y}} + \frac{1}{e^{\frac{t}{y}}}} \]
      5. rec-exp29.5%

        \[\leadsto x + \left(y \cdot z\right) \cdot \frac{e^{\frac{t}{y}} - e^{-\frac{t}{y}}}{e^{\frac{t}{y}} + \color{blue}{e^{-\frac{t}{y}}}} \]
      6. tanh-def-a63.6%

        \[\leadsto x + \left(y \cdot z\right) \cdot \color{blue}{\tanh \left(\frac{t}{y}\right)} \]
      7. associate-*r*69.7%

        \[\leadsto x + \color{blue}{y \cdot \left(z \cdot \tanh \left(\frac{t}{y}\right)\right)} \]
    4. Simplified69.7%

      \[\leadsto x + \color{blue}{y \cdot \left(z \cdot \tanh \left(\frac{t}{y}\right)\right)} \]
    5. Taylor expanded in y around inf 62.4%

      \[\leadsto \color{blue}{x + t \cdot z} \]
    6. Step-by-step derivation
      1. +-commutative62.4%

        \[\leadsto \color{blue}{t \cdot z + x} \]
      2. *-commutative62.4%

        \[\leadsto \color{blue}{z \cdot t} + x \]
    7. Simplified62.4%

      \[\leadsto \color{blue}{z \cdot t + x} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification65.7%

    \[\leadsto \begin{array}{l} \mathbf{if}\;y \leq 2.15 \cdot 10^{-10}:\\ \;\;\;\;x\\ \mathbf{else}:\\ \;\;\;\;x + z \cdot t\\ \end{array} \]

Alternative 7: 60.2% accurate, 213.0× speedup?

\[\begin{array}{l} \\ x \end{array} \]
(FPCore (x y z t) :precision binary64 x)
double code(double x, double y, double z, double t) {
	return x;
}
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
end function
public static double code(double x, double y, double z, double t) {
	return x;
}
def code(x, y, z, t):
	return x
function code(x, y, z, t)
	return x
end
function tmp = code(x, y, z, t)
	tmp = x;
end
code[x_, y_, z_, t_] := x
\begin{array}{l}

\\
x
\end{array}
Derivation
  1. Initial program 92.5%

    \[x + \left(y \cdot z\right) \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right) \]
  2. Step-by-step derivation
    1. +-commutative92.5%

      \[\leadsto \color{blue}{\left(y \cdot z\right) \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right) + x} \]
    2. associate-*l*96.3%

      \[\leadsto \color{blue}{y \cdot \left(z \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right)\right)} + x \]
    3. fma-def96.3%

      \[\leadsto \color{blue}{\mathsf{fma}\left(y, z \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right), x\right)} \]
  3. Simplified96.3%

    \[\leadsto \color{blue}{\mathsf{fma}\left(y, z \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right), x\right)} \]
  4. Taylor expanded in y around 0 58.8%

    \[\leadsto \color{blue}{x} \]
  5. Final simplification58.8%

    \[\leadsto x \]

Developer target: 97.1% accurate, 1.0× speedup?

\[\begin{array}{l} \\ x + y \cdot \left(z \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right)\right) \end{array} \]
(FPCore (x y z t)
 :precision binary64
 (+ x (* y (* z (- (tanh (/ t y)) (tanh (/ x y)))))))
double code(double x, double y, double z, double t) {
	return x + (y * (z * (tanh((t / y)) - tanh((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 = x + (y * (z * (tanh((t / y)) - tanh((x / y)))))
end function
public static double code(double x, double y, double z, double t) {
	return x + (y * (z * (Math.tanh((t / y)) - Math.tanh((x / y)))));
}
def code(x, y, z, t):
	return x + (y * (z * (math.tanh((t / y)) - math.tanh((x / y)))))
function code(x, y, z, t)
	return Float64(x + Float64(y * Float64(z * Float64(tanh(Float64(t / y)) - tanh(Float64(x / y))))))
end
function tmp = code(x, y, z, t)
	tmp = x + (y * (z * (tanh((t / y)) - tanh((x / y)))));
end
code[x_, y_, z_, t_] := N[(x + N[(y * N[(z * N[(N[Tanh[N[(t / y), $MachinePrecision]], $MachinePrecision] - N[Tanh[N[(x / y), $MachinePrecision]], $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]), $MachinePrecision]
\begin{array}{l}

\\
x + y \cdot \left(z \cdot \left(\tanh \left(\frac{t}{y}\right) - \tanh \left(\frac{x}{y}\right)\right)\right)
\end{array}

Reproduce

?
herbie shell --seed 2023301 
(FPCore (x y z t)
  :name "SynthBasics:moogVCF from YampaSynth-0.2"
  :precision binary64

  :herbie-target
  (+ x (* y (* z (- (tanh (/ t y)) (tanh (/ x y))))))

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