Beckmann Distribution sample, tan2theta, alphax == alphay

Percentage Accurate: 55.8% → 89.9%
Time: 5.5s
Alternatives: 4
Speedup: 10.5×

Specification

?
\[\left(0.0001 \leq \alpha \land \alpha \leq 1\right) \land \left(2.328306437 \cdot 10^{-10} \leq u0 \land u0 \leq 1\right)\]
\[\begin{array}{l} \\ \left(\left(-\alpha\right) \cdot \alpha\right) \cdot \log \left(1 - u0\right) \end{array} \]
(FPCore (alpha u0)
 :precision binary32
 (* (* (- alpha) alpha) (log (- 1.0 u0))))
float code(float alpha, float u0) {
	return (-alpha * alpha) * logf((1.0f - u0));
}
real(4) function code(alpha, u0)
    real(4), intent (in) :: alpha
    real(4), intent (in) :: u0
    code = (-alpha * alpha) * log((1.0e0 - u0))
end function
function code(alpha, u0)
	return Float32(Float32(Float32(-alpha) * alpha) * log(Float32(Float32(1.0) - u0)))
end
function tmp = code(alpha, u0)
	tmp = (-alpha * alpha) * log((single(1.0) - u0));
end
\begin{array}{l}

\\
\left(\left(-\alpha\right) \cdot \alpha\right) \cdot \log \left(1 - u0\right)
\end{array}

Sampling outcomes in binary32 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 4 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: 55.8% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \left(\left(-\alpha\right) \cdot \alpha\right) \cdot \log \left(1 - u0\right) \end{array} \]
(FPCore (alpha u0)
 :precision binary32
 (* (* (- alpha) alpha) (log (- 1.0 u0))))
float code(float alpha, float u0) {
	return (-alpha * alpha) * logf((1.0f - u0));
}
real(4) function code(alpha, u0)
    real(4), intent (in) :: alpha
    real(4), intent (in) :: u0
    code = (-alpha * alpha) * log((1.0e0 - u0))
end function
function code(alpha, u0)
	return Float32(Float32(Float32(-alpha) * alpha) * log(Float32(Float32(1.0) - u0)))
end
function tmp = code(alpha, u0)
	tmp = (-alpha * alpha) * log((single(1.0) - u0));
end
\begin{array}{l}

\\
\left(\left(-\alpha\right) \cdot \alpha\right) \cdot \log \left(1 - u0\right)
\end{array}

Alternative 1: 89.9% accurate, 0.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;1 - u0 \leq 0.9998940229415894:\\ \;\;\;\;\left(\frac{1}{\frac{-1}{\alpha}} \cdot \alpha\right) \cdot \log \left(1 - u0\right)\\ \mathbf{else}:\\ \;\;\;\;\left(\alpha \cdot \alpha\right) \cdot u0\\ \end{array} \end{array} \]
(FPCore (alpha u0)
 :precision binary32
 (if (<= (- 1.0 u0) 0.9998940229415894)
   (* (* (/ 1.0 (/ -1.0 alpha)) alpha) (log (- 1.0 u0)))
   (* (* alpha alpha) u0)))
float code(float alpha, float u0) {
	float tmp;
	if ((1.0f - u0) <= 0.9998940229415894f) {
		tmp = ((1.0f / (-1.0f / alpha)) * alpha) * logf((1.0f - u0));
	} else {
		tmp = (alpha * alpha) * u0;
	}
	return tmp;
}
real(4) function code(alpha, u0)
    real(4), intent (in) :: alpha
    real(4), intent (in) :: u0
    real(4) :: tmp
    if ((1.0e0 - u0) <= 0.9998940229415894e0) then
        tmp = ((1.0e0 / ((-1.0e0) / alpha)) * alpha) * log((1.0e0 - u0))
    else
        tmp = (alpha * alpha) * u0
    end if
    code = tmp
end function
function code(alpha, u0)
	tmp = Float32(0.0)
	if (Float32(Float32(1.0) - u0) <= Float32(0.9998940229415894))
		tmp = Float32(Float32(Float32(Float32(1.0) / Float32(Float32(-1.0) / alpha)) * alpha) * log(Float32(Float32(1.0) - u0)));
	else
		tmp = Float32(Float32(alpha * alpha) * u0);
	end
	return tmp
end
function tmp_2 = code(alpha, u0)
	tmp = single(0.0);
	if ((single(1.0) - u0) <= single(0.9998940229415894))
		tmp = ((single(1.0) / (single(-1.0) / alpha)) * alpha) * log((single(1.0) - u0));
	else
		tmp = (alpha * alpha) * u0;
	end
	tmp_2 = tmp;
end
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;1 - u0 \leq 0.9998940229415894:\\
\;\;\;\;\left(\frac{1}{\frac{-1}{\alpha}} \cdot \alpha\right) \cdot \log \left(1 - u0\right)\\

\mathbf{else}:\\
\;\;\;\;\left(\alpha \cdot \alpha\right) \cdot u0\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (-.f32 #s(literal 1 binary32) u0) < 0.999894023

    1. Initial program 84.5%

      \[\left(\left(-\alpha\right) \cdot \alpha\right) \cdot \log \left(1 - u0\right) \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. lift-neg.f32N/A

        \[\leadsto \left(\color{blue}{\left(\mathsf{neg}\left(\alpha\right)\right)} \cdot \alpha\right) \cdot \log \left(1 - u0\right) \]
      2. neg-sub0N/A

        \[\leadsto \left(\color{blue}{\left(0 - \alpha\right)} \cdot \alpha\right) \cdot \log \left(1 - u0\right) \]
      3. flip3--N/A

        \[\leadsto \left(\color{blue}{\frac{{0}^{3} - {\alpha}^{3}}{0 \cdot 0 + \left(\alpha \cdot \alpha + 0 \cdot \alpha\right)}} \cdot \alpha\right) \cdot \log \left(1 - u0\right) \]
      4. clear-numN/A

        \[\leadsto \left(\color{blue}{\frac{1}{\frac{0 \cdot 0 + \left(\alpha \cdot \alpha + 0 \cdot \alpha\right)}{{0}^{3} - {\alpha}^{3}}}} \cdot \alpha\right) \cdot \log \left(1 - u0\right) \]
      5. lower-/.f32N/A

        \[\leadsto \left(\color{blue}{\frac{1}{\frac{0 \cdot 0 + \left(\alpha \cdot \alpha + 0 \cdot \alpha\right)}{{0}^{3} - {\alpha}^{3}}}} \cdot \alpha\right) \cdot \log \left(1 - u0\right) \]
      6. metadata-evalN/A

        \[\leadsto \left(\frac{1}{\frac{\color{blue}{0} + \left(\alpha \cdot \alpha + 0 \cdot \alpha\right)}{{0}^{3} - {\alpha}^{3}}} \cdot \alpha\right) \cdot \log \left(1 - u0\right) \]
      7. +-lft-identityN/A

        \[\leadsto \left(\frac{1}{\frac{\color{blue}{\alpha \cdot \alpha + 0 \cdot \alpha}}{{0}^{3} - {\alpha}^{3}}} \cdot \alpha\right) \cdot \log \left(1 - u0\right) \]
      8. mul0-lftN/A

        \[\leadsto \left(\frac{1}{\frac{\alpha \cdot \alpha + \color{blue}{0}}{{0}^{3} - {\alpha}^{3}}} \cdot \alpha\right) \cdot \log \left(1 - u0\right) \]
      9. +-rgt-identityN/A

        \[\leadsto \left(\frac{1}{\frac{\color{blue}{\alpha \cdot \alpha}}{{0}^{3} - {\alpha}^{3}}} \cdot \alpha\right) \cdot \log \left(1 - u0\right) \]
      10. clear-numN/A

        \[\leadsto \left(\frac{1}{\color{blue}{\frac{1}{\frac{{0}^{3} - {\alpha}^{3}}{\alpha \cdot \alpha}}}} \cdot \alpha\right) \cdot \log \left(1 - u0\right) \]
      11. +-rgt-identityN/A

        \[\leadsto \left(\frac{1}{\frac{1}{\frac{{0}^{3} - {\alpha}^{3}}{\color{blue}{\alpha \cdot \alpha + 0}}}} \cdot \alpha\right) \cdot \log \left(1 - u0\right) \]
      12. mul0-lftN/A

        \[\leadsto \left(\frac{1}{\frac{1}{\frac{{0}^{3} - {\alpha}^{3}}{\alpha \cdot \alpha + \color{blue}{0 \cdot \alpha}}}} \cdot \alpha\right) \cdot \log \left(1 - u0\right) \]
      13. +-lft-identityN/A

        \[\leadsto \left(\frac{1}{\frac{1}{\frac{{0}^{3} - {\alpha}^{3}}{\color{blue}{0 + \left(\alpha \cdot \alpha + 0 \cdot \alpha\right)}}}} \cdot \alpha\right) \cdot \log \left(1 - u0\right) \]
      14. metadata-evalN/A

        \[\leadsto \left(\frac{1}{\frac{1}{\frac{{0}^{3} - {\alpha}^{3}}{\color{blue}{0 \cdot 0} + \left(\alpha \cdot \alpha + 0 \cdot \alpha\right)}}} \cdot \alpha\right) \cdot \log \left(1 - u0\right) \]
      15. flip3--N/A

        \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{0 - \alpha}}} \cdot \alpha\right) \cdot \log \left(1 - u0\right) \]
      16. neg-sub0N/A

        \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{\mathsf{neg}\left(\alpha\right)}}} \cdot \alpha\right) \cdot \log \left(1 - u0\right) \]
      17. lift-neg.f32N/A

        \[\leadsto \left(\frac{1}{\frac{1}{\color{blue}{-\alpha}}} \cdot \alpha\right) \cdot \log \left(1 - u0\right) \]
      18. lower-/.f3284.6

        \[\leadsto \left(\frac{1}{\color{blue}{\frac{1}{-\alpha}}} \cdot \alpha\right) \cdot \log \left(1 - u0\right) \]
    4. Applied rewrites84.6%

      \[\leadsto \left(\color{blue}{\frac{1}{\frac{1}{-\alpha}}} \cdot \alpha\right) \cdot \log \left(1 - u0\right) \]

    if 0.999894023 < (-.f32 #s(literal 1 binary32) u0)

    1. Initial program 37.0%

      \[\left(\left(-\alpha\right) \cdot \alpha\right) \cdot \log \left(1 - u0\right) \]
    2. Add Preprocessing
    3. Taylor expanded in u0 around 0

      \[\leadsto \color{blue}{{\alpha}^{2} \cdot u0} \]
    4. Step-by-step derivation
      1. lower-*.f32N/A

        \[\leadsto \color{blue}{{\alpha}^{2} \cdot u0} \]
      2. unpow2N/A

        \[\leadsto \color{blue}{\left(\alpha \cdot \alpha\right)} \cdot u0 \]
      3. lower-*.f3290.6

        \[\leadsto \color{blue}{\left(\alpha \cdot \alpha\right)} \cdot u0 \]
    5. Applied rewrites90.6%

      \[\leadsto \color{blue}{\left(\alpha \cdot \alpha\right) \cdot u0} \]
  3. Recombined 2 regimes into one program.
  4. Final simplification88.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;1 - u0 \leq 0.9998940229415894:\\ \;\;\;\;\left(\frac{1}{\frac{-1}{\alpha}} \cdot \alpha\right) \cdot \log \left(1 - u0\right)\\ \mathbf{else}:\\ \;\;\;\;\left(\alpha \cdot \alpha\right) \cdot u0\\ \end{array} \]
  5. Add Preprocessing

Alternative 2: 89.9% accurate, 0.8× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;u0 \leq 0.00010599999950500205:\\ \;\;\;\;\left(\alpha \cdot \alpha\right) \cdot u0\\ \mathbf{else}:\\ \;\;\;\;\frac{\alpha}{\frac{-1}{\alpha}} \cdot \log \left(1 - u0\right)\\ \end{array} \end{array} \]
(FPCore (alpha u0)
 :precision binary32
 (if (<= u0 0.00010599999950500205)
   (* (* alpha alpha) u0)
   (* (/ alpha (/ -1.0 alpha)) (log (- 1.0 u0)))))
float code(float alpha, float u0) {
	float tmp;
	if (u0 <= 0.00010599999950500205f) {
		tmp = (alpha * alpha) * u0;
	} else {
		tmp = (alpha / (-1.0f / alpha)) * logf((1.0f - u0));
	}
	return tmp;
}
real(4) function code(alpha, u0)
    real(4), intent (in) :: alpha
    real(4), intent (in) :: u0
    real(4) :: tmp
    if (u0 <= 0.00010599999950500205e0) then
        tmp = (alpha * alpha) * u0
    else
        tmp = (alpha / ((-1.0e0) / alpha)) * log((1.0e0 - u0))
    end if
    code = tmp
end function
function code(alpha, u0)
	tmp = Float32(0.0)
	if (u0 <= Float32(0.00010599999950500205))
		tmp = Float32(Float32(alpha * alpha) * u0);
	else
		tmp = Float32(Float32(alpha / Float32(Float32(-1.0) / alpha)) * log(Float32(Float32(1.0) - u0)));
	end
	return tmp
end
function tmp_2 = code(alpha, u0)
	tmp = single(0.0);
	if (u0 <= single(0.00010599999950500205))
		tmp = (alpha * alpha) * u0;
	else
		tmp = (alpha / (single(-1.0) / alpha)) * log((single(1.0) - u0));
	end
	tmp_2 = tmp;
end
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;u0 \leq 0.00010599999950500205:\\
\;\;\;\;\left(\alpha \cdot \alpha\right) \cdot u0\\

\mathbf{else}:\\
\;\;\;\;\frac{\alpha}{\frac{-1}{\alpha}} \cdot \log \left(1 - u0\right)\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if u0 < 1.06e-4

    1. Initial program 37.0%

      \[\left(\left(-\alpha\right) \cdot \alpha\right) \cdot \log \left(1 - u0\right) \]
    2. Add Preprocessing
    3. Taylor expanded in u0 around 0

      \[\leadsto \color{blue}{{\alpha}^{2} \cdot u0} \]
    4. Step-by-step derivation
      1. lower-*.f32N/A

        \[\leadsto \color{blue}{{\alpha}^{2} \cdot u0} \]
      2. unpow2N/A

        \[\leadsto \color{blue}{\left(\alpha \cdot \alpha\right)} \cdot u0 \]
      3. lower-*.f3290.6

        \[\leadsto \color{blue}{\left(\alpha \cdot \alpha\right)} \cdot u0 \]
    5. Applied rewrites90.6%

      \[\leadsto \color{blue}{\left(\alpha \cdot \alpha\right) \cdot u0} \]

    if 1.06e-4 < u0

    1. Initial program 84.5%

      \[\left(\left(-\alpha\right) \cdot \alpha\right) \cdot \log \left(1 - u0\right) \]
    2. Add Preprocessing
    3. Step-by-step derivation
      1. lift-*.f32N/A

        \[\leadsto \color{blue}{\left(\left(-\alpha\right) \cdot \alpha\right)} \cdot \log \left(1 - u0\right) \]
      2. *-commutativeN/A

        \[\leadsto \color{blue}{\left(\alpha \cdot \left(-\alpha\right)\right)} \cdot \log \left(1 - u0\right) \]
      3. lift-neg.f32N/A

        \[\leadsto \left(\alpha \cdot \color{blue}{\left(\mathsf{neg}\left(\alpha\right)\right)}\right) \cdot \log \left(1 - u0\right) \]
      4. neg-sub0N/A

        \[\leadsto \left(\alpha \cdot \color{blue}{\left(0 - \alpha\right)}\right) \cdot \log \left(1 - u0\right) \]
      5. flip3--N/A

        \[\leadsto \left(\alpha \cdot \color{blue}{\frac{{0}^{3} - {\alpha}^{3}}{0 \cdot 0 + \left(\alpha \cdot \alpha + 0 \cdot \alpha\right)}}\right) \cdot \log \left(1 - u0\right) \]
      6. clear-numN/A

        \[\leadsto \left(\alpha \cdot \color{blue}{\frac{1}{\frac{0 \cdot 0 + \left(\alpha \cdot \alpha + 0 \cdot \alpha\right)}{{0}^{3} - {\alpha}^{3}}}}\right) \cdot \log \left(1 - u0\right) \]
      7. un-div-invN/A

        \[\leadsto \color{blue}{\frac{\alpha}{\frac{0 \cdot 0 + \left(\alpha \cdot \alpha + 0 \cdot \alpha\right)}{{0}^{3} - {\alpha}^{3}}}} \cdot \log \left(1 - u0\right) \]
      8. lower-/.f32N/A

        \[\leadsto \color{blue}{\frac{\alpha}{\frac{0 \cdot 0 + \left(\alpha \cdot \alpha + 0 \cdot \alpha\right)}{{0}^{3} - {\alpha}^{3}}}} \cdot \log \left(1 - u0\right) \]
      9. metadata-evalN/A

        \[\leadsto \frac{\alpha}{\frac{\color{blue}{0} + \left(\alpha \cdot \alpha + 0 \cdot \alpha\right)}{{0}^{3} - {\alpha}^{3}}} \cdot \log \left(1 - u0\right) \]
      10. +-lft-identityN/A

        \[\leadsto \frac{\alpha}{\frac{\color{blue}{\alpha \cdot \alpha + 0 \cdot \alpha}}{{0}^{3} - {\alpha}^{3}}} \cdot \log \left(1 - u0\right) \]
      11. mul0-lftN/A

        \[\leadsto \frac{\alpha}{\frac{\alpha \cdot \alpha + \color{blue}{0}}{{0}^{3} - {\alpha}^{3}}} \cdot \log \left(1 - u0\right) \]
      12. +-rgt-identityN/A

        \[\leadsto \frac{\alpha}{\frac{\color{blue}{\alpha \cdot \alpha}}{{0}^{3} - {\alpha}^{3}}} \cdot \log \left(1 - u0\right) \]
      13. clear-numN/A

        \[\leadsto \frac{\alpha}{\color{blue}{\frac{1}{\frac{{0}^{3} - {\alpha}^{3}}{\alpha \cdot \alpha}}}} \cdot \log \left(1 - u0\right) \]
      14. +-rgt-identityN/A

        \[\leadsto \frac{\alpha}{\frac{1}{\frac{{0}^{3} - {\alpha}^{3}}{\color{blue}{\alpha \cdot \alpha + 0}}}} \cdot \log \left(1 - u0\right) \]
      15. mul0-lftN/A

        \[\leadsto \frac{\alpha}{\frac{1}{\frac{{0}^{3} - {\alpha}^{3}}{\alpha \cdot \alpha + \color{blue}{0 \cdot \alpha}}}} \cdot \log \left(1 - u0\right) \]
      16. +-lft-identityN/A

        \[\leadsto \frac{\alpha}{\frac{1}{\frac{{0}^{3} - {\alpha}^{3}}{\color{blue}{0 + \left(\alpha \cdot \alpha + 0 \cdot \alpha\right)}}}} \cdot \log \left(1 - u0\right) \]
      17. metadata-evalN/A

        \[\leadsto \frac{\alpha}{\frac{1}{\frac{{0}^{3} - {\alpha}^{3}}{\color{blue}{0 \cdot 0} + \left(\alpha \cdot \alpha + 0 \cdot \alpha\right)}}} \cdot \log \left(1 - u0\right) \]
      18. flip3--N/A

        \[\leadsto \frac{\alpha}{\frac{1}{\color{blue}{0 - \alpha}}} \cdot \log \left(1 - u0\right) \]
      19. neg-sub0N/A

        \[\leadsto \frac{\alpha}{\frac{1}{\color{blue}{\mathsf{neg}\left(\alpha\right)}}} \cdot \log \left(1 - u0\right) \]
      20. lift-neg.f32N/A

        \[\leadsto \frac{\alpha}{\frac{1}{\color{blue}{-\alpha}}} \cdot \log \left(1 - u0\right) \]
      21. lower-/.f3284.5

        \[\leadsto \frac{\alpha}{\color{blue}{\frac{1}{-\alpha}}} \cdot \log \left(1 - u0\right) \]
    4. Applied rewrites84.5%

      \[\leadsto \color{blue}{\frac{\alpha}{\frac{1}{-\alpha}}} \cdot \log \left(1 - u0\right) \]
  3. Recombined 2 regimes into one program.
  4. Final simplification88.0%

    \[\leadsto \begin{array}{l} \mathbf{if}\;u0 \leq 0.00010599999950500205:\\ \;\;\;\;\left(\alpha \cdot \alpha\right) \cdot u0\\ \mathbf{else}:\\ \;\;\;\;\frac{\alpha}{\frac{-1}{\alpha}} \cdot \log \left(1 - u0\right)\\ \end{array} \]
  5. Add Preprocessing

Alternative 3: 89.9% accurate, 0.9× speedup?

\[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;1 - u0 \leq 0.9998940229415894:\\ \;\;\;\;\left(\left(-\alpha\right) \cdot \alpha\right) \cdot \log \left(1 - u0\right)\\ \mathbf{else}:\\ \;\;\;\;\left(\alpha \cdot \alpha\right) \cdot u0\\ \end{array} \end{array} \]
(FPCore (alpha u0)
 :precision binary32
 (if (<= (- 1.0 u0) 0.9998940229415894)
   (* (* (- alpha) alpha) (log (- 1.0 u0)))
   (* (* alpha alpha) u0)))
float code(float alpha, float u0) {
	float tmp;
	if ((1.0f - u0) <= 0.9998940229415894f) {
		tmp = (-alpha * alpha) * logf((1.0f - u0));
	} else {
		tmp = (alpha * alpha) * u0;
	}
	return tmp;
}
real(4) function code(alpha, u0)
    real(4), intent (in) :: alpha
    real(4), intent (in) :: u0
    real(4) :: tmp
    if ((1.0e0 - u0) <= 0.9998940229415894e0) then
        tmp = (-alpha * alpha) * log((1.0e0 - u0))
    else
        tmp = (alpha * alpha) * u0
    end if
    code = tmp
end function
function code(alpha, u0)
	tmp = Float32(0.0)
	if (Float32(Float32(1.0) - u0) <= Float32(0.9998940229415894))
		tmp = Float32(Float32(Float32(-alpha) * alpha) * log(Float32(Float32(1.0) - u0)));
	else
		tmp = Float32(Float32(alpha * alpha) * u0);
	end
	return tmp
end
function tmp_2 = code(alpha, u0)
	tmp = single(0.0);
	if ((single(1.0) - u0) <= single(0.9998940229415894))
		tmp = (-alpha * alpha) * log((single(1.0) - u0));
	else
		tmp = (alpha * alpha) * u0;
	end
	tmp_2 = tmp;
end
\begin{array}{l}

\\
\begin{array}{l}
\mathbf{if}\;1 - u0 \leq 0.9998940229415894:\\
\;\;\;\;\left(\left(-\alpha\right) \cdot \alpha\right) \cdot \log \left(1 - u0\right)\\

\mathbf{else}:\\
\;\;\;\;\left(\alpha \cdot \alpha\right) \cdot u0\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (-.f32 #s(literal 1 binary32) u0) < 0.999894023

    1. Initial program 84.5%

      \[\left(\left(-\alpha\right) \cdot \alpha\right) \cdot \log \left(1 - u0\right) \]
    2. Add Preprocessing

    if 0.999894023 < (-.f32 #s(literal 1 binary32) u0)

    1. Initial program 37.0%

      \[\left(\left(-\alpha\right) \cdot \alpha\right) \cdot \log \left(1 - u0\right) \]
    2. Add Preprocessing
    3. Taylor expanded in u0 around 0

      \[\leadsto \color{blue}{{\alpha}^{2} \cdot u0} \]
    4. Step-by-step derivation
      1. lower-*.f32N/A

        \[\leadsto \color{blue}{{\alpha}^{2} \cdot u0} \]
      2. unpow2N/A

        \[\leadsto \color{blue}{\left(\alpha \cdot \alpha\right)} \cdot u0 \]
      3. lower-*.f3290.6

        \[\leadsto \color{blue}{\left(\alpha \cdot \alpha\right)} \cdot u0 \]
    5. Applied rewrites90.6%

      \[\leadsto \color{blue}{\left(\alpha \cdot \alpha\right) \cdot u0} \]
  3. Recombined 2 regimes into one program.
  4. Add Preprocessing

Alternative 4: 74.7% accurate, 10.5× speedup?

\[\begin{array}{l} \\ \left(\alpha \cdot \alpha\right) \cdot u0 \end{array} \]
(FPCore (alpha u0) :precision binary32 (* (* alpha alpha) u0))
float code(float alpha, float u0) {
	return (alpha * alpha) * u0;
}
real(4) function code(alpha, u0)
    real(4), intent (in) :: alpha
    real(4), intent (in) :: u0
    code = (alpha * alpha) * u0
end function
function code(alpha, u0)
	return Float32(Float32(alpha * alpha) * u0)
end
function tmp = code(alpha, u0)
	tmp = (alpha * alpha) * u0;
end
\begin{array}{l}

\\
\left(\alpha \cdot \alpha\right) \cdot u0
\end{array}
Derivation
  1. Initial program 56.8%

    \[\left(\left(-\alpha\right) \cdot \alpha\right) \cdot \log \left(1 - u0\right) \]
  2. Add Preprocessing
  3. Taylor expanded in u0 around 0

    \[\leadsto \color{blue}{{\alpha}^{2} \cdot u0} \]
  4. Step-by-step derivation
    1. lower-*.f32N/A

      \[\leadsto \color{blue}{{\alpha}^{2} \cdot u0} \]
    2. unpow2N/A

      \[\leadsto \color{blue}{\left(\alpha \cdot \alpha\right)} \cdot u0 \]
    3. lower-*.f3274.7

      \[\leadsto \color{blue}{\left(\alpha \cdot \alpha\right)} \cdot u0 \]
  5. Applied rewrites74.7%

    \[\leadsto \color{blue}{\left(\alpha \cdot \alpha\right) \cdot u0} \]
  6. Add Preprocessing

Reproduce

?
herbie shell --seed 2024319 
(FPCore (alpha u0)
  :name "Beckmann Distribution sample, tan2theta, alphax == alphay"
  :precision binary32
  :pre (and (and (<= 0.0001 alpha) (<= alpha 1.0)) (and (<= 2.328306437e-10 u0) (<= u0 1.0)))
  (* (* (- alpha) alpha) (log (- 1.0 u0))))