Trowbridge-Reitz Sample, near normal, slope_x

Percentage Accurate: 99.0% → 99.0%
Time: 8.2s
Alternatives: 8
Speedup: 1.0×

Specification

?
\[\left(\left(cosTheta\_i > 0.9999 \land cosTheta\_i \leq 1\right) \land \left(2.328306437 \cdot 10^{-10} \leq u1 \land u1 \leq 1\right)\right) \land \left(2.328306437 \cdot 10^{-10} \leq u2 \land u2 \leq 1\right)\]
\[\begin{array}{l} \\ \sqrt{\frac{u1}{1 - u1}} \cdot \cos \left(6.28318530718 \cdot u2\right) \end{array} \]
(FPCore (cosTheta_i u1 u2)
 :precision binary32
 (* (sqrt (/ u1 (- 1.0 u1))) (cos (* 6.28318530718 u2))))
float code(float cosTheta_i, float u1, float u2) {
	return sqrtf((u1 / (1.0f - u1))) * cosf((6.28318530718f * u2));
}
real(4) function code(costheta_i, u1, u2)
    real(4), intent (in) :: costheta_i
    real(4), intent (in) :: u1
    real(4), intent (in) :: u2
    code = sqrt((u1 / (1.0e0 - u1))) * cos((6.28318530718e0 * u2))
end function
function code(cosTheta_i, u1, u2)
	return Float32(sqrt(Float32(u1 / Float32(Float32(1.0) - u1))) * cos(Float32(Float32(6.28318530718) * u2)))
end
function tmp = code(cosTheta_i, u1, u2)
	tmp = sqrt((u1 / (single(1.0) - u1))) * cos((single(6.28318530718) * u2));
end
\begin{array}{l}

\\
\sqrt{\frac{u1}{1 - u1}} \cdot \cos \left(6.28318530718 \cdot u2\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 8 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: 99.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \sqrt{\frac{u1}{1 - u1}} \cdot \cos \left(6.28318530718 \cdot u2\right) \end{array} \]
(FPCore (cosTheta_i u1 u2)
 :precision binary32
 (* (sqrt (/ u1 (- 1.0 u1))) (cos (* 6.28318530718 u2))))
float code(float cosTheta_i, float u1, float u2) {
	return sqrtf((u1 / (1.0f - u1))) * cosf((6.28318530718f * u2));
}
real(4) function code(costheta_i, u1, u2)
    real(4), intent (in) :: costheta_i
    real(4), intent (in) :: u1
    real(4), intent (in) :: u2
    code = sqrt((u1 / (1.0e0 - u1))) * cos((6.28318530718e0 * u2))
end function
function code(cosTheta_i, u1, u2)
	return Float32(sqrt(Float32(u1 / Float32(Float32(1.0) - u1))) * cos(Float32(Float32(6.28318530718) * u2)))
end
function tmp = code(cosTheta_i, u1, u2)
	tmp = sqrt((u1 / (single(1.0) - u1))) * cos((single(6.28318530718) * u2));
end
\begin{array}{l}

\\
\sqrt{\frac{u1}{1 - u1}} \cdot \cos \left(6.28318530718 \cdot u2\right)
\end{array}

Alternative 1: 99.0% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \sqrt{\frac{u1}{1 - u1}} \cdot \cos \left(6.28318530718 \cdot u2\right) \end{array} \]
(FPCore (cosTheta_i u1 u2)
 :precision binary32
 (* (sqrt (/ u1 (- 1.0 u1))) (cos (* 6.28318530718 u2))))
float code(float cosTheta_i, float u1, float u2) {
	return sqrtf((u1 / (1.0f - u1))) * cosf((6.28318530718f * u2));
}
real(4) function code(costheta_i, u1, u2)
    real(4), intent (in) :: costheta_i
    real(4), intent (in) :: u1
    real(4), intent (in) :: u2
    code = sqrt((u1 / (1.0e0 - u1))) * cos((6.28318530718e0 * u2))
end function
function code(cosTheta_i, u1, u2)
	return Float32(sqrt(Float32(u1 / Float32(Float32(1.0) - u1))) * cos(Float32(Float32(6.28318530718) * u2)))
end
function tmp = code(cosTheta_i, u1, u2)
	tmp = sqrt((u1 / (single(1.0) - u1))) * cos((single(6.28318530718) * u2));
end
\begin{array}{l}

\\
\sqrt{\frac{u1}{1 - u1}} \cdot \cos \left(6.28318530718 \cdot u2\right)
\end{array}
Derivation
  1. Initial program 99.1%

    \[\sqrt{\frac{u1}{1 - u1}} \cdot \cos \left(6.28318530718 \cdot u2\right) \]
  2. Add Preprocessing
  3. Add Preprocessing

Alternative 2: 93.9% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \sqrt{\frac{u1}{1 - u1}}\\ t_1 := \cos \left(6.28318530718 \cdot u2\right)\\ \mathbf{if}\;t\_0 \cdot t\_1 \leq 0.06700000166893005:\\ \;\;\;\;\sqrt{u1 \cdot u1 + u1} \cdot t\_1\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \end{array} \]
(FPCore (cosTheta_i u1 u2)
 :precision binary32
 (let* ((t_0 (sqrt (/ u1 (- 1.0 u1)))) (t_1 (cos (* 6.28318530718 u2))))
   (if (<= (* t_0 t_1) 0.06700000166893005)
     (* (sqrt (+ (* u1 u1) u1)) t_1)
     t_0)))
float code(float cosTheta_i, float u1, float u2) {
	float t_0 = sqrtf((u1 / (1.0f - u1)));
	float t_1 = cosf((6.28318530718f * u2));
	float tmp;
	if ((t_0 * t_1) <= 0.06700000166893005f) {
		tmp = sqrtf(((u1 * u1) + u1)) * t_1;
	} else {
		tmp = t_0;
	}
	return tmp;
}
real(4) function code(costheta_i, u1, u2)
    real(4), intent (in) :: costheta_i
    real(4), intent (in) :: u1
    real(4), intent (in) :: u2
    real(4) :: t_0
    real(4) :: t_1
    real(4) :: tmp
    t_0 = sqrt((u1 / (1.0e0 - u1)))
    t_1 = cos((6.28318530718e0 * u2))
    if ((t_0 * t_1) <= 0.06700000166893005e0) then
        tmp = sqrt(((u1 * u1) + u1)) * t_1
    else
        tmp = t_0
    end if
    code = tmp
end function
function code(cosTheta_i, u1, u2)
	t_0 = sqrt(Float32(u1 / Float32(Float32(1.0) - u1)))
	t_1 = cos(Float32(Float32(6.28318530718) * u2))
	tmp = Float32(0.0)
	if (Float32(t_0 * t_1) <= Float32(0.06700000166893005))
		tmp = Float32(sqrt(Float32(Float32(u1 * u1) + u1)) * t_1);
	else
		tmp = t_0;
	end
	return tmp
end
function tmp_2 = code(cosTheta_i, u1, u2)
	t_0 = sqrt((u1 / (single(1.0) - u1)));
	t_1 = cos((single(6.28318530718) * u2));
	tmp = single(0.0);
	if ((t_0 * t_1) <= single(0.06700000166893005))
		tmp = sqrt(((u1 * u1) + u1)) * t_1;
	else
		tmp = t_0;
	end
	tmp_2 = tmp;
end
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \sqrt{\frac{u1}{1 - u1}}\\
t_1 := \cos \left(6.28318530718 \cdot u2\right)\\
\mathbf{if}\;t\_0 \cdot t\_1 \leq 0.06700000166893005:\\
\;\;\;\;\sqrt{u1 \cdot u1 + u1} \cdot t\_1\\

\mathbf{else}:\\
\;\;\;\;t\_0\\


\end{array}
\end{array}
Derivation
  1. Split input into 2 regimes
  2. if (*.f32 (sqrt.f32 (/.f32 u1 (-.f32 #s(literal 1 binary32) u1))) (cos.f32 (*.f32 #s(literal 314159265359/50000000000 binary32) u2))) < 0.0670000017

    1. Initial program 99.0%

      \[\sqrt{\frac{u1}{1 - u1}} \cdot \cos \left(6.28318530718 \cdot u2\right) \]
    2. Add Preprocessing
    3. Taylor expanded in u1 around 0

      \[\leadsto \sqrt{\color{blue}{u1 \cdot \left(1 + u1\right)}} \cdot \cos \left(\frac{314159265359}{50000000000} \cdot u2\right) \]
    4. Step-by-step derivation
      1. +-commutativeN/A

        \[\leadsto \sqrt{u1 \cdot \color{blue}{\left(u1 + 1\right)}} \cdot \cos \left(\frac{314159265359}{50000000000} \cdot u2\right) \]
      2. distribute-lft-inN/A

        \[\leadsto \sqrt{\color{blue}{u1 \cdot u1 + u1 \cdot 1}} \cdot \cos \left(\frac{314159265359}{50000000000} \cdot u2\right) \]
      3. *-rgt-identityN/A

        \[\leadsto \sqrt{u1 \cdot u1 + \color{blue}{u1}} \cdot \cos \left(\frac{314159265359}{50000000000} \cdot u2\right) \]
      4. lower-fma.f3266.0

        \[\leadsto \sqrt{\color{blue}{\mathsf{fma}\left(u1, u1, u1\right)}} \cdot \cos \left(6.28318530718 \cdot u2\right) \]
    5. Applied rewrites65.2%

      \[\leadsto \sqrt{\color{blue}{\mathsf{fma}\left(u1, u1, u1\right)}} \cdot \cos \left(6.28318530718 \cdot u2\right) \]
    6. Step-by-step derivation
      1. Applied rewrites97.1%

        \[\leadsto \sqrt{u1 \cdot u1 + \color{blue}{u1}} \cdot \cos \left(6.28318530718 \cdot u2\right) \]

      if 0.0670000017 < (*.f32 (sqrt.f32 (/.f32 u1 (-.f32 #s(literal 1 binary32) u1))) (cos.f32 (*.f32 #s(literal 314159265359/50000000000 binary32) u2)))

      1. Initial program 99.6%

        \[\sqrt{\frac{u1}{1 - u1}} \cdot \cos \left(6.28318530718 \cdot u2\right) \]
      2. Add Preprocessing
      3. Taylor expanded in u2 around 0

        \[\leadsto \color{blue}{\sqrt{\frac{u1}{1 - u1}}} \]
      4. Step-by-step derivation
        1. lower-sqrt.f32N/A

          \[\leadsto \color{blue}{\sqrt{\frac{u1}{1 - u1}}} \]
        2. lower-/.f32N/A

          \[\leadsto \sqrt{\color{blue}{\frac{u1}{1 - u1}}} \]
        3. lower--.f3289.2

          \[\leadsto \sqrt{\frac{u1}{\color{blue}{1 - u1}}} \]
      5. Applied rewrites89.2%

        \[\leadsto \color{blue}{\sqrt{\frac{u1}{1 - u1}}} \]
    7. Recombined 2 regimes into one program.
    8. Add Preprocessing

    Alternative 3: 89.8% accurate, 0.6× speedup?

    \[\begin{array}{l} \\ \begin{array}{l} t_0 := \cos \left(6.28318530718 \cdot u2\right)\\ \mathbf{if}\;t\_0 \leq 0.999983012676239:\\ \;\;\;\;\sqrt{u1} \cdot t\_0\\ \mathbf{else}:\\ \;\;\;\;\sqrt{\frac{u1}{1 - u1}}\\ \end{array} \end{array} \]
    (FPCore (cosTheta_i u1 u2)
     :precision binary32
     (let* ((t_0 (cos (* 6.28318530718 u2))))
       (if (<= t_0 0.999983012676239) (* (sqrt u1) t_0) (sqrt (/ u1 (- 1.0 u1))))))
    float code(float cosTheta_i, float u1, float u2) {
    	float t_0 = cosf((6.28318530718f * u2));
    	float tmp;
    	if (t_0 <= 0.999983012676239f) {
    		tmp = sqrtf(u1) * t_0;
    	} else {
    		tmp = sqrtf((u1 / (1.0f - u1)));
    	}
    	return tmp;
    }
    
    real(4) function code(costheta_i, u1, u2)
        real(4), intent (in) :: costheta_i
        real(4), intent (in) :: u1
        real(4), intent (in) :: u2
        real(4) :: t_0
        real(4) :: tmp
        t_0 = cos((6.28318530718e0 * u2))
        if (t_0 <= 0.999983012676239e0) then
            tmp = sqrt(u1) * t_0
        else
            tmp = sqrt((u1 / (1.0e0 - u1)))
        end if
        code = tmp
    end function
    
    function code(cosTheta_i, u1, u2)
    	t_0 = cos(Float32(Float32(6.28318530718) * u2))
    	tmp = Float32(0.0)
    	if (t_0 <= Float32(0.999983012676239))
    		tmp = Float32(sqrt(u1) * t_0);
    	else
    		tmp = sqrt(Float32(u1 / Float32(Float32(1.0) - u1)));
    	end
    	return tmp
    end
    
    function tmp_2 = code(cosTheta_i, u1, u2)
    	t_0 = cos((single(6.28318530718) * u2));
    	tmp = single(0.0);
    	if (t_0 <= single(0.999983012676239))
    		tmp = sqrt(u1) * t_0;
    	else
    		tmp = sqrt((u1 / (single(1.0) - u1)));
    	end
    	tmp_2 = tmp;
    end
    
    \begin{array}{l}
    
    \\
    \begin{array}{l}
    t_0 := \cos \left(6.28318530718 \cdot u2\right)\\
    \mathbf{if}\;t\_0 \leq 0.999983012676239:\\
    \;\;\;\;\sqrt{u1} \cdot t\_0\\
    
    \mathbf{else}:\\
    \;\;\;\;\sqrt{\frac{u1}{1 - u1}}\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 2 regimes
    2. if (cos.f32 (*.f32 #s(literal 314159265359/50000000000 binary32) u2)) < 0.999983013

      1. Initial program 98.2%

        \[\sqrt{\frac{u1}{1 - u1}} \cdot \cos \left(6.28318530718 \cdot u2\right) \]
      2. Add Preprocessing
      3. Taylor expanded in u1 around 0

        \[\leadsto \color{blue}{\sqrt{u1}} \cdot \cos \left(\frac{314159265359}{50000000000} \cdot u2\right) \]
      4. Step-by-step derivation
        1. lower-sqrt.f3276.7

          \[\leadsto \color{blue}{\sqrt{u1}} \cdot \cos \left(6.28318530718 \cdot u2\right) \]
      5. Applied rewrites76.7%

        \[\leadsto \color{blue}{\sqrt{u1}} \cdot \cos \left(6.28318530718 \cdot u2\right) \]

      if 0.999983013 < (cos.f32 (*.f32 #s(literal 314159265359/50000000000 binary32) u2))

      1. Initial program 99.5%

        \[\sqrt{\frac{u1}{1 - u1}} \cdot \cos \left(6.28318530718 \cdot u2\right) \]
      2. Add Preprocessing
      3. Taylor expanded in u2 around 0

        \[\leadsto \color{blue}{\sqrt{\frac{u1}{1 - u1}}} \]
      4. Step-by-step derivation
        1. lower-sqrt.f32N/A

          \[\leadsto \color{blue}{\sqrt{\frac{u1}{1 - u1}}} \]
        2. lower-/.f32N/A

          \[\leadsto \sqrt{\color{blue}{\frac{u1}{1 - u1}}} \]
        3. lower--.f3297.7

          \[\leadsto \sqrt{\frac{u1}{\color{blue}{1 - u1}}} \]
      5. Applied rewrites97.7%

        \[\leadsto \color{blue}{\sqrt{\frac{u1}{1 - u1}}} \]
    3. Recombined 2 regimes into one program.
    4. Add Preprocessing

    Alternative 4: 93.7% accurate, 1.0× speedup?

    \[\begin{array}{l} \\ \begin{array}{l} \mathbf{if}\;6.28318530718 \cdot u2 \leq 0.0006000000284984708:\\ \;\;\;\;\sqrt{\frac{u1}{1 - u1}}\\ \mathbf{else}:\\ \;\;\;\;\sqrt{u1 \cdot \left(1 + u1\right)} \cdot \cos \left(6.28318530718 \cdot u2\right)\\ \end{array} \end{array} \]
    (FPCore (cosTheta_i u1 u2)
     :precision binary32
     (if (<= (* 6.28318530718 u2) 0.0006000000284984708)
       (sqrt (/ u1 (- 1.0 u1)))
       (* (sqrt (* u1 (+ 1.0 u1))) (cos (* 6.28318530718 u2)))))
    float code(float cosTheta_i, float u1, float u2) {
    	float tmp;
    	if ((6.28318530718f * u2) <= 0.0006000000284984708f) {
    		tmp = sqrtf((u1 / (1.0f - u1)));
    	} else {
    		tmp = sqrtf((u1 * (1.0f + u1))) * cosf((6.28318530718f * u2));
    	}
    	return tmp;
    }
    
    real(4) function code(costheta_i, u1, u2)
        real(4), intent (in) :: costheta_i
        real(4), intent (in) :: u1
        real(4), intent (in) :: u2
        real(4) :: tmp
        if ((6.28318530718e0 * u2) <= 0.0006000000284984708e0) then
            tmp = sqrt((u1 / (1.0e0 - u1)))
        else
            tmp = sqrt((u1 * (1.0e0 + u1))) * cos((6.28318530718e0 * u2))
        end if
        code = tmp
    end function
    
    function code(cosTheta_i, u1, u2)
    	tmp = Float32(0.0)
    	if (Float32(Float32(6.28318530718) * u2) <= Float32(0.0006000000284984708))
    		tmp = sqrt(Float32(u1 / Float32(Float32(1.0) - u1)));
    	else
    		tmp = Float32(sqrt(Float32(u1 * Float32(Float32(1.0) + u1))) * cos(Float32(Float32(6.28318530718) * u2)));
    	end
    	return tmp
    end
    
    function tmp_2 = code(cosTheta_i, u1, u2)
    	tmp = single(0.0);
    	if ((single(6.28318530718) * u2) <= single(0.0006000000284984708))
    		tmp = sqrt((u1 / (single(1.0) - u1)));
    	else
    		tmp = sqrt((u1 * (single(1.0) + u1))) * cos((single(6.28318530718) * u2));
    	end
    	tmp_2 = tmp;
    end
    
    \begin{array}{l}
    
    \\
    \begin{array}{l}
    \mathbf{if}\;6.28318530718 \cdot u2 \leq 0.0006000000284984708:\\
    \;\;\;\;\sqrt{\frac{u1}{1 - u1}}\\
    
    \mathbf{else}:\\
    \;\;\;\;\sqrt{u1 \cdot \left(1 + u1\right)} \cdot \cos \left(6.28318530718 \cdot u2\right)\\
    
    
    \end{array}
    \end{array}
    
    Derivation
    1. Split input into 2 regimes
    2. if (*.f32 #s(literal 314159265359/50000000000 binary32) u2) < 6.00000028e-4

      1. Initial program 99.6%

        \[\sqrt{\frac{u1}{1 - u1}} \cdot \cos \left(6.28318530718 \cdot u2\right) \]
      2. Add Preprocessing
      3. Taylor expanded in u2 around 0

        \[\leadsto \color{blue}{\sqrt{\frac{u1}{1 - u1}}} \]
      4. Step-by-step derivation
        1. lower-sqrt.f32N/A

          \[\leadsto \color{blue}{\sqrt{\frac{u1}{1 - u1}}} \]
        2. lower-/.f32N/A

          \[\leadsto \sqrt{\color{blue}{\frac{u1}{1 - u1}}} \]
        3. lower--.f3299.5

          \[\leadsto \sqrt{\frac{u1}{\color{blue}{1 - u1}}} \]
      5. Applied rewrites99.5%

        \[\leadsto \color{blue}{\sqrt{\frac{u1}{1 - u1}}} \]

      if 6.00000028e-4 < (*.f32 #s(literal 314159265359/50000000000 binary32) u2)

      1. Initial program 98.4%

        \[\sqrt{\frac{u1}{1 - u1}} \cdot \cos \left(6.28318530718 \cdot u2\right) \]
      2. Add Preprocessing
      3. Applied rewrites98.4%

        \[\leadsto \sqrt{\color{blue}{u1 \cdot \frac{1}{1 - u1}}} \cdot \cos \left(6.28318530718 \cdot u2\right) \]
      4. Taylor expanded in u1 around 0

        \[\leadsto \sqrt{u1 \cdot \color{blue}{\left(1 + u1\right)}} \cdot \cos \left(\frac{314159265359}{50000000000} \cdot u2\right) \]
      5. Step-by-step derivation
        1. lower-+.f3289.5

          \[\leadsto \sqrt{u1 \cdot \color{blue}{\left(1 + u1\right)}} \cdot \cos \left(6.28318530718 \cdot u2\right) \]
      6. Applied rewrites89.5%

        \[\leadsto \sqrt{u1 \cdot \color{blue}{\left(1 + u1\right)}} \cdot \cos \left(6.28318530718 \cdot u2\right) \]
    3. Recombined 2 regimes into one program.
    4. Add Preprocessing

    Alternative 5: 80.2% accurate, 5.4× speedup?

    \[\begin{array}{l} \\ \sqrt{\frac{u1}{1 - u1}} \end{array} \]
    (FPCore (cosTheta_i u1 u2) :precision binary32 (sqrt (/ u1 (- 1.0 u1))))
    float code(float cosTheta_i, float u1, float u2) {
    	return sqrtf((u1 / (1.0f - u1)));
    }
    
    real(4) function code(costheta_i, u1, u2)
        real(4), intent (in) :: costheta_i
        real(4), intent (in) :: u1
        real(4), intent (in) :: u2
        code = sqrt((u1 / (1.0e0 - u1)))
    end function
    
    function code(cosTheta_i, u1, u2)
    	return sqrt(Float32(u1 / Float32(Float32(1.0) - u1)))
    end
    
    function tmp = code(cosTheta_i, u1, u2)
    	tmp = sqrt((u1 / (single(1.0) - u1)));
    end
    
    \begin{array}{l}
    
    \\
    \sqrt{\frac{u1}{1 - u1}}
    \end{array}
    
    Derivation
    1. Initial program 99.1%

      \[\sqrt{\frac{u1}{1 - u1}} \cdot \cos \left(6.28318530718 \cdot u2\right) \]
    2. Add Preprocessing
    3. Taylor expanded in u2 around 0

      \[\leadsto \color{blue}{\sqrt{\frac{u1}{1 - u1}}} \]
    4. Step-by-step derivation
      1. lower-sqrt.f32N/A

        \[\leadsto \color{blue}{\sqrt{\frac{u1}{1 - u1}}} \]
      2. lower-/.f32N/A

        \[\leadsto \sqrt{\color{blue}{\frac{u1}{1 - u1}}} \]
      3. lower--.f3281.6

        \[\leadsto \sqrt{\frac{u1}{\color{blue}{1 - u1}}} \]
    5. Applied rewrites81.6%

      \[\leadsto \color{blue}{\sqrt{\frac{u1}{1 - u1}}} \]
    6. Add Preprocessing

    Alternative 6: 63.2% accurate, 7.9× speedup?

    \[\begin{array}{l} \\ \sqrt{\mathsf{fma}\left(u1, u1, u1\right)} \end{array} \]
    (FPCore (cosTheta_i u1 u2) :precision binary32 (sqrt (fma u1 u1 u1)))
    float code(float cosTheta_i, float u1, float u2) {
    	return sqrtf(fmaf(u1, u1, u1));
    }
    
    function code(cosTheta_i, u1, u2)
    	return sqrt(fma(u1, u1, u1))
    end
    
    \begin{array}{l}
    
    \\
    \sqrt{\mathsf{fma}\left(u1, u1, u1\right)}
    \end{array}
    
    Derivation
    1. Initial program 99.1%

      \[\sqrt{\frac{u1}{1 - u1}} \cdot \cos \left(6.28318530718 \cdot u2\right) \]
    2. Add Preprocessing
    3. Taylor expanded in u2 around 0

      \[\leadsto \color{blue}{\sqrt{\frac{u1}{1 - u1}}} \]
    4. Step-by-step derivation
      1. lower-sqrt.f32N/A

        \[\leadsto \color{blue}{\sqrt{\frac{u1}{1 - u1}}} \]
      2. lower-/.f32N/A

        \[\leadsto \sqrt{\color{blue}{\frac{u1}{1 - u1}}} \]
      3. lower--.f3281.6

        \[\leadsto \sqrt{\frac{u1}{\color{blue}{1 - u1}}} \]
    5. Applied rewrites81.6%

      \[\leadsto \color{blue}{\sqrt{\frac{u1}{1 - u1}}} \]
    6. Taylor expanded in u1 around inf

      \[\leadsto \sqrt{\frac{u1}{-1 \cdot u1}} \]
    7. Step-by-step derivation
      1. Applied rewrites-0.0%

        \[\leadsto \sqrt{\frac{u1}{-u1}} \]
      2. Taylor expanded in u1 around 0

        \[\leadsto \sqrt{u1 \cdot \left(1 + u1\right)} \]
      3. Step-by-step derivation
        1. Applied rewrites65.5%

          \[\leadsto \sqrt{\mathsf{fma}\left(u1, u1, u1\right)} \]
        2. Add Preprocessing

        Alternative 7: 14.5% accurate, 9.0× speedup?

        \[\begin{array}{l} \\ -1 - \frac{-1.5}{u1} \end{array} \]
        (FPCore (cosTheta_i u1 u2) :precision binary32 (- -1.0 (/ -1.5 u1)))
        float code(float cosTheta_i, float u1, float u2) {
        	return -1.0f - (-1.5f / u1);
        }
        
        real(4) function code(costheta_i, u1, u2)
            real(4), intent (in) :: costheta_i
            real(4), intent (in) :: u1
            real(4), intent (in) :: u2
            code = (-1.0e0) - ((-1.5e0) / u1)
        end function
        
        function code(cosTheta_i, u1, u2)
        	return Float32(Float32(-1.0) - Float32(Float32(-1.5) / u1))
        end
        
        function tmp = code(cosTheta_i, u1, u2)
        	tmp = single(-1.0) - (single(-1.5) / u1);
        end
        
        \begin{array}{l}
        
        \\
        -1 - \frac{-1.5}{u1}
        \end{array}
        
        Derivation
        1. Initial program 99.1%

          \[\sqrt{\frac{u1}{1 - u1}} \cdot \cos \left(6.28318530718 \cdot u2\right) \]
        2. Add Preprocessing
        3. Taylor expanded in u2 around 0

          \[\leadsto \color{blue}{\sqrt{\frac{u1}{1 - u1}}} \]
        4. Step-by-step derivation
          1. lower-sqrt.f32N/A

            \[\leadsto \color{blue}{\sqrt{\frac{u1}{1 - u1}}} \]
          2. lower-/.f32N/A

            \[\leadsto \sqrt{\color{blue}{\frac{u1}{1 - u1}}} \]
          3. lower--.f3281.6

            \[\leadsto \sqrt{\frac{u1}{\color{blue}{1 - u1}}} \]
        5. Applied rewrites81.6%

          \[\leadsto \color{blue}{\sqrt{\frac{u1}{1 - u1}}} \]
        6. Applied rewrites73.4%

          \[\leadsto \sqrt{\frac{u1}{\frac{\mathsf{fma}\left(u1, u1, 1\right)}{u1 \cdot u1 - 1} \cdot \left(u1 - 1\right)}} \]
        7. Applied rewrites62.1%

          \[\leadsto \sqrt{\frac{u1}{\frac{\frac{-1}{u1 - 1} \cdot \frac{-1}{u1 - 1} - \frac{u1 \cdot u1}{1 - u1} \cdot \frac{u1 \cdot u1}{1 - u1}}{1 - u1}}} \]
        8. Taylor expanded in u1 around -inf

          \[\leadsto \frac{3}{2} \cdot \frac{1}{u1} + \color{blue}{{\left(\sqrt{-1}\right)}^{2}} \]
        9. Step-by-step derivation
          1. Applied rewrites14.2%

            \[\leadsto -1 - \color{blue}{\frac{-1.5}{u1}} \]
          2. Add Preprocessing

          Alternative 8: 4.0% accurate, 135.0× speedup?

          \[\begin{array}{l} \\ -1 \end{array} \]
          (FPCore (cosTheta_i u1 u2) :precision binary32 -1.0)
          float code(float cosTheta_i, float u1, float u2) {
          	return -1.0f;
          }
          
          real(4) function code(costheta_i, u1, u2)
              real(4), intent (in) :: costheta_i
              real(4), intent (in) :: u1
              real(4), intent (in) :: u2
              code = -1.0e0
          end function
          
          function code(cosTheta_i, u1, u2)
          	return Float32(-1.0)
          end
          
          function tmp = code(cosTheta_i, u1, u2)
          	tmp = single(-1.0);
          end
          
          \begin{array}{l}
          
          \\
          -1
          \end{array}
          
          Derivation
          1. Initial program 99.1%

            \[\sqrt{\frac{u1}{1 - u1}} \cdot \cos \left(6.28318530718 \cdot u2\right) \]
          2. Add Preprocessing
          3. Taylor expanded in u2 around 0

            \[\leadsto \color{blue}{\sqrt{\frac{u1}{1 - u1}}} \]
          4. Step-by-step derivation
            1. lower-sqrt.f32N/A

              \[\leadsto \color{blue}{\sqrt{\frac{u1}{1 - u1}}} \]
            2. lower-/.f32N/A

              \[\leadsto \sqrt{\color{blue}{\frac{u1}{1 - u1}}} \]
            3. lower--.f3281.6

              \[\leadsto \sqrt{\frac{u1}{\color{blue}{1 - u1}}} \]
          5. Applied rewrites81.6%

            \[\leadsto \color{blue}{\sqrt{\frac{u1}{1 - u1}}} \]
          6. Applied rewrites73.0%

            \[\leadsto \sqrt{\frac{u1}{\frac{\mathsf{fma}\left(u1, u1, 1\right)}{u1 \cdot u1 - 1} \cdot \left(u1 - 1\right)}} \]
          7. Applied rewrites62.1%

            \[\leadsto \sqrt{\frac{u1}{\frac{\frac{-1}{u1 - 1} \cdot \frac{-1}{u1 - 1} - \frac{u1 \cdot u1}{1 - u1} \cdot \frac{u1 \cdot u1}{1 - u1}}{1 - u1}}} \]
          8. Taylor expanded in u1 around -inf

            \[\leadsto {\left(\sqrt{-1}\right)}^{\color{blue}{2}} \]
          9. Step-by-step derivation
            1. Applied rewrites4.0%

              \[\leadsto -1 \]
            2. Add Preprocessing

            Reproduce

            ?
            herbie shell --seed 2024332 
            (FPCore (cosTheta_i u1 u2)
              :name "Trowbridge-Reitz Sample, near normal, slope_x"
              :precision binary32
              :pre (and (and (and (> cosTheta_i 0.9999) (<= cosTheta_i 1.0)) (and (<= 2.328306437e-10 u1) (<= u1 1.0))) (and (<= 2.328306437e-10 u2) (<= u2 1.0)))
              (* (sqrt (/ u1 (- 1.0 u1))) (cos (* 6.28318530718 u2))))