Beckmann Sample, normalization factor

Percentage Accurate: 97.9% → 99.5%
Time: 18.0s
Alternatives: 13
Speedup: 1.0×

Specification

?
\[\left(0 < cosTheta \land cosTheta < 0.9999\right) \land \left(-1 < c \land c < 1\right)\]
\[\begin{array}{l} \\ \frac{1}{\left(1 + c\right) + \left(\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right) \cdot e^{\left(-cosTheta\right) \cdot cosTheta}} \end{array} \]
(FPCore (cosTheta c)
 :precision binary32
 (/
  1.0
  (+
   (+ 1.0 c)
   (*
    (* (/ 1.0 (sqrt PI)) (/ (sqrt (- (- 1.0 cosTheta) cosTheta)) cosTheta))
    (exp (* (- cosTheta) cosTheta))))))
float code(float cosTheta, float c) {
	return 1.0f / ((1.0f + c) + (((1.0f / sqrtf(((float) M_PI))) * (sqrtf(((1.0f - cosTheta) - cosTheta)) / cosTheta)) * expf((-cosTheta * cosTheta))));
}
function code(cosTheta, c)
	return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32(Float32(Float32(Float32(1.0) / sqrt(Float32(pi))) * Float32(sqrt(Float32(Float32(Float32(1.0) - cosTheta) - cosTheta)) / cosTheta)) * exp(Float32(Float32(-cosTheta) * cosTheta)))))
end
function tmp = code(cosTheta, c)
	tmp = single(1.0) / ((single(1.0) + c) + (((single(1.0) / sqrt(single(pi))) * (sqrt(((single(1.0) - cosTheta) - cosTheta)) / cosTheta)) * exp((-cosTheta * cosTheta))));
end
\begin{array}{l}

\\
\frac{1}{\left(1 + c\right) + \left(\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right) \cdot e^{\left(-cosTheta\right) \cdot cosTheta}}
\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 13 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: 97.9% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{1}{\left(1 + c\right) + \left(\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right) \cdot e^{\left(-cosTheta\right) \cdot cosTheta}} \end{array} \]
(FPCore (cosTheta c)
 :precision binary32
 (/
  1.0
  (+
   (+ 1.0 c)
   (*
    (* (/ 1.0 (sqrt PI)) (/ (sqrt (- (- 1.0 cosTheta) cosTheta)) cosTheta))
    (exp (* (- cosTheta) cosTheta))))))
float code(float cosTheta, float c) {
	return 1.0f / ((1.0f + c) + (((1.0f / sqrtf(((float) M_PI))) * (sqrtf(((1.0f - cosTheta) - cosTheta)) / cosTheta)) * expf((-cosTheta * cosTheta))));
}
function code(cosTheta, c)
	return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32(Float32(Float32(Float32(1.0) / sqrt(Float32(pi))) * Float32(sqrt(Float32(Float32(Float32(1.0) - cosTheta) - cosTheta)) / cosTheta)) * exp(Float32(Float32(-cosTheta) * cosTheta)))))
end
function tmp = code(cosTheta, c)
	tmp = single(1.0) / ((single(1.0) + c) + (((single(1.0) / sqrt(single(pi))) * (sqrt(((single(1.0) - cosTheta) - cosTheta)) / cosTheta)) * exp((-cosTheta * cosTheta))));
end
\begin{array}{l}

\\
\frac{1}{\left(1 + c\right) + \left(\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right) \cdot e^{\left(-cosTheta\right) \cdot cosTheta}}
\end{array}

Alternative 1: 99.5% accurate, 0.2× speedup?

\[\begin{array}{l} \\ \langle \left( \frac{1}{c + \left(1 + \frac{\sqrt{\frac{\mathsf{fma}\left(-2, cosTheta, 1\right)}{\pi}}}{cosTheta \cdot e^{{cosTheta}^{2}}}\right)} \right)_{\text{binary64}} \rangle_{\text{binary32}} \end{array} \]
(FPCore (cosTheta c)
 :precision binary32
 (cast
  (!
   :precision
   binary64
   (/
    1.0
    (+
     c
     (+
      1.0
      (/
       (sqrt (/ (fma -2.0 cosTheta 1.0) PI))
       (* cosTheta (exp (pow cosTheta 2.0))))))))))
float code(float cosTheta, float c) {
	double tmp = 1.0 / (((double) c) + (1.0 + (sqrt((fma(-2.0, cosTheta, 1.0) / ((double) M_PI))) / (((double) cosTheta) * exp(pow(cosTheta, 2.0))))));
	return (float) tmp;
}
function code(cosTheta, c)
	tmp = Float64(1.0 / Float64(Float64(c) + Float64(1.0 + Float64(sqrt(Float64(fma(-2.0, cosTheta, 1.0) / pi)) / Float64(Float64(cosTheta) * exp((cosTheta ^ 2.0)))))))
	return Float32(tmp)
end
\begin{array}{l}

\\
\langle \left( \frac{1}{c + \left(1 + \frac{\sqrt{\frac{\mathsf{fma}\left(-2, cosTheta, 1\right)}{\pi}}}{cosTheta \cdot e^{{cosTheta}^{2}}}\right)} \right)_{\text{binary64}} \rangle_{\text{binary32}}
\end{array}
Derivation
  1. Initial program 99.5%

    \[\langle \frac{1}{\left(1 + c\right) + \frac{\frac{\sqrt{1 + cosTheta \cdot -2}}{\sqrt{\pi} \cdot cosTheta}}{{\left(e^{cosTheta}\right)}^{cosTheta}}} \rangle_{\text{binary64}} \]
  2. Step-by-step derivation
    1. div-inv99.5%

      \[\leadsto \langle \color{blue}{1} \cdot \frac{1}{\left(1 + c\right) + \frac{\frac{\sqrt{1 + cosTheta \cdot -2}}{\sqrt{\pi} \cdot cosTheta}}{{\left(e^{cosTheta}\right)}^{cosTheta}}} \rangle_{\text{binary64}} \]
    2. associate-+l+99.5%

      \[\leadsto \langle 1 \cdot \frac{1}{1 + \left(c + \frac{\frac{\sqrt{1 + cosTheta \cdot -2}}{\sqrt{\pi} \cdot cosTheta}}{{\left(e^{cosTheta}\right)}^{cosTheta}}\right)} \rangle_{\text{binary64}} \]
    3. associate-/r*99.5%

      \[\leadsto \langle 1 \cdot \frac{1}{1 + \left(c + \frac{\frac{\frac{\sqrt{1 + cosTheta \cdot -2}}{\sqrt{\pi}}}{cosTheta}}{{\left(e^{cosTheta}\right)}^{cosTheta}}\right)} \rangle_{\text{binary64}} \]
    4. associate-/l/99.5%

      \[\leadsto \langle 1 \cdot \frac{1}{1 + \left(c + \frac{\frac{\sqrt{1 + cosTheta \cdot -2}}{\sqrt{\pi}}}{{\left(e^{cosTheta}\right)}^{cosTheta} \cdot cosTheta}\right)} \rangle_{\text{binary64}} \]
  3. Applied egg-rr99.5%

    \[\leadsto \langle \color{blue}{1} \cdot \frac{1}{1 + \left(c + \frac{\sqrt{\frac{\mathsf{fma}\left(cosTheta, -2, 1\right)}{\pi}}}{e^{{cosTheta}^{2}} \cdot cosTheta}\right)} \rangle_{\text{binary64}} \]
  4. Step-by-step derivation
    1. *-lft-identity99.5%

      \[\leadsto \langle \frac{\color{blue}{1}}{1 + \left(c + \frac{\sqrt{\frac{\mathsf{fma}\left(cosTheta, -2, 1\right)}{\pi}}}{e^{{cosTheta}^{2}} \cdot cosTheta}\right)} \rangle_{\text{binary64}} \]
    2. +-commutative99.5%

      \[\leadsto \langle \frac{1}{\left(c + \frac{\sqrt{\frac{\mathsf{fma}\left(cosTheta, -2, 1\right)}{\pi}}}{e^{{cosTheta}^{2}} \cdot cosTheta}\right) + 1} \rangle_{\text{binary64}} \]
    3. associate-+l+99.5%

      \[\leadsto \langle \frac{1}{c + \left(\frac{\sqrt{\frac{\mathsf{fma}\left(cosTheta, -2, 1\right)}{\pi}}}{e^{{cosTheta}^{2}} \cdot cosTheta} + 1\right)} \rangle_{\text{binary64}} \]
    4. fma-udef99.5%

      \[\leadsto \langle \frac{1}{c + \left(\frac{\sqrt{\frac{cosTheta \cdot -2 + 1}{\pi}}}{e^{{cosTheta}^{2}} \cdot cosTheta} + 1\right)} \rangle_{\text{binary64}} \]
    5. *-commutative99.5%

      \[\leadsto \langle \frac{1}{c + \left(\frac{\sqrt{\frac{-2 \cdot cosTheta + 1}{\pi}}}{e^{{cosTheta}^{2}} \cdot cosTheta} + 1\right)} \rangle_{\text{binary64}} \]
    6. fma-def99.5%

      \[\leadsto \langle \frac{1}{c + \left(\frac{\sqrt{\frac{\mathsf{fma}\left(-2, cosTheta, 1\right)}{\pi}}}{e^{{cosTheta}^{2}} \cdot cosTheta} + 1\right)} \rangle_{\text{binary64}} \]
    7. *-commutative99.5%

      \[\leadsto \langle \frac{1}{c + \left(\frac{\sqrt{\frac{\mathsf{fma}\left(-2, cosTheta, 1\right)}{\pi}}}{cosTheta \cdot e^{{cosTheta}^{2}}} + 1\right)} \rangle_{\text{binary64}} \]
  5. Simplified99.5%

    \[\leadsto \langle \frac{\color{blue}{1}}{c + \left(\frac{\sqrt{\frac{\mathsf{fma}\left(-2, cosTheta, 1\right)}{\pi}}}{cosTheta \cdot e^{{cosTheta}^{2}}} + 1\right)} \rangle_{\text{binary64}} \]
  6. Final simplification99.5%

    \[\leadsto \langle \frac{1}{c + \left(1 + \frac{\sqrt{\frac{\mathsf{fma}\left(-2, cosTheta, 1\right)}{\pi}}}{cosTheta \cdot e^{{cosTheta}^{2}}}\right)} \rangle_{\text{binary64}} \]

Alternative 2: 99.0% accurate, 0.4× speedup?

\[\begin{array}{l} \\ \frac{1}{\left(1 + c\right) + \langle \left( \left(\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{1 - cosTheta \cdot 2}}{cosTheta}\right) \right)_{\text{binary64}} \rangle_{\text{binary32}} \cdot e^{-cosTheta \cdot cosTheta}} \end{array} \]
(FPCore (cosTheta c)
 :precision binary32
 (/
  1.0
  (+
   (+ 1.0 c)
   (*
    (cast
     (!
      :precision
      binary64
      (* (/ 1.0 (sqrt PI)) (/ (sqrt (- 1.0 (* cosTheta 2.0))) cosTheta))))
    (exp (- (* cosTheta cosTheta)))))))
float code(float cosTheta, float c) {
	double tmp = (1.0 / sqrt(((double) M_PI))) * (sqrt((1.0 - (((double) cosTheta) * 2.0))) / ((double) cosTheta));
	return 1.0f / ((1.0f + c) + (((float) tmp) * expf(-(cosTheta * cosTheta))));
}
function code(cosTheta, c)
	tmp = Float64(Float64(1.0 / sqrt(pi)) * Float64(sqrt(Float64(1.0 - Float64(Float64(cosTheta) * 2.0))) / Float64(cosTheta)))
	return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32(Float32(tmp) * exp(Float32(-Float32(cosTheta * cosTheta))))))
end
function tmp_2 = code(cosTheta, c)
	tmp = (1.0 / sqrt(pi)) * (sqrt((1.0 - (double(cosTheta) * 2.0))) / double(cosTheta));
	tmp_2 = single(1.0) / ((single(1.0) + c) + single((single(tmp) * double(exp(-(cosTheta * cosTheta))))));
end
\begin{array}{l}

\\
\frac{1}{\left(1 + c\right) + \langle \left( \left(\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{1 - cosTheta \cdot 2}}{cosTheta}\right) \right)_{\text{binary64}} \rangle_{\text{binary32}} \cdot e^{-cosTheta \cdot cosTheta}}
\end{array}
Derivation
  1. Initial program 97.9%

    \[\frac{1}{\left(1 + c\right) + \left(\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right) \cdot e^{\left(-cosTheta\right) \cdot cosTheta}} \]
  2. Step-by-step derivation
    1. rewrite-binary32/binary6498.9%

      \[\leadsto \color{blue}{\frac{1}{\left(1 + c\right) + \langle \left(\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right) \rangle_{\text{binary64}} \cdot e^{\left(-cosTheta\right) \cdot cosTheta}}} \]
  3. Applied rewrite-once98.9%

    \[\leadsto \frac{1}{\left(1 + c\right) + \color{blue}{\langle \color{blue}{\left(\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right)} \rangle_{\text{binary64}}} \cdot e^{\left(-cosTheta\right) \cdot cosTheta}} \]
  4. Step-by-step derivation
    1. associate--r+98.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \langle \left(\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{1 - \left(cosTheta + cosTheta\right)}}{cosTheta}\right) \rangle_{\text{binary64}} \cdot e^{\left(-cosTheta\right) \cdot cosTheta}} \]
    2. count-298.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \langle \left(\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{1 - 2 \cdot cosTheta}}{cosTheta}\right) \rangle_{\text{binary64}} \cdot e^{\left(-cosTheta\right) \cdot cosTheta}} \]
  5. Simplified98.9%

    \[\leadsto \frac{1}{\left(1 + c\right) + \color{blue}{\langle \color{blue}{\left(\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{1 - 2 \cdot cosTheta}}{cosTheta}\right)} \rangle_{\text{binary64}}} \cdot e^{\left(-cosTheta\right) \cdot cosTheta}} \]
  6. Final simplification98.9%

    \[\leadsto \frac{1}{\left(1 + c\right) + \langle \left(\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{1 - cosTheta \cdot 2}}{cosTheta}\right) \rangle_{\text{binary64}} \cdot e^{-cosTheta \cdot cosTheta}} \]

Alternative 3: 98.9% accurate, 0.5× speedup?

\[\begin{array}{l} \\ \frac{1}{\left(1 + c\right) + \frac{\frac{\sqrt{1 + -2 \cdot cosTheta}}{\langle \left( cosTheta \cdot \sqrt{\pi} \right)_{\text{binary64}} \rangle_{\text{binary32}}}}{{\left(e^{cosTheta}\right)}^{cosTheta}}} \end{array} \]
(FPCore (cosTheta c)
 :precision binary32
 (/
  1.0
  (+
   (+ 1.0 c)
   (/
    (/
     (sqrt (+ 1.0 (* -2.0 cosTheta)))
     (cast (! :precision binary64 (* cosTheta (sqrt PI)))))
    (pow (exp cosTheta) cosTheta)))))
float code(float cosTheta, float c) {
	double tmp = ((double) cosTheta) * sqrt(((double) M_PI));
	return 1.0f / ((1.0f + c) + ((sqrtf((1.0f + (-2.0f * cosTheta))) / ((float) tmp)) / powf(expf(cosTheta), cosTheta)));
}
function code(cosTheta, c)
	tmp = Float64(Float64(cosTheta) * sqrt(pi))
	return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32(Float32(sqrt(Float32(Float32(1.0) + Float32(Float32(-2.0) * cosTheta))) / Float32(tmp)) / (exp(cosTheta) ^ cosTheta))))
end
function tmp_2 = code(cosTheta, c)
	tmp = double(cosTheta) * sqrt(pi);
	tmp_2 = single(1.0) / ((single(1.0) + c) + (single((double(sqrt((single(1.0) + (single(-2.0) * cosTheta)))) / single(tmp))) / (exp(cosTheta) ^ cosTheta)));
end
\begin{array}{l}

\\
\frac{1}{\left(1 + c\right) + \frac{\frac{\sqrt{1 + -2 \cdot cosTheta}}{\langle \left( cosTheta \cdot \sqrt{\pi} \right)_{\text{binary64}} \rangle_{\text{binary32}}}}{{\left(e^{cosTheta}\right)}^{cosTheta}}}
\end{array}
Derivation
  1. Initial program 97.9%

    \[\frac{1}{\left(1 + c\right) + \left(\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right) \cdot e^{\left(-cosTheta\right) \cdot cosTheta}} \]
  2. Step-by-step derivation
    1. *-commutative97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \color{blue}{\left(\frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta} \cdot \frac{1}{\sqrt{\pi}}\right)} \cdot e^{\left(-cosTheta\right) \cdot cosTheta}} \]
    2. associate-*l*97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \color{blue}{\frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta} \cdot \left(\frac{1}{\sqrt{\pi}} \cdot e^{\left(-cosTheta\right) \cdot cosTheta}\right)}} \]
    3. /-rgt-identity97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta} \cdot \left(\color{blue}{\frac{\frac{1}{\sqrt{\pi}}}{1}} \cdot e^{\left(-cosTheta\right) \cdot cosTheta}\right)} \]
    4. associate-/r/97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta} \cdot \color{blue}{\frac{\frac{1}{\sqrt{\pi}}}{\frac{1}{e^{\left(-cosTheta\right) \cdot cosTheta}}}}} \]
    5. exp-neg97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta} \cdot \frac{\frac{1}{\sqrt{\pi}}}{\color{blue}{e^{-\left(-cosTheta\right) \cdot cosTheta}}}} \]
    6. distribute-lft-neg-out97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta} \cdot \frac{\frac{1}{\sqrt{\pi}}}{e^{\color{blue}{\left(-\left(-cosTheta\right)\right) \cdot cosTheta}}}} \]
    7. remove-double-neg97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta} \cdot \frac{\frac{1}{\sqrt{\pi}}}{e^{\color{blue}{cosTheta} \cdot cosTheta}}} \]
    8. associate-*r/97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \color{blue}{\frac{\frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta} \cdot \frac{1}{\sqrt{\pi}}}{e^{cosTheta \cdot cosTheta}}}} \]
    9. *-commutative97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \frac{\color{blue}{\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}}}{e^{cosTheta \cdot cosTheta}}} \]
  3. Simplified98.5%

    \[\leadsto \color{blue}{\frac{1}{\left(1 + c\right) + \frac{\frac{\sqrt{1 + cosTheta \cdot -2}}{\sqrt{\pi} \cdot cosTheta}}{{\left(e^{cosTheta}\right)}^{cosTheta}}}} \]
  4. Step-by-step derivation
    1. rewrite-binary32/binary6498.9%

      \[\leadsto \color{blue}{\frac{1}{\left(1 + c\right) + \frac{\frac{\sqrt{1 + cosTheta \cdot -2}}{\langle \sqrt{\pi} \cdot cosTheta \rangle_{\text{binary64}}}}{{\left(e^{cosTheta}\right)}^{cosTheta}}}} \]
  5. Applied rewrite-once98.9%

    \[\leadsto \frac{1}{\left(1 + c\right) + \frac{\frac{\sqrt{1 + cosTheta \cdot -2}}{\color{blue}{\langle \color{blue}{\sqrt{\pi} \cdot cosTheta} \rangle_{\text{binary64}}}}}{{\left(e^{cosTheta}\right)}^{cosTheta}}} \]
  6. Final simplification98.9%

    \[\leadsto \frac{1}{\left(1 + c\right) + \frac{\frac{\sqrt{1 + -2 \cdot cosTheta}}{\langle cosTheta \cdot \sqrt{\pi} \rangle_{\text{binary64}}}}{{\left(e^{cosTheta}\right)}^{cosTheta}}} \]

Alternative 4: 98.5% accurate, 0.8× speedup?

\[\begin{array}{l} \\ \frac{1}{\left(1 + c\right) + \frac{\frac{\sqrt{1 + -2 \cdot cosTheta}}{cosTheta \cdot \sqrt{\pi}}}{{\left(e^{cosTheta}\right)}^{cosTheta}}} \end{array} \]
(FPCore (cosTheta c)
 :precision binary32
 (/
  1.0
  (+
   (+ 1.0 c)
   (/
    (/ (sqrt (+ 1.0 (* -2.0 cosTheta))) (* cosTheta (sqrt PI)))
    (pow (exp cosTheta) cosTheta)))))
float code(float cosTheta, float c) {
	return 1.0f / ((1.0f + c) + ((sqrtf((1.0f + (-2.0f * cosTheta))) / (cosTheta * sqrtf(((float) M_PI)))) / powf(expf(cosTheta), cosTheta)));
}
function code(cosTheta, c)
	return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32(Float32(sqrt(Float32(Float32(1.0) + Float32(Float32(-2.0) * cosTheta))) / Float32(cosTheta * sqrt(Float32(pi)))) / (exp(cosTheta) ^ cosTheta))))
end
function tmp = code(cosTheta, c)
	tmp = single(1.0) / ((single(1.0) + c) + ((sqrt((single(1.0) + (single(-2.0) * cosTheta))) / (cosTheta * sqrt(single(pi)))) / (exp(cosTheta) ^ cosTheta)));
end
\begin{array}{l}

\\
\frac{1}{\left(1 + c\right) + \frac{\frac{\sqrt{1 + -2 \cdot cosTheta}}{cosTheta \cdot \sqrt{\pi}}}{{\left(e^{cosTheta}\right)}^{cosTheta}}}
\end{array}
Derivation
  1. Initial program 97.9%

    \[\frac{1}{\left(1 + c\right) + \left(\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right) \cdot e^{\left(-cosTheta\right) \cdot cosTheta}} \]
  2. Step-by-step derivation
    1. *-commutative97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \color{blue}{\left(\frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta} \cdot \frac{1}{\sqrt{\pi}}\right)} \cdot e^{\left(-cosTheta\right) \cdot cosTheta}} \]
    2. associate-*l*97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \color{blue}{\frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta} \cdot \left(\frac{1}{\sqrt{\pi}} \cdot e^{\left(-cosTheta\right) \cdot cosTheta}\right)}} \]
    3. /-rgt-identity97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta} \cdot \left(\color{blue}{\frac{\frac{1}{\sqrt{\pi}}}{1}} \cdot e^{\left(-cosTheta\right) \cdot cosTheta}\right)} \]
    4. associate-/r/97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta} \cdot \color{blue}{\frac{\frac{1}{\sqrt{\pi}}}{\frac{1}{e^{\left(-cosTheta\right) \cdot cosTheta}}}}} \]
    5. exp-neg97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta} \cdot \frac{\frac{1}{\sqrt{\pi}}}{\color{blue}{e^{-\left(-cosTheta\right) \cdot cosTheta}}}} \]
    6. distribute-lft-neg-out97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta} \cdot \frac{\frac{1}{\sqrt{\pi}}}{e^{\color{blue}{\left(-\left(-cosTheta\right)\right) \cdot cosTheta}}}} \]
    7. remove-double-neg97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta} \cdot \frac{\frac{1}{\sqrt{\pi}}}{e^{\color{blue}{cosTheta} \cdot cosTheta}}} \]
    8. associate-*r/97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \color{blue}{\frac{\frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta} \cdot \frac{1}{\sqrt{\pi}}}{e^{cosTheta \cdot cosTheta}}}} \]
    9. *-commutative97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \frac{\color{blue}{\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}}}{e^{cosTheta \cdot cosTheta}}} \]
  3. Simplified98.5%

    \[\leadsto \color{blue}{\frac{1}{\left(1 + c\right) + \frac{\frac{\sqrt{1 + cosTheta \cdot -2}}{\sqrt{\pi} \cdot cosTheta}}{{\left(e^{cosTheta}\right)}^{cosTheta}}}} \]
  4. Final simplification98.5%

    \[\leadsto \frac{1}{\left(1 + c\right) + \frac{\frac{\sqrt{1 + -2 \cdot cosTheta}}{cosTheta \cdot \sqrt{\pi}}}{{\left(e^{cosTheta}\right)}^{cosTheta}}} \]

Alternative 5: 97.9% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{1}{\left(1 + c\right) + e^{-cosTheta \cdot cosTheta} \cdot \left({\pi}^{-0.5} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right)} \end{array} \]
(FPCore (cosTheta c)
 :precision binary32
 (/
  1.0
  (+
   (+ 1.0 c)
   (*
    (exp (- (* cosTheta cosTheta)))
    (* (pow PI -0.5) (/ (sqrt (- (- 1.0 cosTheta) cosTheta)) cosTheta))))))
float code(float cosTheta, float c) {
	return 1.0f / ((1.0f + c) + (expf(-(cosTheta * cosTheta)) * (powf(((float) M_PI), -0.5f) * (sqrtf(((1.0f - cosTheta) - cosTheta)) / cosTheta))));
}
function code(cosTheta, c)
	return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32(exp(Float32(-Float32(cosTheta * cosTheta))) * Float32((Float32(pi) ^ Float32(-0.5)) * Float32(sqrt(Float32(Float32(Float32(1.0) - cosTheta) - cosTheta)) / cosTheta)))))
end
function tmp = code(cosTheta, c)
	tmp = single(1.0) / ((single(1.0) + c) + (exp(-(cosTheta * cosTheta)) * ((single(pi) ^ single(-0.5)) * (sqrt(((single(1.0) - cosTheta) - cosTheta)) / cosTheta))));
end
\begin{array}{l}

\\
\frac{1}{\left(1 + c\right) + e^{-cosTheta \cdot cosTheta} \cdot \left({\pi}^{-0.5} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right)}
\end{array}
Derivation
  1. Initial program 97.9%

    \[\frac{1}{\left(1 + c\right) + \left(\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right) \cdot e^{\left(-cosTheta\right) \cdot cosTheta}} \]
  2. Step-by-step derivation
    1. div-inv96.5%

      \[\leadsto \frac{1}{\left(1 + c\right) + \color{blue}{\left(1 \cdot \frac{1}{\sqrt{\pi}}\right)} \cdot \left(\left(-1.5 \cdot cosTheta + \left(\left(cosTheta \cdot cosTheta\right) \cdot 0.5 + \frac{1}{cosTheta}\right)\right) - 1\right)} \]
    2. pow1/296.5%

      \[\leadsto \frac{1}{\left(1 + c\right) + \left(1 \cdot \frac{1}{\color{blue}{{\pi}^{0.5}}}\right) \cdot \left(\left(-1.5 \cdot cosTheta + \left(\left(cosTheta \cdot cosTheta\right) \cdot 0.5 + \frac{1}{cosTheta}\right)\right) - 1\right)} \]
    3. pow-flip96.5%

      \[\leadsto \frac{1}{\left(1 + c\right) + \left(1 \cdot \color{blue}{{\pi}^{\left(-0.5\right)}}\right) \cdot \left(\left(-1.5 \cdot cosTheta + \left(\left(cosTheta \cdot cosTheta\right) \cdot 0.5 + \frac{1}{cosTheta}\right)\right) - 1\right)} \]
    4. metadata-eval96.5%

      \[\leadsto \frac{1}{\left(1 + c\right) + \left(1 \cdot {\pi}^{\color{blue}{-0.5}}\right) \cdot \left(\left(-1.5 \cdot cosTheta + \left(\left(cosTheta \cdot cosTheta\right) \cdot 0.5 + \frac{1}{cosTheta}\right)\right) - 1\right)} \]
  3. Applied egg-rr97.9%

    \[\leadsto \frac{1}{\left(1 + c\right) + \left(\color{blue}{\left(1 \cdot {\pi}^{-0.5}\right)} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right) \cdot e^{\left(-cosTheta\right) \cdot cosTheta}} \]
  4. Step-by-step derivation
    1. *-lft-identity96.5%

      \[\leadsto \frac{1}{\left(1 + c\right) + \color{blue}{{\pi}^{-0.5}} \cdot \left(\left(-1.5 \cdot cosTheta + \left(\left(cosTheta \cdot cosTheta\right) \cdot 0.5 + \frac{1}{cosTheta}\right)\right) - 1\right)} \]
  5. Simplified97.9%

    \[\leadsto \frac{1}{\left(1 + c\right) + \left(\color{blue}{{\pi}^{-0.5}} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right) \cdot e^{\left(-cosTheta\right) \cdot cosTheta}} \]
  6. Final simplification97.9%

    \[\leadsto \frac{1}{\left(1 + c\right) + e^{-cosTheta \cdot cosTheta} \cdot \left({\pi}^{-0.5} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right)} \]

Alternative 6: 97.6% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \frac{1}{1 + \frac{\sqrt{\frac{\mathsf{fma}\left(cosTheta, -2, 1\right)}{\pi}}}{cosTheta \cdot e^{cosTheta \cdot cosTheta}}} \end{array} \]
(FPCore (cosTheta c)
 :precision binary32
 (/
  1.0
  (+
   1.0
   (/
    (sqrt (/ (fma cosTheta -2.0 1.0) PI))
    (* cosTheta (exp (* cosTheta cosTheta)))))))
float code(float cosTheta, float c) {
	return 1.0f / (1.0f + (sqrtf((fmaf(cosTheta, -2.0f, 1.0f) / ((float) M_PI))) / (cosTheta * expf((cosTheta * cosTheta)))));
}
function code(cosTheta, c)
	return Float32(Float32(1.0) / Float32(Float32(1.0) + Float32(sqrt(Float32(fma(cosTheta, Float32(-2.0), Float32(1.0)) / Float32(pi))) / Float32(cosTheta * exp(Float32(cosTheta * cosTheta))))))
end
\begin{array}{l}

\\
\frac{1}{1 + \frac{\sqrt{\frac{\mathsf{fma}\left(cosTheta, -2, 1\right)}{\pi}}}{cosTheta \cdot e^{cosTheta \cdot cosTheta}}}
\end{array}
Derivation
  1. Initial program 97.9%

    \[\frac{1}{\left(1 + c\right) + \left(\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right) \cdot e^{\left(-cosTheta\right) \cdot cosTheta}} \]
  2. Taylor expanded in c around 0 97.8%

    \[\leadsto \color{blue}{\frac{1}{1 + \frac{e^{-1 \cdot {cosTheta}^{2}}}{cosTheta} \cdot \sqrt{\frac{1 - 2 \cdot cosTheta}{\pi}}}} \]
  3. Step-by-step derivation
    1. mul-1-neg97.8%

      \[\leadsto \frac{1}{1 + \frac{e^{\color{blue}{-{cosTheta}^{2}}}}{cosTheta} \cdot \sqrt{\frac{1 - 2 \cdot cosTheta}{\pi}}} \]
    2. exp-neg97.8%

      \[\leadsto \frac{1}{1 + \frac{\color{blue}{\frac{1}{e^{{cosTheta}^{2}}}}}{cosTheta} \cdot \sqrt{\frac{1 - 2 \cdot cosTheta}{\pi}}} \]
    3. unpow297.8%

      \[\leadsto \frac{1}{1 + \frac{\frac{1}{e^{\color{blue}{cosTheta \cdot cosTheta}}}}{cosTheta} \cdot \sqrt{\frac{1 - 2 \cdot cosTheta}{\pi}}} \]
    4. exp-prod97.8%

      \[\leadsto \frac{1}{1 + \frac{\frac{1}{\color{blue}{{\left(e^{cosTheta}\right)}^{cosTheta}}}}{cosTheta} \cdot \sqrt{\frac{1 - 2 \cdot cosTheta}{\pi}}} \]
    5. associate-/r*97.8%

      \[\leadsto \frac{1}{1 + \color{blue}{\frac{1}{{\left(e^{cosTheta}\right)}^{cosTheta} \cdot cosTheta}} \cdot \sqrt{\frac{1 - 2 \cdot cosTheta}{\pi}}} \]
    6. exp-prod97.8%

      \[\leadsto \frac{1}{1 + \frac{1}{\color{blue}{e^{cosTheta \cdot cosTheta}} \cdot cosTheta} \cdot \sqrt{\frac{1 - 2 \cdot cosTheta}{\pi}}} \]
    7. unpow297.8%

      \[\leadsto \frac{1}{1 + \frac{1}{e^{\color{blue}{{cosTheta}^{2}}} \cdot cosTheta} \cdot \sqrt{\frac{1 - 2 \cdot cosTheta}{\pi}}} \]
    8. *-commutative97.8%

      \[\leadsto \frac{1}{1 + \frac{1}{\color{blue}{cosTheta \cdot e^{{cosTheta}^{2}}}} \cdot \sqrt{\frac{1 - 2 \cdot cosTheta}{\pi}}} \]
    9. cancel-sign-sub-inv97.8%

      \[\leadsto \frac{1}{1 + \frac{1}{cosTheta \cdot e^{{cosTheta}^{2}}} \cdot \sqrt{\frac{\color{blue}{1 + \left(-2\right) \cdot cosTheta}}{\pi}}} \]
    10. metadata-eval97.8%

      \[\leadsto \frac{1}{1 + \frac{1}{cosTheta \cdot e^{{cosTheta}^{2}}} \cdot \sqrt{\frac{1 + \color{blue}{-2} \cdot cosTheta}{\pi}}} \]
  4. Simplified97.9%

    \[\leadsto \color{blue}{\frac{1}{1 + \frac{\sqrt{\frac{\mathsf{fma}\left(cosTheta, -2, 1\right)}{\pi}}}{cosTheta \cdot e^{cosTheta \cdot cosTheta}}}} \]
  5. Final simplification97.9%

    \[\leadsto \frac{1}{1 + \frac{\sqrt{\frac{\mathsf{fma}\left(cosTheta, -2, 1\right)}{\pi}}}{cosTheta \cdot e^{cosTheta \cdot cosTheta}}} \]

Alternative 7: 96.9% accurate, 1.3× speedup?

\[\begin{array}{l} \\ \frac{1}{\left(1 + c\right) + {\pi}^{-0.5} \cdot \left(\left(-1 + \mathsf{fma}\left(0.5, cosTheta \cdot cosTheta, \frac{1}{cosTheta}\right)\right) + cosTheta \cdot -1.5\right)} \end{array} \]
(FPCore (cosTheta c)
 :precision binary32
 (/
  1.0
  (+
   (+ 1.0 c)
   (*
    (pow PI -0.5)
    (+
     (+ -1.0 (fma 0.5 (* cosTheta cosTheta) (/ 1.0 cosTheta)))
     (* cosTheta -1.5))))))
float code(float cosTheta, float c) {
	return 1.0f / ((1.0f + c) + (powf(((float) M_PI), -0.5f) * ((-1.0f + fmaf(0.5f, (cosTheta * cosTheta), (1.0f / cosTheta))) + (cosTheta * -1.5f))));
}
function code(cosTheta, c)
	return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32((Float32(pi) ^ Float32(-0.5)) * Float32(Float32(Float32(-1.0) + fma(Float32(0.5), Float32(cosTheta * cosTheta), Float32(Float32(1.0) / cosTheta))) + Float32(cosTheta * Float32(-1.5))))))
end
\begin{array}{l}

\\
\frac{1}{\left(1 + c\right) + {\pi}^{-0.5} \cdot \left(\left(-1 + \mathsf{fma}\left(0.5, cosTheta \cdot cosTheta, \frac{1}{cosTheta}\right)\right) + cosTheta \cdot -1.5\right)}
\end{array}
Derivation
  1. Initial program 97.9%

    \[\frac{1}{\left(1 + c\right) + \left(\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right) \cdot e^{\left(-cosTheta\right) \cdot cosTheta}} \]
  2. Step-by-step derivation
    1. associate-*l*97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \color{blue}{\frac{1}{\sqrt{\pi}} \cdot \left(\frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta} \cdot e^{\left(-cosTheta\right) \cdot cosTheta}\right)}} \]
    2. associate--l-97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \left(\frac{\sqrt{\color{blue}{1 - \left(cosTheta + cosTheta\right)}}}{cosTheta} \cdot e^{\left(-cosTheta\right) \cdot cosTheta}\right)} \]
    3. *-commutative97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \left(\frac{\sqrt{1 - \left(cosTheta + cosTheta\right)}}{cosTheta} \cdot e^{\color{blue}{cosTheta \cdot \left(-cosTheta\right)}}\right)} \]
    4. exp-prod97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \left(\frac{\sqrt{1 - \left(cosTheta + cosTheta\right)}}{cosTheta} \cdot \color{blue}{{\left(e^{cosTheta}\right)}^{\left(-cosTheta\right)}}\right)} \]
  3. Simplified97.9%

    \[\leadsto \color{blue}{\frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \left(\frac{\sqrt{1 - \left(cosTheta + cosTheta\right)}}{cosTheta} \cdot {\left(e^{cosTheta}\right)}^{\left(-cosTheta\right)}\right)}} \]
  4. Taylor expanded in cosTheta around 0 96.5%

    \[\leadsto \frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \color{blue}{\left(\left(-1.5 \cdot cosTheta + \left(0.5 \cdot {cosTheta}^{2} + \frac{1}{cosTheta}\right)\right) - 1\right)}} \]
  5. Step-by-step derivation
    1. associate--l+96.5%

      \[\leadsto \frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \color{blue}{\left(-1.5 \cdot cosTheta + \left(\left(0.5 \cdot {cosTheta}^{2} + \frac{1}{cosTheta}\right) - 1\right)\right)}} \]
    2. distribute-lft-in96.5%

      \[\leadsto \frac{1}{\left(1 + c\right) + \color{blue}{\left(\frac{1}{\sqrt{\pi}} \cdot \left(-1.5 \cdot cosTheta\right) + \frac{1}{\sqrt{\pi}} \cdot \left(\left(0.5 \cdot {cosTheta}^{2} + \frac{1}{cosTheta}\right) - 1\right)\right)}} \]
    3. inv-pow96.5%

      \[\leadsto \frac{1}{\left(1 + c\right) + \left(\color{blue}{{\left(\sqrt{\pi}\right)}^{-1}} \cdot \left(-1.5 \cdot cosTheta\right) + \frac{1}{\sqrt{\pi}} \cdot \left(\left(0.5 \cdot {cosTheta}^{2} + \frac{1}{cosTheta}\right) - 1\right)\right)} \]
    4. sqrt-pow296.5%

      \[\leadsto \frac{1}{\left(1 + c\right) + \left(\color{blue}{{\pi}^{\left(\frac{-1}{2}\right)}} \cdot \left(-1.5 \cdot cosTheta\right) + \frac{1}{\sqrt{\pi}} \cdot \left(\left(0.5 \cdot {cosTheta}^{2} + \frac{1}{cosTheta}\right) - 1\right)\right)} \]
    5. metadata-eval96.5%

      \[\leadsto \frac{1}{\left(1 + c\right) + \left({\pi}^{\color{blue}{-0.5}} \cdot \left(-1.5 \cdot cosTheta\right) + \frac{1}{\sqrt{\pi}} \cdot \left(\left(0.5 \cdot {cosTheta}^{2} + \frac{1}{cosTheta}\right) - 1\right)\right)} \]
    6. *-commutative96.5%

      \[\leadsto \frac{1}{\left(1 + c\right) + \left({\pi}^{-0.5} \cdot \color{blue}{\left(cosTheta \cdot -1.5\right)} + \frac{1}{\sqrt{\pi}} \cdot \left(\left(0.5 \cdot {cosTheta}^{2} + \frac{1}{cosTheta}\right) - 1\right)\right)} \]
    7. inv-pow96.5%

      \[\leadsto \frac{1}{\left(1 + c\right) + \left({\pi}^{-0.5} \cdot \left(cosTheta \cdot -1.5\right) + \color{blue}{{\left(\sqrt{\pi}\right)}^{-1}} \cdot \left(\left(0.5 \cdot {cosTheta}^{2} + \frac{1}{cosTheta}\right) - 1\right)\right)} \]
    8. sqrt-pow296.5%

      \[\leadsto \frac{1}{\left(1 + c\right) + \left({\pi}^{-0.5} \cdot \left(cosTheta \cdot -1.5\right) + \color{blue}{{\pi}^{\left(\frac{-1}{2}\right)}} \cdot \left(\left(0.5 \cdot {cosTheta}^{2} + \frac{1}{cosTheta}\right) - 1\right)\right)} \]
    9. metadata-eval96.5%

      \[\leadsto \frac{1}{\left(1 + c\right) + \left({\pi}^{-0.5} \cdot \left(cosTheta \cdot -1.5\right) + {\pi}^{\color{blue}{-0.5}} \cdot \left(\left(0.5 \cdot {cosTheta}^{2} + \frac{1}{cosTheta}\right) - 1\right)\right)} \]
    10. sub-neg96.5%

      \[\leadsto \frac{1}{\left(1 + c\right) + \left({\pi}^{-0.5} \cdot \left(cosTheta \cdot -1.5\right) + {\pi}^{-0.5} \cdot \color{blue}{\left(\left(0.5 \cdot {cosTheta}^{2} + \frac{1}{cosTheta}\right) + \left(-1\right)\right)}\right)} \]
    11. fma-def96.5%

      \[\leadsto \frac{1}{\left(1 + c\right) + \left({\pi}^{-0.5} \cdot \left(cosTheta \cdot -1.5\right) + {\pi}^{-0.5} \cdot \left(\color{blue}{\mathsf{fma}\left(0.5, {cosTheta}^{2}, \frac{1}{cosTheta}\right)} + \left(-1\right)\right)\right)} \]
    12. unpow296.5%

      \[\leadsto \frac{1}{\left(1 + c\right) + \left({\pi}^{-0.5} \cdot \left(cosTheta \cdot -1.5\right) + {\pi}^{-0.5} \cdot \left(\mathsf{fma}\left(0.5, \color{blue}{cosTheta \cdot cosTheta}, \frac{1}{cosTheta}\right) + \left(-1\right)\right)\right)} \]
    13. metadata-eval96.5%

      \[\leadsto \frac{1}{\left(1 + c\right) + \left({\pi}^{-0.5} \cdot \left(cosTheta \cdot -1.5\right) + {\pi}^{-0.5} \cdot \left(\mathsf{fma}\left(0.5, cosTheta \cdot cosTheta, \frac{1}{cosTheta}\right) + \color{blue}{-1}\right)\right)} \]
  6. Applied egg-rr96.5%

    \[\leadsto \frac{1}{\left(1 + c\right) + \color{blue}{\left({\pi}^{-0.5} \cdot \left(cosTheta \cdot -1.5\right) + {\pi}^{-0.5} \cdot \left(\mathsf{fma}\left(0.5, cosTheta \cdot cosTheta, \frac{1}{cosTheta}\right) + -1\right)\right)}} \]
  7. Step-by-step derivation
    1. distribute-lft-out96.5%

      \[\leadsto \frac{1}{\left(1 + c\right) + \color{blue}{{\pi}^{-0.5} \cdot \left(cosTheta \cdot -1.5 + \left(\mathsf{fma}\left(0.5, cosTheta \cdot cosTheta, \frac{1}{cosTheta}\right) + -1\right)\right)}} \]
    2. +-commutative96.5%

      \[\leadsto \frac{1}{\left(1 + c\right) + {\pi}^{-0.5} \cdot \left(cosTheta \cdot -1.5 + \color{blue}{\left(-1 + \mathsf{fma}\left(0.5, cosTheta \cdot cosTheta, \frac{1}{cosTheta}\right)\right)}\right)} \]
  8. Simplified96.5%

    \[\leadsto \frac{1}{\left(1 + c\right) + \color{blue}{{\pi}^{-0.5} \cdot \left(cosTheta \cdot -1.5 + \left(-1 + \mathsf{fma}\left(0.5, cosTheta \cdot cosTheta, \frac{1}{cosTheta}\right)\right)\right)}} \]
  9. Final simplification96.5%

    \[\leadsto \frac{1}{\left(1 + c\right) + {\pi}^{-0.5} \cdot \left(\left(-1 + \mathsf{fma}\left(0.5, cosTheta \cdot cosTheta, \frac{1}{cosTheta}\right)\right) + cosTheta \cdot -1.5\right)} \]

Alternative 8: 96.9% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \frac{1}{\left(1 + c\right) + {\pi}^{-0.5} \cdot \left(-1 + \left(cosTheta \cdot -1.5 + \left(\frac{1}{cosTheta} + \left(cosTheta \cdot cosTheta\right) \cdot 0.5\right)\right)\right)} \end{array} \]
(FPCore (cosTheta c)
 :precision binary32
 (/
  1.0
  (+
   (+ 1.0 c)
   (*
    (pow PI -0.5)
    (+
     -1.0
     (+
      (* cosTheta -1.5)
      (+ (/ 1.0 cosTheta) (* (* cosTheta cosTheta) 0.5))))))))
float code(float cosTheta, float c) {
	return 1.0f / ((1.0f + c) + (powf(((float) M_PI), -0.5f) * (-1.0f + ((cosTheta * -1.5f) + ((1.0f / cosTheta) + ((cosTheta * cosTheta) * 0.5f))))));
}
function code(cosTheta, c)
	return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32((Float32(pi) ^ Float32(-0.5)) * Float32(Float32(-1.0) + Float32(Float32(cosTheta * Float32(-1.5)) + Float32(Float32(Float32(1.0) / cosTheta) + Float32(Float32(cosTheta * cosTheta) * Float32(0.5))))))))
end
function tmp = code(cosTheta, c)
	tmp = single(1.0) / ((single(1.0) + c) + ((single(pi) ^ single(-0.5)) * (single(-1.0) + ((cosTheta * single(-1.5)) + ((single(1.0) / cosTheta) + ((cosTheta * cosTheta) * single(0.5)))))));
end
\begin{array}{l}

\\
\frac{1}{\left(1 + c\right) + {\pi}^{-0.5} \cdot \left(-1 + \left(cosTheta \cdot -1.5 + \left(\frac{1}{cosTheta} + \left(cosTheta \cdot cosTheta\right) \cdot 0.5\right)\right)\right)}
\end{array}
Derivation
  1. Initial program 97.9%

    \[\frac{1}{\left(1 + c\right) + \left(\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right) \cdot e^{\left(-cosTheta\right) \cdot cosTheta}} \]
  2. Step-by-step derivation
    1. associate-*l*97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \color{blue}{\frac{1}{\sqrt{\pi}} \cdot \left(\frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta} \cdot e^{\left(-cosTheta\right) \cdot cosTheta}\right)}} \]
    2. associate--l-97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \left(\frac{\sqrt{\color{blue}{1 - \left(cosTheta + cosTheta\right)}}}{cosTheta} \cdot e^{\left(-cosTheta\right) \cdot cosTheta}\right)} \]
    3. *-commutative97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \left(\frac{\sqrt{1 - \left(cosTheta + cosTheta\right)}}{cosTheta} \cdot e^{\color{blue}{cosTheta \cdot \left(-cosTheta\right)}}\right)} \]
    4. exp-prod97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \left(\frac{\sqrt{1 - \left(cosTheta + cosTheta\right)}}{cosTheta} \cdot \color{blue}{{\left(e^{cosTheta}\right)}^{\left(-cosTheta\right)}}\right)} \]
  3. Simplified97.9%

    \[\leadsto \color{blue}{\frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \left(\frac{\sqrt{1 - \left(cosTheta + cosTheta\right)}}{cosTheta} \cdot {\left(e^{cosTheta}\right)}^{\left(-cosTheta\right)}\right)}} \]
  4. Taylor expanded in cosTheta around 0 96.5%

    \[\leadsto \frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \color{blue}{\left(\left(-1.5 \cdot cosTheta + \left(0.5 \cdot {cosTheta}^{2} + \frac{1}{cosTheta}\right)\right) - 1\right)}} \]
  5. Step-by-step derivation
    1. add-exp-log_binary3296.5%

      \[\leadsto \color{blue}{\frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \left(\left(-1.5 \cdot cosTheta + \left(e^{\log \left(0.5 \cdot {cosTheta}^{2}\right)} + \frac{1}{cosTheta}\right)\right) - 1\right)}} \]
  6. Applied rewrite-once96.5%

    \[\leadsto \frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \left(\left(-1.5 \cdot cosTheta + \left(\color{blue}{e^{\log \left(0.5 \cdot {cosTheta}^{2}\right)}} + \frac{1}{cosTheta}\right)\right) - 1\right)} \]
  7. Step-by-step derivation
    1. rem-exp-log96.5%

      \[\leadsto \frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \left(\left(-1.5 \cdot cosTheta + \left(\color{blue}{0.5 \cdot {cosTheta}^{2}} + \frac{1}{cosTheta}\right)\right) - 1\right)} \]
    2. *-commutative96.5%

      \[\leadsto \frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \left(\left(-1.5 \cdot cosTheta + \left(\color{blue}{{cosTheta}^{2} \cdot 0.5} + \frac{1}{cosTheta}\right)\right) - 1\right)} \]
    3. unpow296.5%

      \[\leadsto \frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \left(\left(-1.5 \cdot cosTheta + \left(\color{blue}{\left(cosTheta \cdot cosTheta\right)} \cdot 0.5 + \frac{1}{cosTheta}\right)\right) - 1\right)} \]
  8. Simplified96.5%

    \[\leadsto \frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \left(\left(-1.5 \cdot cosTheta + \left(\color{blue}{\left(cosTheta \cdot cosTheta\right) \cdot 0.5} + \frac{1}{cosTheta}\right)\right) - 1\right)} \]
  9. Step-by-step derivation
    1. div-inv96.5%

      \[\leadsto \frac{1}{\left(1 + c\right) + \color{blue}{\left(1 \cdot \frac{1}{\sqrt{\pi}}\right)} \cdot \left(\left(-1.5 \cdot cosTheta + \left(\left(cosTheta \cdot cosTheta\right) \cdot 0.5 + \frac{1}{cosTheta}\right)\right) - 1\right)} \]
    2. pow1/296.5%

      \[\leadsto \frac{1}{\left(1 + c\right) + \left(1 \cdot \frac{1}{\color{blue}{{\pi}^{0.5}}}\right) \cdot \left(\left(-1.5 \cdot cosTheta + \left(\left(cosTheta \cdot cosTheta\right) \cdot 0.5 + \frac{1}{cosTheta}\right)\right) - 1\right)} \]
    3. pow-flip96.5%

      \[\leadsto \frac{1}{\left(1 + c\right) + \left(1 \cdot \color{blue}{{\pi}^{\left(-0.5\right)}}\right) \cdot \left(\left(-1.5 \cdot cosTheta + \left(\left(cosTheta \cdot cosTheta\right) \cdot 0.5 + \frac{1}{cosTheta}\right)\right) - 1\right)} \]
    4. metadata-eval96.5%

      \[\leadsto \frac{1}{\left(1 + c\right) + \left(1 \cdot {\pi}^{\color{blue}{-0.5}}\right) \cdot \left(\left(-1.5 \cdot cosTheta + \left(\left(cosTheta \cdot cosTheta\right) \cdot 0.5 + \frac{1}{cosTheta}\right)\right) - 1\right)} \]
  10. Applied egg-rr96.5%

    \[\leadsto \frac{1}{\left(1 + c\right) + \color{blue}{\left(1 \cdot {\pi}^{-0.5}\right)} \cdot \left(\left(-1.5 \cdot cosTheta + \left(\left(cosTheta \cdot cosTheta\right) \cdot 0.5 + \frac{1}{cosTheta}\right)\right) - 1\right)} \]
  11. Step-by-step derivation
    1. *-lft-identity96.5%

      \[\leadsto \frac{1}{\left(1 + c\right) + \color{blue}{{\pi}^{-0.5}} \cdot \left(\left(-1.5 \cdot cosTheta + \left(\left(cosTheta \cdot cosTheta\right) \cdot 0.5 + \frac{1}{cosTheta}\right)\right) - 1\right)} \]
  12. Simplified96.5%

    \[\leadsto \frac{1}{\left(1 + c\right) + \color{blue}{{\pi}^{-0.5}} \cdot \left(\left(-1.5 \cdot cosTheta + \left(\left(cosTheta \cdot cosTheta\right) \cdot 0.5 + \frac{1}{cosTheta}\right)\right) - 1\right)} \]
  13. Final simplification96.5%

    \[\leadsto \frac{1}{\left(1 + c\right) + {\pi}^{-0.5} \cdot \left(-1 + \left(cosTheta \cdot -1.5 + \left(\frac{1}{cosTheta} + \left(cosTheta \cdot cosTheta\right) \cdot 0.5\right)\right)\right)} \]

Alternative 9: 96.4% accurate, 1.9× speedup?

\[\begin{array}{l} \\ \frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \left(-1 + \left(\frac{1}{cosTheta} + cosTheta \cdot -1.5\right)\right)} \end{array} \]
(FPCore (cosTheta c)
 :precision binary32
 (/
  1.0
  (+
   (+ 1.0 c)
   (* (/ 1.0 (sqrt PI)) (+ -1.0 (+ (/ 1.0 cosTheta) (* cosTheta -1.5)))))))
float code(float cosTheta, float c) {
	return 1.0f / ((1.0f + c) + ((1.0f / sqrtf(((float) M_PI))) * (-1.0f + ((1.0f / cosTheta) + (cosTheta * -1.5f)))));
}
function code(cosTheta, c)
	return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32(Float32(Float32(1.0) / sqrt(Float32(pi))) * Float32(Float32(-1.0) + Float32(Float32(Float32(1.0) / cosTheta) + Float32(cosTheta * Float32(-1.5)))))))
end
function tmp = code(cosTheta, c)
	tmp = single(1.0) / ((single(1.0) + c) + ((single(1.0) / sqrt(single(pi))) * (single(-1.0) + ((single(1.0) / cosTheta) + (cosTheta * single(-1.5))))));
end
\begin{array}{l}

\\
\frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \left(-1 + \left(\frac{1}{cosTheta} + cosTheta \cdot -1.5\right)\right)}
\end{array}
Derivation
  1. Initial program 97.9%

    \[\frac{1}{\left(1 + c\right) + \left(\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right) \cdot e^{\left(-cosTheta\right) \cdot cosTheta}} \]
  2. Step-by-step derivation
    1. associate-*l*97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \color{blue}{\frac{1}{\sqrt{\pi}} \cdot \left(\frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta} \cdot e^{\left(-cosTheta\right) \cdot cosTheta}\right)}} \]
    2. associate--l-97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \left(\frac{\sqrt{\color{blue}{1 - \left(cosTheta + cosTheta\right)}}}{cosTheta} \cdot e^{\left(-cosTheta\right) \cdot cosTheta}\right)} \]
    3. *-commutative97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \left(\frac{\sqrt{1 - \left(cosTheta + cosTheta\right)}}{cosTheta} \cdot e^{\color{blue}{cosTheta \cdot \left(-cosTheta\right)}}\right)} \]
    4. exp-prod97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \left(\frac{\sqrt{1 - \left(cosTheta + cosTheta\right)}}{cosTheta} \cdot \color{blue}{{\left(e^{cosTheta}\right)}^{\left(-cosTheta\right)}}\right)} \]
  3. Simplified97.9%

    \[\leadsto \color{blue}{\frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \left(\frac{\sqrt{1 - \left(cosTheta + cosTheta\right)}}{cosTheta} \cdot {\left(e^{cosTheta}\right)}^{\left(-cosTheta\right)}\right)}} \]
  4. Taylor expanded in cosTheta around 0 95.8%

    \[\leadsto \frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \color{blue}{\left(\left(-1.5 \cdot cosTheta + \frac{1}{cosTheta}\right) - 1\right)}} \]
  5. Final simplification95.8%

    \[\leadsto \frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \left(-1 + \left(\frac{1}{cosTheta} + cosTheta \cdot -1.5\right)\right)} \]

Alternative 10: 95.1% accurate, 2.0× speedup?

\[\begin{array}{l} \\ \frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \left(-1 + \frac{1}{cosTheta}\right)} \end{array} \]
(FPCore (cosTheta c)
 :precision binary32
 (/ 1.0 (+ (+ 1.0 c) (* (/ 1.0 (sqrt PI)) (+ -1.0 (/ 1.0 cosTheta))))))
float code(float cosTheta, float c) {
	return 1.0f / ((1.0f + c) + ((1.0f / sqrtf(((float) M_PI))) * (-1.0f + (1.0f / cosTheta))));
}
function code(cosTheta, c)
	return Float32(Float32(1.0) / Float32(Float32(Float32(1.0) + c) + Float32(Float32(Float32(1.0) / sqrt(Float32(pi))) * Float32(Float32(-1.0) + Float32(Float32(1.0) / cosTheta)))))
end
function tmp = code(cosTheta, c)
	tmp = single(1.0) / ((single(1.0) + c) + ((single(1.0) / sqrt(single(pi))) * (single(-1.0) + (single(1.0) / cosTheta))));
end
\begin{array}{l}

\\
\frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \left(-1 + \frac{1}{cosTheta}\right)}
\end{array}
Derivation
  1. Initial program 97.9%

    \[\frac{1}{\left(1 + c\right) + \left(\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right) \cdot e^{\left(-cosTheta\right) \cdot cosTheta}} \]
  2. Step-by-step derivation
    1. associate-*l*97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \color{blue}{\frac{1}{\sqrt{\pi}} \cdot \left(\frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta} \cdot e^{\left(-cosTheta\right) \cdot cosTheta}\right)}} \]
    2. associate--l-97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \left(\frac{\sqrt{\color{blue}{1 - \left(cosTheta + cosTheta\right)}}}{cosTheta} \cdot e^{\left(-cosTheta\right) \cdot cosTheta}\right)} \]
    3. *-commutative97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \left(\frac{\sqrt{1 - \left(cosTheta + cosTheta\right)}}{cosTheta} \cdot e^{\color{blue}{cosTheta \cdot \left(-cosTheta\right)}}\right)} \]
    4. exp-prod97.9%

      \[\leadsto \frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \left(\frac{\sqrt{1 - \left(cosTheta + cosTheta\right)}}{cosTheta} \cdot \color{blue}{{\left(e^{cosTheta}\right)}^{\left(-cosTheta\right)}}\right)} \]
  3. Simplified97.9%

    \[\leadsto \color{blue}{\frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \left(\frac{\sqrt{1 - \left(cosTheta + cosTheta\right)}}{cosTheta} \cdot {\left(e^{cosTheta}\right)}^{\left(-cosTheta\right)}\right)}} \]
  4. Taylor expanded in cosTheta around 0 94.4%

    \[\leadsto \frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \color{blue}{\left(\frac{1}{cosTheta} - 1\right)}} \]
  5. Final simplification94.4%

    \[\leadsto \frac{1}{\left(1 + c\right) + \frac{1}{\sqrt{\pi}} \cdot \left(-1 + \frac{1}{cosTheta}\right)} \]

Alternative 11: 93.1% accurate, 2.1× speedup?

\[\begin{array}{l} \\ cosTheta \cdot \sqrt{\pi} \end{array} \]
(FPCore (cosTheta c) :precision binary32 (* cosTheta (sqrt PI)))
float code(float cosTheta, float c) {
	return cosTheta * sqrtf(((float) M_PI));
}
function code(cosTheta, c)
	return Float32(cosTheta * sqrt(Float32(pi)))
end
function tmp = code(cosTheta, c)
	tmp = cosTheta * sqrt(single(pi));
end
\begin{array}{l}

\\
cosTheta \cdot \sqrt{\pi}
\end{array}
Derivation
  1. Initial program 97.9%

    \[\frac{1}{\left(1 + c\right) + \left(\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right) \cdot e^{\left(-cosTheta\right) \cdot cosTheta}} \]
  2. Taylor expanded in cosTheta around 0 92.8%

    \[\leadsto \color{blue}{cosTheta \cdot \sqrt{\pi}} \]
  3. Final simplification92.8%

    \[\leadsto cosTheta \cdot \sqrt{\pi} \]

Alternative 12: 10.8% accurate, 140.3× speedup?

\[\begin{array}{l} \\ 1 - c \end{array} \]
(FPCore (cosTheta c) :precision binary32 (- 1.0 c))
float code(float cosTheta, float c) {
	return 1.0f - c;
}
real(4) function code(costheta, c)
    real(4), intent (in) :: costheta
    real(4), intent (in) :: c
    code = 1.0e0 - c
end function
function code(cosTheta, c)
	return Float32(Float32(1.0) - c)
end
function tmp = code(cosTheta, c)
	tmp = single(1.0) - c;
end
\begin{array}{l}

\\
1 - c
\end{array}
Derivation
  1. Initial program 97.9%

    \[\frac{1}{\left(1 + c\right) + \left(\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right) \cdot e^{\left(-cosTheta\right) \cdot cosTheta}} \]
  2. Taylor expanded in cosTheta around inf 10.8%

    \[\leadsto \color{blue}{\frac{1}{1 + c}} \]
  3. Taylor expanded in c around 0 10.8%

    \[\leadsto \color{blue}{1 + -1 \cdot c} \]
  4. Step-by-step derivation
    1. neg-mul-110.8%

      \[\leadsto 1 + \color{blue}{\left(-c\right)} \]
    2. sub-neg10.8%

      \[\leadsto \color{blue}{1 - c} \]
  5. Simplified10.8%

    \[\leadsto \color{blue}{1 - c} \]
  6. Final simplification10.8%

    \[\leadsto 1 - c \]

Alternative 13: 10.8% accurate, 421.0× speedup?

\[\begin{array}{l} \\ 1 \end{array} \]
(FPCore (cosTheta c) :precision binary32 1.0)
float code(float cosTheta, float c) {
	return 1.0f;
}
real(4) function code(costheta, c)
    real(4), intent (in) :: costheta
    real(4), intent (in) :: c
    code = 1.0e0
end function
function code(cosTheta, c)
	return Float32(1.0)
end
function tmp = code(cosTheta, c)
	tmp = single(1.0);
end
\begin{array}{l}

\\
1
\end{array}
Derivation
  1. Initial program 97.9%

    \[\frac{1}{\left(1 + c\right) + \left(\frac{1}{\sqrt{\pi}} \cdot \frac{\sqrt{\left(1 - cosTheta\right) - cosTheta}}{cosTheta}\right) \cdot e^{\left(-cosTheta\right) \cdot cosTheta}} \]
  2. Taylor expanded in cosTheta around inf 10.8%

    \[\leadsto \color{blue}{\frac{1}{1 + c}} \]
  3. Taylor expanded in c around 0 10.8%

    \[\leadsto \color{blue}{1} \]
  4. Final simplification10.8%

    \[\leadsto 1 \]

Reproduce

?
herbie shell --seed 2023297 
(FPCore (cosTheta c)
  :name "Beckmann Sample, normalization factor"
  :precision binary32
  :pre (and (and (< 0.0 cosTheta) (< cosTheta 0.9999)) (and (< -1.0 c) (< c 1.0)))
  (/ 1.0 (+ (+ 1.0 c) (* (* (/ 1.0 (sqrt PI)) (/ (sqrt (- (- 1.0 cosTheta) cosTheta)) cosTheta)) (exp (* (- cosTheta) cosTheta))))))