
(FPCore (cosTheta_i cosTheta_O sinTheta_i sinTheta_O v)
:precision binary32
(exp
(+
(+
(-
(- (/ (* cosTheta_i cosTheta_O) v) (/ (* sinTheta_i sinTheta_O) v))
(/ 1.0 v))
0.6931)
(log (/ 1.0 (* 2.0 v))))))
float code(float cosTheta_i, float cosTheta_O, float sinTheta_i, float sinTheta_O, float v) {
return expf(((((((cosTheta_i * cosTheta_O) / v) - ((sinTheta_i * sinTheta_O) / v)) - (1.0f / v)) + 0.6931f) + logf((1.0f / (2.0f * v)))));
}
real(4) function code(costheta_i, costheta_o, sintheta_i, sintheta_o, v)
real(4), intent (in) :: costheta_i
real(4), intent (in) :: costheta_o
real(4), intent (in) :: sintheta_i
real(4), intent (in) :: sintheta_o
real(4), intent (in) :: v
code = exp(((((((costheta_i * costheta_o) / v) - ((sintheta_i * sintheta_o) / v)) - (1.0e0 / v)) + 0.6931e0) + log((1.0e0 / (2.0e0 * v)))))
end function
function code(cosTheta_i, cosTheta_O, sinTheta_i, sinTheta_O, v) return exp(Float32(Float32(Float32(Float32(Float32(Float32(cosTheta_i * cosTheta_O) / v) - Float32(Float32(sinTheta_i * sinTheta_O) / v)) - Float32(Float32(1.0) / v)) + Float32(0.6931)) + log(Float32(Float32(1.0) / Float32(Float32(2.0) * v))))) end
function tmp = code(cosTheta_i, cosTheta_O, sinTheta_i, sinTheta_O, v) tmp = exp(((((((cosTheta_i * cosTheta_O) / v) - ((sinTheta_i * sinTheta_O) / v)) - (single(1.0) / v)) + single(0.6931)) + log((single(1.0) / (single(2.0) * v))))); end
\begin{array}{l}
\\
e^{\left(\left(\left(\frac{cosTheta\_i \cdot cosTheta\_O}{v} - \frac{sinTheta\_i \cdot sinTheta\_O}{v}\right) - \frac{1}{v}\right) + 0.6931\right) + \log \left(\frac{1}{2 \cdot v}\right)}
\end{array}
Sampling outcomes in binary32 precision:
Herbie found 10 alternatives:
| Alternative | Accuracy | Speedup |
|---|
(FPCore (cosTheta_i cosTheta_O sinTheta_i sinTheta_O v)
:precision binary32
(exp
(+
(+
(-
(- (/ (* cosTheta_i cosTheta_O) v) (/ (* sinTheta_i sinTheta_O) v))
(/ 1.0 v))
0.6931)
(log (/ 1.0 (* 2.0 v))))))
float code(float cosTheta_i, float cosTheta_O, float sinTheta_i, float sinTheta_O, float v) {
return expf(((((((cosTheta_i * cosTheta_O) / v) - ((sinTheta_i * sinTheta_O) / v)) - (1.0f / v)) + 0.6931f) + logf((1.0f / (2.0f * v)))));
}
real(4) function code(costheta_i, costheta_o, sintheta_i, sintheta_o, v)
real(4), intent (in) :: costheta_i
real(4), intent (in) :: costheta_o
real(4), intent (in) :: sintheta_i
real(4), intent (in) :: sintheta_o
real(4), intent (in) :: v
code = exp(((((((costheta_i * costheta_o) / v) - ((sintheta_i * sintheta_o) / v)) - (1.0e0 / v)) + 0.6931e0) + log((1.0e0 / (2.0e0 * v)))))
end function
function code(cosTheta_i, cosTheta_O, sinTheta_i, sinTheta_O, v) return exp(Float32(Float32(Float32(Float32(Float32(Float32(cosTheta_i * cosTheta_O) / v) - Float32(Float32(sinTheta_i * sinTheta_O) / v)) - Float32(Float32(1.0) / v)) + Float32(0.6931)) + log(Float32(Float32(1.0) / Float32(Float32(2.0) * v))))) end
function tmp = code(cosTheta_i, cosTheta_O, sinTheta_i, sinTheta_O, v) tmp = exp(((((((cosTheta_i * cosTheta_O) / v) - ((sinTheta_i * sinTheta_O) / v)) - (single(1.0) / v)) + single(0.6931)) + log((single(1.0) / (single(2.0) * v))))); end
\begin{array}{l}
\\
e^{\left(\left(\left(\frac{cosTheta\_i \cdot cosTheta\_O}{v} - \frac{sinTheta\_i \cdot sinTheta\_O}{v}\right) - \frac{1}{v}\right) + 0.6931\right) + \log \left(\frac{1}{2 \cdot v}\right)}
\end{array}
(FPCore (cosTheta_i cosTheta_O sinTheta_i sinTheta_O v) :precision binary32 (* (* 0.5 (/ 1.0 (/ v (exp 0.6931)))) (pow E (/ (fma sinTheta_O sinTheta_i 1.0) (- v)))))
float code(float cosTheta_i, float cosTheta_O, float sinTheta_i, float sinTheta_O, float v) {
return (0.5f * (1.0f / (v / expf(0.6931f)))) * powf(((float) M_E), (fmaf(sinTheta_O, sinTheta_i, 1.0f) / -v));
}
function code(cosTheta_i, cosTheta_O, sinTheta_i, sinTheta_O, v) return Float32(Float32(Float32(0.5) * Float32(Float32(1.0) / Float32(v / exp(Float32(0.6931))))) * (Float32(exp(1)) ^ Float32(fma(sinTheta_O, sinTheta_i, Float32(1.0)) / Float32(-v)))) end
\begin{array}{l}
\\
\left(0.5 \cdot \frac{1}{\frac{v}{e^{0.6931}}}\right) \cdot {e}^{\left(\frac{\mathsf{fma}\left(sinTheta\_O, sinTheta\_i, 1\right)}{-v}\right)}
\end{array}
Initial program 99.6%
associate-+l+99.6%
associate--l-99.6%
associate-/l*99.6%
associate-/l*99.6%
associate-/r*99.6%
metadata-eval99.6%
Simplified99.6%
Taylor expanded in cosTheta_i around 0 99.6%
*-un-lft-identity99.6%
exp-prod99.7%
exp-1-e99.7%
+-commutative99.7%
associate-/l*99.7%
fma-define99.7%
Applied egg-rr99.7%
exp-1-e99.7%
sub-neg99.7%
unpow-prod-up99.7%
pow-exp99.7%
*-un-lft-identity99.7%
+-commutative99.7%
exp-sum99.7%
add-exp-log99.7%
exp-1-e99.7%
Applied egg-rr99.7%
associate-*l/99.7%
associate-*r/99.7%
fma-undefine99.7%
+-commutative99.7%
*-lft-identity99.7%
metadata-eval99.7%
cancel-sign-sub-inv99.7%
associate-*r/99.7%
associate-*r/99.7%
div-sub99.7%
distribute-neg-frac299.7%
cancel-sign-sub-inv99.7%
metadata-eval99.7%
*-lft-identity99.7%
+-commutative99.7%
fma-define99.7%
Simplified99.7%
clear-num99.7%
inv-pow99.7%
Applied egg-rr99.7%
unpow-199.7%
Simplified99.7%
Final simplification99.7%
(FPCore (cosTheta_i cosTheta_O sinTheta_i sinTheta_O v) :precision binary32 (* (pow E (/ (fma sinTheta_O sinTheta_i 1.0) (- v))) (* 0.5 (/ (exp 0.6931) v))))
float code(float cosTheta_i, float cosTheta_O, float sinTheta_i, float sinTheta_O, float v) {
return powf(((float) M_E), (fmaf(sinTheta_O, sinTheta_i, 1.0f) / -v)) * (0.5f * (expf(0.6931f) / v));
}
function code(cosTheta_i, cosTheta_O, sinTheta_i, sinTheta_O, v) return Float32((Float32(exp(1)) ^ Float32(fma(sinTheta_O, sinTheta_i, Float32(1.0)) / Float32(-v))) * Float32(Float32(0.5) * Float32(exp(Float32(0.6931)) / v))) end
\begin{array}{l}
\\
{e}^{\left(\frac{\mathsf{fma}\left(sinTheta\_O, sinTheta\_i, 1\right)}{-v}\right)} \cdot \left(0.5 \cdot \frac{e^{0.6931}}{v}\right)
\end{array}
Initial program 99.6%
associate-+l+99.6%
associate--l-99.6%
associate-/l*99.6%
associate-/l*99.6%
associate-/r*99.6%
metadata-eval99.6%
Simplified99.6%
Taylor expanded in cosTheta_i around 0 99.6%
*-un-lft-identity99.6%
exp-prod99.7%
exp-1-e99.7%
+-commutative99.7%
associate-/l*99.7%
fma-define99.7%
Applied egg-rr99.7%
exp-1-e99.7%
sub-neg99.7%
unpow-prod-up99.7%
pow-exp99.7%
*-un-lft-identity99.7%
+-commutative99.7%
exp-sum99.7%
add-exp-log99.7%
exp-1-e99.7%
Applied egg-rr99.7%
associate-*l/99.7%
associate-*r/99.7%
fma-undefine99.7%
+-commutative99.7%
*-lft-identity99.7%
metadata-eval99.7%
cancel-sign-sub-inv99.7%
associate-*r/99.7%
associate-*r/99.7%
div-sub99.7%
distribute-neg-frac299.7%
cancel-sign-sub-inv99.7%
metadata-eval99.7%
*-lft-identity99.7%
+-commutative99.7%
fma-define99.7%
Simplified99.7%
Final simplification99.7%
(FPCore (cosTheta_i cosTheta_O sinTheta_i sinTheta_O v) :precision binary32 (* (* 0.5 (/ (exp 0.6931) v)) (pow E (/ -1.0 v))))
float code(float cosTheta_i, float cosTheta_O, float sinTheta_i, float sinTheta_O, float v) {
return (0.5f * (expf(0.6931f) / v)) * powf(((float) M_E), (-1.0f / v));
}
function code(cosTheta_i, cosTheta_O, sinTheta_i, sinTheta_O, v) return Float32(Float32(Float32(0.5) * Float32(exp(Float32(0.6931)) / v)) * (Float32(exp(1)) ^ Float32(Float32(-1.0) / v))) end
function tmp = code(cosTheta_i, cosTheta_O, sinTheta_i, sinTheta_O, v) tmp = (single(0.5) * (exp(single(0.6931)) / v)) * (single(2.71828182845904523536) ^ (single(-1.0) / v)); end
\begin{array}{l}
\\
\left(0.5 \cdot \frac{e^{0.6931}}{v}\right) \cdot {e}^{\left(\frac{-1}{v}\right)}
\end{array}
Initial program 99.6%
associate-+l+99.6%
associate--l-99.6%
associate-/l*99.6%
associate-/l*99.6%
associate-/r*99.6%
metadata-eval99.6%
Simplified99.6%
Taylor expanded in cosTheta_i around 0 99.6%
*-un-lft-identity99.6%
exp-prod99.7%
exp-1-e99.7%
+-commutative99.7%
associate-/l*99.7%
fma-define99.7%
Applied egg-rr99.7%
exp-1-e99.7%
sub-neg99.7%
unpow-prod-up99.7%
pow-exp99.7%
*-un-lft-identity99.7%
+-commutative99.7%
exp-sum99.7%
add-exp-log99.7%
exp-1-e99.7%
Applied egg-rr99.7%
associate-*l/99.7%
associate-*r/99.7%
fma-undefine99.7%
+-commutative99.7%
*-lft-identity99.7%
metadata-eval99.7%
cancel-sign-sub-inv99.7%
associate-*r/99.7%
associate-*r/99.7%
div-sub99.7%
distribute-neg-frac299.7%
cancel-sign-sub-inv99.7%
metadata-eval99.7%
*-lft-identity99.7%
+-commutative99.7%
fma-define99.7%
Simplified99.7%
Taylor expanded in sinTheta_O around 0 99.7%
Final simplification99.7%
(FPCore (cosTheta_i cosTheta_O sinTheta_i sinTheta_O v)
:precision binary32
(*
(/ 0.5 v)
(pow
E
(+
0.6931
(+
(/ (- (* cosTheta_i cosTheta_O) (* sinTheta_O sinTheta_i)) v)
(/ -1.0 v))))))
float code(float cosTheta_i, float cosTheta_O, float sinTheta_i, float sinTheta_O, float v) {
return (0.5f / v) * powf(((float) M_E), (0.6931f + ((((cosTheta_i * cosTheta_O) - (sinTheta_O * sinTheta_i)) / v) + (-1.0f / v))));
}
function code(cosTheta_i, cosTheta_O, sinTheta_i, sinTheta_O, v) return Float32(Float32(Float32(0.5) / v) * (Float32(exp(1)) ^ Float32(Float32(0.6931) + Float32(Float32(Float32(Float32(cosTheta_i * cosTheta_O) - Float32(sinTheta_O * sinTheta_i)) / v) + Float32(Float32(-1.0) / v))))) end
function tmp = code(cosTheta_i, cosTheta_O, sinTheta_i, sinTheta_O, v) tmp = (single(0.5) / v) * (single(2.71828182845904523536) ^ (single(0.6931) + ((((cosTheta_i * cosTheta_O) - (sinTheta_O * sinTheta_i)) / v) + (single(-1.0) / v)))); end
\begin{array}{l}
\\
\frac{0.5}{v} \cdot {e}^{\left(0.6931 + \left(\frac{cosTheta\_i \cdot cosTheta\_O - sinTheta\_O \cdot sinTheta\_i}{v} + \frac{-1}{v}\right)\right)}
\end{array}
Initial program 99.6%
exp-sum99.7%
*-commutative99.7%
rem-exp-log99.7%
associate-/r*99.7%
metadata-eval99.7%
associate--l-99.7%
associate-/l*99.7%
associate-/l*99.7%
fma-define99.7%
Simplified99.7%
*-un-lft-identity99.7%
exp-prod99.7%
fma-define99.7%
associate--r+99.7%
associate-*r/99.7%
associate-*r/99.7%
sub-div99.7%
Applied egg-rr99.7%
Final simplification99.7%
(FPCore (cosTheta_i cosTheta_O sinTheta_i sinTheta_O v) :precision binary32 (* (/ 0.5 v) (exp (+ 0.6931 (/ (- -1.0 (* sinTheta_O sinTheta_i)) v)))))
float code(float cosTheta_i, float cosTheta_O, float sinTheta_i, float sinTheta_O, float v) {
return (0.5f / v) * expf((0.6931f + ((-1.0f - (sinTheta_O * sinTheta_i)) / v)));
}
real(4) function code(costheta_i, costheta_o, sintheta_i, sintheta_o, v)
real(4), intent (in) :: costheta_i
real(4), intent (in) :: costheta_o
real(4), intent (in) :: sintheta_i
real(4), intent (in) :: sintheta_o
real(4), intent (in) :: v
code = (0.5e0 / v) * exp((0.6931e0 + (((-1.0e0) - (sintheta_o * sintheta_i)) / v)))
end function
function code(cosTheta_i, cosTheta_O, sinTheta_i, sinTheta_O, v) return Float32(Float32(Float32(0.5) / v) * exp(Float32(Float32(0.6931) + Float32(Float32(Float32(-1.0) - Float32(sinTheta_O * sinTheta_i)) / v)))) end
function tmp = code(cosTheta_i, cosTheta_O, sinTheta_i, sinTheta_O, v) tmp = (single(0.5) / v) * exp((single(0.6931) + ((single(-1.0) - (sinTheta_O * sinTheta_i)) / v))); end
\begin{array}{l}
\\
\frac{0.5}{v} \cdot e^{0.6931 + \frac{-1 - sinTheta\_O \cdot sinTheta\_i}{v}}
\end{array}
Initial program 99.6%
exp-sum99.7%
*-commutative99.7%
rem-exp-log99.7%
associate-/r*99.7%
metadata-eval99.7%
associate--l-99.7%
associate-/l*99.7%
associate-/l*99.7%
fma-define99.7%
Simplified99.7%
Taylor expanded in cosTheta_i around 0 99.7%
Taylor expanded in v around inf 99.7%
mul-1-neg99.7%
Simplified99.7%
Final simplification99.7%
(FPCore (cosTheta_i cosTheta_O sinTheta_i sinTheta_O v) :precision binary32 (* (/ 0.5 v) (exp (+ 0.6931 (/ -1.0 v)))))
float code(float cosTheta_i, float cosTheta_O, float sinTheta_i, float sinTheta_O, float v) {
return (0.5f / v) * expf((0.6931f + (-1.0f / v)));
}
real(4) function code(costheta_i, costheta_o, sintheta_i, sintheta_o, v)
real(4), intent (in) :: costheta_i
real(4), intent (in) :: costheta_o
real(4), intent (in) :: sintheta_i
real(4), intent (in) :: sintheta_o
real(4), intent (in) :: v
code = (0.5e0 / v) * exp((0.6931e0 + ((-1.0e0) / v)))
end function
function code(cosTheta_i, cosTheta_O, sinTheta_i, sinTheta_O, v) return Float32(Float32(Float32(0.5) / v) * exp(Float32(Float32(0.6931) + Float32(Float32(-1.0) / v)))) end
function tmp = code(cosTheta_i, cosTheta_O, sinTheta_i, sinTheta_O, v) tmp = (single(0.5) / v) * exp((single(0.6931) + (single(-1.0) / v))); end
\begin{array}{l}
\\
\frac{0.5}{v} \cdot e^{0.6931 + \frac{-1}{v}}
\end{array}
Initial program 99.6%
exp-sum99.7%
*-commutative99.7%
rem-exp-log99.7%
associate-/r*99.7%
metadata-eval99.7%
associate--l-99.7%
associate-/l*99.7%
associate-/l*99.7%
fma-define99.7%
Simplified99.7%
Taylor expanded in cosTheta_i around 0 99.7%
Taylor expanded in sinTheta_O around 0 99.6%
Final simplification99.6%
(FPCore (cosTheta_i cosTheta_O sinTheta_i sinTheta_O v) :precision binary32 (exp (/ (+ (* cosTheta_i cosTheta_O) -1.0) v)))
float code(float cosTheta_i, float cosTheta_O, float sinTheta_i, float sinTheta_O, float v) {
return expf((((cosTheta_i * cosTheta_O) + -1.0f) / v));
}
real(4) function code(costheta_i, costheta_o, sintheta_i, sintheta_o, v)
real(4), intent (in) :: costheta_i
real(4), intent (in) :: costheta_o
real(4), intent (in) :: sintheta_i
real(4), intent (in) :: sintheta_o
real(4), intent (in) :: v
code = exp((((costheta_i * costheta_o) + (-1.0e0)) / v))
end function
function code(cosTheta_i, cosTheta_O, sinTheta_i, sinTheta_O, v) return exp(Float32(Float32(Float32(cosTheta_i * cosTheta_O) + Float32(-1.0)) / v)) end
function tmp = code(cosTheta_i, cosTheta_O, sinTheta_i, sinTheta_O, v) tmp = exp((((cosTheta_i * cosTheta_O) + single(-1.0)) / v)); end
\begin{array}{l}
\\
e^{\frac{cosTheta\_i \cdot cosTheta\_O + -1}{v}}
\end{array}
Initial program 99.6%
associate-+l+99.6%
associate--l-99.6%
associate-/l*99.6%
associate-/l*99.6%
associate-/r*99.6%
metadata-eval99.6%
Simplified99.6%
Taylor expanded in v around 0 97.2%
+-commutative97.2%
Simplified97.2%
Taylor expanded in sinTheta_O around 0 97.2%
Final simplification97.2%
(FPCore (cosTheta_i cosTheta_O sinTheta_i sinTheta_O v) :precision binary32 (exp (* sinTheta_O (/ sinTheta_i (- v)))))
float code(float cosTheta_i, float cosTheta_O, float sinTheta_i, float sinTheta_O, float v) {
return expf((sinTheta_O * (sinTheta_i / -v)));
}
real(4) function code(costheta_i, costheta_o, sintheta_i, sintheta_o, v)
real(4), intent (in) :: costheta_i
real(4), intent (in) :: costheta_o
real(4), intent (in) :: sintheta_i
real(4), intent (in) :: sintheta_o
real(4), intent (in) :: v
code = exp((sintheta_o * (sintheta_i / -v)))
end function
function code(cosTheta_i, cosTheta_O, sinTheta_i, sinTheta_O, v) return exp(Float32(sinTheta_O * Float32(sinTheta_i / Float32(-v)))) end
function tmp = code(cosTheta_i, cosTheta_O, sinTheta_i, sinTheta_O, v) tmp = exp((sinTheta_O * (sinTheta_i / -v))); end
\begin{array}{l}
\\
e^{sinTheta\_O \cdot \frac{sinTheta\_i}{-v}}
\end{array}
Initial program 99.6%
associate-+l+99.6%
associate--l-99.6%
associate-/l*99.6%
associate-/l*99.6%
associate-/r*99.6%
metadata-eval99.6%
Simplified99.6%
Taylor expanded in sinTheta_i around inf 13.9%
mul-1-neg13.9%
associate-/l*13.9%
distribute-rgt-neg-in13.9%
distribute-frac-neg213.9%
Simplified13.9%
Final simplification13.9%
(FPCore (cosTheta_i cosTheta_O sinTheta_i sinTheta_O v) :precision binary32 (exp (/ sinTheta_O (/ v sinTheta_i))))
float code(float cosTheta_i, float cosTheta_O, float sinTheta_i, float sinTheta_O, float v) {
return expf((sinTheta_O / (v / sinTheta_i)));
}
real(4) function code(costheta_i, costheta_o, sintheta_i, sintheta_o, v)
real(4), intent (in) :: costheta_i
real(4), intent (in) :: costheta_o
real(4), intent (in) :: sintheta_i
real(4), intent (in) :: sintheta_o
real(4), intent (in) :: v
code = exp((sintheta_o / (v / sintheta_i)))
end function
function code(cosTheta_i, cosTheta_O, sinTheta_i, sinTheta_O, v) return exp(Float32(sinTheta_O / Float32(v / sinTheta_i))) end
function tmp = code(cosTheta_i, cosTheta_O, sinTheta_i, sinTheta_O, v) tmp = exp((sinTheta_O / (v / sinTheta_i))); end
\begin{array}{l}
\\
e^{\frac{sinTheta\_O}{\frac{v}{sinTheta\_i}}}
\end{array}
Initial program 99.6%
associate-+l+99.6%
associate--l-99.6%
associate-/l*99.6%
associate-/l*99.6%
associate-/r*99.6%
metadata-eval99.6%
Simplified99.6%
Taylor expanded in sinTheta_i around inf 13.9%
mul-1-neg13.9%
associate-/l*13.9%
distribute-rgt-neg-in13.9%
distribute-frac-neg213.9%
Simplified13.9%
clear-num13.9%
un-div-inv13.9%
add-sqr-sqrt-0.0%
sqrt-unprod26.6%
sqr-neg26.6%
sqrt-unprod12.8%
add-sqr-sqrt12.8%
Applied egg-rr12.8%
Final simplification12.8%
(FPCore (cosTheta_i cosTheta_O sinTheta_i sinTheta_O v) :precision binary32 1.0)
float code(float cosTheta_i, float cosTheta_O, float sinTheta_i, float sinTheta_O, float v) {
return 1.0f;
}
real(4) function code(costheta_i, costheta_o, sintheta_i, sintheta_o, v)
real(4), intent (in) :: costheta_i
real(4), intent (in) :: costheta_o
real(4), intent (in) :: sintheta_i
real(4), intent (in) :: sintheta_o
real(4), intent (in) :: v
code = 1.0e0
end function
function code(cosTheta_i, cosTheta_O, sinTheta_i, sinTheta_O, v) return Float32(1.0) end
function tmp = code(cosTheta_i, cosTheta_O, sinTheta_i, sinTheta_O, v) tmp = single(1.0); end
\begin{array}{l}
\\
1
\end{array}
Initial program 99.6%
associate-+l+99.6%
associate--l-99.6%
associate-/l*99.6%
associate-/l*99.6%
associate-/r*99.6%
metadata-eval99.6%
Simplified99.6%
Taylor expanded in v around 0 97.2%
+-commutative97.2%
Simplified97.2%
Taylor expanded in v around inf 6.5%
Final simplification6.5%
herbie shell --seed 2024080
(FPCore (cosTheta_i cosTheta_O sinTheta_i sinTheta_O v)
:name "HairBSDF, Mp, lower"
:precision binary32
:pre (and (and (and (and (and (<= -1.0 cosTheta_i) (<= cosTheta_i 1.0)) (and (<= -1.0 cosTheta_O) (<= cosTheta_O 1.0))) (and (<= -1.0 sinTheta_i) (<= sinTheta_i 1.0))) (and (<= -1.0 sinTheta_O) (<= sinTheta_O 1.0))) (and (<= -1.5707964 v) (<= v 0.1)))
(exp (+ (+ (- (- (/ (* cosTheta_i cosTheta_O) v) (/ (* sinTheta_i sinTheta_O) v)) (/ 1.0 v)) 0.6931) (log (/ 1.0 (* 2.0 v))))))