Curve intersection, scale width based on ribbon orientation

Percentage Accurate: 97.4% → 98.9%
Time: 9.8s
Alternatives: 8
Speedup: 45.9×

Specification

?
\[\left(\left(\left(0 \leq normAngle \land normAngle \leq \frac{\mathsf{PI}\left(\right)}{2}\right) \land \left(-1 \leq n0\_i \land n0\_i \leq 1\right)\right) \land \left(-1 \leq n1\_i \land n1\_i \leq 1\right)\right) \land \left(2.328306437 \cdot 10^{-10} \leq u \land u \leq 1\right)\]
\[\begin{array}{l} \\ \begin{array}{l} t_0 := \frac{1}{\sin normAngle}\\ \left(\sin \left(\left(1 - u\right) \cdot normAngle\right) \cdot t\_0\right) \cdot n0\_i + \left(\sin \left(u \cdot normAngle\right) \cdot t\_0\right) \cdot n1\_i \end{array} \end{array} \]
(FPCore (normAngle u n0_i n1_i)
 :precision binary32
 (let* ((t_0 (/ 1.0 (sin normAngle))))
   (+
    (* (* (sin (* (- 1.0 u) normAngle)) t_0) n0_i)
    (* (* (sin (* u normAngle)) t_0) n1_i))))
float code(float normAngle, float u, float n0_i, float n1_i) {
	float t_0 = 1.0f / sinf(normAngle);
	return ((sinf(((1.0f - u) * normAngle)) * t_0) * n0_i) + ((sinf((u * normAngle)) * t_0) * n1_i);
}
module fmin_fmax_functions
    implicit none
    private
    public fmax
    public fmin

    interface fmax
        module procedure fmax88
        module procedure fmax44
        module procedure fmax84
        module procedure fmax48
    end interface
    interface fmin
        module procedure fmin88
        module procedure fmin44
        module procedure fmin84
        module procedure fmin48
    end interface
contains
    real(8) function fmax88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(4) function fmax44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(8) function fmax84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmax48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
    end function
    real(8) function fmin88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(4) function fmin44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(8) function fmin84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmin48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
    end function
end module

real(4) function code(normangle, u, n0_i, n1_i)
use fmin_fmax_functions
    real(4), intent (in) :: normangle
    real(4), intent (in) :: u
    real(4), intent (in) :: n0_i
    real(4), intent (in) :: n1_i
    real(4) :: t_0
    t_0 = 1.0e0 / sin(normangle)
    code = ((sin(((1.0e0 - u) * normangle)) * t_0) * n0_i) + ((sin((u * normangle)) * t_0) * n1_i)
end function
function code(normAngle, u, n0_i, n1_i)
	t_0 = Float32(Float32(1.0) / sin(normAngle))
	return Float32(Float32(Float32(sin(Float32(Float32(Float32(1.0) - u) * normAngle)) * t_0) * n0_i) + Float32(Float32(sin(Float32(u * normAngle)) * t_0) * n1_i))
end
function tmp = code(normAngle, u, n0_i, n1_i)
	t_0 = single(1.0) / sin(normAngle);
	tmp = ((sin(((single(1.0) - u) * normAngle)) * t_0) * n0_i) + ((sin((u * normAngle)) * t_0) * n1_i);
end
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \frac{1}{\sin normAngle}\\
\left(\sin \left(\left(1 - u\right) \cdot normAngle\right) \cdot t\_0\right) \cdot n0\_i + \left(\sin \left(u \cdot normAngle\right) \cdot t\_0\right) \cdot n1\_i
\end{array}
\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: 97.4% accurate, 1.0× speedup?

\[\begin{array}{l} \\ \begin{array}{l} t_0 := \frac{1}{\sin normAngle}\\ \left(\sin \left(\left(1 - u\right) \cdot normAngle\right) \cdot t\_0\right) \cdot n0\_i + \left(\sin \left(u \cdot normAngle\right) \cdot t\_0\right) \cdot n1\_i \end{array} \end{array} \]
(FPCore (normAngle u n0_i n1_i)
 :precision binary32
 (let* ((t_0 (/ 1.0 (sin normAngle))))
   (+
    (* (* (sin (* (- 1.0 u) normAngle)) t_0) n0_i)
    (* (* (sin (* u normAngle)) t_0) n1_i))))
float code(float normAngle, float u, float n0_i, float n1_i) {
	float t_0 = 1.0f / sinf(normAngle);
	return ((sinf(((1.0f - u) * normAngle)) * t_0) * n0_i) + ((sinf((u * normAngle)) * t_0) * n1_i);
}
module fmin_fmax_functions
    implicit none
    private
    public fmax
    public fmin

    interface fmax
        module procedure fmax88
        module procedure fmax44
        module procedure fmax84
        module procedure fmax48
    end interface
    interface fmin
        module procedure fmin88
        module procedure fmin44
        module procedure fmin84
        module procedure fmin48
    end interface
contains
    real(8) function fmax88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(4) function fmax44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, max(x, y), y /= y), x /= x)
    end function
    real(8) function fmax84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmax48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
    end function
    real(8) function fmin88(x, y) result (res)
        real(8), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(4) function fmin44(x, y) result (res)
        real(4), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(y, merge(x, min(x, y), y /= y), x /= x)
    end function
    real(8) function fmin84(x, y) result(res)
        real(8), intent (in) :: x
        real(4), intent (in) :: y
        res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
    end function
    real(8) function fmin48(x, y) result(res)
        real(4), intent (in) :: x
        real(8), intent (in) :: y
        res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
    end function
end module

real(4) function code(normangle, u, n0_i, n1_i)
use fmin_fmax_functions
    real(4), intent (in) :: normangle
    real(4), intent (in) :: u
    real(4), intent (in) :: n0_i
    real(4), intent (in) :: n1_i
    real(4) :: t_0
    t_0 = 1.0e0 / sin(normangle)
    code = ((sin(((1.0e0 - u) * normangle)) * t_0) * n0_i) + ((sin((u * normangle)) * t_0) * n1_i)
end function
function code(normAngle, u, n0_i, n1_i)
	t_0 = Float32(Float32(1.0) / sin(normAngle))
	return Float32(Float32(Float32(sin(Float32(Float32(Float32(1.0) - u) * normAngle)) * t_0) * n0_i) + Float32(Float32(sin(Float32(u * normAngle)) * t_0) * n1_i))
end
function tmp = code(normAngle, u, n0_i, n1_i)
	t_0 = single(1.0) / sin(normAngle);
	tmp = ((sin(((single(1.0) - u) * normAngle)) * t_0) * n0_i) + ((sin((u * normAngle)) * t_0) * n1_i);
end
\begin{array}{l}

\\
\begin{array}{l}
t_0 := \frac{1}{\sin normAngle}\\
\left(\sin \left(\left(1 - u\right) \cdot normAngle\right) \cdot t\_0\right) \cdot n0\_i + \left(\sin \left(u \cdot normAngle\right) \cdot t\_0\right) \cdot n1\_i
\end{array}
\end{array}

Alternative 1: 98.9% accurate, 8.1× speedup?

\[\begin{array}{l} \\ \mathsf{fma}\left(\left(n1\_i - n0\_i\right) + \mathsf{fma}\left(-0.5 \cdot n0\_i, \left(normAngle \cdot normAngle\right) \cdot u, \left(\left(normAngle \cdot normAngle\right) \cdot -0.16666666666666666\right) \cdot \left(-2 \cdot n0\_i - n1\_i\right)\right), u, n0\_i\right) \end{array} \]
(FPCore (normAngle u n0_i n1_i)
 :precision binary32
 (fma
  (+
   (- n1_i n0_i)
   (fma
    (* -0.5 n0_i)
    (* (* normAngle normAngle) u)
    (*
     (* (* normAngle normAngle) -0.16666666666666666)
     (- (* -2.0 n0_i) n1_i))))
  u
  n0_i))
float code(float normAngle, float u, float n0_i, float n1_i) {
	return fmaf(((n1_i - n0_i) + fmaf((-0.5f * n0_i), ((normAngle * normAngle) * u), (((normAngle * normAngle) * -0.16666666666666666f) * ((-2.0f * n0_i) - n1_i)))), u, n0_i);
}
function code(normAngle, u, n0_i, n1_i)
	return fma(Float32(Float32(n1_i - n0_i) + fma(Float32(Float32(-0.5) * n0_i), Float32(Float32(normAngle * normAngle) * u), Float32(Float32(Float32(normAngle * normAngle) * Float32(-0.16666666666666666)) * Float32(Float32(Float32(-2.0) * n0_i) - n1_i)))), u, n0_i)
end
\begin{array}{l}

\\
\mathsf{fma}\left(\left(n1\_i - n0\_i\right) + \mathsf{fma}\left(-0.5 \cdot n0\_i, \left(normAngle \cdot normAngle\right) \cdot u, \left(\left(normAngle \cdot normAngle\right) \cdot -0.16666666666666666\right) \cdot \left(-2 \cdot n0\_i - n1\_i\right)\right), u, n0\_i\right)
\end{array}
Derivation
  1. Initial program 95.7%

    \[\left(\sin \left(\left(1 - u\right) \cdot normAngle\right) \cdot \frac{1}{\sin normAngle}\right) \cdot n0\_i + \left(\sin \left(u \cdot normAngle\right) \cdot \frac{1}{\sin normAngle}\right) \cdot n1\_i \]
  2. Add Preprocessing
  3. Taylor expanded in normAngle around 0

    \[\leadsto \color{blue}{n0\_i \cdot \left(1 - u\right) + \left(n1\_i \cdot u + {normAngle}^{2} \cdot \left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right)\right)\right)} \]
  4. Step-by-step derivation
    1. associate-+r+N/A

      \[\leadsto \left(n0\_i \cdot \left(1 - u\right) + n1\_i \cdot u\right) + \color{blue}{{normAngle}^{2} \cdot \left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right)\right)} \]
    2. +-commutativeN/A

      \[\leadsto {normAngle}^{2} \cdot \left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right)\right) + \color{blue}{\left(n0\_i \cdot \left(1 - u\right) + n1\_i \cdot u\right)} \]
    3. *-commutativeN/A

      \[\leadsto \left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right)\right) \cdot {normAngle}^{2} + \left(\color{blue}{n0\_i \cdot \left(1 - u\right)} + n1\_i \cdot u\right) \]
    4. lower-fma.f32N/A

      \[\leadsto \mathsf{fma}\left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right), \color{blue}{{normAngle}^{2}}, n0\_i \cdot \left(1 - u\right) + n1\_i \cdot u\right) \]
  5. Applied rewrites98.5%

    \[\leadsto \color{blue}{\mathsf{fma}\left(-0.16666666666666666 \cdot \left(\mathsf{fma}\left({u}^{3}, n1\_i, {\left(1 - u\right)}^{3} \cdot n0\_i\right) - \mathsf{fma}\left(1 - u, n0\_i, n1\_i \cdot u\right)\right), normAngle \cdot normAngle, \mathsf{fma}\left(1 - u, n0\_i, n1\_i \cdot u\right)\right)} \]
  6. Taylor expanded in u around 0

    \[\leadsto n0\_i + \color{blue}{u \cdot \left(n1\_i + \left(-1 \cdot n0\_i + \frac{-1}{6} \cdot \left({normAngle}^{2} \cdot \left(-3 \cdot n0\_i - \left(n1\_i + -1 \cdot n0\_i\right)\right)\right)\right)\right)} \]
  7. Step-by-step derivation
    1. +-commutativeN/A

      \[\leadsto u \cdot \left(n1\_i + \left(-1 \cdot n0\_i + \frac{-1}{6} \cdot \left({normAngle}^{2} \cdot \left(-3 \cdot n0\_i - \left(n1\_i + -1 \cdot n0\_i\right)\right)\right)\right)\right) + n0\_i \]
    2. *-commutativeN/A

      \[\leadsto \left(n1\_i + \left(-1 \cdot n0\_i + \frac{-1}{6} \cdot \left({normAngle}^{2} \cdot \left(-3 \cdot n0\_i - \left(n1\_i + -1 \cdot n0\_i\right)\right)\right)\right)\right) \cdot u + n0\_i \]
    3. lower-fma.f32N/A

      \[\leadsto \mathsf{fma}\left(n1\_i + \left(-1 \cdot n0\_i + \frac{-1}{6} \cdot \left({normAngle}^{2} \cdot \left(-3 \cdot n0\_i - \left(n1\_i + -1 \cdot n0\_i\right)\right)\right)\right), u, n0\_i\right) \]
  8. Applied rewrites98.8%

    \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\left(\left(-3 \cdot n0\_i - n1\_i\right) - \left(-n0\_i\right)\right) \cdot \left(normAngle \cdot normAngle\right), -0.16666666666666666, -n0\_i\right) + n1\_i, \color{blue}{u}, n0\_i\right) \]
  9. Taylor expanded in u around 0

    \[\leadsto n0\_i + \color{blue}{u \cdot \left(n1\_i + \left(-1 \cdot n0\_i + \left(\frac{-1}{2} \cdot \left(n0\_i \cdot \left({normAngle}^{2} \cdot u\right)\right) + \frac{-1}{6} \cdot \left({normAngle}^{2} \cdot \left(-3 \cdot n0\_i - \left(n1\_i + -1 \cdot n0\_i\right)\right)\right)\right)\right)\right)} \]
  10. Applied rewrites98.9%

    \[\leadsto \mathsf{fma}\left(\left(n1\_i - n0\_i\right) + \mathsf{fma}\left(-0.5 \cdot n0\_i, \left(normAngle \cdot normAngle\right) \cdot u, \left(\left(normAngle \cdot normAngle\right) \cdot -0.16666666666666666\right) \cdot \left(-2 \cdot n0\_i - n1\_i\right)\right), \color{blue}{u}, n0\_i\right) \]
  11. Add Preprocessing

Alternative 2: 98.8% accurate, 9.8× speedup?

\[\begin{array}{l} \\ \mathsf{fma}\left(\mathsf{fma}\left(\left(normAngle \cdot normAngle\right) \cdot -0.16666666666666666, -2 \cdot n0\_i, \mathsf{fma}\left(0.16666666666666666, normAngle \cdot normAngle, 1\right) \cdot n1\_i - n0\_i\right), u, n0\_i\right) \end{array} \]
(FPCore (normAngle u n0_i n1_i)
 :precision binary32
 (fma
  (fma
   (* (* normAngle normAngle) -0.16666666666666666)
   (* -2.0 n0_i)
   (- (* (fma 0.16666666666666666 (* normAngle normAngle) 1.0) n1_i) n0_i))
  u
  n0_i))
float code(float normAngle, float u, float n0_i, float n1_i) {
	return fmaf(fmaf(((normAngle * normAngle) * -0.16666666666666666f), (-2.0f * n0_i), ((fmaf(0.16666666666666666f, (normAngle * normAngle), 1.0f) * n1_i) - n0_i)), u, n0_i);
}
function code(normAngle, u, n0_i, n1_i)
	return fma(fma(Float32(Float32(normAngle * normAngle) * Float32(-0.16666666666666666)), Float32(Float32(-2.0) * n0_i), Float32(Float32(fma(Float32(0.16666666666666666), Float32(normAngle * normAngle), Float32(1.0)) * n1_i) - n0_i)), u, n0_i)
end
\begin{array}{l}

\\
\mathsf{fma}\left(\mathsf{fma}\left(\left(normAngle \cdot normAngle\right) \cdot -0.16666666666666666, -2 \cdot n0\_i, \mathsf{fma}\left(0.16666666666666666, normAngle \cdot normAngle, 1\right) \cdot n1\_i - n0\_i\right), u, n0\_i\right)
\end{array}
Derivation
  1. Initial program 95.7%

    \[\left(\sin \left(\left(1 - u\right) \cdot normAngle\right) \cdot \frac{1}{\sin normAngle}\right) \cdot n0\_i + \left(\sin \left(u \cdot normAngle\right) \cdot \frac{1}{\sin normAngle}\right) \cdot n1\_i \]
  2. Add Preprocessing
  3. Taylor expanded in normAngle around 0

    \[\leadsto \color{blue}{n0\_i \cdot \left(1 - u\right) + \left(n1\_i \cdot u + {normAngle}^{2} \cdot \left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right)\right)\right)} \]
  4. Step-by-step derivation
    1. associate-+r+N/A

      \[\leadsto \left(n0\_i \cdot \left(1 - u\right) + n1\_i \cdot u\right) + \color{blue}{{normAngle}^{2} \cdot \left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right)\right)} \]
    2. +-commutativeN/A

      \[\leadsto {normAngle}^{2} \cdot \left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right)\right) + \color{blue}{\left(n0\_i \cdot \left(1 - u\right) + n1\_i \cdot u\right)} \]
    3. *-commutativeN/A

      \[\leadsto \left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right)\right) \cdot {normAngle}^{2} + \left(\color{blue}{n0\_i \cdot \left(1 - u\right)} + n1\_i \cdot u\right) \]
    4. lower-fma.f32N/A

      \[\leadsto \mathsf{fma}\left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right), \color{blue}{{normAngle}^{2}}, n0\_i \cdot \left(1 - u\right) + n1\_i \cdot u\right) \]
  5. Applied rewrites98.5%

    \[\leadsto \color{blue}{\mathsf{fma}\left(-0.16666666666666666 \cdot \left(\mathsf{fma}\left({u}^{3}, n1\_i, {\left(1 - u\right)}^{3} \cdot n0\_i\right) - \mathsf{fma}\left(1 - u, n0\_i, n1\_i \cdot u\right)\right), normAngle \cdot normAngle, \mathsf{fma}\left(1 - u, n0\_i, n1\_i \cdot u\right)\right)} \]
  6. Taylor expanded in u around 0

    \[\leadsto n0\_i + \color{blue}{u \cdot \left(n1\_i + \left(-1 \cdot n0\_i + \frac{-1}{6} \cdot \left({normAngle}^{2} \cdot \left(-3 \cdot n0\_i - \left(n1\_i + -1 \cdot n0\_i\right)\right)\right)\right)\right)} \]
  7. Step-by-step derivation
    1. +-commutativeN/A

      \[\leadsto u \cdot \left(n1\_i + \left(-1 \cdot n0\_i + \frac{-1}{6} \cdot \left({normAngle}^{2} \cdot \left(-3 \cdot n0\_i - \left(n1\_i + -1 \cdot n0\_i\right)\right)\right)\right)\right) + n0\_i \]
    2. *-commutativeN/A

      \[\leadsto \left(n1\_i + \left(-1 \cdot n0\_i + \frac{-1}{6} \cdot \left({normAngle}^{2} \cdot \left(-3 \cdot n0\_i - \left(n1\_i + -1 \cdot n0\_i\right)\right)\right)\right)\right) \cdot u + n0\_i \]
    3. lower-fma.f32N/A

      \[\leadsto \mathsf{fma}\left(n1\_i + \left(-1 \cdot n0\_i + \frac{-1}{6} \cdot \left({normAngle}^{2} \cdot \left(-3 \cdot n0\_i - \left(n1\_i + -1 \cdot n0\_i\right)\right)\right)\right), u, n0\_i\right) \]
  8. Applied rewrites98.8%

    \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\left(\left(-3 \cdot n0\_i - n1\_i\right) - \left(-n0\_i\right)\right) \cdot \left(normAngle \cdot normAngle\right), -0.16666666666666666, -n0\_i\right) + n1\_i, \color{blue}{u}, n0\_i\right) \]
  9. Taylor expanded in n1_i around 0

    \[\leadsto \mathsf{fma}\left(\left(\frac{-1}{6} \cdot \left({normAngle}^{2} \cdot \left(n0\_i + -3 \cdot n0\_i\right)\right) + n1\_i \cdot \left(1 + \frac{1}{6} \cdot {normAngle}^{2}\right)\right) - n0\_i, u, n0\_i\right) \]
  10. Step-by-step derivation
    1. associate--l+N/A

      \[\leadsto \mathsf{fma}\left(\frac{-1}{6} \cdot \left({normAngle}^{2} \cdot \left(n0\_i + -3 \cdot n0\_i\right)\right) + \left(n1\_i \cdot \left(1 + \frac{1}{6} \cdot {normAngle}^{2}\right) - n0\_i\right), u, n0\_i\right) \]
    2. associate-*r*N/A

      \[\leadsto \mathsf{fma}\left(\left(\frac{-1}{6} \cdot {normAngle}^{2}\right) \cdot \left(n0\_i + -3 \cdot n0\_i\right) + \left(n1\_i \cdot \left(1 + \frac{1}{6} \cdot {normAngle}^{2}\right) - n0\_i\right), u, n0\_i\right) \]
    3. lower-fma.f32N/A

      \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\frac{-1}{6} \cdot {normAngle}^{2}, n0\_i + -3 \cdot n0\_i, n1\_i \cdot \left(1 + \frac{1}{6} \cdot {normAngle}^{2}\right) - n0\_i\right), u, n0\_i\right) \]
    4. *-commutativeN/A

      \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left({normAngle}^{2} \cdot \frac{-1}{6}, n0\_i + -3 \cdot n0\_i, n1\_i \cdot \left(1 + \frac{1}{6} \cdot {normAngle}^{2}\right) - n0\_i\right), u, n0\_i\right) \]
    5. lower-*.f32N/A

      \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left({normAngle}^{2} \cdot \frac{-1}{6}, n0\_i + -3 \cdot n0\_i, n1\_i \cdot \left(1 + \frac{1}{6} \cdot {normAngle}^{2}\right) - n0\_i\right), u, n0\_i\right) \]
    6. unpow2N/A

      \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\left(normAngle \cdot normAngle\right) \cdot \frac{-1}{6}, n0\_i + -3 \cdot n0\_i, n1\_i \cdot \left(1 + \frac{1}{6} \cdot {normAngle}^{2}\right) - n0\_i\right), u, n0\_i\right) \]
    7. lower-*.f32N/A

      \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\left(normAngle \cdot normAngle\right) \cdot \frac{-1}{6}, n0\_i + -3 \cdot n0\_i, n1\_i \cdot \left(1 + \frac{1}{6} \cdot {normAngle}^{2}\right) - n0\_i\right), u, n0\_i\right) \]
    8. distribute-rgt1-inN/A

      \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\left(normAngle \cdot normAngle\right) \cdot \frac{-1}{6}, \left(-3 + 1\right) \cdot n0\_i, n1\_i \cdot \left(1 + \frac{1}{6} \cdot {normAngle}^{2}\right) - n0\_i\right), u, n0\_i\right) \]
    9. metadata-evalN/A

      \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\left(normAngle \cdot normAngle\right) \cdot \frac{-1}{6}, -2 \cdot n0\_i, n1\_i \cdot \left(1 + \frac{1}{6} \cdot {normAngle}^{2}\right) - n0\_i\right), u, n0\_i\right) \]
    10. lower-*.f32N/A

      \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\left(normAngle \cdot normAngle\right) \cdot \frac{-1}{6}, -2 \cdot n0\_i, n1\_i \cdot \left(1 + \frac{1}{6} \cdot {normAngle}^{2}\right) - n0\_i\right), u, n0\_i\right) \]
    11. lower--.f32N/A

      \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\left(normAngle \cdot normAngle\right) \cdot \frac{-1}{6}, -2 \cdot n0\_i, n1\_i \cdot \left(1 + \frac{1}{6} \cdot {normAngle}^{2}\right) - n0\_i\right), u, n0\_i\right) \]
    12. *-commutativeN/A

      \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\left(normAngle \cdot normAngle\right) \cdot \frac{-1}{6}, -2 \cdot n0\_i, \left(1 + \frac{1}{6} \cdot {normAngle}^{2}\right) \cdot n1\_i - n0\_i\right), u, n0\_i\right) \]
    13. lower-*.f32N/A

      \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\left(normAngle \cdot normAngle\right) \cdot \frac{-1}{6}, -2 \cdot n0\_i, \left(1 + \frac{1}{6} \cdot {normAngle}^{2}\right) \cdot n1\_i - n0\_i\right), u, n0\_i\right) \]
    14. +-commutativeN/A

      \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\left(normAngle \cdot normAngle\right) \cdot \frac{-1}{6}, -2 \cdot n0\_i, \left(\frac{1}{6} \cdot {normAngle}^{2} + 1\right) \cdot n1\_i - n0\_i\right), u, n0\_i\right) \]
    15. lower-fma.f32N/A

      \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\left(normAngle \cdot normAngle\right) \cdot \frac{-1}{6}, -2 \cdot n0\_i, \mathsf{fma}\left(\frac{1}{6}, {normAngle}^{2}, 1\right) \cdot n1\_i - n0\_i\right), u, n0\_i\right) \]
    16. unpow2N/A

      \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\left(normAngle \cdot normAngle\right) \cdot \frac{-1}{6}, -2 \cdot n0\_i, \mathsf{fma}\left(\frac{1}{6}, normAngle \cdot normAngle, 1\right) \cdot n1\_i - n0\_i\right), u, n0\_i\right) \]
    17. lower-*.f3298.8

      \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\left(normAngle \cdot normAngle\right) \cdot -0.16666666666666666, -2 \cdot n0\_i, \mathsf{fma}\left(0.16666666666666666, normAngle \cdot normAngle, 1\right) \cdot n1\_i - n0\_i\right), u, n0\_i\right) \]
  11. Applied rewrites98.8%

    \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\left(normAngle \cdot normAngle\right) \cdot -0.16666666666666666, -2 \cdot n0\_i, \mathsf{fma}\left(0.16666666666666666, normAngle \cdot normAngle, 1\right) \cdot n1\_i - n0\_i\right), u, n0\_i\right) \]
  12. Add Preprocessing

Alternative 3: 98.9% accurate, 11.8× speedup?

\[\begin{array}{l} \\ \mathsf{fma}\left(\mathsf{fma}\left(\left(\left(-3 \cdot n0\_i - n1\_i\right) + n0\_i\right) \cdot \left(normAngle \cdot normAngle\right), -0.16666666666666666, -n0\_i\right) + n1\_i, u, n0\_i\right) \end{array} \]
(FPCore (normAngle u n0_i n1_i)
 :precision binary32
 (fma
  (+
   (fma
    (* (+ (- (* -3.0 n0_i) n1_i) n0_i) (* normAngle normAngle))
    -0.16666666666666666
    (- n0_i))
   n1_i)
  u
  n0_i))
float code(float normAngle, float u, float n0_i, float n1_i) {
	return fmaf((fmaf(((((-3.0f * n0_i) - n1_i) + n0_i) * (normAngle * normAngle)), -0.16666666666666666f, -n0_i) + n1_i), u, n0_i);
}
function code(normAngle, u, n0_i, n1_i)
	return fma(Float32(fma(Float32(Float32(Float32(Float32(Float32(-3.0) * n0_i) - n1_i) + n0_i) * Float32(normAngle * normAngle)), Float32(-0.16666666666666666), Float32(-n0_i)) + n1_i), u, n0_i)
end
\begin{array}{l}

\\
\mathsf{fma}\left(\mathsf{fma}\left(\left(\left(-3 \cdot n0\_i - n1\_i\right) + n0\_i\right) \cdot \left(normAngle \cdot normAngle\right), -0.16666666666666666, -n0\_i\right) + n1\_i, u, n0\_i\right)
\end{array}
Derivation
  1. Initial program 95.7%

    \[\left(\sin \left(\left(1 - u\right) \cdot normAngle\right) \cdot \frac{1}{\sin normAngle}\right) \cdot n0\_i + \left(\sin \left(u \cdot normAngle\right) \cdot \frac{1}{\sin normAngle}\right) \cdot n1\_i \]
  2. Add Preprocessing
  3. Taylor expanded in normAngle around 0

    \[\leadsto \color{blue}{n0\_i \cdot \left(1 - u\right) + \left(n1\_i \cdot u + {normAngle}^{2} \cdot \left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right)\right)\right)} \]
  4. Step-by-step derivation
    1. associate-+r+N/A

      \[\leadsto \left(n0\_i \cdot \left(1 - u\right) + n1\_i \cdot u\right) + \color{blue}{{normAngle}^{2} \cdot \left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right)\right)} \]
    2. +-commutativeN/A

      \[\leadsto {normAngle}^{2} \cdot \left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right)\right) + \color{blue}{\left(n0\_i \cdot \left(1 - u\right) + n1\_i \cdot u\right)} \]
    3. *-commutativeN/A

      \[\leadsto \left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right)\right) \cdot {normAngle}^{2} + \left(\color{blue}{n0\_i \cdot \left(1 - u\right)} + n1\_i \cdot u\right) \]
    4. lower-fma.f32N/A

      \[\leadsto \mathsf{fma}\left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right), \color{blue}{{normAngle}^{2}}, n0\_i \cdot \left(1 - u\right) + n1\_i \cdot u\right) \]
  5. Applied rewrites98.5%

    \[\leadsto \color{blue}{\mathsf{fma}\left(-0.16666666666666666 \cdot \left(\mathsf{fma}\left({u}^{3}, n1\_i, {\left(1 - u\right)}^{3} \cdot n0\_i\right) - \mathsf{fma}\left(1 - u, n0\_i, n1\_i \cdot u\right)\right), normAngle \cdot normAngle, \mathsf{fma}\left(1 - u, n0\_i, n1\_i \cdot u\right)\right)} \]
  6. Taylor expanded in u around 0

    \[\leadsto n0\_i + \color{blue}{u \cdot \left(n1\_i + \left(-1 \cdot n0\_i + \frac{-1}{6} \cdot \left({normAngle}^{2} \cdot \left(-3 \cdot n0\_i - \left(n1\_i + -1 \cdot n0\_i\right)\right)\right)\right)\right)} \]
  7. Step-by-step derivation
    1. +-commutativeN/A

      \[\leadsto u \cdot \left(n1\_i + \left(-1 \cdot n0\_i + \frac{-1}{6} \cdot \left({normAngle}^{2} \cdot \left(-3 \cdot n0\_i - \left(n1\_i + -1 \cdot n0\_i\right)\right)\right)\right)\right) + n0\_i \]
    2. *-commutativeN/A

      \[\leadsto \left(n1\_i + \left(-1 \cdot n0\_i + \frac{-1}{6} \cdot \left({normAngle}^{2} \cdot \left(-3 \cdot n0\_i - \left(n1\_i + -1 \cdot n0\_i\right)\right)\right)\right)\right) \cdot u + n0\_i \]
    3. lower-fma.f32N/A

      \[\leadsto \mathsf{fma}\left(n1\_i + \left(-1 \cdot n0\_i + \frac{-1}{6} \cdot \left({normAngle}^{2} \cdot \left(-3 \cdot n0\_i - \left(n1\_i + -1 \cdot n0\_i\right)\right)\right)\right), u, n0\_i\right) \]
  8. Applied rewrites98.8%

    \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\left(\left(-3 \cdot n0\_i - n1\_i\right) - \left(-n0\_i\right)\right) \cdot \left(normAngle \cdot normAngle\right), -0.16666666666666666, -n0\_i\right) + n1\_i, \color{blue}{u}, n0\_i\right) \]
  9. Final simplification98.8%

    \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\left(\left(-3 \cdot n0\_i - n1\_i\right) + n0\_i\right) \cdot \left(normAngle \cdot normAngle\right), -0.16666666666666666, -n0\_i\right) + n1\_i, u, n0\_i\right) \]
  10. Add Preprocessing

Alternative 4: 98.6% accurate, 13.9× speedup?

\[\begin{array}{l} \\ \mathsf{fma}\left(\mathsf{fma}\left(\left(\left(-n1\_i\right) + n0\_i\right) \cdot \left(normAngle \cdot normAngle\right), -0.16666666666666666, -n0\_i\right) + n1\_i, u, n0\_i\right) \end{array} \]
(FPCore (normAngle u n0_i n1_i)
 :precision binary32
 (fma
  (+
   (fma
    (* (+ (- n1_i) n0_i) (* normAngle normAngle))
    -0.16666666666666666
    (- n0_i))
   n1_i)
  u
  n0_i))
float code(float normAngle, float u, float n0_i, float n1_i) {
	return fmaf((fmaf(((-n1_i + n0_i) * (normAngle * normAngle)), -0.16666666666666666f, -n0_i) + n1_i), u, n0_i);
}
function code(normAngle, u, n0_i, n1_i)
	return fma(Float32(fma(Float32(Float32(Float32(-n1_i) + n0_i) * Float32(normAngle * normAngle)), Float32(-0.16666666666666666), Float32(-n0_i)) + n1_i), u, n0_i)
end
\begin{array}{l}

\\
\mathsf{fma}\left(\mathsf{fma}\left(\left(\left(-n1\_i\right) + n0\_i\right) \cdot \left(normAngle \cdot normAngle\right), -0.16666666666666666, -n0\_i\right) + n1\_i, u, n0\_i\right)
\end{array}
Derivation
  1. Initial program 95.7%

    \[\left(\sin \left(\left(1 - u\right) \cdot normAngle\right) \cdot \frac{1}{\sin normAngle}\right) \cdot n0\_i + \left(\sin \left(u \cdot normAngle\right) \cdot \frac{1}{\sin normAngle}\right) \cdot n1\_i \]
  2. Add Preprocessing
  3. Taylor expanded in normAngle around 0

    \[\leadsto \color{blue}{n0\_i \cdot \left(1 - u\right) + \left(n1\_i \cdot u + {normAngle}^{2} \cdot \left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right)\right)\right)} \]
  4. Step-by-step derivation
    1. associate-+r+N/A

      \[\leadsto \left(n0\_i \cdot \left(1 - u\right) + n1\_i \cdot u\right) + \color{blue}{{normAngle}^{2} \cdot \left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right)\right)} \]
    2. +-commutativeN/A

      \[\leadsto {normAngle}^{2} \cdot \left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right)\right) + \color{blue}{\left(n0\_i \cdot \left(1 - u\right) + n1\_i \cdot u\right)} \]
    3. *-commutativeN/A

      \[\leadsto \left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right)\right) \cdot {normAngle}^{2} + \left(\color{blue}{n0\_i \cdot \left(1 - u\right)} + n1\_i \cdot u\right) \]
    4. lower-fma.f32N/A

      \[\leadsto \mathsf{fma}\left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right), \color{blue}{{normAngle}^{2}}, n0\_i \cdot \left(1 - u\right) + n1\_i \cdot u\right) \]
  5. Applied rewrites98.5%

    \[\leadsto \color{blue}{\mathsf{fma}\left(-0.16666666666666666 \cdot \left(\mathsf{fma}\left({u}^{3}, n1\_i, {\left(1 - u\right)}^{3} \cdot n0\_i\right) - \mathsf{fma}\left(1 - u, n0\_i, n1\_i \cdot u\right)\right), normAngle \cdot normAngle, \mathsf{fma}\left(1 - u, n0\_i, n1\_i \cdot u\right)\right)} \]
  6. Taylor expanded in u around 0

    \[\leadsto n0\_i + \color{blue}{u \cdot \left(n1\_i + \left(-1 \cdot n0\_i + \frac{-1}{6} \cdot \left({normAngle}^{2} \cdot \left(-3 \cdot n0\_i - \left(n1\_i + -1 \cdot n0\_i\right)\right)\right)\right)\right)} \]
  7. Step-by-step derivation
    1. +-commutativeN/A

      \[\leadsto u \cdot \left(n1\_i + \left(-1 \cdot n0\_i + \frac{-1}{6} \cdot \left({normAngle}^{2} \cdot \left(-3 \cdot n0\_i - \left(n1\_i + -1 \cdot n0\_i\right)\right)\right)\right)\right) + n0\_i \]
    2. *-commutativeN/A

      \[\leadsto \left(n1\_i + \left(-1 \cdot n0\_i + \frac{-1}{6} \cdot \left({normAngle}^{2} \cdot \left(-3 \cdot n0\_i - \left(n1\_i + -1 \cdot n0\_i\right)\right)\right)\right)\right) \cdot u + n0\_i \]
    3. lower-fma.f32N/A

      \[\leadsto \mathsf{fma}\left(n1\_i + \left(-1 \cdot n0\_i + \frac{-1}{6} \cdot \left({normAngle}^{2} \cdot \left(-3 \cdot n0\_i - \left(n1\_i + -1 \cdot n0\_i\right)\right)\right)\right), u, n0\_i\right) \]
  8. Applied rewrites98.8%

    \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\left(\left(-3 \cdot n0\_i - n1\_i\right) - \left(-n0\_i\right)\right) \cdot \left(normAngle \cdot normAngle\right), -0.16666666666666666, -n0\_i\right) + n1\_i, \color{blue}{u}, n0\_i\right) \]
  9. Taylor expanded in n0_i around 0

    \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\left(-1 \cdot n1\_i - \left(-n0\_i\right)\right) \cdot \left(normAngle \cdot normAngle\right), \frac{-1}{6}, -n0\_i\right) + n1\_i, u, n0\_i\right) \]
  10. Step-by-step derivation
    1. mul-1-negN/A

      \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\left(\left(\mathsf{neg}\left(n1\_i\right)\right) - \left(-n0\_i\right)\right) \cdot \left(normAngle \cdot normAngle\right), \frac{-1}{6}, -n0\_i\right) + n1\_i, u, n0\_i\right) \]
    2. lower-neg.f3298.7

      \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\left(\left(-n1\_i\right) - \left(-n0\_i\right)\right) \cdot \left(normAngle \cdot normAngle\right), -0.16666666666666666, -n0\_i\right) + n1\_i, u, n0\_i\right) \]
  11. Applied rewrites98.7%

    \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\left(\left(-n1\_i\right) - \left(-n0\_i\right)\right) \cdot \left(normAngle \cdot normAngle\right), -0.16666666666666666, -n0\_i\right) + n1\_i, u, n0\_i\right) \]
  12. Final simplification98.7%

    \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\left(\left(-n1\_i\right) + n0\_i\right) \cdot \left(normAngle \cdot normAngle\right), -0.16666666666666666, -n0\_i\right) + n1\_i, u, n0\_i\right) \]
  13. Add Preprocessing

Alternative 5: 98.7% accurate, 16.4× speedup?

\[\begin{array}{l} \\ \mathsf{fma}\left(\left(n1\_i - n0\_i\right) + \left(\left(normAngle \cdot normAngle\right) \cdot n1\_i\right) \cdot 0.16666666666666666, u, n0\_i\right) \end{array} \]
(FPCore (normAngle u n0_i n1_i)
 :precision binary32
 (fma
  (+ (- n1_i n0_i) (* (* (* normAngle normAngle) n1_i) 0.16666666666666666))
  u
  n0_i))
float code(float normAngle, float u, float n0_i, float n1_i) {
	return fmaf(((n1_i - n0_i) + (((normAngle * normAngle) * n1_i) * 0.16666666666666666f)), u, n0_i);
}
function code(normAngle, u, n0_i, n1_i)
	return fma(Float32(Float32(n1_i - n0_i) + Float32(Float32(Float32(normAngle * normAngle) * n1_i) * Float32(0.16666666666666666))), u, n0_i)
end
\begin{array}{l}

\\
\mathsf{fma}\left(\left(n1\_i - n0\_i\right) + \left(\left(normAngle \cdot normAngle\right) \cdot n1\_i\right) \cdot 0.16666666666666666, u, n0\_i\right)
\end{array}
Derivation
  1. Initial program 95.7%

    \[\left(\sin \left(\left(1 - u\right) \cdot normAngle\right) \cdot \frac{1}{\sin normAngle}\right) \cdot n0\_i + \left(\sin \left(u \cdot normAngle\right) \cdot \frac{1}{\sin normAngle}\right) \cdot n1\_i \]
  2. Add Preprocessing
  3. Taylor expanded in normAngle around 0

    \[\leadsto \color{blue}{n0\_i \cdot \left(1 - u\right) + \left(n1\_i \cdot u + {normAngle}^{2} \cdot \left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right)\right)\right)} \]
  4. Step-by-step derivation
    1. associate-+r+N/A

      \[\leadsto \left(n0\_i \cdot \left(1 - u\right) + n1\_i \cdot u\right) + \color{blue}{{normAngle}^{2} \cdot \left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right)\right)} \]
    2. +-commutativeN/A

      \[\leadsto {normAngle}^{2} \cdot \left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right)\right) + \color{blue}{\left(n0\_i \cdot \left(1 - u\right) + n1\_i \cdot u\right)} \]
    3. *-commutativeN/A

      \[\leadsto \left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right)\right) \cdot {normAngle}^{2} + \left(\color{blue}{n0\_i \cdot \left(1 - u\right)} + n1\_i \cdot u\right) \]
    4. lower-fma.f32N/A

      \[\leadsto \mathsf{fma}\left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right), \color{blue}{{normAngle}^{2}}, n0\_i \cdot \left(1 - u\right) + n1\_i \cdot u\right) \]
  5. Applied rewrites98.5%

    \[\leadsto \color{blue}{\mathsf{fma}\left(-0.16666666666666666 \cdot \left(\mathsf{fma}\left({u}^{3}, n1\_i, {\left(1 - u\right)}^{3} \cdot n0\_i\right) - \mathsf{fma}\left(1 - u, n0\_i, n1\_i \cdot u\right)\right), normAngle \cdot normAngle, \mathsf{fma}\left(1 - u, n0\_i, n1\_i \cdot u\right)\right)} \]
  6. Taylor expanded in u around 0

    \[\leadsto n0\_i + \color{blue}{u \cdot \left(n1\_i + \left(-1 \cdot n0\_i + \frac{-1}{6} \cdot \left({normAngle}^{2} \cdot \left(-3 \cdot n0\_i - \left(n1\_i + -1 \cdot n0\_i\right)\right)\right)\right)\right)} \]
  7. Step-by-step derivation
    1. +-commutativeN/A

      \[\leadsto u \cdot \left(n1\_i + \left(-1 \cdot n0\_i + \frac{-1}{6} \cdot \left({normAngle}^{2} \cdot \left(-3 \cdot n0\_i - \left(n1\_i + -1 \cdot n0\_i\right)\right)\right)\right)\right) + n0\_i \]
    2. *-commutativeN/A

      \[\leadsto \left(n1\_i + \left(-1 \cdot n0\_i + \frac{-1}{6} \cdot \left({normAngle}^{2} \cdot \left(-3 \cdot n0\_i - \left(n1\_i + -1 \cdot n0\_i\right)\right)\right)\right)\right) \cdot u + n0\_i \]
    3. lower-fma.f32N/A

      \[\leadsto \mathsf{fma}\left(n1\_i + \left(-1 \cdot n0\_i + \frac{-1}{6} \cdot \left({normAngle}^{2} \cdot \left(-3 \cdot n0\_i - \left(n1\_i + -1 \cdot n0\_i\right)\right)\right)\right), u, n0\_i\right) \]
  8. Applied rewrites98.8%

    \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\left(\left(-3 \cdot n0\_i - n1\_i\right) - \left(-n0\_i\right)\right) \cdot \left(normAngle \cdot normAngle\right), -0.16666666666666666, -n0\_i\right) + n1\_i, \color{blue}{u}, n0\_i\right) \]
  9. Taylor expanded in u around 0

    \[\leadsto n0\_i + \color{blue}{u \cdot \left(n1\_i + \left(-1 \cdot n0\_i + \left(\frac{-1}{2} \cdot \left(n0\_i \cdot \left({normAngle}^{2} \cdot u\right)\right) + \frac{-1}{6} \cdot \left({normAngle}^{2} \cdot \left(-3 \cdot n0\_i - \left(n1\_i + -1 \cdot n0\_i\right)\right)\right)\right)\right)\right)} \]
  10. Applied rewrites98.9%

    \[\leadsto \mathsf{fma}\left(\left(n1\_i - n0\_i\right) + \mathsf{fma}\left(-0.5 \cdot n0\_i, \left(normAngle \cdot normAngle\right) \cdot u, \left(\left(normAngle \cdot normAngle\right) \cdot -0.16666666666666666\right) \cdot \left(-2 \cdot n0\_i - n1\_i\right)\right), \color{blue}{u}, n0\_i\right) \]
  11. Taylor expanded in n0_i around 0

    \[\leadsto \mathsf{fma}\left(\left(n1\_i - n0\_i\right) + \frac{1}{6} \cdot \left(n1\_i \cdot {normAngle}^{2}\right), u, n0\_i\right) \]
  12. Step-by-step derivation
    1. *-commutativeN/A

      \[\leadsto \mathsf{fma}\left(\left(n1\_i - n0\_i\right) + \left(n1\_i \cdot {normAngle}^{2}\right) \cdot \frac{1}{6}, u, n0\_i\right) \]
    2. lower-*.f32N/A

      \[\leadsto \mathsf{fma}\left(\left(n1\_i - n0\_i\right) + \left(n1\_i \cdot {normAngle}^{2}\right) \cdot \frac{1}{6}, u, n0\_i\right) \]
    3. *-commutativeN/A

      \[\leadsto \mathsf{fma}\left(\left(n1\_i - n0\_i\right) + \left({normAngle}^{2} \cdot n1\_i\right) \cdot \frac{1}{6}, u, n0\_i\right) \]
    4. lower-*.f32N/A

      \[\leadsto \mathsf{fma}\left(\left(n1\_i - n0\_i\right) + \left({normAngle}^{2} \cdot n1\_i\right) \cdot \frac{1}{6}, u, n0\_i\right) \]
    5. unpow2N/A

      \[\leadsto \mathsf{fma}\left(\left(n1\_i - n0\_i\right) + \left(\left(normAngle \cdot normAngle\right) \cdot n1\_i\right) \cdot \frac{1}{6}, u, n0\_i\right) \]
    6. lower-*.f3298.7

      \[\leadsto \mathsf{fma}\left(\left(n1\_i - n0\_i\right) + \left(\left(normAngle \cdot normAngle\right) \cdot n1\_i\right) \cdot 0.16666666666666666, u, n0\_i\right) \]
  13. Applied rewrites98.7%

    \[\leadsto \mathsf{fma}\left(\left(n1\_i - n0\_i\right) + \left(\left(normAngle \cdot normAngle\right) \cdot n1\_i\right) \cdot 0.16666666666666666, u, n0\_i\right) \]
  14. Add Preprocessing

Alternative 6: 98.0% accurate, 45.9× speedup?

\[\begin{array}{l} \\ \mathsf{fma}\left(n1\_i - n0\_i, u, n0\_i\right) \end{array} \]
(FPCore (normAngle u n0_i n1_i) :precision binary32 (fma (- n1_i n0_i) u n0_i))
float code(float normAngle, float u, float n0_i, float n1_i) {
	return fmaf((n1_i - n0_i), u, n0_i);
}
function code(normAngle, u, n0_i, n1_i)
	return fma(Float32(n1_i - n0_i), u, n0_i)
end
\begin{array}{l}

\\
\mathsf{fma}\left(n1\_i - n0\_i, u, n0\_i\right)
\end{array}
Derivation
  1. Initial program 95.7%

    \[\left(\sin \left(\left(1 - u\right) \cdot normAngle\right) \cdot \frac{1}{\sin normAngle}\right) \cdot n0\_i + \left(\sin \left(u \cdot normAngle\right) \cdot \frac{1}{\sin normAngle}\right) \cdot n1\_i \]
  2. Add Preprocessing
  3. Taylor expanded in normAngle around 0

    \[\leadsto \color{blue}{n0\_i \cdot \left(1 - u\right) + \left(n1\_i \cdot u + {normAngle}^{2} \cdot \left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right)\right)\right)} \]
  4. Step-by-step derivation
    1. associate-+r+N/A

      \[\leadsto \left(n0\_i \cdot \left(1 - u\right) + n1\_i \cdot u\right) + \color{blue}{{normAngle}^{2} \cdot \left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right)\right)} \]
    2. +-commutativeN/A

      \[\leadsto {normAngle}^{2} \cdot \left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right)\right) + \color{blue}{\left(n0\_i \cdot \left(1 - u\right) + n1\_i \cdot u\right)} \]
    3. *-commutativeN/A

      \[\leadsto \left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right)\right) \cdot {normAngle}^{2} + \left(\color{blue}{n0\_i \cdot \left(1 - u\right)} + n1\_i \cdot u\right) \]
    4. lower-fma.f32N/A

      \[\leadsto \mathsf{fma}\left(\left(\frac{-1}{6} \cdot \left(n0\_i \cdot {\left(1 - u\right)}^{3}\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \left(\frac{-1}{6} \cdot \left(n0\_i \cdot \left(1 - u\right)\right) + \frac{-1}{6} \cdot \left(n1\_i \cdot u\right)\right), \color{blue}{{normAngle}^{2}}, n0\_i \cdot \left(1 - u\right) + n1\_i \cdot u\right) \]
  5. Applied rewrites98.5%

    \[\leadsto \color{blue}{\mathsf{fma}\left(-0.16666666666666666 \cdot \left(\mathsf{fma}\left({u}^{3}, n1\_i, {\left(1 - u\right)}^{3} \cdot n0\_i\right) - \mathsf{fma}\left(1 - u, n0\_i, n1\_i \cdot u\right)\right), normAngle \cdot normAngle, \mathsf{fma}\left(1 - u, n0\_i, n1\_i \cdot u\right)\right)} \]
  6. Taylor expanded in u around 0

    \[\leadsto n0\_i + \color{blue}{u \cdot \left(n1\_i + \left(-1 \cdot n0\_i + \frac{-1}{6} \cdot \left({normAngle}^{2} \cdot \left(-3 \cdot n0\_i - \left(n1\_i + -1 \cdot n0\_i\right)\right)\right)\right)\right)} \]
  7. Step-by-step derivation
    1. +-commutativeN/A

      \[\leadsto u \cdot \left(n1\_i + \left(-1 \cdot n0\_i + \frac{-1}{6} \cdot \left({normAngle}^{2} \cdot \left(-3 \cdot n0\_i - \left(n1\_i + -1 \cdot n0\_i\right)\right)\right)\right)\right) + n0\_i \]
    2. *-commutativeN/A

      \[\leadsto \left(n1\_i + \left(-1 \cdot n0\_i + \frac{-1}{6} \cdot \left({normAngle}^{2} \cdot \left(-3 \cdot n0\_i - \left(n1\_i + -1 \cdot n0\_i\right)\right)\right)\right)\right) \cdot u + n0\_i \]
    3. lower-fma.f32N/A

      \[\leadsto \mathsf{fma}\left(n1\_i + \left(-1 \cdot n0\_i + \frac{-1}{6} \cdot \left({normAngle}^{2} \cdot \left(-3 \cdot n0\_i - \left(n1\_i + -1 \cdot n0\_i\right)\right)\right)\right), u, n0\_i\right) \]
  8. Applied rewrites98.8%

    \[\leadsto \mathsf{fma}\left(\mathsf{fma}\left(\left(\left(-3 \cdot n0\_i - n1\_i\right) - \left(-n0\_i\right)\right) \cdot \left(normAngle \cdot normAngle\right), -0.16666666666666666, -n0\_i\right) + n1\_i, \color{blue}{u}, n0\_i\right) \]
  9. Taylor expanded in normAngle around 0

    \[\leadsto \mathsf{fma}\left(n1\_i - n0\_i, u, n0\_i\right) \]
  10. Step-by-step derivation
    1. lower--.f3297.6

      \[\leadsto \mathsf{fma}\left(n1\_i - n0\_i, u, n0\_i\right) \]
  11. Applied rewrites97.6%

    \[\leadsto \mathsf{fma}\left(n1\_i - n0\_i, u, n0\_i\right) \]
  12. Add Preprocessing

Alternative 7: 81.5% accurate, 65.6× speedup?

\[\begin{array}{l} \\ \mathsf{fma}\left(u, n1\_i, n0\_i\right) \end{array} \]
(FPCore (normAngle u n0_i n1_i) :precision binary32 (fma u n1_i n0_i))
float code(float normAngle, float u, float n0_i, float n1_i) {
	return fmaf(u, n1_i, n0_i);
}
function code(normAngle, u, n0_i, n1_i)
	return fma(u, n1_i, n0_i)
end
\begin{array}{l}

\\
\mathsf{fma}\left(u, n1\_i, n0\_i\right)
\end{array}
Derivation
  1. Initial program 95.7%

    \[\left(\sin \left(\left(1 - u\right) \cdot normAngle\right) \cdot \frac{1}{\sin normAngle}\right) \cdot n0\_i + \left(\sin \left(u \cdot normAngle\right) \cdot \frac{1}{\sin normAngle}\right) \cdot n1\_i \]
  2. Add Preprocessing
  3. Taylor expanded in u around 0

    \[\leadsto \color{blue}{n0\_i} + \left(\sin \left(u \cdot normAngle\right) \cdot \frac{1}{\sin normAngle}\right) \cdot n1\_i \]
  4. Step-by-step derivation
    1. Applied rewrites76.9%

      \[\leadsto \color{blue}{n0\_i} + \left(\sin \left(u \cdot normAngle\right) \cdot \frac{1}{\sin normAngle}\right) \cdot n1\_i \]
    2. Taylor expanded in normAngle around 0

      \[\leadsto n0\_i + \color{blue}{u} \cdot n1\_i \]
    3. Step-by-step derivation
      1. Applied rewrites78.3%

        \[\leadsto n0\_i + \color{blue}{u} \cdot n1\_i \]
      2. Step-by-step derivation
        1. lift-+.f32N/A

          \[\leadsto \color{blue}{n0\_i + u \cdot n1\_i} \]
        2. +-commutativeN/A

          \[\leadsto \color{blue}{u \cdot n1\_i + n0\_i} \]
        3. lift-*.f32N/A

          \[\leadsto \color{blue}{u \cdot n1\_i} + n0\_i \]
        4. lower-fma.f3278.4

          \[\leadsto \color{blue}{\mathsf{fma}\left(u, n1\_i, n0\_i\right)} \]
      3. Applied rewrites78.4%

        \[\leadsto \color{blue}{\mathsf{fma}\left(u, n1\_i, n0\_i\right)} \]
      4. Add Preprocessing

      Alternative 8: 47.1% accurate, 459.0× speedup?

      \[\begin{array}{l} \\ n0\_i \end{array} \]
      (FPCore (normAngle u n0_i n1_i) :precision binary32 n0_i)
      float code(float normAngle, float u, float n0_i, float n1_i) {
      	return n0_i;
      }
      
      module fmin_fmax_functions
          implicit none
          private
          public fmax
          public fmin
      
          interface fmax
              module procedure fmax88
              module procedure fmax44
              module procedure fmax84
              module procedure fmax48
          end interface
          interface fmin
              module procedure fmin88
              module procedure fmin44
              module procedure fmin84
              module procedure fmin48
          end interface
      contains
          real(8) function fmax88(x, y) result (res)
              real(8), intent (in) :: x
              real(8), intent (in) :: y
              res = merge(y, merge(x, max(x, y), y /= y), x /= x)
          end function
          real(4) function fmax44(x, y) result (res)
              real(4), intent (in) :: x
              real(4), intent (in) :: y
              res = merge(y, merge(x, max(x, y), y /= y), x /= x)
          end function
          real(8) function fmax84(x, y) result(res)
              real(8), intent (in) :: x
              real(4), intent (in) :: y
              res = merge(dble(y), merge(x, max(x, dble(y)), y /= y), x /= x)
          end function
          real(8) function fmax48(x, y) result(res)
              real(4), intent (in) :: x
              real(8), intent (in) :: y
              res = merge(y, merge(dble(x), max(dble(x), y), y /= y), x /= x)
          end function
          real(8) function fmin88(x, y) result (res)
              real(8), intent (in) :: x
              real(8), intent (in) :: y
              res = merge(y, merge(x, min(x, y), y /= y), x /= x)
          end function
          real(4) function fmin44(x, y) result (res)
              real(4), intent (in) :: x
              real(4), intent (in) :: y
              res = merge(y, merge(x, min(x, y), y /= y), x /= x)
          end function
          real(8) function fmin84(x, y) result(res)
              real(8), intent (in) :: x
              real(4), intent (in) :: y
              res = merge(dble(y), merge(x, min(x, dble(y)), y /= y), x /= x)
          end function
          real(8) function fmin48(x, y) result(res)
              real(4), intent (in) :: x
              real(8), intent (in) :: y
              res = merge(y, merge(dble(x), min(dble(x), y), y /= y), x /= x)
          end function
      end module
      
      real(4) function code(normangle, u, n0_i, n1_i)
      use fmin_fmax_functions
          real(4), intent (in) :: normangle
          real(4), intent (in) :: u
          real(4), intent (in) :: n0_i
          real(4), intent (in) :: n1_i
          code = n0_i
      end function
      
      function code(normAngle, u, n0_i, n1_i)
      	return n0_i
      end
      
      function tmp = code(normAngle, u, n0_i, n1_i)
      	tmp = n0_i;
      end
      
      \begin{array}{l}
      
      \\
      n0\_i
      \end{array}
      
      Derivation
      1. Initial program 95.7%

        \[\left(\sin \left(\left(1 - u\right) \cdot normAngle\right) \cdot \frac{1}{\sin normAngle}\right) \cdot n0\_i + \left(\sin \left(u \cdot normAngle\right) \cdot \frac{1}{\sin normAngle}\right) \cdot n1\_i \]
      2. Add Preprocessing
      3. Taylor expanded in u around 0

        \[\leadsto \color{blue}{n0\_i} \]
      4. Step-by-step derivation
        1. Applied rewrites42.5%

          \[\leadsto \color{blue}{n0\_i} \]
        2. Add Preprocessing

        Reproduce

        ?
        herbie shell --seed 2025026 
        (FPCore (normAngle u n0_i n1_i)
          :name "Curve intersection, scale width based on ribbon orientation"
          :precision binary32
          :pre (and (and (and (and (<= 0.0 normAngle) (<= normAngle (/ (PI) 2.0))) (and (<= -1.0 n0_i) (<= n0_i 1.0))) (and (<= -1.0 n1_i) (<= n1_i 1.0))) (and (<= 2.328306437e-10 u) (<= u 1.0)))
          (+ (* (* (sin (* (- 1.0 u) normAngle)) (/ 1.0 (sin normAngle))) n0_i) (* (* (sin (* u normAngle)) (/ 1.0 (sin normAngle))) n1_i)))