Curve intersection, scale width based on ribbon orientation

Percentage Accurate: 97.3% → 99.0%
Time: 5.6s
Alternatives: 5
Speedup: 19.5×

Specification

?
\[\left(\left(\left(0 \leq normAngle \land normAngle \leq \frac{\pi}{2}\right) \land \left(-1 \leq n0\_i \land n0\_i \leq 1\right)\right) \land \left(-1 \leq n1\_i \land n1\_i \leq 1\right)\right) \land \left(2.328306437 \cdot 10^{-10} \leq u \land u \leq 1\right)\]
\[\begin{array}{l} t_0 := \frac{1}{\sin normAngle}\\ \left(\sin \left(\left(1 - u\right) \cdot normAngle\right) \cdot t\_0\right) \cdot n0\_i + \left(\sin \left(u \cdot normAngle\right) \cdot t\_0\right) \cdot n1\_i \end{array} \]
(FPCore (normAngle u n0_i n1_i)
  :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)))
  (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);
}
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}
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}

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 5 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: 97.3% accurate, 1.0× speedup?

\[\left(\left(\left(0 \leq normAngle \land normAngle \leq \frac{\pi}{2}\right) \land \left(-1 \leq n0\_i \land n0\_i \leq 1\right)\right) \land \left(-1 \leq n1\_i \land n1\_i \leq 1\right)\right) \land \left(2.328306437 \cdot 10^{-10} \leq u \land u \leq 1\right)\]
\[\begin{array}{l} t_0 := \frac{1}{\sin normAngle}\\ \left(\sin \left(\left(1 - u\right) \cdot normAngle\right) \cdot t\_0\right) \cdot n0\_i + \left(\sin \left(u \cdot normAngle\right) \cdot t\_0\right) \cdot n1\_i \end{array} \]
(FPCore (normAngle u n0_i n1_i)
  :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)))
  (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);
}
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}
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}

Alternative 1: 99.0% accurate, 6.7× speedup?

\[\left(\left(\left(0 \leq normAngle \land normAngle \leq \frac{\pi}{2}\right) \land \left(-1 \leq n0\_i \land n0\_i \leq 1\right)\right) \land \left(-1 \leq n1\_i \land n1\_i \leq 1\right)\right) \land \left(2.328306437 \cdot 10^{-10} \leq u \land u \leq 1\right)\]
\[\mathsf{fma}\left(\left(n1\_i - n0\_i\right) - \mathsf{fma}\left(-0.3333333333333333, n0\_i, -0.16666666666666666 \cdot n1\_i\right) \cdot \left(normAngle \cdot normAngle\right), u, n0\_i\right) \]
(FPCore (normAngle u n0_i n1_i)
  :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)))
  (fma
 (-
  (- n1_i n0_i)
  (*
   (fma -0.3333333333333333 n0_i (* -0.16666666666666666 n1_i))
   (* normAngle normAngle)))
 u
 n0_i))
float code(float normAngle, float u, float n0_i, float n1_i) {
	return fmaf(((n1_i - n0_i) - (fmaf(-0.3333333333333333f, n0_i, (-0.16666666666666666f * n1_i)) * (normAngle * normAngle))), u, n0_i);
}
function code(normAngle, u, n0_i, n1_i)
	return fma(Float32(Float32(n1_i - n0_i) - Float32(fma(Float32(-0.3333333333333333), n0_i, Float32(Float32(-0.16666666666666666) * n1_i)) * Float32(normAngle * normAngle))), u, n0_i)
end
\mathsf{fma}\left(\left(n1\_i - n0\_i\right) - \mathsf{fma}\left(-0.3333333333333333, n0\_i, -0.16666666666666666 \cdot n1\_i\right) \cdot \left(normAngle \cdot normAngle\right), u, n0\_i\right)
Derivation
  1. Initial program 97.3%

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

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

      \[\leadsto \mathsf{fma}\left(n0\_i, 1 - u, \mathsf{fma}\left(n1\_i, u, {normAngle}^{2} \cdot \left(\mathsf{fma}\left(-0.16666666666666666, n0\_i \cdot {\left(1 - u\right)}^{3}, -0.16666666666666666 \cdot \left(n1\_i \cdot {u}^{3}\right)\right) - \mathsf{fma}\left(-0.16666666666666666, n0\_i \cdot \left(1 - u\right), -0.16666666666666666 \cdot \left(n1\_i \cdot u\right)\right)\right)\right)\right) \]
    2. Taylor expanded in u around 0

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

        \[\leadsto n0\_i + u \cdot \left(n1\_i + \mathsf{fma}\left(-1, n0\_i, {normAngle}^{2} \cdot \left(0.5 \cdot n0\_i - \mathsf{fma}\left(-0.16666666666666666, n1\_i, 0.16666666666666666 \cdot n0\_i\right)\right)\right)\right) \]
      2. Applied rewrites99.0%

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

        \[\leadsto \mathsf{fma}\left(\left(n1\_i - n0\_i\right) - \left(\frac{-1}{3} \cdot n0\_i + \frac{-1}{6} \cdot n1\_i\right) \cdot \left(normAngle \cdot normAngle\right), u, n0\_i\right) \]
      4. Step-by-step derivation
        1. Applied rewrites99.0%

          \[\leadsto \mathsf{fma}\left(\left(n1\_i - n0\_i\right) - \mathsf{fma}\left(-0.3333333333333333, n0\_i, -0.16666666666666666 \cdot n1\_i\right) \cdot \left(normAngle \cdot normAngle\right), u, n0\_i\right) \]
        2. Add Preprocessing

        Alternative 2: 98.1% accurate, 19.5× speedup?

        \[\left(\left(\left(0 \leq normAngle \land normAngle \leq \frac{\pi}{2}\right) \land \left(-1 \leq n0\_i \land n0\_i \leq 1\right)\right) \land \left(-1 \leq n1\_i \land n1\_i \leq 1\right)\right) \land \left(2.328306437 \cdot 10^{-10} \leq u \land u \leq 1\right)\]
        \[\mathsf{fma}\left(n1\_i - n0\_i, u, n0\_i\right) \]
        (FPCore (normAngle u n0_i n1_i)
          :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)))
          (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
        
        \mathsf{fma}\left(n1\_i - n0\_i, u, n0\_i\right)
        
        Derivation
        1. Initial program 97.3%

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

          \[\leadsto n0\_i + u \cdot \left(-1 \cdot \frac{n0\_i \cdot \left(normAngle \cdot \cos normAngle\right)}{\sin normAngle} + \frac{n1\_i \cdot normAngle}{\sin normAngle}\right) \]
        3. Step-by-step derivation
          1. Applied rewrites88.8%

            \[\leadsto n0\_i + u \cdot \mathsf{fma}\left(-1, \frac{n0\_i \cdot \left(normAngle \cdot \cos normAngle\right)}{\sin normAngle}, \frac{n1\_i \cdot normAngle}{\sin normAngle}\right) \]
          2. Taylor expanded in normAngle around 0

            \[\leadsto n0\_i + u \cdot \left(n1\_i + -1 \cdot n0\_i\right) \]
          3. Step-by-step derivation
            1. Applied rewrites98.0%

              \[\leadsto n0\_i + u \cdot \left(n1\_i + -1 \cdot n0\_i\right) \]
            2. Applied rewrites98.1%

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

            Alternative 3: 81.8% accurate, 28.0× speedup?

            \[\left(\left(\left(0 \leq normAngle \land normAngle \leq \frac{\pi}{2}\right) \land \left(-1 \leq n0\_i \land n0\_i \leq 1\right)\right) \land \left(-1 \leq n1\_i \land n1\_i \leq 1\right)\right) \land \left(2.328306437 \cdot 10^{-10} \leq u \land u \leq 1\right)\]
            \[\mathsf{fma}\left(u, n1\_i, n0\_i\right) \]
            (FPCore (normAngle u n0_i n1_i)
              :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)))
              (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
            
            \mathsf{fma}\left(u, n1\_i, n0\_i\right)
            
            Derivation
            1. Initial program 97.3%

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

              \[\leadsto n0\_i + \left(\sin \left(u \cdot normAngle\right) \cdot \frac{1}{\sin normAngle}\right) \cdot n1\_i \]
            3. Step-by-step derivation
              1. Applied rewrites81.3%

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

                \[\leadsto n0\_i + u \cdot n1\_i \]
              3. Step-by-step derivation
                1. Applied rewrites81.7%

                  \[\leadsto n0\_i + u \cdot n1\_i \]
                2. Step-by-step derivation
                  1. Applied rewrites81.8%

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

                  Alternative 4: 60.1% accurate, 12.3× speedup?

                  \[\left(\left(\left(0 \leq normAngle \land normAngle \leq \frac{\pi}{2}\right) \land \left(-1 \leq n0\_i \land n0\_i \leq 1\right)\right) \land \left(-1 \leq n1\_i \land n1\_i \leq 1\right)\right) \land \left(2.328306437 \cdot 10^{-10} \leq u \land u \leq 1\right)\]
                  \[\begin{array}{l} t_0 := -\left(-u\right) \cdot n1\_i\\ \mathbf{if}\;n1\_i \leq -1.4564692236958598 \cdot 10^{-18}:\\ \;\;\;\;t\_0\\ \mathbf{elif}\;n1\_i \leq 1.1249517491201857 \cdot 10^{-22}:\\ \;\;\;\;\left(-n0\_i\right) \cdot -1\\ \mathbf{else}:\\ \;\;\;\;t\_0\\ \end{array} \]
                  (FPCore (normAngle u n0_i n1_i)
                    :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)))
                    (let* ((t_0 (- (* (- u) n1_i))))
                    (if (<= n1_i -1.4564692236958598e-18)
                      t_0
                      (if (<= n1_i 1.1249517491201857e-22) (* (- n0_i) -1.0) t_0))))
                  float code(float normAngle, float u, float n0_i, float n1_i) {
                  	float t_0 = -(-u * n1_i);
                  	float tmp;
                  	if (n1_i <= -1.4564692236958598e-18f) {
                  		tmp = t_0;
                  	} else if (n1_i <= 1.1249517491201857e-22f) {
                  		tmp = -n0_i * -1.0f;
                  	} else {
                  		tmp = t_0;
                  	}
                  	return tmp;
                  }
                  
                  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
                      real(4) :: tmp
                      t_0 = -(-u * n1_i)
                      if (n1_i <= (-1.4564692236958598e-18)) then
                          tmp = t_0
                      else if (n1_i <= 1.1249517491201857e-22) then
                          tmp = -n0_i * (-1.0e0)
                      else
                          tmp = t_0
                      end if
                      code = tmp
                  end function
                  
                  function code(normAngle, u, n0_i, n1_i)
                  	t_0 = Float32(-Float32(Float32(-u) * n1_i))
                  	tmp = Float32(0.0)
                  	if (n1_i <= Float32(-1.4564692236958598e-18))
                  		tmp = t_0;
                  	elseif (n1_i <= Float32(1.1249517491201857e-22))
                  		tmp = Float32(Float32(-n0_i) * Float32(-1.0));
                  	else
                  		tmp = t_0;
                  	end
                  	return tmp
                  end
                  
                  function tmp_2 = code(normAngle, u, n0_i, n1_i)
                  	t_0 = -(-u * n1_i);
                  	tmp = single(0.0);
                  	if (n1_i <= single(-1.4564692236958598e-18))
                  		tmp = t_0;
                  	elseif (n1_i <= single(1.1249517491201857e-22))
                  		tmp = -n0_i * single(-1.0);
                  	else
                  		tmp = t_0;
                  	end
                  	tmp_2 = tmp;
                  end
                  
                  \begin{array}{l}
                  t_0 := -\left(-u\right) \cdot n1\_i\\
                  \mathbf{if}\;n1\_i \leq -1.4564692236958598 \cdot 10^{-18}:\\
                  \;\;\;\;t\_0\\
                  
                  \mathbf{elif}\;n1\_i \leq 1.1249517491201857 \cdot 10^{-22}:\\
                  \;\;\;\;\left(-n0\_i\right) \cdot -1\\
                  
                  \mathbf{else}:\\
                  \;\;\;\;t\_0\\
                  
                  
                  \end{array}
                  
                  Derivation
                  1. Split input into 2 regimes
                  2. if n1_i < -1.45646922e-18 or 1.12495175e-22 < n1_i

                    1. Initial program 97.3%

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

                      \[\leadsto n0\_i \cdot \left(1 - u\right) + n1\_i \cdot u \]
                    3. Step-by-step derivation
                      1. Applied rewrites97.8%

                        \[\leadsto \mathsf{fma}\left(n0\_i, 1 - u, n1\_i \cdot u\right) \]
                      2. Taylor expanded in n0_i around -inf

                        \[\leadsto -1 \cdot \left(n0\_i \cdot \left(-1 \cdot \left(1 - u\right) + -1 \cdot \frac{n1\_i \cdot u}{n0\_i}\right)\right) \]
                      3. Step-by-step derivation
                        1. Applied rewrites97.6%

                          \[\leadsto -1 \cdot \left(n0\_i \cdot \mathsf{fma}\left(-1, 1 - u, -1 \cdot \frac{n1\_i \cdot u}{n0\_i}\right)\right) \]
                        2. Taylor expanded in n0_i around 0

                          \[\leadsto -1 \cdot \left(-1 \cdot \left(n1\_i \cdot u\right)\right) \]
                        3. Step-by-step derivation
                          1. Applied rewrites37.9%

                            \[\leadsto -1 \cdot \left(-1 \cdot \left(n1\_i \cdot u\right)\right) \]
                          2. Applied rewrites37.9%

                            \[\leadsto -\left(-u\right) \cdot n1\_i \]

                          if -1.45646922e-18 < n1_i < 1.12495175e-22

                          1. Initial program 97.3%

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

                            \[\leadsto n0\_i \cdot \left(1 - u\right) + n1\_i \cdot u \]
                          3. Step-by-step derivation
                            1. Applied rewrites97.8%

                              \[\leadsto \mathsf{fma}\left(n0\_i, 1 - u, n1\_i \cdot u\right) \]
                            2. Taylor expanded in n0_i around -inf

                              \[\leadsto -1 \cdot \left(n0\_i \cdot \left(-1 \cdot \left(1 - u\right) + -1 \cdot \frac{n1\_i \cdot u}{n0\_i}\right)\right) \]
                            3. Step-by-step derivation
                              1. Applied rewrites97.6%

                                \[\leadsto -1 \cdot \left(n0\_i \cdot \mathsf{fma}\left(-1, 1 - u, -1 \cdot \frac{n1\_i \cdot u}{n0\_i}\right)\right) \]
                              2. Taylor expanded in u around 0

                                \[\leadsto -1 \cdot \left(n0\_i \cdot -1\right) \]
                              3. Step-by-step derivation
                                1. Applied rewrites47.5%

                                  \[\leadsto -1 \cdot \left(n0\_i \cdot -1\right) \]
                                2. Applied rewrites47.5%

                                  \[\leadsto \left(-n0\_i\right) \cdot -1 \]
                              4. Recombined 2 regimes into one program.
                              5. Add Preprocessing

                              Alternative 5: 47.5% accurate, 33.6× speedup?

                              \[\left(\left(\left(0 \leq normAngle \land normAngle \leq \frac{\pi}{2}\right) \land \left(-1 \leq n0\_i \land n0\_i \leq 1\right)\right) \land \left(-1 \leq n1\_i \land n1\_i \leq 1\right)\right) \land \left(2.328306437 \cdot 10^{-10} \leq u \land u \leq 1\right)\]
                              \[\left(-n0\_i\right) \cdot -1 \]
                              (FPCore (normAngle u n0_i n1_i)
                                :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)))
                                (* (- n0_i) -1.0))
                              float code(float normAngle, float u, float n0_i, float n1_i) {
                              	return -n0_i * -1.0f;
                              }
                              
                              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 * (-1.0e0)
                              end function
                              
                              function code(normAngle, u, n0_i, n1_i)
                              	return Float32(Float32(-n0_i) * Float32(-1.0))
                              end
                              
                              function tmp = code(normAngle, u, n0_i, n1_i)
                              	tmp = -n0_i * single(-1.0);
                              end
                              
                              \left(-n0\_i\right) \cdot -1
                              
                              Derivation
                              1. Initial program 97.3%

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

                                \[\leadsto n0\_i \cdot \left(1 - u\right) + n1\_i \cdot u \]
                              3. Step-by-step derivation
                                1. Applied rewrites97.8%

                                  \[\leadsto \mathsf{fma}\left(n0\_i, 1 - u, n1\_i \cdot u\right) \]
                                2. Taylor expanded in n0_i around -inf

                                  \[\leadsto -1 \cdot \left(n0\_i \cdot \left(-1 \cdot \left(1 - u\right) + -1 \cdot \frac{n1\_i \cdot u}{n0\_i}\right)\right) \]
                                3. Step-by-step derivation
                                  1. Applied rewrites97.6%

                                    \[\leadsto -1 \cdot \left(n0\_i \cdot \mathsf{fma}\left(-1, 1 - u, -1 \cdot \frac{n1\_i \cdot u}{n0\_i}\right)\right) \]
                                  2. Taylor expanded in u around 0

                                    \[\leadsto -1 \cdot \left(n0\_i \cdot -1\right) \]
                                  3. Step-by-step derivation
                                    1. Applied rewrites47.5%

                                      \[\leadsto -1 \cdot \left(n0\_i \cdot -1\right) \]
                                    2. Applied rewrites47.5%

                                      \[\leadsto \left(-n0\_i\right) \cdot -1 \]
                                    3. Add Preprocessing

                                    Reproduce

                                    ?
                                    herbie shell --seed 2026070 
                                    (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)))