\[\cos \left(x + \varepsilon\right) - \cos x\]
Test:
NMSE problem 3.3.5
Bits:
128 bits
Bits error versus x
Bits error versus eps
Time: 17.4 s
Input Error: 17.6
Output Error: 2.8
Log:
Profile: 🕒
\(\begin{cases} \frac{\frac{{\left({\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)}^3\right)}^3 - {\left({\left(\cos x\right)}^3\right)}^3}{{\left({\left(\cos \varepsilon \cdot \cos x - \sin \varepsilon \cdot \sin x\right)}^3\right)}^2 + \left({\left({\left(\cos x\right)}^3\right)}^2 + {\left(\cos \varepsilon \cdot \cos x - \sin \varepsilon \cdot \sin x\right)}^3 \cdot {\left(\cos x\right)}^3\right)}}{(\left(\cos \varepsilon \cdot \cos x - \sin \varepsilon \cdot \sin x\right) * \left((\left(\cos \varepsilon\right) * \left(\cos x\right) + \left(\cos x\right))_* - \sin \varepsilon \cdot \sin x\right) + \left(\cos x \cdot \cos x\right))_*} & \text{when } \varepsilon \le -0.00020185983f0 \\ \left(\varepsilon \cdot \frac{1}{6}\right) \cdot {x}^3 - \varepsilon \cdot (\frac{1}{2} * \varepsilon + x)_* & \text{when } \varepsilon \le 4.484475f-09 \\ \left(\log_* (1 + (e^{\cos x \cdot \cos \varepsilon} - 1)^*) - \sin x \cdot \sin \varepsilon\right) - \cos x & \text{otherwise} \end{cases}\)

    if eps < -0.00020185983f0

    1. Started with
      \[\cos \left(x + \varepsilon\right) - \cos x\]
      14.9
    2. Using strategy rm
      14.9
    3. Applied cos-sum to get
      \[\color{red}{\cos \left(x + \varepsilon\right)} - \cos x \leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x\]
      1.4
    4. Using strategy rm
      1.4
    5. Applied flip3-- to get
      \[\color{red}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right) - \cos x} \leadsto \color{blue}{\frac{{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)}^{3} - {\left(\cos x\right)}^{3}}{{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)}^2 + \left({\left(\cos x\right)}^2 + \left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right) \cdot \cos x\right)}}\]
      1.6
    6. Applied simplify to get
      \[\frac{\color{red}{{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)}^{3} - {\left(\cos x\right)}^{3}}}{{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)}^2 + \left({\left(\cos x\right)}^2 + \left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right) \cdot \cos x\right)} \leadsto \frac{\color{blue}{{\left(\cos \varepsilon \cdot \cos x - \sin \varepsilon \cdot \sin x\right)}^3 - {\left(\cos x\right)}^3}}{{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)}^2 + \left({\left(\cos x\right)}^2 + \left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right) \cdot \cos x\right)}\]
      1.4
    7. Applied simplify to get
      \[\frac{{\left(\cos \varepsilon \cdot \cos x - \sin \varepsilon \cdot \sin x\right)}^3 - {\left(\cos x\right)}^3}{\color{red}{{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)}^2 + \left({\left(\cos x\right)}^2 + \left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right) \cdot \cos x\right)}} \leadsto \frac{{\left(\cos \varepsilon \cdot \cos x - \sin \varepsilon \cdot \sin x\right)}^3 - {\left(\cos x\right)}^3}{\color{blue}{(\left(\cos \varepsilon \cdot \cos x - \sin \varepsilon \cdot \sin x\right) * \left((\left(\cos \varepsilon\right) * \left(\cos x\right) + \left(\cos x\right))_* - \sin \varepsilon \cdot \sin x\right) + \left(\cos x \cdot \cos x\right))_*}}\]
      1.5
    8. Using strategy rm
      1.5
    9. Applied flip3-- to get
      \[\frac{\color{red}{{\left(\cos \varepsilon \cdot \cos x - \sin \varepsilon \cdot \sin x\right)}^3 - {\left(\cos x\right)}^3}}{(\left(\cos \varepsilon \cdot \cos x - \sin \varepsilon \cdot \sin x\right) * \left((\left(\cos \varepsilon\right) * \left(\cos x\right) + \left(\cos x\right))_* - \sin \varepsilon \cdot \sin x\right) + \left(\cos x \cdot \cos x\right))_*} \leadsto \frac{\color{blue}{\frac{{\left({\left(\cos \varepsilon \cdot \cos x - \sin \varepsilon \cdot \sin x\right)}^3\right)}^{3} - {\left({\left(\cos x\right)}^3\right)}^{3}}{{\left({\left(\cos \varepsilon \cdot \cos x - \sin \varepsilon \cdot \sin x\right)}^3\right)}^2 + \left({\left({\left(\cos x\right)}^3\right)}^2 + {\left(\cos \varepsilon \cdot \cos x - \sin \varepsilon \cdot \sin x\right)}^3 \cdot {\left(\cos x\right)}^3\right)}}}{(\left(\cos \varepsilon \cdot \cos x - \sin \varepsilon \cdot \sin x\right) * \left((\left(\cos \varepsilon\right) * \left(\cos x\right) + \left(\cos x\right))_* - \sin \varepsilon \cdot \sin x\right) + \left(\cos x \cdot \cos x\right))_*}\]
      1.7
    10. Applied simplify to get
      \[\frac{\frac{\color{red}{{\left({\left(\cos \varepsilon \cdot \cos x - \sin \varepsilon \cdot \sin x\right)}^3\right)}^{3} - {\left({\left(\cos x\right)}^3\right)}^{3}}}{{\left({\left(\cos \varepsilon \cdot \cos x - \sin \varepsilon \cdot \sin x\right)}^3\right)}^2 + \left({\left({\left(\cos x\right)}^3\right)}^2 + {\left(\cos \varepsilon \cdot \cos x - \sin \varepsilon \cdot \sin x\right)}^3 \cdot {\left(\cos x\right)}^3\right)}}{(\left(\cos \varepsilon \cdot \cos x - \sin \varepsilon \cdot \sin x\right) * \left((\left(\cos \varepsilon\right) * \left(\cos x\right) + \left(\cos x\right))_* - \sin \varepsilon \cdot \sin x\right) + \left(\cos x \cdot \cos x\right))_*} \leadsto \frac{\frac{\color{blue}{{\left({\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)}^3\right)}^3 - {\left({\left(\cos x\right)}^3\right)}^3}}{{\left({\left(\cos \varepsilon \cdot \cos x - \sin \varepsilon \cdot \sin x\right)}^3\right)}^2 + \left({\left({\left(\cos x\right)}^3\right)}^2 + {\left(\cos \varepsilon \cdot \cos x - \sin \varepsilon \cdot \sin x\right)}^3 \cdot {\left(\cos x\right)}^3\right)}}{(\left(\cos \varepsilon \cdot \cos x - \sin \varepsilon \cdot \sin x\right) * \left((\left(\cos \varepsilon\right) * \left(\cos x\right) + \left(\cos x\right))_* - \sin \varepsilon \cdot \sin x\right) + \left(\cos x \cdot \cos x\right))_*}\]
      1.5

    if -0.00020185983f0 < eps < 4.484475f-09

    1. Started with
      \[\cos \left(x + \varepsilon\right) - \cos x\]
      21.7
    2. Applied taylor to get
      \[\cos \left(x + \varepsilon\right) - \cos x \leadsto \frac{1}{6} \cdot \left(\varepsilon \cdot {x}^{3}\right) - \left(\frac{1}{2} \cdot {\varepsilon}^2 + \varepsilon \cdot x\right)\]
      3.9
    3. Taylor expanded around 0 to get
      \[\color{red}{\frac{1}{6} \cdot \left(\varepsilon \cdot {x}^{3}\right) - \left(\frac{1}{2} \cdot {\varepsilon}^2 + \varepsilon \cdot x\right)} \leadsto \color{blue}{\frac{1}{6} \cdot \left(\varepsilon \cdot {x}^{3}\right) - \left(\frac{1}{2} \cdot {\varepsilon}^2 + \varepsilon \cdot x\right)}\]
      3.9
    4. Applied simplify to get
      \[\color{red}{\frac{1}{6} \cdot \left(\varepsilon \cdot {x}^{3}\right) - \left(\frac{1}{2} \cdot {\varepsilon}^2 + \varepsilon \cdot x\right)} \leadsto \color{blue}{\left(\varepsilon \cdot \frac{1}{6}\right) \cdot {x}^3 - \varepsilon \cdot (\frac{1}{2} * \varepsilon + x)_*}\]
      3.9

    if 4.484475f-09 < eps

    1. Started with
      \[\cos \left(x + \varepsilon\right) - \cos x\]
      15.8
    2. Using strategy rm
      15.8
    3. Applied cos-sum to get
      \[\color{red}{\cos \left(x + \varepsilon\right)} - \cos x \leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x\]
      2.4
    4. Using strategy rm
      2.4
    5. Applied log1p-expm1-u to get
      \[\left(\color{red}{\cos x \cdot \cos \varepsilon} - \sin x \cdot \sin \varepsilon\right) - \cos x \leadsto \left(\color{blue}{\log_* (1 + (e^{\cos x \cdot \cos \varepsilon} - 1)^*)} - \sin x \cdot \sin \varepsilon\right) - \cos x\]
      2.8

  1. Removed slow pow expressions

Original test:


(lambda ((x default) (eps default))
  #:name "NMSE problem 3.3.5"
  (- (cos (+ x eps)) (cos x)))