\[\cos \left(x + \varepsilon\right) - \cos x\]
Test:
NMSE problem 3.3.5
Bits:
128 bits
Bits error versus x
Bits error versus eps
Time: 15.4 s
Input Error: 18.3
Output Error: 0.8
Log:
Profile: 🕒
\(\begin{cases} \left(\cos x \cdot \cos \varepsilon - \log_* (1 + (e^{{\left(\sqrt[3]{\sin x} \cdot \sqrt[3]{\sin \varepsilon}\right)}^3} - 1)^*)\right) - \cos x & \text{when } \varepsilon \le -3.0129406f-05 \\ (\left(-\sin x\right) * \left(\sin \varepsilon\right) + \left({\varepsilon}^2 \cdot \left(-\frac{1}{2}\right)\right))_* & \text{when } \varepsilon \le 0.024397144f0 \\ \frac{{\left(\cos x \cdot \cos \varepsilon\right)}^2 - {\left(\sin x \cdot \sin \varepsilon\right)}^2}{(\left(\sin x\right) * \left(\sin \varepsilon\right) + \left(\cos \varepsilon \cdot \cos x\right))_*} - \cos x & \text{otherwise} \end{cases}\)

    if eps < -3.0129406f-05

    1. Started with
      \[\cos \left(x + \varepsilon\right) - \cos x\]
      14.9
    2. Using strategy rm
      14.9
    3. Applied cos-sum to get
      \[\color{red}{\cos \left(x + \varepsilon\right)} - \cos x \leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x\]
      1.5
    4. Using strategy rm
      1.5
    5. Applied log1p-expm1-u to get
      \[\left(\cos x \cdot \cos \varepsilon - \color{red}{\sin x \cdot \sin \varepsilon}\right) - \cos x \leadsto \left(\cos x \cdot \cos \varepsilon - \color{blue}{\log_* (1 + (e^{\sin x \cdot \sin \varepsilon} - 1)^*)}\right) - \cos x\]
      1.5
    6. Using strategy rm
      1.5
    7. Applied add-cube-cbrt to get
      \[\left(\cos x \cdot \cos \varepsilon - \log_* (1 + (e^{\sin x \cdot \color{red}{\sin \varepsilon}} - 1)^*)\right) - \cos x \leadsto \left(\cos x \cdot \cos \varepsilon - \log_* (1 + (e^{\sin x \cdot \color{blue}{{\left(\sqrt[3]{\sin \varepsilon}\right)}^3}} - 1)^*)\right) - \cos x\]
      1.6
    8. Applied add-cube-cbrt to get
      \[\left(\cos x \cdot \cos \varepsilon - \log_* (1 + (e^{\color{red}{\sin x} \cdot {\left(\sqrt[3]{\sin \varepsilon}\right)}^3} - 1)^*)\right) - \cos x \leadsto \left(\cos x \cdot \cos \varepsilon - \log_* (1 + (e^{\color{blue}{{\left(\sqrt[3]{\sin x}\right)}^3} \cdot {\left(\sqrt[3]{\sin \varepsilon}\right)}^3} - 1)^*)\right) - \cos x\]
      1.6
    9. Applied cube-unprod to get
      \[\left(\cos x \cdot \cos \varepsilon - \log_* (1 + (e^{\color{red}{{\left(\sqrt[3]{\sin x}\right)}^3 \cdot {\left(\sqrt[3]{\sin \varepsilon}\right)}^3}} - 1)^*)\right) - \cos x \leadsto \left(\cos x \cdot \cos \varepsilon - \log_* (1 + (e^{\color{blue}{{\left(\sqrt[3]{\sin x} \cdot \sqrt[3]{\sin \varepsilon}\right)}^3}} - 1)^*)\right) - \cos x\]
      1.6

    if -3.0129406f-05 < eps < 0.024397144f0

    1. Started with
      \[\cos \left(x + \varepsilon\right) - \cos x\]
      22.7
    2. Using strategy rm
      22.7
    3. Applied cos-sum to get
      \[\color{red}{\cos \left(x + \varepsilon\right)} - \cos x \leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x\]
      18.5
    4. Using strategy rm
      18.5
    5. Applied log1p-expm1-u to get
      \[\left(\cos x \cdot \cos \varepsilon - \color{red}{\sin x \cdot \sin \varepsilon}\right) - \cos x \leadsto \left(\cos x \cdot \cos \varepsilon - \color{blue}{\log_* (1 + (e^{\sin x \cdot \sin \varepsilon} - 1)^*)}\right) - \cos x\]
      18.5
    6. Applied taylor to get
      \[\left(\cos x \cdot \cos \varepsilon - \log_* (1 + (e^{\sin x \cdot \sin \varepsilon} - 1)^*)\right) - \cos x \leadsto -\left(\frac{1}{2} \cdot {\varepsilon}^2 + \log_* (1 + (e^{\sin x \cdot \sin \varepsilon} - 1)^*)\right)\]
      0.2
    7. Taylor expanded around 0 to get
      \[\color{red}{-\left(\frac{1}{2} \cdot {\varepsilon}^2 + \log_* (1 + (e^{\sin x \cdot \sin \varepsilon} - 1)^*)\right)} \leadsto \color{blue}{-\left(\frac{1}{2} \cdot {\varepsilon}^2 + \log_* (1 + (e^{\sin x \cdot \sin \varepsilon} - 1)^*)\right)}\]
      0.2
    8. Applied simplify to get
      \[\color{red}{-\left(\frac{1}{2} \cdot {\varepsilon}^2 + \log_* (1 + (e^{\sin x \cdot \sin \varepsilon} - 1)^*)\right)} \leadsto \color{blue}{(\left(-\sin x\right) * \left(\sin \varepsilon\right) + \left(\left(-\varepsilon\right) \cdot \left(\varepsilon \cdot \frac{1}{2}\right)\right))_*}\]
      0.1
    9. Applied simplify to get
      \[(\left(-\sin x\right) * \left(\sin \varepsilon\right) + \color{red}{\left(\left(-\varepsilon\right) \cdot \left(\varepsilon \cdot \frac{1}{2}\right)\right)})_* \leadsto (\left(-\sin x\right) * \left(\sin \varepsilon\right) + \color{blue}{\left({\varepsilon}^2 \cdot \left(-\frac{1}{2}\right)\right)})_*\]
      0.1

    if 0.024397144f0 < eps

    1. Started with
      \[\cos \left(x + \varepsilon\right) - \cos x\]
      14.5
    2. Using strategy rm
      14.5
    3. Applied cos-sum to get
      \[\color{red}{\cos \left(x + \varepsilon\right)} - \cos x \leadsto \color{blue}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x\]
      0.8
    4. Using strategy rm
      0.8
    5. Applied flip-- to get
      \[\color{red}{\left(\cos x \cdot \cos \varepsilon - \sin x \cdot \sin \varepsilon\right)} - \cos x \leadsto \color{blue}{\frac{{\left(\cos x \cdot \cos \varepsilon\right)}^2 - {\left(\sin x \cdot \sin \varepsilon\right)}^2}{\cos x \cdot \cos \varepsilon + \sin x \cdot \sin \varepsilon}} - \cos x\]
      0.8
    6. Applied simplify to get
      \[\frac{{\left(\cos x \cdot \cos \varepsilon\right)}^2 - {\left(\sin x \cdot \sin \varepsilon\right)}^2}{\color{red}{\cos x \cdot \cos \varepsilon + \sin x \cdot \sin \varepsilon}} - \cos x \leadsto \frac{{\left(\cos x \cdot \cos \varepsilon\right)}^2 - {\left(\sin x \cdot \sin \varepsilon\right)}^2}{\color{blue}{(\left(\sin x\right) * \left(\sin \varepsilon\right) + \left(\cos \varepsilon \cdot \cos x\right))_*}} - \cos x\]
      0.9

  1. Removed slow pow expressions

Original test:


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