3 ms·

This seems off: >> f(x) = x^2 >> f''(4) 0.9995297887

• paddim8 5y ago
  Oh yeah, derivatives of higher order being less accurate is a known problem. I forgot to specify that, thanks!
  • Bootvis 5y ago
    Maybe best to just disable it for now, I played with e^x as well and the results were off as well. Ignoring these, I really like Kalk!
    • paddim8 5y ago
      Thank you! Yeah, or at least give a warning.
      • jll29 5y ago
        Beautiful Web GUI, beautiful source code, "cargo install kalk_cli" && it works like a charm! Thanks for sharing this.
        • paddim8 5y ago
          Thank you so much! This is my first (and only) Rust project so I'm a bit nervous about the code quality.
  • whiterock 5y ago
    look into Dual numbers. That way there is no accuracy loss. More generally look into AD (automatic differentiation). thanks me later, cheers
    • longemen3000 5y ago
      Maybe the derivation could be done by the complex step trick, if programing an AD system is too hard
  • onhn 5y ago
    Note that if f(x) = x^2 then the second derivative f''(x) = 2, so it looks like you're off by a factor of 2 (as well as the accuracy issue).
• deleted 5y ago
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