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# Basic Calc functionality for engineering or electronics
Christopher Howard (he/him) - IRC: lispmacs or lispmacs[work], gemini capsule: gemini://gem.librehacker.com, <mailto:christopher@librehacker.com>

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An introduction to some of the basic Algebra and Calculus functionality in Calc, as might be useful in engineering or electronics.

About the speaker:

Christopher Howard is a simulator technician in Fairbanks, Alaska, and a GNU Emacs user for a little over a decade. My technical interests are focused on analog computing and modeling with differential equations.

## Discussion / notes

-   Q: How sophisticated an ordinary differential equation solver would
    be useful? There are some C libraries one ould try to build upon,
    but there are many corner cases, stiff, non-stiff is one
    categorization, but an explicit Runge Kutta would work for many
    non-stiff equations
    -   A: I don't really have any opinions right now about the
        approximation methods. For me, what I really want is one of
        those old style languages where you basically just type in the
        list of differential equations and don't have to do any other
        computer programming, or know the details of another programming
        language. I played around a bit with python-dda, though it has
        some deficiencies. There are some graphical free software
        programs where you do this sort of thing with blocks, but they
        all depend on Java which is problematic in Guix.
-   Q: Is there a way to see the input of a custom function? E.g. if you
    forget the order of f and C in the example you showed
    -   A: Let's see... there is calc-user-define-edit. One calc also
        view the file where the definitions are stored, though that is a
        somewhat obscure format.
-   Q: Have you tried interacting with calc via org-babel (first thing
    that came to mind when you said that you'd like to annotate
    values)? Any thoughts on that? How about rendering gnuplots on org
    documents via calc?
    -   A: I played around with org-babel a few years ago but haven't
        really had any need or interest in it of late.
- Q: Who is in charge of calc development anyway? Is there an active maintainer?
- Nice talk.
- Thanks for the cool talk! I've been using Calc quite a lot recently for linear algebra work. I also use it quite often for unit conversion. There's a package called calc-currency which is very useful but unfortunately does not seem to be maintained anymore.
- I'm going to have to rewatch this talk.
- thanks for your talk! Calc strikes me as one of those really powerful things I should spend time learning a little more about one of these days =)
- calc is suprisingly good at datetime math.
- I mostly use it for that and unit conversion.  I don't do any fancy calculus like lispmacs did in his talk.
- Funny, I'm studying computer engineering and just a few weeks ago I'd decided to properly learn how to use calc myself.


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