path: root/2025/info/calc-after.md

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<div class="transcript transcript-mainVideo"><a name="calc-mainVideo-transcript"></a><h1>Transcript</h1>


<div class="transcript-heading">[[!template new="1" text="""Introduction""" start="00:00:03.620" video="mainVideo-calc" id="subtitle"]]</div>[[!template text="""Hello, my name is Christopher Howard and welcome to my talk.""" start="00:00:03.620" video="mainVideo-calc" id="subtitle"]]
[[!template text="""This is basically an introduction""" start="00:00:08.800" video="mainVideo-calc" id="subtitle"]]
[[!template text="""to the built-in Emacs calculator,""" start="00:00:11.320" video="mainVideo-calc" id="subtitle"]]
[[!template text="""properly known as Emacs Calc,""" start="00:00:15.120" video="mainVideo-calc" id="subtitle"]]
[[!template text="""particularly from the perspective of someone""" start="00:00:18.320" video="mainVideo-calc" id="subtitle"]]
[[!template text="""with a technical background such as engineering or electronics.""" start="00:00:21.440" video="mainVideo-calc" id="subtitle"]]
[[!template text="""I will say, though, my personal interest is not really""" start="00:00:27.560" video="mainVideo-calc" id="subtitle"]]
[[!template text="""in digital computing or digital calculators,""" start="00:00:32.880" video="mainVideo-calc" id="subtitle"]]
[[!template text="""but lately has been focused more on analog computing.""" start="00:00:37.840" video="mainVideo-calc" id="subtitle"]]
[[!template text="""I have, for example, been working to master""" start="00:00:42.520" video="mainVideo-calc" id="subtitle"]]
[[!template text="""the venerable slide rule, a mechanical computer""" start="00:00:46.800" video="mainVideo-calc" id="subtitle"]]
[[!template text="""that calculates multiplication powers and logarithms.""" start="00:00:50.840" video="mainVideo-calc" id="subtitle"]]
[[!template text="""Here's a picture of one.""" start="00:00:57.320" video="mainVideo-calc" id="subtitle"]]
[[!template text="""It's a physical tool that was used for hundreds of years""" start="00:01:02.200" video="mainVideo-calc" id="subtitle"]]
[[!template text="""for this sort of thing""" start="00:01:06.800" video="mainVideo-calc" id="subtitle"]]
[[!template text="""before the handheld calculator was made popular.""" start="00:01:09.000" video="mainVideo-calc" id="subtitle"]]
[[!template text="""And I also had a project that I did""" start="00:01:16.680" video="mainVideo-calc" id="subtitle"]]
[[!template text="""for a while to several months""" start="00:01:18.640" video="mainVideo-calc" id="subtitle"]]
[[!template text="""to build an electronic analog computer.""" start="00:01:21.120" video="mainVideo-calc" id="subtitle"]]
[[!template text="""A rudimentary attempt of mine, but it's functional,""" start="00:01:33.120" video="mainVideo-calc" id="subtitle"]]
[[!template text="""and it's basically a 1960s or 1970s style""" start="00:01:38.680" video="mainVideo-calc" id="subtitle"]]
[[!template text="""electronic analog computer built very much on a budget,""" start="00:01:43.400" video="mainVideo-calc" id="subtitle"]]
[[!template text="""but the box in the middle is the computer proper""" start="00:01:48.840" video="mainVideo-calc" id="subtitle"]]
[[!template text="""which has most of the components inside of it""" start="00:01:52.560" video="mainVideo-calc" id="subtitle"]]
[[!template text="""as well as the potentiometers for setting values,""" start="00:01:55.720" video="mainVideo-calc" id="subtitle"]]
[[!template text="""and an operation switch.""" start="00:02:00.200" video="mainVideo-calc" id="subtitle"]]
[[!template text="""There's a patch panel on the left""" start="00:02:02.040" video="mainVideo-calc" id="subtitle"]]
[[!template text="""for connecting the different integrators,""" start="00:02:04.400" video="mainVideo-calc" id="subtitle"]]
[[!template text="""amplifiers, multipliers, and so forth together.""" start="00:02:07.120" video="mainVideo-calc" id="subtitle"]]
[[!template text="""Then the output of the simulation is displayed""" start="00:02:11.320" video="mainVideo-calc" id="subtitle"]]
[[!template text="""on the oscilloscope on the right side,""" start="00:02:16.920" video="mainVideo-calc" id="subtitle"]]
[[!template text="""which is a digital oscilloscope.""" start="00:02:19.800" video="mainVideo-calc" id="subtitle"]]
[[!template text="""To be honest, I think that a talk about analog computing""" start="00:02:25.480" video="mainVideo-calc" id="subtitle"]]
[[!template text="""would be much more interesting""" start="00:02:28.440" video="mainVideo-calc" id="subtitle"]]
[[!template text="""than the talk that I'm about to give,""" start="00:02:30.200" video="mainVideo-calc" id="subtitle"]]
[[!template text="""but unfortunately that would be out of scope for EmacsConf.""" start="00:02:32.040" video="mainVideo-calc" id="subtitle"]]

<div class="transcript-heading">[[!template new="1" text="""What is Calc?""" start="00:02:36.640" video="mainVideo-calc" id="subtitle"]]</div>[[!template text="""So instead I will talk about Emacs Calc,""" start="00:02:36.640" video="mainVideo-calc" id="subtitle"]]
[[!template text="""the digital calculator built into Emacs.""" start="00:02:39.920" video="mainVideo-calc" id="subtitle"]]
[[!template text="""Emacs Calc, while not being a replacement for software""" start="00:02:43.360" video="mainVideo-calc" id="subtitle"]]
[[!template text="""like GNU Octave, does have advanced calculator functionality""" start="00:02:47.520" video="mainVideo-calc" id="subtitle"]]
[[!template text="""that can be useful in engineering, electronics,""" start="00:02:51.480" video="mainVideo-calc" id="subtitle"]]
[[!template text="""or other technical applications. So I don't want to oversell it,""" start="00:02:55.040" video="mainVideo-calc" id="subtitle"]]
[[!template text="""but I think functionality-wise, Calc is somewhere in between""" start="00:03:00.760" video="mainVideo-calc" id="subtitle"]]
[[!template text="""what you'd expect of a decent scientific calculator""" start="00:03:06.480" video="mainVideo-calc" id="subtitle"]]
[[!template text="""and an advanced graphics calculator.""" start="00:03:12.240" video="mainVideo-calc" id="subtitle"]]
[[!template text="""So this talk I'll mention is not intended to be a tutorial""" start="00:03:23.940" video="mainVideo-calc" id="subtitle"]]
[[!template text="""but only a brief introduction to Calc.""" start="00:03:28.840" video="mainVideo-calc" id="subtitle"]]
[[!template text="""Please refer to the built-in Calc info manual""" start="00:03:33.840" video="mainVideo-calc" id="subtitle"]]
[[!template text="""for detailed instructions on how to complete operations.""" start="00:03:37.440" video="mainVideo-calc" id="subtitle"]]
[[!template text="""Turn off my volume here.""" start="00:03:46.740" video="mainVideo-calc" id="subtitle"]]
[[!template text="""The documentation for Emacs Calc is built-in,""" start="00:04:01.480" video="mainVideo-calc" id="subtitle"]]
[[!template text="""although on some distributions you may have to install""" start="00:04:05.720" video="mainVideo-calc" id="subtitle"]]
[[!template text="""the Emacs documentation separately for licensing reasons.""" start="00:04:10.440" video="mainVideo-calc" id="subtitle"]]
[[!template text="""Calc presents itself as a stack-based calculator""" start="00:04:24.480" video="mainVideo-calc" id="subtitle"]]
[[!template text="""where entries are dropped onto a stack""" start="00:04:28.600" video="mainVideo-calc" id="subtitle"]]
[[!template text="""and then an operation is performed on the stack entries.""" start="00:04:31.600" video="mainVideo-calc" id="subtitle"]]
[[!template text="""For example, I can drop 1.23 onto the stack,""" start="00:04:36.740" video="mainVideo-calc" id="subtitle"]]
[[!template text="""and then 8.56, and then multiply them together.""" start="00:04:42.900" video="mainVideo-calc" id="subtitle"]]

<div class="transcript-heading">[[!template new="1" text="""calc-algebraic-entry""" start="00:04:54.280" video="mainVideo-calc" id="subtitle"]]</div>[[!template text="""It may present itself as a stack-based calculator,""" start="00:04:54.280" video="mainVideo-calc" id="subtitle"]]
[[!template text="""but indeed, Calc is also capable of accepting input""" start="00:05:01.560" video="mainVideo-calc" id="subtitle"]]
[[!template text="""in the more well-known algebraic format""" start="00:05:05.400" video="mainVideo-calc" id="subtitle"]]
[[!template text="""by using the calc-algebraic-entry command,""" start="00:05:07.740" video="mainVideo-calc" id="subtitle"]]
[[!template text="""which by default is bound to the apostrophe (') key.""" start="00:05:10.760" video="mainVideo-calc" id="subtitle"]]
[[!template text="""So you type the apostrophe key, enter the algebraic input,""" start="00:05:15.000" video="mainVideo-calc" id="subtitle"]]
[[!template text="""including parentheses as needed.""" start="00:05:19.760" video="mainVideo-calc" id="subtitle"]]
[[!template text="""For example, here's a calculation of the resonance frequency""" start="00:05:22.760" video="mainVideo-calc" id="subtitle"]]
[[!template text="""of a coil which has an inductance of 250 microhenries""" start="00:05:28.200" video="mainVideo-calc" id="subtitle"]]
[[!template text="""and 160 picofarads, taken from one of my electronics handbooks.""" start="00:05:35.040" video="mainVideo-calc" id="subtitle"]]
[[!template text="""The formula for that is 1 over 2 pi""" start="00:05:41.060" video="mainVideo-calc" id="subtitle"]]
[[!template text="""and then the square root of our inductance""" start="00:05:50.020" video="mainVideo-calc" id="subtitle"]]
[[!template text="""which is in this case 250 microfarads - excuse me, microhenries""" start="00:05:57.440" video="mainVideo-calc" id="subtitle"]]
[[!template text="""and then the capacitance is 160 picofarads.""" start="00:06:06.280" video="mainVideo-calc" id="subtitle"]]
[[!template text="""Small typo here.""" start="00:06:19.400" video="mainVideo-calc" id="subtitle"]]
[[!template text="""Now I need to evaluate that one more time,""" start="00:06:24.400" video="mainVideo-calc" id="subtitle"]]
[[!template text="""because pi is a symbol.""" start="00:06:26.640" video="mainVideo-calc" id="subtitle"]]
[[!template text="""I get about 800 kHz resonant frequency.""" start="00:06:30.920" video="mainVideo-calc" id="subtitle"]]

<div class="transcript-heading">[[!template new="1" text="""calc-roll-down""" start="00:06:37.399" video="mainVideo-calc" id="subtitle"]]</div>[[!template text="""The command calc-roll-down,""" start="00:06:37.399" video="mainVideo-calc" id="subtitle"]]
[[!template text="""which by default is bound to the TAB key,""" start="00:06:41.680" video="mainVideo-calc" id="subtitle"]]
[[!template text="""will swap the top two stack entries,""" start="00:06:44.200" video="mainVideo-calc" id="subtitle"]]
[[!template text="""which is sometimes useful if you need to manipulate something""" start="00:06:47.920" video="mainVideo-calc" id="subtitle"]]
[[!template text="""that's further down the stack.""" start="00:06:51.560" video="mainVideo-calc" id="subtitle"]]
[[!template text="""So I can swap this around and say multiply by two""" start="00:06:57.000" video="mainVideo-calc" id="subtitle"]]
[[!template text="""and then put it back where it was.""" start="00:07:02.040" video="mainVideo-calc" id="subtitle"]]
[[!template text="""This command is also capable of rolling the entire stack.""" start="00:07:05.480" video="mainVideo-calc" id="subtitle"]]
[[!template text="""Say I want to shift them all around.""" start="00:07:14.040" video="mainVideo-calc" id="subtitle"]]
[[!template text="""This can be done by passing extra arguments""" start="00:07:18.900" video="mainVideo-calc" id="subtitle"]]
[[!template text="""to the calc-roll-down function.""" start="00:07:21.400" video="mainVideo-calc" id="subtitle"]]
[[!template text="""That's a little bit inconvenient to do manually,""" start="00:07:23.560" video="mainVideo-calc" id="subtitle"]]
[[!template text="""so in my init file, I defined here a key definition""" start="00:07:28.280" video="mainVideo-calc" id="subtitle"]]
[[!template text="""that passes in those arguments correctly.""" start="00:07:40.080" video="mainVideo-calc" id="subtitle"]]
[[!template text="""I attached this to shift-tab,""" start="00:07:45.760" video="mainVideo-calc" id="subtitle"]]
[[!template text="""so this way, I can roll the entire stack.""" start="00:07:49.180" video="mainVideo-calc" id="subtitle"]]
[[!template text="""Then I could change one entry here""" start="00:07:52.320" video="mainVideo-calc" id="subtitle"]]
[[!template text="""and then put it back where it was.""" start="00:07:56.160" video="mainVideo-calc" id="subtitle"]]
[[!template text="""So Calc does algebraic input.""" start="00:08:03.460" video="mainVideo-calc" id="subtitle"]]

<div class="transcript-heading">[[!template new="1" text="""Advanced functions""" start="00:08:07.760" video="mainVideo-calc" id="subtitle"]]</div>[[!template text="""It also does advanced functions""" start="00:08:07.760" video="mainVideo-calc" id="subtitle"]]
[[!template text="""that you would expect any handheld scientific calculator,""" start="00:08:10.160" video="mainVideo-calc" id="subtitle"]]
[[!template text="""including trigonometric functions.""" start="00:08:15.600" video="mainVideo-calc" id="subtitle"]]
[[!template text="""For example, we can get the sine of a number.""" start="00:08:19.160" video="mainVideo-calc" id="subtitle"]]
[[!template text="""Now I'll mention here that Calc has multiple modes.""" start="00:08:25.320" video="mainVideo-calc" id="subtitle"]]
[[!template text="""Right now it's in degree mode.""" start="00:08:30.720" video="mainVideo-calc" id="subtitle"]]
[[!template text="""You can switch over to radian mode if you want.""" start="00:08:32.320" video="mainVideo-calc" id="subtitle"]]
[[!template text="""I'm going to put it back in degrees.""" start="00:08:38.160" video="mainVideo-calc" id="subtitle"]]
[[!template text="""Drop 12 degrees on the stack, and then get the sine of that.""" start="00:08:42.800" video="mainVideo-calc" id="subtitle"]]
[[!template text="""And then with the inverse sine function, I can put it back.""" start="00:08:49.800" video="mainVideo-calc" id="subtitle"]]

<div class="transcript-heading">[[!template new="1" text="""Solving equations with calc-solve-for""" start="00:08:58.180" video="mainVideo-calc" id="subtitle"]]</div>[[!template text="""Calc also has the nifty ability to solve equations for you""" start="00:08:58.180" video="mainVideo-calc" id="subtitle"]]
[[!template text="""so long as the equation is not too complicated.""" start="00:09:07.520" video="mainVideo-calc" id="subtitle"]]
[[!template text="""This is using the calc-solve-for function.""" start="00:09:13.920" video="mainVideo-calc" id="subtitle"]]
[[!template text="""For example, we could enter in an equation algebraically,""" start="00:09:19.960" video="mainVideo-calc" id="subtitle"]]
[[!template text="""then run calc-solve-for, and we just have to tell it""" start="00:09:31.700" video="mainVideo-calc" id="subtitle"]]
[[!template text="""what variable we want to solve for. And there we go.""" start="00:09:36.680" video="mainVideo-calc" id="subtitle"]]
[[!template text="""We can do this manually as well""" start="00:09:41.000" video="mainVideo-calc" id="subtitle"]]
[[!template text="""just so you can see that we get the same result.""" start="00:09:43.200" video="mainVideo-calc" id="subtitle"]]

<div class="transcript-heading">[[!template new="1" text="""Systems of equations""" start="00:09:54.720" video="mainVideo-calc" id="subtitle"]]</div>[[!template text="""Calc is also able to solve systems of equations.""" start="00:09:54.720" video="mainVideo-calc" id="subtitle"]]
[[!template text="""We can put more than one equation on the stack,""" start="00:09:57.960" video="mainVideo-calc" id="subtitle"]]
[[!template text="""and then solve for several variables.""" start="00:10:03.440" video="mainVideo-calc" id="subtitle"]]
[[!template text="""To give a technical example for this,""" start="00:10:08.960" video="mainVideo-calc" id="subtitle"]]
[[!template text="""I'll show you a resistor network scribble that I did recently.""" start="00:10:13.320" video="mainVideo-calc" id="subtitle"]]
[[!template text="""Hopefully you can see that. Basically,""" start="00:10:30.660" video="mainVideo-calc" id="subtitle"]]
[[!template text="""it's fairly simple, a pretty simple resistor network""" start="00:10:32.820" video="mainVideo-calc" id="subtitle"]]
[[!template text="""with 1 kilo ohm and 10 kilo ohm resistors,""" start="00:10:38.720" video="mainVideo-calc" id="subtitle"]]
[[!template text="""and using the loop methods, we are calculating the currents,""" start="00:10:42.160" video="mainVideo-calc" id="subtitle"]]
[[!template text="""the current in each loop, and then that current can be used""" start="00:10:48.960" video="mainVideo-calc" id="subtitle"]]
[[!template text="""to solve for the voltage of each individual resistor""" start="00:10:52.760" video="mainVideo-calc" id="subtitle"]]
[[!template text="""if we want to. So at the bottom there we have the equations""" start="00:10:58.840" video="mainVideo-calc" id="subtitle"]]
[[!template text="""that we come up with as we work through each loop.""" start="00:11:06.200" video="mainVideo-calc" id="subtitle"]]
[[!template text="""And I'm going to paste that into Calc.""" start="00:11:11.520" video="mainVideo-calc" id="subtitle"]]
[[!template text="""To save some time, I'm going to copy and paste that""" start="00:11:19.580" video="mainVideo-calc" id="subtitle"]]
[[!template text="""from my notes instead of typing it out.""" start="00:11:22.720" video="mainVideo-calc" id="subtitle"]]
[[!template text="""So we have two equations there on the stack""" start="00:11:34.260" video="mainVideo-calc" id="subtitle"]]
[[!template text="""in one stack entry. We run that calc-solve-for function again,""" start="00:11:38.260" video="mainVideo-calc" id="subtitle"]]
[[!template text="""and we tell it which variables we want to solve for.""" start="00:11:44.720" video="mainVideo-calc" id="subtitle"]]
[[!template text="""And voila! Those are our currents,""" start="00:11:49.900" video="mainVideo-calc" id="subtitle"]]
[[!template text="""which we can then use to get the voltages""" start="00:11:51.960" video="mainVideo-calc" id="subtitle"]]
[[!template text="""for the individual resistors.""" start="00:11:55.720" video="mainVideo-calc" id="subtitle"]]

<div class="transcript-heading">[[!template new="1" text="""calc-find-root""" start="00:12:00.080" video="mainVideo-calc" id="subtitle"]]</div>[[!template text="""I'll just briefly mention""" start="00:12:00.080" video="mainVideo-calc" id="subtitle"]]
[[!template text="""that if Calc is not able to solve an equation""" start="00:12:02.000" video="mainVideo-calc" id="subtitle"]]
[[!template text="""with calc-solve-for,""" start="00:12:05.840" video="mainVideo-calc" id="subtitle"]]
[[!template text="""then you might be helped by another calc function""" start="00:12:07.780" video="mainVideo-calc" id="subtitle"]]
[[!template text="""called calc-find-root.""" start="00:12:10.280" video="mainVideo-calc" id="subtitle"]]
[[!template text="""This function basically does a manual search""" start="00:12:11.560" video="mainVideo-calc" id="subtitle"]]
[[!template text="""for a numerical solution to the equation.""" start="00:12:14.440" video="mainVideo-calc" id="subtitle"]]
[[!template text="""And there's the documentation page on that.""" start="00:12:30.200" video="mainVideo-calc" id="subtitle"]]

<div class="transcript-heading">[[!template new="1" text="""Derivatives and integrals""" start="00:12:39.960" video="mainVideo-calc" id="subtitle"]]</div>[[!template text="""Calc can also solve or find derivatives of functions,""" start="00:12:39.960" video="mainVideo-calc" id="subtitle"]]
[[!template text="""at least the more straightforward functions.""" start="00:12:44.040" video="mainVideo-calc" id="subtitle"]]
[[!template text="""For a simple example,""" start="00:12:47.580" video="mainVideo-calc" id="subtitle"]]
[[!template text="""we can get the derivative of that""" start="00:12:49.840" video="mainVideo-calc" id="subtitle"]]
[[!template text="""with the derivative function.""" start="00:13:00.560" video="mainVideo-calc" id="subtitle"]]
[[!template text="""On the other hand, Calc is also capable of figuring out""" start="00:13:11.980" video="mainVideo-calc" id="subtitle"]]
[[!template text="""indefinite integrals.""" start="00:13:17.160" video="mainVideo-calc" id="subtitle"]]
[[!template text="""Say we put that function back on the stack,""" start="00:13:22.100" video="mainVideo-calc" id="subtitle"]]
[[!template text="""and this time, we call the integral function.""" start="00:13:26.860" video="mainVideo-calc" id="subtitle"]]
[[!template text="""There you go. Of course, you have to add""" start="00:13:32.560" video="mainVideo-calc" id="subtitle"]]
[[!template text="""your own constant of integration.""" start="00:13:35.080" video="mainVideo-calc" id="subtitle"]]
[[!template text="""For integrals that Calc cannot figure out symbolically,""" start="00:13:39.820" video="mainVideo-calc" id="subtitle"]]
[[!template text="""a numerical integration method is available""" start="00:13:43.400" video="mainVideo-calc" id="subtitle"]]
[[!template text="""through the calc-num-integral command, which is documented...""" start="00:13:46.080" video="mainVideo-calc" id="subtitle"]]
[[!template text="""The function  documentation is available here, more or less.""" start="00:13:59.999" video="mainVideo-calc" id="subtitle"]]

<div class="transcript-heading">[[!template new="1" text="""Programmable functions""" start="00:14:17.540" video="mainVideo-calc" id="subtitle"]]</div>[[!template text="""I definitely need to mention""" start="00:14:17.540" video="mainVideo-calc" id="subtitle"]]
[[!template text="""that Calc is capable of doing programmable functions.""" start="00:14:20.400" video="mainVideo-calc" id="subtitle"]]
[[!template text="""That is to say, you can program your own functions into Calc.""" start="00:14:24.760" video="mainVideo-calc" id="subtitle"]]
[[!template text="""There are three separate ways to do this.""" start="00:14:29.620" video="mainVideo-calc" id="subtitle"]]
[[!template text="""One is through a macro method""" start="00:14:32.240" video="mainVideo-calc" id="subtitle"]]
[[!template text="""similar to Emacs's usual keyboard macros.""" start="00:14:36.280" video="mainVideo-calc" id="subtitle"]]
[[!template text="""The second method is to transform an algebraic function""" start="00:14:41.540" video="mainVideo-calc" id="subtitle"]]
[[!template text="""into a stored function definition.""" start="00:14:46.520" video="mainVideo-calc" id="subtitle"]]
[[!template text="""And the third is to use Elisp directly.""" start="00:14:50.860" video="mainVideo-calc" id="subtitle"]]
[[!template text="""Personally, I find that the second method""" start="00:14:54.060" video="mainVideo-calc" id="subtitle"]]
[[!template text="""is the most practical, the most convenient and practical""" start="00:14:56.600" video="mainVideo-calc" id="subtitle"]]
[[!template text="""in my opinion. So I'll give a quick example of that.""" start="00:15:01.800" video="mainVideo-calc" id="subtitle"]]
[[!template text="""So I could... Let's say I wanted to have a function""" start="00:15:08.060" video="mainVideo-calc" id="subtitle"]]
[[!template text="""for calculating capacitive reactance.""" start="00:15:14.160" video="mainVideo-calc" id="subtitle"]]
[[!template text="""I'll define that in algebraic mode first.""" start="00:15:20.700" video="mainVideo-calc" id="subtitle"]]
[[!template text="""The function for that is 1 over 2 pi""" start="00:15:28.900" video="mainVideo-calc" id="subtitle"]]
[[!template text="""the frequency and the capacitance.""" start="00:15:33.640" video="mainVideo-calc" id="subtitle"]]
[[!template text="""Drop that on the stack. You see, it does automatically""" start="00:15:41.600" video="mainVideo-calc" id="subtitle"]]
[[!template text="""get simplified a little bit, but it's the same function.""" start="00:15:44.960" video="mainVideo-calc" id="subtitle"]]
[[!template text="""And then I press letters Z and F. Do that again.""" start="00:15:52.080" video="mainVideo-calc" id="subtitle"]]
[[!template text="""Z and F to start transforming that into a stored function.""" start="00:15:58.840" video="mainVideo-calc" id="subtitle"]]
[[!template text="""It asks me to select a user key, a single key press.""" start="00:16:06.240" video="mainVideo-calc" id="subtitle"]]
[[!template text="""I'll use the letter c.""" start="00:16:11.040" video="mainVideo-calc" id="subtitle"]]
[[!template text="""Then it's going to ask for a longer command name.""" start="00:16:15.480" video="mainVideo-calc" id="subtitle"]]
[[!template text="""I've actually defined this once before, so it prefilled in""" start="00:16:19.080" video="mainVideo-calc" id="subtitle"]]
[[!template text="""that command name.""" start="00:16:24.640" video="mainVideo-calc" id="subtitle"]]
[[!template text="""Then I need to enter which variables in the formula""" start="00:16:38.340" video="mainVideo-calc" id="subtitle"]]
[[!template text="""are actual arguments, rather than just symbols""" start="00:16:43.000" video="mainVideo-calc" id="subtitle"]]
[[!template text="""to be evaluated later. I prefer to put this in with frequency""" start="00:16:46.560" video="mainVideo-calc" id="subtitle"]]
[[!template text="""and the capacitance after that,""" start="00:16:52.560" video="mainVideo-calc" id="subtitle"]]
[[!template text="""but actually in this particular case,""" start="00:16:54.280" video="mainVideo-calc" id="subtitle"]]
[[!template text="""it doesn't matter at all to the mathematics.""" start="00:16:57.800" video="mainVideo-calc" id="subtitle"]]
[[!template text="""So, now all I have to do, that this is defined,""" start="00:17:07.340" video="mainVideo-calc" id="subtitle"]]
[[!template text="""is I can drop the frequency on the stack,""" start="00:17:11.400" video="mainVideo-calc" id="subtitle"]]
[[!template text="""which we'll say, for this example, will be 4.5 MHz,""" start="00:17:15.200" video="mainVideo-calc" id="subtitle"]]
[[!template text="""and then drop on the capacitance, which in this example""" start="00:17:24.400" video="mainVideo-calc" id="subtitle"]]
[[!template text="""will be 22 pF.""" start="00:17:32.280" video="mainVideo-calc" id="subtitle"]]
[[!template text="""Then I'll call the function that I just defined.""" start="00:17:40.320" video="mainVideo-calc" id="subtitle"]]
[[!template text="""I don't really like having to try to remember""" start="00:17:42.440" video="mainVideo-calc" id="subtitle"]]
[[!template text="""the short letters that I've come up with,""" start="00:17:45.240" video="mainVideo-calc" id="subtitle"]]
[[!template text="""so I'll just use the longer name.""" start="00:17:48.680" video="mainVideo-calc" id="subtitle"]]
[[!template text="""I need to evaluate one more time""" start="00:17:57.840" video="mainVideo-calc" id="subtitle"]]
[[!template text="""because the symbol pi is in there and not yet evaluated.""" start="00:17:59.800" video="mainVideo-calc" id="subtitle"]]
[[!template text="""And so if I've done that right,""" start="00:18:05.620" video="mainVideo-calc" id="subtitle"]]
[[!template text="""we have a capacitive reactance of about 1600 ohms.""" start="00:18:07.540" video="mainVideo-calc" id="subtitle"]]

<div class="transcript-heading">[[!template new="1" text="""Plotting""" start="00:18:12.160" video="mainVideo-calc" id="subtitle"]]</div>[[!template text="""As the last feature that I'll mention here,""" start="00:18:12.160" video="mainVideo-calc" id="subtitle"]]
[[!template text="""Emacs Calc does have an interface with gnuplot,""" start="00:18:16.840" video="mainVideo-calc" id="subtitle"]]
[[!template text="""if you want to have Calc work as your graphing calculator.""" start="00:18:24.060" video="mainVideo-calc" id="subtitle"]]
[[!template text="""I do need to be honest and mention""" start="00:18:30.800" video="mainVideo-calc" id="subtitle"]]
[[!template text="""that I don't generally use it myself""" start="00:18:33.160" video="mainVideo-calc" id="subtitle"]]
[[!template text="""because there's another program in GNOME""" start="00:18:35.580" video="mainVideo-calc" id="subtitle"]]
[[!template text="""that I've found to be generally more convenient""" start="00:18:39.720" video="mainVideo-calc" id="subtitle"]]
[[!template text="""for the things that I want to graph quickly.""" start="00:18:43.500" video="mainVideo-calc" id="subtitle"]]
[[!template text="""But I think I can give you a simple example.""" start="00:18:47.400" video="mainVideo-calc" id="subtitle"]]
[[!template text="""So first, we need to drop a range on the stack.""" start="00:18:53.400" video="mainVideo-calc" id="subtitle"]]
[[!template text="""Let's say 0 to 10.""" start="00:19:00.340" video="mainVideo-calc" id="subtitle"]]
[[!template text="""And then we need to drop the function on the stack.""" start="00:19:06.620" video="mainVideo-calc" id="subtitle"]]
[[!template text="""And then I believe it's the letters g and f that graph this.""" start="00:19:11.640" video="mainVideo-calc" id="subtitle"]]
[[!template text="""Let's see. Yep, there we go.""" start="00:19:17.840" video="mainVideo-calc" id="subtitle"]]
[[!template text="""So there's our function and it looks nice.""" start="00:19:22.320" video="mainVideo-calc" id="subtitle"]]
[[!template text="""That was pretty easy.""" start="00:19:25.060" video="mainVideo-calc" id="subtitle"]]
[[!template text="""That's the fast way to do it.""" start="00:19:26.660" video="mainVideo-calc" id="subtitle"]]
[[!template text="""I will, as a disclaimer, mention that""" start="00:19:29.020" video="mainVideo-calc" id="subtitle"]]
[[!template text="""using this quick approach,""" start="00:19:32.840" video="mainVideo-calc" id="subtitle"]]
[[!template text="""that sometimes more complicated graphs""" start="00:19:34.160" video="mainVideo-calc" id="subtitle"]]
[[!template text="""will not turn out nicely,""" start="00:19:38.760" video="mainVideo-calc" id="subtitle"]]
[[!template text="""because by default, the resolution will be pretty low.""" start="00:19:40.000" video="mainVideo-calc" id="subtitle"]]
[[!template text="""That is to say it's... gnuplot is going to be""" start="00:19:44.340" video="mainVideo-calc" id="subtitle"]]
[[!template text="""skipping a lot of points""" start="00:19:48.120" video="mainVideo-calc" id="subtitle"]]
[[!template text="""and so you'll have to learn a bit more""" start="00:19:49.900" video="mainVideo-calc" id="subtitle"]]
[[!template text="""about how to use the interface,""" start="00:19:52.040" video="mainVideo-calc" id="subtitle"]]
[[!template text="""what parameters to pass if you want all your graphs""" start="00:19:55.320" video="mainVideo-calc" id="subtitle"]]
[[!template text="""to come out looking nice.""" start="00:19:59.520" video="mainVideo-calc" id="subtitle"]]
[[!template text="""So that covers all the features that I wanted to cover.""" start="00:20:03.700" video="mainVideo-calc" id="subtitle"]]

<div class="transcript-heading">[[!template new="1" text="""Wish list""" start="00:20:08.800" video="mainVideo-calc" id="subtitle"]]</div>[[!template text="""I wanted to briefly mention a wish list of items""" start="00:20:08.800" video="mainVideo-calc" id="subtitle"]]
[[!template text="""that I'd like to see in Calc.""" start="00:20:13.280" video="mainVideo-calc" id="subtitle"]]
[[!template text="""One of them would be improper integrals.""" start="00:20:16.680" video="mainVideo-calc" id="subtitle"]]
[[!template text="""So that's like our definite integrals""" start="00:20:23.640" video="mainVideo-calc" id="subtitle"]]
[[!template text="""except for where a limit of integration is infinity.""" start="00:20:25.160" video="mainVideo-calc" id="subtitle"]]
[[!template text="""That's something that can be useful in a few applications.""" start="00:20:32.860" video="mainVideo-calc" id="subtitle"]]
[[!template text="""Something else that would be neat to have would be""" start="00:20:38.560" video="mainVideo-calc" id="subtitle"]]
[[!template text="""annotations for row entries. So for example""" start="00:20:41.080" video="mainVideo-calc" id="subtitle"]]
[[!template text="""if I was putting together a sum of numbers""" start="00:20:45.680" video="mainVideo-calc" id="subtitle"]]
[[!template text="""for, say, my monthly budget,""" start="00:20:48.820" video="mainVideo-calc" id="subtitle"]]
[[!template text="""let's say I was paying $2,000 for my rent""" start="00:20:53.280" video="mainVideo-calc" id="subtitle"]]
[[!template text="""and let's say $800 a month for my groceries,""" start="00:20:57.480" video="mainVideo-calc" id="subtitle"]]
[[!template text="""(a lot of kids to feed there)""" start="00:21:03.832" video="mainVideo-calc" id="subtitle"]]
[[!template text="""and then say another $60 for dining out, and so on,""" start="00:21:07.932" video="mainVideo-calc" id="subtitle"]]
[[!template text="""it would be nice if there was some way""" start="00:21:14.566" video="mainVideo-calc" id="subtitle"]]
[[!template text="""to put a little annotation next to each number""" start="00:21:18.260" video="mainVideo-calc" id="subtitle"]]
[[!template text="""so that you could remember""" start="00:21:21.320" video="mainVideo-calc" id="subtitle"]]
[[!template text="""what the meaning of that number was more easily.""" start="00:21:23.400" video="mainVideo-calc" id="subtitle"]]
[[!template text="""I actually looked into programming this into Calc myself,""" start="00:21:27.040" video="mainVideo-calc" id="subtitle"]]
[[!template text="""but discovered that it would require reprogramming""" start="00:21:31.200" video="mainVideo-calc" id="subtitle"]]
[[!template text="""quite a bit of Calc to make that work well""" start="00:21:35.920" video="mainVideo-calc" id="subtitle"]]
[[!template text="""across all calc functionality,""" start="00:21:41.840" video="mainVideo-calc" id="subtitle"]]
[[!template text="""and so, eventually, I gave up.""" start="00:21:43.480" video="mainVideo-calc" id="subtitle"]]
[[!template text="""But I'd still really like to have that feature.""" start="00:21:46.940" video="mainVideo-calc" id="subtitle"]]
[[!template text="""The final thing, though""" start="00:21:51.140" video="mainVideo-calc" id="subtitle"]]
[[!template text="""I think this would not necessarily belong in Calc,""" start="00:21:52.040" video="mainVideo-calc" id="subtitle"]]
[[!template text="""I think it would be cool if Emacs had some way""" start="00:21:54.580" video="mainVideo-calc" id="subtitle"]]
[[!template text="""to run numerical solutions""" start="00:21:57.920" video="mainVideo-calc" id="subtitle"]]
[[!template text="""for systems of differential equations,""" start="00:22:00.600" video="mainVideo-calc" id="subtitle"]]
[[!template text="""also known as a differential analyzer.""" start="00:22:02.600" video="mainVideo-calc" id="subtitle"]]
[[!template text="""So this would allow you to be able to set up simulation models""" start="00:22:06.020" video="mainVideo-calc" id="subtitle"]]
[[!template text="""involving systems of differential equations,""" start="00:22:09.280" video="mainVideo-calc" id="subtitle"]]
[[!template text="""for example, a spring mass system, or pressure temperature,""" start="00:22:11.680" video="mainVideo-calc" id="subtitle"]]
[[!template text="""or what have you, and then run the simulation""" start="00:22:14.880" video="mainVideo-calc" id="subtitle"]]
[[!template text="""using numerical approximation.""" start="00:22:18.040" video="mainVideo-calc" id="subtitle"]]
[[!template text="""Maybe it would be silly""" start="00:22:22.120" video="mainVideo-calc" id="subtitle"]]
[[!template text="""to actually put that in Calc itself,""" start="00:22:24.080" video="mainVideo-calc" id="subtitle"]]
[[!template text="""but a nice interface maybe to some other software,""" start="00:22:26.000" video="mainVideo-calc" id="subtitle"]]
[[!template text="""simple software that did that,""" start="00:22:30.340" video="mainVideo-calc" id="subtitle"]]
[[!template text="""an easy to use interface for that""" start="00:22:33.300" video="mainVideo-calc" id="subtitle"]]
[[!template text="""would be really great.""" start="00:22:35.780" video="mainVideo-calc" id="subtitle"]]

<div class="transcript-heading">[[!template new="1" text="""Wrapping up""" start="00:22:38.600" video="mainVideo-calc" id="subtitle"]]</div>[[!template text="""So that's my entire talk.""" start="00:22:38.600" video="mainVideo-calc" id="subtitle"]]
[[!template text="""I'll just mention some information.""" start="00:22:41.801" video="mainVideo-calc" id="subtitle"]]
[[!template text="""If you want to learn more about me""" start="00:22:44.535" video="mainVideo-calc" id="subtitle"]]
[[!template text="""or things that I'm interested in,""" start="00:22:48.366" video="mainVideo-calc" id="subtitle"]]
[[!template text="""I do not any longer have a web presence.""" start="00:22:50.120" video="mainVideo-calc" id="subtitle"]]
[[!template text="""I don't have a website anymore,""" start="00:22:57.780" video="mainVideo-calc" id="subtitle"]]
[[!template text="""but I do have a Gemini capsule""" start="00:22:59.660" video="mainVideo-calc" id="subtitle"]]
[[!template text="""that I post to all the time.""" start="00:23:03.360" video="mainVideo-calc" id="subtitle"]]
[[!template text="""And if you can install, if you're willing to install the...""" start="00:23:07.140" video="mainVideo-calc" id="subtitle"]]
[[!template text="""Gemini browser known as Elpher""" start="00:23:13.880" video="mainVideo-calc" id="subtitle"]]
[[!template text="""into Emacs, which is available from ELPA,""" start="00:23:19.080" video="mainVideo-calc" id="subtitle"]]
[[!template text="""then you can browse directly to it""" start="00:23:23.699" video="mainVideo-calc" id="subtitle"]]
[[!template text="""and look around my Gemini capsule.""" start="00:23:27.360" video="mainVideo-calc" id="subtitle"]]
[[!template text="""Thank you very much.""" start="00:23:31.440" video="mainVideo-calc" id="subtitle"]]

</div>

Captioner: sachac

Questions or comments? Please e-mail [christopher@librehacker.com](mailto:christopher@librehacker.com?subject=Comment%20for%20EmacsConf%202023%20calc%3A%20Basic%20Calc%20functionality%20for%20engineering%20or%20electronics)


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