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[LUG]Re: intro 1st message - my programming and computing interests

 

To DCLug, new person,
Attention: rich_met <dcglug@xxxxxxxxxxxxxxx>
Attention DCGLug    list@xxxxxxxxxxxxx

Copy: Visible: Eion MacDonald <eionmac@xxxxxxxxxxxxxx>
Dear   Sir,
20230307
Re: [LUG]intro 1st message - my programming and computing interests

Welcome from Warrington, UK ( A rather remote corresponding member)

You are most welcome to DCGLug.

I would comment that you are much more learned in computing that myself who is only a user of Linux systems. (No coding or programming base)

I trust you will enjoy the group, as it has taught me by reading the answers to emails a lot about Linux use, since when I started as a 'complete novice user'.

Welcome.
Kindest regards
Eion MacDonald


On 07/03/2023 09:43, rich_met wrote:
Hi there
I should be showing up as "rich_met" and I'm down West Cornwall.

I realised I've been "ploughing a lone furrow" for far too long so
reaching out to the group.
20 years ago was in Cambridge and member of Linux User Group there.
In meantime, not been member of any club or group association with any
computing.

Where am I at now...

I code mostly in emacs-lisp so it's right there in the emacs
text-processor.

eg. "topmost" "user-level" program for doing (Euler-Bernoulli) beam
looks like this

(defun beam-fmax-rhs-simple-cload
   (shs-width
    shs-depth
    shs-thk
    shs-length
    shs-stl-sigmamax ;; typically yield stress
    )
   "for an RHS - max.force it will bear in central load simple beam
best if all dimensions & values in SI / metres, etc
Order of args matches order going into ma2nd calc / fn"
   (simple-support-dblbeam-loadcap
    (beam-moment-capacity
     shs-stl-sigmamax
     (beam-sect-mod-z-d
      (ma2nd-rhs-b-h-t shs-width shs-depth shs-thk)
      shs-depth))
    shs-length))

so you can see at a glance I go

2nd moment of area (purely geometric property)
  v
section modulus (purely geometric property)
  v
beam moment capacity (combine geometry and material property)
  v
"simple" centrally loaded beam capacity (given length, force it will bear)

which is the normal progression of a beam calculation.

An example of "real world" design I made and got used is here
http://www.weldsmith.co.uk/tech/struct/210314_ebbeam_drillplat/19_drillplat_calcs.html
"Cantilever drilling platform - analysis using beam calculations"


I also do Finite Element Analysis modelling for stresses and strains -
simply use an integrated software package for doing that.
eg.
http://www.weldsmith.co.uk/tech/struct/210216_bcfwtt_fea3d/210216_bcfwtt_fea3d.html
"FEA3D : BCFWTT RHS beam top surface around test weld"

"BCFWTT" is this physical "real world" test
http://www.weldsmith.co.uk/tech/struct/210122_fwtest_rig/210122_fwtest_testrig.html


Recently I did this which converts decimal GPS coordinates -
eg. Google Maps
to "human-usable" / "nautical chart" Degrees Minutes and Seconds

entire code:

(defun lat-long-degdeci-to-dms (latdeci longdeci)
   (format "%s %s %s"
   (abs-degdeci-to-abs-deg-min-sec (abs latdeci) (if (minusp latdeci) 'S 'N))
    " " ;; easy jdi customisable way to separate lat. and long. output
   (abs-degdeci-to-abs-deg-min-sec (abs longdeci) (if (minusp longdeci) 'W 'E))))

(defun abs-degdeci-to-abs-deg-min-sec (absdegdeci dirncardinal)
   "Deg-decimal to DMS format output"
   (if (minusp absdegdeci)
       "error - cannot handle negative arguments"
     (let ((decix60 (* (mod absdegdeci 1) 60)))
      (format "%03dd %02d' %04.1f'' %s" (truncate absdegdeci) (truncate decix60) (* (mod decix60 1) 60) dirncardinal))))

For example - Berry Head lighthouse is at (North, East)
50.39954886056384, -3.483553379652956
(lat-long-degdeci-to-dms 50.39954886056384 -3.483553379652956)
"050d 23' 58.4'' N   003d 29' 00.8'' W"
which is correct - that is the position of Berry Head lighthouse on a
nautical chart which uses the "WGS84" datum.
If you paste
050 23' 58.4" N   003 29' 00.8" W
into Google Maps it will show a pin on the lighthouse...

But all of this done in total isolation
(learned Lisp-style programming from a book 20 years ago with Paul
  Graham's "On Lisp"
  http://www.paulgraham.com/onlisp.html)

So have no idea whether there might be much better ways of achieving
the goal.


Computers and Computing - 10 year old "mac-air" still going and couple
of years ago managed to get it to upload lots more software from
"fink" site, so all happiness there.

Which has left the "Raspberry Pi" computer, which works wonderfully,
neglected.

By the way I learned Linux when needed a supercomputer in the 1990's.

Had doing 10's of hours runs when then "Windows95" would "fall-over"
about every 4 hours and couldn't really be used at all for ad-hoc
programming (no segmentation -> allocated space, and only that space,
in which a program is permitted to run).

I'd have some use of an embedded device - eying the Raspberry Pi card
which came with the computer.
Measure something like hydraulic pressure from a sensor, log it and
maybe control something to do with that hydraulic pressure.

Anyone interested in any of these things?
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--
Regards
Eion MacDonald

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