### Homepage of Hermann Stamm-Wilbrandt

I&C
Information and Contact

Future:
studying in my 60s

Primes:
a080076.json, sorted array of all 122,742 Proth primes less than 2^40 (> 10^12)
repo containing all Proth primes k*2^m+1 with odd 0<k<1200 and all 0<m<3,600,000
Phi3.gp: 72 Phi(3,x) primes from top 5000 known primes (t5k.org), and verification of fast determination of sqrt(-1) (mod p)

repo: 10:45:01h AMD 7600X computation of "sqrt(-1) (mod p)" (and sum of two squares) for 9,383,761-digit prime p
repo: sqrt(-1) (mod p) as well as sum of squares p=x^2+y^2 for 6 Colbert primes p
repo: About 6.7 day computation of "sqrt(-1) (mod p)" for 11,887,192-digit prime p, largest known prime =1 (mod 4)
Later I learned how to determine sqrt(-1) (mod p) for that p=Phi(3,-516693^1048576) and sum of two squares in just 347ms in total … ;-)
repo: [x,y,s] for top 10 known primes p with s²=-1 (mod p) and p=x²+y² (all above 6million decimal digits)

The 5,000 largest known primes

RSA_numbers_factored
and their prime factors for those that have been factored sofar (up to RSA-250).
Provides access to prime factorization dictionaries for p-1 and q-1 for RSA-l=n=p*q as well
(up to RSA-220), for efficient totient_2() and reduced_totient_2() functions.
Python script is transpiled manually to RSA_numbers_factored.js for use in browser and with nodejs;
using arbitrary precision arithmetic BigInt type (Python number type provides arbitrary precision arithmetic).
Github repo:
https://github.com/Hermann-SW/RSA_numbers_factored

planar_graph_playground

199x technical reports:

Chapter 8 of (1) "Generation of random (maximal) planar graphs" repo:
https://github.com/Hermann-SW/randomgraph

I started planar_graph_playground repo
https://github.com/Hermann-SW/planar_graph_playground
in 4/2022, 28 years after I stopped similar project as University researcher.

This time as multi language library (JavaScript, Python and C++).

C++ fastest, Python slowest, JavaScript allows for browser (2D graphics: SVG, 3D graphics: JSCAD):

Github repo contains first 30579 non-isomorphic fullerenes (C20..C70) and 1267 IPR (Independent Pentagon Region) fullerenes (I60..I100):

2D embedding demo online (SVG):
https://hermann-sw.github.io/planar_graph_playground/

2D PostScript output as well:
(planar graphs are 4colorable, there is a linear time 5coloring algorithm, and even simpler linear time six_coloring(G))

Planar graph embedding onto sphere is not that easy. Just mapping plane embedding onto sphere and then using spring embedder might unravel (left) all vertices into same place (right):

Work in progress algorithm node.tetra.js OpenSCAD output:

The repo provides spherical edge, half vertex and vertex text, and spherical polygon modules/functions to generate sphere embedding OpenSCAD/JSCAD output.

Provides "vertex()" and "edge()" OpenSCAD modules for drawing graph onto cube[oid] as well, here visualization of "cube[oid] shortest surface path problem" solution, details: https://forums.raspberrypi.com/viewtopic.php?p=2038730#p2038730 (orange/blue/yellow shortest paths pass through 3/4/5 faces, from single bottom face start point to top face target point)

cuboid_shortest_paths
Determine and visualize shortest paths between single point on bottom face and many points on top face of cuboid (in browser):
https://hermann-sw.github.io/cuboid_shortest_paths/
ezxdisp
yet another simple graphics library (C, from 2007, now on gitghub):
https://github.com/Hermann-SW/ezxdisp

boost_graph_library
Boost provides free peer-reviewed portable C++ source libraries

straight_line_graphviz.cpp takes a LEDA format undirected graph as input.
Then calls BGL (Boost Graph Library) "make_connected()", "make_biconnected_planar()",
"make_maximal_planar()" and finally "chrobak_payne_straight_line_drawing()" to create the
vertex coordinates of a planar staight line drawing. Makes use of pos="x,y!" feature that neato
layout engine provides, and dot layout engine does not. So neato is not used as layout engine
at all, but only to display the straight line drawing determined with this gist using GraphvizFiddle.
`\$ GraphvizFiddle.py chromium-browser <(./straight_line_graphviz <(randomgraph 8 -o - -t cubic_Halin -s 123456))`

`\$ GraphvizFiddle.py chromium-browser <(../straight_line_graphviz <(./dot2leda <(curl -s https://stamm-wilbrandt.de/C60.dot)))`

Above graph has twenty 6-gons and twelve 5-gons, you are likely to know that graph — C60 is also called "football fullerene":

3Dprinting
Stacked Ikea Lack tables host my Prusa MINI+ 3Dprinter with OctoPi holder:

I use borescope nozzle camera, can switch in OctoPrint between nozzle and scene view:

92cm high paper drinking straw C60 (football) fullerene, hanging 3m high, without any glue. With 3Dprinted connectors:
https://forum.prusa3d.com/forum/english-forum-awesome-prints-hall-of-fame/toothpick-polyhedra-fullerenes/

 Blog HermannSW on twitter,  and Arduino and Raspberry forums Hermann-SW on github (gists) (priorartdatabase — patents) [Record Breaking Optimization ResultsUsing the Ruin and Recreate Principle]=> myCE myAndroid myFrameless

Tools / Games
C/C++ scripts   /   (tcc) "-run" option for gcc and g++   (for Linux ELF, verified for x86_64 and armv7l)
ELF executable gets compiled into RAM, and executed from there — no auxiliary filesystem files!
<pbmtobraille/> (C)  <echo-e.to.braille.html> (web)
 ⠀⠀⣀⠀⣀⣀⠀⢹⣀⠀⡀⣀⢀⡀⢀⣄⡀⢀⡀⠈⣇⡀⢀⢀⡀⢀⡀⢀⡁⢹⠈⡇⠀⣀⠀⢀⠇⣀⠀⠀⠀⠀⢀⠎⢀⠞⠉⠺⠈⢆ ⠒⠭⣀⠀⢸⠀⡇⢸⠀⡇⢸⠀⡇⢸⠀⡇⠀⡇⢸⠀⡇⢸⠀⡏⠀⡕⢺⠀⡇⢸⠀⡇⢸⡒⢃⡜⠀⣀⠭⠒⠀⠀⢸⠀⠘⣄⠀⣠⠀⢸ ⠀⠀⠀⠀⣸⡉⠀⠈⠉⠀⠉⠁⠉⠈⠁⠈⠁⠈⠁⠀⠉⠁⠈⠉⠀⠈⠁⠉⠉⠉⠉⠉⠀⠉⠁⠁⠀⠀⠀⠀⠀⠀⠈⢆⠀⠈⠉⠁⢀⠎
<simple_client-side_bookmarklet_creator/>   (JavaScript)
<GraphvizFiddle/>   (online Graphviz editor&layout [based on Viz.js])
<uʍopǝpᴉsd∩/>   ("foobar" → "ɹɐqooɟ" [browser XQuery])
<n-queens.xsl.xml/>   (n-queens, 4 ≤ n ≤ 9 [browser XSLT])
<peg-solitaire/>   (1-player board game [browser XSLT])
It knows all solutions for 33/37/39 pegs English/French/3-3-2-2 boards.
You may choose "Cheat" link (based on 1+16+64=81GB data files on this website).
There are 2,990,375,067 good positions for French board that allow to end with single peg on target field (forum link).
Instructions on how to revert a move can be found just above that posting (animation):

XSL
XSL (Extensible Stylesheet Language), xsl-list (Open Forum on XSL), related articles and files

Neckarsteig
Hiking 9 stage Neckarsteig in 4 days

E3BM
Eberbach 3-Mountain Marathon

myRunning & myStreak
My running activities and last 575 day Running StreakRunning abroad
(see DUV at bottom for my Ultra marathons)

A day outside of Las Vegas:
3h run through Red Rock Canyon, 325 miles drive through Death Valley.

oeis.org (The On-Line Encyclopedia of Integer Sequences)
my submissions (ordered by "modified")

new binomial formula "C(a+b,c) = sum(k=0..a, …" and animation in A007318

Blue links in .svg work; "10-edge CCs" at bottom right uses GraphvizFiddle mentioned above for display.
Before that, submitted 4 interlaced bisections found manually.

Robotics
 Raspberry camera / gstreamer / raspivid / raspiraw Teaser video of a closing mouse trap; the whole closing is completed in 0.01s(!). This is an animation from Raspberry v2 camera 640x75 video captured at 1007fps(!), played at 1fps. When the mouse trap bar touches down, it hits the black piezo igniter, showing a spark in front (this is frame 1281) Multiple exposures of 84.3m/s (303km/h) inflight airgun bullet (1012x760 frame scaled to 25%, github repo) Nearly ultrasonic speed (340m/s) 3Dprinted pellet shot with airgun. Captured 5 times inflight by five 10000lm flashes of 2µs(!) duration each: https://forums.raspberrypi.com/viewtopic.php?p=1952629#p1956584 The front 10000lm led on side does not look too bright (each of its 100 led spots does light for 10µs in total). Re: Night sky time-lapse with v3 camera Smallest radius bright circular arc is Polaris, very close to center of rotation of northern hemisphere 180° M12 lens mounted reversed on Raspberry HQ camera as macro lens. Results in microscope with 0.21µm/pixel(!), here pin point of lancet. Measured length is 63.1px * 0.21µm/px = 13.251µm! https://forums.raspberrypi.com/viewtopic.php?t=210605&start=100#p1686246 https://www.youtube.com/watch?v=s-SjTs8gBPA "First microscope xyz journey over micrometer and lanzet" x/y steps â 5µm, z steps â 7µm! Me captured from 50m high, part of photo taken from Raspberry Pi0 with v1 camera, attached to cheap RC airplane: https://forums.raspberrypi.com/viewtopic.php?t=190407#p1196344

Find more 2007 images & videos here (German language)
 2007 2021 runaway robot 1-wheel braked
2-wheel balancing (fast) line following robot (current, w/ camera and green laser point)

 KISS (Keep It Simple, Stupid) algorithms hardware principals I used for robotics

 https://github.com/Hermann-SW/4DoF_robot_arm (video) Wireless control Eachine E52 FPV drone (via TCP replay [attack])

 2015 73g "robot" 96g Arduino uno robotspeed 3.1m/s or 11.16km/hforum postingyoutube video High speed Arduino uno robotmax. speed 14.37m/s or 51.72km/hyoutube videoanimated .gif slowed down by factor 10LEDs used as photo marker while braking, on start 4 LEDs on , after 1800ms braking delay only 1 (power) LED left on, details in forum posting 2017 Loosing big outrunner motor wheel with bullet at 60km/h can be dangerous for top mounted camera ;-) https://forum.arduino.cc/t/motor-test-station-mts/319852/42 Arduecat (Arduino Due Caterpillar robot)speed to be determinedforum threadyoutube video of unplanned backward roll high in the air full stop back wheelies • U-turn w/o speed (>2m/s) reduction • just swap one motor's direction for some time • slowed down by factor 90/25=3.6 • 90fps slowmo youtube video • positions at start of (overshooted) U-turn, at 90°, 180° and finally before going straight again • Arduebot can do similar U-turn

ESP8266  esp8266/arduino
 Standalone small outdoor #Wifi #access #point and #webserver based on #ESP8266-01 with #LiPo! [1] [2] [3] [4] 6g in total version Wireless ESP01S Payload drop mechanismaddon for drone (14.4× slower than real)

 5. ... __1Q# 5. ... __1R# 5. ... __1B# 5. ... __1N# 4. ... b__# 5. ... Kf6# 6. ... 0-0-0# 6. ... 0-0# 5. ... Kd8# 5. ... Kd6# 6. ... _x_ ep# immortal single move mode   animation sct_map