[HN Gopher] Ohmaps: your image montage is a resistor network
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Ohmaps: your image montage is a resistor network
Author : occular
Score : 38 points
Date : 2024-11-12 12:44 UTC (10 hours ago)
(HTM) web link (hunsley.io)
(TXT) w3m dump (hunsley.io)
| occular wrote:
| Part 2:
|
| https://hunsley.io/posts/2024/image-montage-is-resistor-netw...
| dylan604 wrote:
| If you read TFA and got to the end, the link for part 2 is
| right there. If you didn't read TFA, why would part 2 be
| something someone would be interested in?
| MeteorMarc wrote:
| The 3k2 resistor in the Mondriaan network should be 300 ohm,
| because its height is 3.2 times its width.
| OisinMoran wrote:
| Very fun! I'm always a big of things being viewed as other things
| --no idea why though!
| dvh wrote:
| If you liked this you are gonna like R-2R DAC.
| twwwt wrote:
| Ok, if the spatial concept of aspect ratio is the equivalent of
| electrical resistance, and given the analogy in the article of
| the painting and the resistor network, what is the equivalence of
| color then? Frequency?
| strken wrote:
| This is neat!
|
| When I was fresh out of uni, I got asked to build a system to
| show recommendations to people based on a graph of connections
| between them. I tried to mentally think about these as a network
| of resistors, which led me to dimensionality reduction and from
| there to alternating least squares. Isomorphisms are fun like
| that: they can help you find techniques when you're stuck on
| something.
| dekhn wrote:
| btw you can also convert graphs to matrices and use standard
| matrix techniques. See the methods section of
| https://www.sciencedirect.com/science/article/pii/S037887330...
| strken wrote:
| Yep! My problem at the time was that I didn't know I _needed_
| a matrix, or which operations would be helpful to perform on
| one, because I didn 't know much about the problem I was
| trying to solve. I ran into a paper about using SVD on
| networks of resistors to simplify them, which pointed me in
| the right direction.
| bgoated01 wrote:
| So these addition formulas that apply to series and parallel
| resistors seem more generally to be formulas for finding the new
| ratio when you have several ratios and want to add them together
| treating the quantity in the numerator or the denominator as
| equal for all ratios. Series circuits have the same current for
| each ratio, and differing voltages, while parallel circuits have
| the same voltage for each ratio and a different current for each.
| Similarly for these aspect ratios, where you want the new ratio
| after adding width or height while setting the other (height or
| width, respectively) equal.
| dekhn wrote:
| IIUC this is similar to how window layout is computed in systems
| like qt.
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