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Ask HN: What weird or hard problems are you trying to solve?

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Re: Ask HN: What weird or hard problems are you trying to solve?

#111

Post by erezsh »

yanovskishai wrote: post #106
erezsh wrote: post #95

I'm trying to replace SQL by building a language that compiles to SQL. It has first-class functions, nicer syntax, better type-system, introspection, and other things you would expect from a modern language. But in the end, you still get SQL's performance, and the ability to use it with dozens of database engines.

As someone who spent handreds of hours writing (and cursing) SQL queries -it definitely sounds compelling.

Just a tiny teaser, you could write something like

    Person { country => name }
And it will output the following SQL:

    -- target: postgres
    SELECT country, array_agg(name) AS name FROM Person GROUP BY country

Re: Ask HN: What weird or hard problems are you trying to solve?

#113

Post by comicjk »

Trying to predict where electrons go in a molecule, but using a classical model. This can be done with supervised machine learning - you can use quantum mechanics to get lots of labeled data - but it's a tough problem, because chemical physicists have very high standards for accuracy.

Re: Ask HN: What weird or hard problems are you trying to solve?

#115

Post by ComputerGuru »

hazeii wrote: post #94

How to measure pedal (and/or crank) angle on a moving bicycle to 0.05 degree. Anyone?

Gyroscope or mems accelerometer. Otherwise convert rotational crank movement to push-pull linear slider (see piston, flywheel, linear actuator, etc) and measure linear change in resistance between contact points (like a cheap caliper does, you can even use a chinesium one off eBay as they have a pin out under the battery tab, if your resulting linear motion is within that scale). You don’t need to drive anything besides the read head, so it should have extremely low losses.

Re: Ask HN: What weird or hard problems are you trying to solve?

#116

Post by LolWolf »

Bounds for the best possible designs for optical devices: well-studied [0, 1, 2, 3, 4], yet really hard.

More specifically, whenever you give a designer a design spec, it is always worth asking, how good is the best possible design for this spec? And, of course, can the designer actually achieve it, or something close to it? This is the question here.

In this scenario, the design spec is the optimization problem (what you want to optimize), the designer then gets to choose how to best approach this problem. In this case, you want to give a number that states, independent of how this problem is solved, what is the best any designer (no matter how smart or sophisticated, how much computational power they have, etc) can hope to do. In many cases giving such a number is actually possible! (See below references.)

-----

[0] https://pubs.acs.org/doi/10.1021/acsphotonics.9b00154 (PDF: http://web.stanford.edu/~boyd/papers/pdf/comp_imposs_res.pdf)

[1] https://arxiv.org/abs/2002.00521

[2] https://arxiv.org/abs/2003.00374

[3] https://arxiv.org/abs/2002.05644

[4] https://arxiv.org/abs/2001.11531

Re: Ask HN: What weird or hard problems are you trying to solve?

#118

Post by erezsh »

closed wrote: post #100
erezsh wrote: post #95

I'm trying to replace SQL by building a language that compiles to SQL. It has first-class functions, nicer syntax, better type-system, introspection, and other things you would expect from a modern language. But in the end, you still get SQL's performance, and the ability to use it with dozens of database engines.

Have you seen the R library dplyr? It is a weirdly powerful data analysis tool, that can also produce SQL queries!

I heard about it but didn't know it can produce SQL. Thanks for the tip!

Re: Ask HN: What weird or hard problems are you trying to solve?

#119

Post by aerovistae »

Telling where the output of an individual stdout print statement ends and the next one begins, so that I could color code my terminal with alternating colors to more easily tell apart individual log messages from a running process by visual differentiation. Turns out this is impossible! Aside from time passing in between outputs, there's no way to tell. It's just a continuous byte stream with no terminating character or pattern.

Re: Ask HN: What weird or hard problems are you trying to solve?

#120

Post by Layvier »

Online learning, particularly personalised learning aimed for self education and continuous learning. I'm trying to model the knowledge space as a graph, index learning material (free online resources right now then user generated content) on this graph and then provide different ways to navigate this space. I'm trying to address the "best way" for someone to learn a specific concept, and to help people identify the knowledge they miss/are looking for. The project would be open, collaborative and a non profit btw.
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