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Ask HN: What interesting problems are you working on?

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Re: Ask HN: What interesting problems are you working on?

#701

Post by beatthatflight »

caspar wrote: post #640
ThisMark wrote: post #626

Earlier quoted context omitted.

For sure. Win 10 Pro x64, 4K screen at 150%. Just tested on Firefox Developer 73.0b6 (64-bit), Chrome 79.0.3945.130 (64-bit), Edge 44.18362.449.0, IE 11.592.18362, all with the same issue [0][1] I think it's just that with the background image being 1880×1253, it isn't wide enough with background-size: auto. I just changed it in FF devtools to background-size: contain, and it looks fine. [0] https://www.dropbox.com/s…

I see this too - see https://imgur.com/a/029OQCn if the parent's screenshots are not enough.

cheers to you too!

Re: Ask HN: What interesting problems are you working on?

#702

Post by jmorgancusick »

sgtnoodle wrote: post #694
jmorgancusick wrote: post #689

Earlier quoted context omitted.

Going to piggyback on this comment, sorry I am a few days late. Where did you get your masters? I have an EE & CS B.S. from RPI plus 3 years of application development experience in the Fin Tech industry. I am strongly considering swapping industries to Embedded Control--that is what I enjoyed most in college--but I am unsure how to break into the industry. Do you recommend a masters or just sending some apps out? I…

I got my bachelors and masters from University of Michigan. It was really just an excuse to stick around for a couple more semesters and do another solar car race. After a few years of experience, the masters doesn't really matter beyond what you personally gained out of the education. There are tons of embedded software projects that lack software engineering rigor. If you're good at unit testing and mocking, for ex…

Thanks for this Sergeant! My hunch was that embedded code was lacking some of the more refined software engineering principles like continuous integration. I'll continue to frame my cover letters around that and give the masters some more thought.

Re: Ask HN: What interesting problems are you working on?

#703

Post by peter303 »

mrpoptart wrote: post #583
peter303 wrote: post #65

Earlier quoted context omitted.

I got budgeting down to two numbers: Total take-home pay past 12 months vs total expenditures past two months. Try to avoid the latter going over 85%.

It's awesome that you have a budget, and a process for doing it. Would you find it useful to know whether or not you can afford something you're about to buy, be it a taco, a couch or a car? Your budget works well in as a reflection process, my budget gives you the constant knowledge of how you're doing right now and how you'll probably be doing in the future.

I use a spreadsheet with rows bulk spending categories and columns months, plus a few summary columns. More than 15 years ago it was just a table on graph paper. I know within a few dollars how much I have earned spent in the past 12 months. The 'budget' is awareness of such spending and trying to keep not much more than the previous year. Stuff happens like a dead car, hospital stay, job change etc. so its not always firm.

Re: Ask HN: What interesting problems are you working on?

#704

Post by tobmlt »

peterwoerner wrote: post #660
tobmlt wrote: post #252

Earlier quoted context omitted.

Hey, thanks for your interest! I've avoided trimmed surfaces, in part because I'm interested in doing one or another kinds of analysis on or with the parametric geometry, and trimmed surfaces are not so easy to work with for some of the finer control I want from my optimization tools. (They often cause comparability issues with export between programs as well, but that becomes more important only if somebody uses you…

I keep coming back to bother you :). One of the newer tricks to make parameter fitting less expensive which has recently been developed is active subspaces. I thought you might be interested in playing around with it. Most of the research is being done out at the Colorado school of mines by Paul Constantine. The basic idea is that you reduce your parameter space to the eigenvectors of the sensitivity matrix with the…

Hey this is cool! I did not see your comment until now. Let me take a look (as soon as I can) and I will see what I can come back to you with.

Yeah Colorado School of Mines! Small world, I am in the metro area. I've actually talked with a physics proff from there about helping with a project.

Re: Ask HN: What interesting problems are you working on?

#705

Post by tobmlt »

peterwoerner wrote: post #660
tobmlt wrote: post #252

Earlier quoted context omitted.

Hey, thanks for your interest! I've avoided trimmed surfaces, in part because I'm interested in doing one or another kinds of analysis on or with the parametric geometry, and trimmed surfaces are not so easy to work with for some of the finer control I want from my optimization tools. (They often cause comparability issues with export between programs as well, but that becomes more important only if somebody uses you…

I keep coming back to bother you :). One of the newer tricks to make parameter fitting less expensive which has recently been developed is active subspaces. I thought you might be interested in playing around with it. Most of the research is being done out at the Colorado school of mines by Paul Constantine. The basic idea is that you reduce your parameter space to the eigenvectors of the sensitivity matrix with the…

Scanning through some literature, does this method require that the input space be equipped with a probability density function “quantifying the variability of the inputs”?

Seems like that would be the (or a function of the) thing we are after in sensitivity analysis.

On the other hand, it appears that I may be able to get away with some naive assumption about this quantity, compute eigenvectors and find the active subspace... and then vary the mode in these directions.

Is this for local or global optimization?

Part of my stuff was about finding a way to guarantee that a particular set of inputs results in a feasible design. (Edit: maybe active subspace could replace this... or exclude poor regions faster)

The other part (the gradient driven part) solves curves and surfaces for shape which conforms to constraints. We really need the fine details to match as the constraints are often of equality type.

From there, it seems this active subspace method could really help in searching the design space. (From what I read, this is the purpose) A more efficient method of response surface design. My stuff is agnostic about this.

Then again, surely it could be of used in more efficiently optimizing constrained curves and surfaces... I will keep thinking but it seems a secondary use at best, or would you agree?

Re: Ask HN: What interesting problems are you working on?

#706

Post by loa_in_ »

nekopa wrote: post #231
loa_in_ wrote: post #214

I'm reworking the (already pretty old) concept of literate programming, basing my research on the implementation written originally by Dr Ross Williams in 70's called funnelweb. Given new hardware of modern times all the ugly hacks and compromises of the C implementation (including ugly delimiters, unnecessary terse syntax, not using a recursive descent parser but relying on byte values while parsing text) a new take…

Do you have anything available for public consumption? I'm a fan of funnelweb and would love to see it updated.

Since you asked, and since people who can use those tools are few and far between... I have made my own take on funnelweb syntax. I would like your opinion. Unfortunately not really documented, so please look at sample (complete) input file.

It's currently in working state. https://raw.githubusercontent.com/loa-in-/python3-dreamwork/...

You can see current output here: https://github.com/loa-in-/python3-dreamwork/tree/testout/te...

Re: Ask HN: What interesting problems are you working on?

#707

Post by waychukucha »

sideproject wrote: post #390
waychukucha wrote: post #301

Earlier quoted context omitted.

I like this and all the best. I have access to close to 50 idle domains I will try see how I can put them to use. Is there a way to customize the news such that it is relevant to each domain?

Yep! That's the idea! :) Via RSS feeds + keywords.

If by any chance you would like help better testing it, I have so many parked domains that I would like to have them on asap. Is there is any other way I can contact you or you can reach me on nash at hoopsup dot com

Re: Ask HN: What interesting problems are you working on?

#708

Post by atheiste »

Chris2048 wrote: post #656
atheiste wrote: post #360

I am working on a blogging platform that does not need any backend (in terms of an app listening for http connections). The overall architecture is an web app that is talking to WebDAV and then pages get build by a static site generator. I use getpelican.com but you can use Hugo or Jekyll based on your preference.

How would that work? surely something needs to serve the static content to a http request?

You are right of course. There is still nginx taking care of everything. The point is that you need nothing but nginx/caddy/Apache.

Currently, I don't know any way how to initiate execution of scripts over http server so there is a systemd timer checking changes in files and recompiling the whole site. This has lot of downsides. The easiest would be if the static generator reacts on existence of a specific file - recompiles the site and removes the file afterwards.

Re: Ask HN: What interesting problems are you working on?

#709

Post by peterwoerner »

tobmlt wrote: post #705
peterwoerner wrote: post #660

Earlier quoted context omitted.

I keep coming back to bother you :). One of the newer tricks to make parameter fitting less expensive which has recently been developed is active subspaces. I thought you might be interested in playing around with it. Most of the research is being done out at the Colorado school of mines by Paul Constantine. The basic idea is that you reduce your parameter space to the eigenvectors of the sensitivity matrix with the…

Scanning through some literature, does this method require that the input space be equipped with a probability density function “quantifying the variability of the inputs”? Seems like that would be the (or a function of the) thing we are after in sensitivity analysis. On the other hand, it appears that I may be able to get away with some naive assumption about this quantity, compute eigenvectors and find the active s…

We should move this conversation to email (as I will check that more frequently and will be more likely to get back to it). See email in my profile.

Active subspace comes from the uncertainty quantification community. If you assume all your parameters are Gaussian, then the sensitivity matrix is directly correlated to the probability density functions. I find it easier to think in terms of the sensitivity matrix, but useful to realize the sensitivity matrix to approximate (complex) probability distributions.

My though was that if you were optimizing have a huge parameter space theta = [theta1, ... thetam] then you could reduce the parameter space by only looking at theta_reduce = [theta | d loss/d theta > threshold] or you could look at active subspaces and change the parameter space to xi = [xi1, ... xi_m] where x_i = SUM a_j theta_j.

xi_i could be given by the largest eigenvectors of the sensitivity matrix S_ij = d^2 loss/dtheta_i dtheta_j

Wouldn't it be nice if hacker news supported latex.

I haven't done any work here, but I suspect I will be doing some of this towards the end of summer.

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