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Ask HN: What problem are you close to solving and how can we help?

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Re: Ask HN: What problem are you close to solving and how can we help?

#241

Post by ww520 »

I’m planning on implementing a transactional (ACID) key-value storage on modern hardware, i.e. SSD and large RAM. The technical choice on question is the type of index storage to use: b+tree, extending hashing, or linear hashing.

There will be an appending WAL for batching the writes and for transaction support. A single checkpoint worker will apply the updates from WAL to the index storage periodically. The updates will be batched, to minimize the random seeks.

Please help me evaluate the three indexing approaches, on the criteria of fast read, fast write, cache friendliness and ease of supporting atomic update during checkpoint.

Re: Ask HN: What problem are you close to solving and how can we help?

#242

Post by jeanlucas »

29athrowaway wrote: post #199
jeanlucas wrote: post #190

Earlier quoted context omitted.

That's exactly the point, and mostly CTOs don't have much people internally to ask help from. I am in a community with some CTOs in Latin America and I see this struggle happen every time.

Latin America is a mess in many ways. VCs there suck, and do not understand that VCs are about inherently risky investments. They want the guarantees of a low risk business with the profitability of a high risk business. Leadership in Latin American companies also sucks. As soon as the company has any revenue, the leadership will go all out and spend it all on themselves on some extravagant lifestyle adjustments rath…

I don't think your take is wrong, I live here and agree with most stuff.

Yeah, Latin America sucks, I already know that.

Now back to my problem...

Re: Ask HN: What problem are you close to solving and how can we help?

#243

Post by tsian2 »

janderson215 wrote: post #114
inglor_cz wrote: post #56

I am a bit ashamed to ask about such a trivial topic on HN, but I am not really sure how AJAX in Wordpress plugins works. I have a plugin that exports some WooCommerce orders into XLS. I would like to add a progress bar via AJAX, because the export may take very long for thousands of orders. But I am not really sure how to use AJAX in context of Wordpress specifically. I would love to see a minimal functional example…

In my experience, accurately reflecting the progress of and AJAX request, so I’ve seen a lot of people (myself included) take the lazy way out and just show an indeterminate spinner or bar just to show that stuff is happening.

It takes a bit of code but if you know the length of the response you're expecting then you can use XHR's "progress" event. Just be aware that the event will happen frequently and contain all the data so far, to avoid inefficient parsing and substring related memory leaks. I think his problem might be more about using JS in WordPress though.

Re: Ask HN: What problem are you close to solving and how can we help?

#244

Post by Const-me »

pgroves wrote: post #218

How to make png encoding much faster? I'm working with large medical images and after a bit of work we can do all the needed processing in under a second (numpy/scipy methods). But then the encoding to png is taking 9-15secs. As a result we have to pre-render all possible configurations and put them on S3 b/c we can't do the processing on demand in a web request. Is there a way to use multiple threads or GPU to encod…

GPGPU is the way to go.

Not terribly hard if you only need 1-2 formats supported, e.g. RGBA8 only. You don't need to port the complete codec, only some initial portion of the pipeline and stream data back from GPUs, the last steps with lossless compression of the stream ain't a good fit for GPUs.

If you want the code to run on a web server, after you'll debug the encoder your next problem is where to deploy. NVidia teslas are frickin expensive. If you wanna run on public clouds, I'd consider their VMs with AMD GPUs.

Re: Ask HN: What problem are you close to solving and how can we help?

#245

Post by oneepic »

graphcolorer wrote: post #219

I have a graph with weighted edges. I want to remove edges to make the graph colorable with N colors (e.g. N=40) such that the total weight of removed edges is minimized. If I'm able to solve this problem, that will complete a project I've been working on for years now to make a working keyboard for a person I know that has cerebral palsy.

Will the graph ever change? Is this a one-time computation?

Re: Ask HN: What problem are you close to solving and how can we help?

#246

Post by jjk166 »

bambax wrote: post #178
xyzzy_plugh wrote: post #172

Earlier quoted context omitted.

The brain you describe is not the brain I possess. Starting is easy.

"starting" is ambiguous. I really meant "getting to work". Thinking about new things and maybe throwing down a few ideas is indeed easy and pleasant. But deciding to spend a few hours to move a project (instead of not) is what the brain hates. It hates commitment, and is very afraid of the opportunity cost.

Nah, I'm with parent commenter on this. When I'm excited about something I have no problem diving into it for hours on end. But when I know that something is 90% done and it just needs to be tidied up, I will do anything other than working on it. Either everything from solving the hardest problem to being completely done happens in one sitting, or it never gets finished.

Re: Ask HN: What problem are you close to solving and how can we help?

#248

Post by betwixthewires »

cyberge99 wrote: post #166
betwixthewires wrote: post #161

Some ZK way to prove that a piece of data was derived from some source, for example, proving a human fingerprint is unique identifying biometric data without showing the data itself or the person it is from and with no trusted authority.

Just thinking out loud here: I think it would require trusted sources (not necessarily a centralized authority) that have validate it and that you trust. You can prove two balls are different colors to a colorblind person by having them show you two balls of X color and proving to them that you can differentiate them (watered down example), but it requires validated externalities (ex, you can see colors they can’t).…

If it did require a trusted source, do you think there would be a way for said source to 1) involve no human administration, 2) behave deterministically and 3) be resistant to attacks that could break either of the above 2? That would also solve the problem.

Re: Ask HN: What problem are you close to solving and how can we help?

#249

Post by oneepic »

graphcolorer wrote: post #219

I have a graph with weighted edges. I want to remove edges to make the graph colorable with N colors (e.g. N=40) such that the total weight of removed edges is minimized. If I'm able to solve this problem, that will complete a project I've been working on for years now to make a working keyboard for a person I know that has cerebral palsy.

Similar to what another commenter said about time, have you tried a backtracking approach by: (1) coloring the whole graph (let's say you end with 42 colors) (2) start with the highest colored nodes (e.g. N=42, which exceeds your threshold of 40) and (3) greedily remove the lowest-weight edges (or maybe, edges to other high-colored nodes) until you are either all colored with 40 colors or we reach an invalid state (ie node no longer in the graph) -- with the latter you can add another edge back and try again by removing the next-lowest edge.

Re: Ask HN: What problem are you close to solving and how can we help?

#250

Post by jpeloquin »

chubot wrote: post #119

These are statistics/math problems that 2 medical professionals I'm seeing are working on, not my own work. But they got me curious. FWIW I worked in "data science" as a software engineer for many years, and did some machine learning, so I have some adjacent experience, but I could use help conceptualizing the problems. Does anyone know of any books or surveys about statistics and medicine, or specifically mechanics…

My research specialty is in orthopedic biomechanics. For the arm motion thing, it sounds like you might want inverse kinematics or inverse dynamics. Take a look at OpenSim: https://simtk.org/projects/opensim

For the oral appliance adjustment, I'm not sure what your output measures of interest are. If they're mechanical maybe you want to do a sensitivity analysis using FEA. Maybe look at FEBio: https://febio.org/

As for books or surveys, biomechanics is huge topic so I'm not sure what to recommend without wasting your time. If you're still defining the problem, maybe run some searches on Pubmed with the "review" and "free full text" boxes checked, and browse the results until you find which sub-sub-topic is relevant to you?

https://pubmed.ncbi.nlm.nih.gov/?term=biomechanics&filter=si...

If no one on the team knows statics, dynamics, and (if you're considering internal strain and stress) continuum mechanics, consider finding a mechanical engineer to help.

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