SDSL – Succinct Data Structure Library 2.0 | Hacker News Reader

SDSL – Succinct Data Structure Library 2.0

github.com

100 pointsespeed22 comments

Erik Demaine [1] gave two good lectures on succinct data structures [2] in the 2012 MIT 6.851 Advanced Data Structures course, and Rajeev Raman [3] just gave a tutorial on succinct data structures [4] at SIGMOD 2018.

NB: SDSL Cheatsheet http://simongog.github.io/assets/data/sdsl-cheatsheet.pdf

[1] http://erikdemaine.org/

[2] MIT 6.851 Succinct Structures I https://www.youtube.com/watch?v=3Y2weLDiUWw II https://www.youtube.com/watch?v=ABX-Hvn8ymE

[3] https://www.cs.le.ac.uk/people/rraman/

[4] SIGMOD 2018 Tutorial: In-memory Representations of Databases via Succinct Data Structures https://www.youtube.com/watch?v=_3q7T_5JaTI

Great stuff. I would add ‘C++’ to the HN title.

I don’t use C++ anymore, and my years with the language were before stdlib. The C++ ecosystem is looking very good, but I am glad to have moved on. I even worked as a C++ mentor and wrote C++ books for McGraw-Hill, but the language was not a good fit for me; I always preferred C for low level stuff and Common Lisp to get work done quickly.

I think/thought there were Python and Julia SDSL libs...does anyone know the state of those?

Note for anyone considering this: it's GPL licensed.

The next version, which is currently under development, will change this to BSD: https://github.com/xxsds/sdsl-lite

Why is this pointed out? Most software has some license.

GPL is an approved open source license. It grands all required freedoms to the users.

The parent comment reads instead as if the software wasn't free. But it is. So there is no problem in using it. Perhaps only politics…

This anti-GPL campaign is slowly getting really tiring!

How is it that merely pointing out the license is considered anti-GPL? Would that fact not be considered a good thing by anyone who favors the GPL?

Pointing to the fact that it's GPL licensed in such a tone sounds like a warning, and I'm quit sure exactly that was the intention. Or else why would someone stress that fact? Never read something along the lines:

"Note for anyone considering this: it's BSD licensed."

The GPL and BSD licenses aren’t symmetric. Nobody warns about something being BSD licensed because you can freely incorporate a BSD licensed library into any project without changing the license of the resulting project. But the reverse is not true - if you embed GPL software in a BSD project (or commercial project), the resulting work must be licensed under the GPL.

I prefer all the opensource software I write to use a BSD style license, because I want to retain the ability to use any of my opensource work in commercial projects. GPL warnings like this are useful for me - it’s good to know that I can’t use this library in any of my projects (at least until they change the license).

Yes. Answering a resounding "No" to the unspoken but common question, "Can my company use this work for free in ways which do not contribute in any way back to the community that granted it to us, thereby reselling free work to improve our profit margin and IP portfolio."

> ...which do not contribute in any way

> ...to improve our profit margin and IP portfolio.

Pretty black and white presumptions (but license talks often end up that way).

If so, what value does your comment bring to the discussion?

Is there no way to criticize GPL without being considered a dead-weight parasite?

Is there no case for not releasing code (immediately) than greed?

Is there no other way to support a person/project other than that code?

Are profit/loss the really the only concern for a project that can’t/won’t release code?

...

> Is there no way to criticize GPL without being considered a dead-weight parasite?

Not with this attitude. "Why can't you just make the case for me?" There aren't many ways of reading this that offer honest intent.

> Is there no case for not releasing code (immediately) than greed?

You tell me what you had in mind. Security POCs come to mind. But since you didn't immediately point that out I think it's unlikely you had it in mind.

> Are profit/loss the really the only concern for a project that can’t/won’t release code?

I guess pride and/or selfishness?

Unless it's AGPL, that answer is actually still "Yes".

What do you mean?

You can use GPL code in your company's servers.

You cannot use GPL code in client binaries that you sell.

You cannot use AGPL code in either.

Thanks. I actually misread their comment as the inverse of what it meant.

GPL2 software can (so far [0]) be locked down via digital restrictions management. GPL3 software can be locked up by turning it into SaaS (software augmented w/ arbitrary surveillance).

Both phenomena are really the market finding ways to undermine the fundamental freedoms that the GPL aimed for.

IMHO rather than talking about "contributing back" I think a better standard is whether it's possible for an author to receive back a derivative of their own work yet be unable to modify it.

[0] I'd personally love to see some GPL2 holders of eg Linux start going after eg Tivo on the grounds that they have not included all of the tools used to customarily build and install the software.

Previous discussion in 2015 with the main authors: https://news.ycombinator.com/item?id=10157558

is there anything close to or similar to this for C?

"Easy and intuitive to use (like the STL"

If you find the STL easy or intuitive, you and I are not from the same universe. :)

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