tgamblin

5 ms·

1.
by tgamblin 8mo ago
The more recent Lifschitz book is the easiest to learn from IMO: - https://www.cs.utexas.edu/~vl/teaching/378/ASP.pdf It starts with basics of using ASP and gives examples in clingo, not math. The Potassco bo
2.
You can have the ore now. It is in New York, a thousand tons of it(en.wikipedia.org)
9 points by tgamblin 11mo ago|0 comments
3.
Spack Package Manager releases v1.0.0(github.com)
3 points by tgamblin 1y ago|0 comments
4.
Spack v1.0(github.com)
1 points by tgamblin 1y ago|0 comments
5.
Spack v1.0 Is Out(github.com)
2 points by tgamblin 1y ago|0 comments
6.
by tgamblin 1y ago
I do for macOS and Linux :). Windows support is also coming along. There isn’t anything particularly special about the HPC world other than the need for many different configurations of the same software for many different CPU and GPU archi
7.
by tgamblin 2y ago
> Datalog is a declarative logic programming language. While it is syntactically a subset of Prolog, Datalog generally uses a bottom-up rather than top-down evaluation model. This difference yields significantly different behavior and pr
8.
Mojibake(en.wikipedia.org)
2 points by tgamblin 2y ago|0 comments
9.
by tgamblin 2y ago
Spack doesn't require any particular prefix... it has a deployment model like nix, and the store can go anywhere. Binary caches are relocatable.
10.
Identifying Dependencies Used via Dlopen()(lwn.net)
3 points by tgamblin 2y ago|0 comments
11.
by tgamblin 2y ago
It's disappointing that this response linked by OP was posted at all. And even more disappointing because context gets lost every time it shows up on HN. The linked email is from an HPE/Cray employee interacting with the upstream
12.
by tgamblin 3y ago
> Maybe it's possible to have multiple _views_ of a filesystem, so via one API you "see" a flat namespace with hashed directories, and with another a conventional hierarchical one Spack supports the notion of arbitrary &qu
13.
by tgamblin 3y ago
FWIW this is what Spack does , and it uses a store layout like nix/guix. here are some chunks of the spack install tree path. All you really need is the hash, but we provide a bit more. $ spack find -p ... cmake@3.27.
14.
by tgamblin 3y ago
There is also `spack develop`, on which people are building hack/build/test loops. You can `spack develop` any package in spack, and easily build with a modified version of something. See also https://github.com/s
15.
by tgamblin 3y ago
This is stolen from @Theophite, sadly now banned: https://images.app.goo.gl/Rv5SK1qqWXZVNSZ56
16.
by tgamblin 3y ago
> I can't count the number of times I've seen people say "md5 is fine for use case xyz" where in some counterintuitive way it wasn't fine. I can count many more times that people told me that md5 was "broken
17.
by tgamblin 3y ago
Which part was hand-wavy/unreasonable? Do you think that dedicated MD5 hardware could become billions or even millions of times more efficient within a decade? If so, why?
18.
by tgamblin 3y ago
The article mentions the key detail: MD5 is broken for cryptography (collisions) but not for second preimage attacks. I was hoping there would be some discussion of just how much more difficult the latter is. It is extremely difficult.
19.
Avoid accidental obscenity with Crockford base32(crockford.com)
2 points by tgamblin 3y ago|0 comments
20.
by tgamblin 3y ago
In Spack we rewrite strings in binaries, strings in text files (including shebangs), and RPATH/RUNPATH values. It's not hard to find store prefixes in binaries -- they have hashes in them so they're easy to identify. It&#x27
21.
by tgamblin 3y ago
Spack dev here. Yep it's mainly used in HPC, but we'd love to see more folks using in other areas. There is windows support now (in addition to linux and macOS), which I think was a roadblock for many, and we have gotten some ver
22.
by tgamblin 3y ago
I’ve done exactly this to manage a test user identity separately from my main GitHub identity, for debugging GitHub apps. I didn’t clone separately, though. I added separate remotes to the repo so I could push a branch to either `github` o
23.
by tgamblin 3y ago
It looks like you can't search "all" anymore. But if you want the same effect you can hack the URL. Specifically: &type=all used to work, but isn't an option anymore &type=story&type=comment seems to do the
24.
by tgamblin 3y ago
FWIW, we do something like this in Spack[1] with `spack config blame`. There are different YAML configs, they can be merged and override each other based on precedence, but we tell you where all the merged values are coming from. Here&#x2
25.
by tgamblin 3y ago
"It failed after 25 dives" is not a 4% failure rate if the failure was caused by deterioration over time (as it likely was here). It's a 100% failure rate over the full life of any given Titan sub. They'll all implode,
26.
by tgamblin 3y ago
Dart as in the language? Dart uses a SAT solver: https://github.com/dart-lang/pub/blob/master/doc/solver.md
27.
by tgamblin 3y ago
Yep, from SAT. Edited. Guess I typed that too fast :)
28.
by tgamblin 3y ago
I read Potassco's Answer Set Solving in Practice book [0] but it's pretty dense. I suspect it would be easier to digest if you read it while also following their course materials, which are all online [1]. These days I recommend p
29.
by tgamblin 3y ago
I definitely recall doing reductions from SAT in Algorithms courses. I think that is a common part of most curricula. I don't recall being taught any practical uses of SAT. It was introduced only in the context of Cook's theore
30.
by tgamblin 3y ago
Love this article and the push to build awareness of what modern SAT solvers can do. It's worth mentioning that there are higher level abstractions that are far more accessible than SAT. If I were teaching a course on this, I would

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