mmarx

6 ms·

1.
by mmarx 2mo ago
> I don't understand why you people act like you're stumped by literally, literally page 1 of computer science. … and yet you didn't stop for a moment to consider that in a field as fast-moving as computer science, a conce
2.
by mmarx 5mo ago
It's already past midnight in New Zealand, e.g.
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by mmarx 8mo ago
In multi-user mode, Nix uses dedicated build users to write to the store. There is also single-user mode, but that also doesn't require a world-writable store.
4.
by mmarx 1y ago
> Theoretically, we could also go for finding the semantically equivalent C code. However, last time I researched, checking semantic equivalency is a very complex problem. I think it was NP hard. Already deciding whether two finite autom
5.
by mmarx 2y ago
This machine has 8 states, so (for actual Turing Machines with an unbounded tape) you'd be looking at BB(8). However, since the tape can only store 24 symbols, the machine only has 8 (states) * 4 (tape symbols) * 24 (tape length) = 768
6.
by mmarx 2y ago
Since the model tape isn't actually infinite, this machine has a finite state space, and termination is therefore decidable. No Turing Award to obtain here …
7.
by mmarx 2y ago
https://github.com/KFearsoff/nix-drama-explained has a good summary of what the contention is about.
8.
Aux.computer: An Alternative to the Nix Ecosystem(aux.computer)
34 points by mmarx 2y ago|35 comments
9.
by mmarx 3y ago
Yes, technically you'll also get a MediaWiki instance there, but the point is really to offer Wikibase (which is a set of extensions upon MediaWiki), the software behind Wikidata.
10.
by mmarx 3y ago
> Before the phaseout started, nuclear contributed more than 20% to electricity generation. That's true, but also quite meaningless. Before the nuclear phaseout started, renewables contributed less than 7% to electricity generation,
11.
by mmarx 3y ago
> Another example of poor decision making is Germany which decided to start shutting down nuclear power plants while they were still burning coal. So last year hard coal and lignite still produced 35.3 percent in German power production
12.
by mmarx 3y ago
from the linked YouTube video: > This is the second time I've successfully tested this on a Class 800. For some reason this time I seem to have actually confused the toilet door controller enough that it decided "screw this&quo
13.
by mmarx 3y ago
Ah, thanks, that was indeed what I was missing.
14.
by mmarx 3y ago
From the truth table, subtraction is clearly truth-preserving, so it cannot actually be functionally complete. What am I missing?
15.
by mmarx 3y ago
Even though halting is generally undecidable, there are still large classes of programs for which you _can_ show termination. If you reject every program for which you cannot show termination, you will also reject some programs that termina
16.
by mmarx 3y ago
Mixing tabs and spaces is a TabError in Python 3, so this would definitely error today.
17.
by mmarx 3y ago
> It would be absurd to compare unary and binary addition relative to the same numeral length. Why? The Turing machine has no concept of numeric values, it only knows about the length of whatever the input is. > Adding one million to
18.
by mmarx 3y ago
> That's comparing apples to oranges, because the two input types have vastly different lengths relative to their value. It really is not, because complexity is fundamentally a function of _the length of the input_ (specifically: it
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by mmarx 3y ago
Actually, an algorithm working on unary input tends to have better computational complexity than an algorithm working on binary input: an algorithm that is polynomial in the numeric value will be a polynomial algorithm on unary input, but
20.
by mmarx 3y ago
Ah, fair enough, though it feels a bit like stretching the definition.
21.
by mmarx 3y ago
I guess it should rather say that NixOS provides 1 and 2, since I don't see how it would be ABI compatible to a major distribution.
22.
by mmarx 4y ago
> > PHP 8.0 is 10 months old, and debian’s upcoming release will be upgrading from 7.3 to 7.4, which will make 7.4 the standard for the next ~3 years (even though it only gets upstream support for 1 more year)… Packaging PHP 8 would
23.
by mmarx 4y ago
TypeScript to Fortran is also broken, generating lots of dlopen/dlsym/dlclose calls (one for every variable, it seems), but never actually doing anything else with it. For what it's worth, Sample 2 generates syntactically inv
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by mmarx 4y ago
> Additionally you have Prolog clauses without Prolog's reasoning power!. SPARQL is just a query language, not a tool for automated reasoning. That's not necessarily bad, however. A direct consequence of this is that finding th
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by mmarx 4y ago
For a Datalog program and a specific database, there is always a finite set of facts the program can possibly derive (that is the “finite grounding” from above), obtained in the following way: for every predicate that appears in the “head”
26.
by mmarx 4y ago
No, Datalog always has a finite (though potentially exponentially large) grounding, since no rule can introduce new values to the database (i.e., it has no “value invention”/“function terms”/“existential quantification”). Some for
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by mmarx 4y ago
Anything involving transitive closure, for example. Say you have a directed graph, encoding an edge from `x` to `y` as `edge(x, y)` (or as a triple `(x, edge, y)`, and you want to find all vertices reachable from `a`. In standard Datalog, y
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by mmarx 5y ago
A few days ago, the Wikidata Query Builder[0] was deployed. It provides a visual interface to generate simple SPARQL queries, and you can show the generated queries. Maybe this can help you in understanding how SPARQL patterns work? [0] ht
29.
by mmarx 5y ago
The conjunctive normal form can be exponentially large in the worst case as well, though, see the footnote in the article. In practice that is not a problem, since it suffices to find a formula in CNF that is satisfiable precisely when the
30.
by mmarx 5y ago
A bidirectional integration, Wikidata Bridge[0], is currently under development. [0] https://www.mediawiki.org/wiki/Wikidata_Bridge

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