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qoez
This article might be good but I always get scared when they use AI art for the header bc I wont know if I'm reading AI slop until i've invested a good amount of time into the article so I just avoid it all together.
neerajsi
It seemed to be ai assisted writing, but it was still interesting to me.
classified
What language is that, and what does `0.25_dp` mean?
chrystalkey
I wondered the same thing. _dp might mean double precision, but the rest is beyond me
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pklausler
Fortran’s types have kinds, which are integer codes that further distinguish various flavors of each type. The ISO standard failed to define their meanings for the built-in types, but with any modern compiler worth using the kind values are the byte sizes. Literal constants can have a kind value as a suffix, and the suffix can be either an integer or a named constant. Fortran codes tend to establish named constants for the “working precision” kind and the next higher precision kind, so that one need only redefine those to compile various versions of a subroutine that work with different precisions.

Even when one isn’t defining named constants for various kinds, it’s still good practice to use them on literal floating constants, since those default to the default kind of REAL in Fortran, not to double precision as in most later languages. A very pernicious pitfall of the language is to (say) assign or initialize X=0.1 instead of X=0.1_8 when X is double precision.

mota7
"... and this is the whole ballgame: ", "jump out immediately", "... and the idea is disarmingly simple", etc etc.

Written by Claude AI. Which is a problem because Claude text is riddled with engagement bait and filler, making it exhausting to read.

hyperhello
Artificial intelligence is a lot like alternative medicine, if it was the thing it said it was it wouldn’t need a name.
nh23423fefe
Damn yall are too exhausted to even read now because you spent so much mental energy trying to pattern match llm-ims instead of reading i guess
sheafification
I doubt outside of a few exceptional cases that one is going to do better on CPU-bound problems than a well-written LAPACK implementation built for the architecture you intend to run on.

Maybe pedagogy was the point? I didn’t really get that from the article, maybe some intention was lost by filtering it through AI.

BigTTYGothGF
LAPACK doesn't do sparse systems.

(On the other hand, I skimmed the article and this might be a banded system, which LAPACK can handle).

sheafification
True, 2D Poisson is only approximately banded. Still, I don’t think I’d bother rolling my own sparse solver. It’s a well-trod problem.
hwita
It looks like this analysis extends to the successive over-relaxation (SOR) method. Does it extend to the symmetric successive over-relaxation method?