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akssri

156 karma · joined May 11, 2015

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akssri··on Why Backprop Goes Backward (2018)
The intuition here is okay - but the math is hand-wavy with imprecise terms like "blow-up" etc.

The statements however, if taken to mean optimality, are also incorrect. Reverse-mode AD (backprop) is generally quite efficient for scalar outputs (more generally, when n_inputs >> n_outputs), but it's not strictly optimal even for this particular scalar-output case.

Consider for eg. a MLP, with 4-layers with dims (1, N, 1, N, 1) - reverse-mode here does ~3N multiplies, but the optimal is ~2N. The optimal ordering for gradient accumulation is in fact NP-hard on general DAGs, but such 'cross-mode' AD is apparently quite hard to implement and not often seen given the marginal gains.

Griewank-Walther's excellent book is a excellent reference for this and much more,

https://epubs.siam.org/doi/book/10.1137/1.9780898717761

They also had a library called ADOL-C that had mixed-mode.

akssri··on I should have loved biology (2020)
This article should be of interest to this crowd.

"Can a biologist fix a radio?—Or, what I learned while studying apoptosis - Yuri Lazebnik"

https://www.cell.com/cancer-cell/fulltext/S1535-6108(02)0013...

akssri··on India has paved the way for charging merchants a fee on UPI transactions
> You have some horrible feeling for UK. Forget that.

You have a serious issue with general comprehension, sir.

I've not once brought up UK or Western countries - my issue was/is/will-be with the Anglophone-Indian elites (who think they're honorary part of UK now ?), who will paint themselves as saints to the world with M.K Gandhi's face, but who are vicious corpulent vessels of the most vile forms of racism from the worst periods of the British-empire of 1 1/2 century before. India has more British laws inherited from this period, while UK itself has completely transformed itself (including the Civil-Service).

I'll not reply to the rest of the screed - that well-studied pedagogical gap of having to spend inordinate amount of time "muggin-up" things in English instead of actually understanding things means that I can't get much across anyway...

akssri··on India has paved the way for charging merchants a fee on UPI transactions
These laws mean zilch - the state of Karnataka, which hosts Bengaluru, where demagogues routinely raise Xenophobia based on language, has exactly 1-school that teaches Science/Mathematics at the high-school level (PUC, 11/12th) in Kannada.

Try using these "laws" and "rights" when you're trying to apply for a university, or asking a IIT to teach you in Hindi/Tamil LOL. These provisions are mostly used to skirt around the (generally onerous) laws by so-called "minority institutions" (eg. Manipal).

It's very disingenous to make such arguments by anyone with their eyes open in India. It's almost like the classic quip (almost a criticism of proto-liberalism) about the British empire: everyone is free in it as long as he's British!

Indians will go to Germany and learn German; go to Japan and learn Japanese; but will resist building anything of value with the culture/language of their own states of residence. The Anglophone-Indians will religiously preach a particularly seductive form of nationalist-liberalism internally for India that continues all the colonial structures of the British empire, because it helps them optimize for their own economic outcomes (ofc. they do this internationally too).

Absurd state of affairs tbh - and it has (eg. Blume Ventures' report) and will keep India poor with the wealth limited to ~5-10% of the population.

akssri··on India has paved the way for charging merchants a fee on UPI transactions
EU laws get written in 24 languages - and the CJEU (the equivalent of SC) doesn't give precedence to any one "master" language. These arguments for a "master-language" (let alone a foreign one), by both Hindi/Tamil nationalists, are cliched and threadbare.

In my opinion, these are just excuses for continued colonial-era English-imposition - because it's often only the aforementioned section that makes such brain-dead arguments.

For all the politically-ostentatious love of their own mother-languages there's not a single technical-university of any great reputation in either of these (it's worse in other Indic languages). The economic-value of these languages is close to zero if not negative.

Sheldon Pollock notes that, even in classical studies and literature, the institutions have turned utterly incompetent and filled with political retainers who can barely hold a mantle to people from previous generations who were experts in linguistics and manuscriptology.

So much for "Hindi/Tamil..." pride...

akssri··on India has paved the way for charging merchants a fee on UPI transactions
I agree with the sentiment - however, even after independence, India has been ruled by the same Anglophone/phile elite with nearly the same set of laws/policies/ interests. Even the Indian constitution comes in large part from the 1935 GoI Act passed in the British Parliament.

(Anglo-)India is of the Anglophones, by the Anglophones and for the Anglophones for all practical purposes.

That's why laws etc. are mandated to be written in this foreign language that's incomprehensible to the majority, and why there's a strict near-apartheid like barrier preventing higher education (and with it, higher employment) to non-Anglophones.

The only reason I imagine we don't hear about this systematic discrimination that prevent downstream material development like industrialization (as opposed to the ethereal one like caste) is perhaps because Western institutions have vested geopolitical interest in having such a large vassal, intellectually if not politically.

akssri··on Japan develops a method to recover up to 90% of lithium from used EV batteries
Between METI, Toyota & others, they appear to have spent > $40B over multiple decades.

It's a bit silly to downplay their investment based on the sales numbers of Toyota Mirai.

akssri··on Japan develops a method to recover up to 90% of lithium from used EV batteries
Some geopolitical context:

https://en.wikipedia.org/wiki/2010_Senkaku_boat_collision_in...

https://www.rusi.org/explore-our-research/publications/comme...

Japan was one of the first countries to be hit with rare-earth export-restrictions by China - going back to 2010. It seems that a lot of policy came out from this unpleasant shock, incl. the decision by Toyota to focus on developing FCEVs which would be less dependent on Chinese supply-chains. Ironically, the resulting vacuum may have actually led to Chinese/American companies gaining market share in the BEV space.

Still, given how things are going, FCEVs (and Japan with it) might actually end-up having the last laugh.

akssri··on AI changes the economics of software rewrites
Au contraire - LLMs are quite bad at large scale pattern fidelity. They'll even forget key details and constraints unless told over and over again. That's why AI-written code has the quality of a patch-on-patch-on-patch.
akssri··on Weave Robotics launches Isaac 1, a $7,999 home robot with Fall 2026 deliveries
This seems to be a redux of the 1x play (which was panned across the internet after the WSJ review).

https://www.youtube.com/watch?v=f3c4mQty_so

The hardware for these machines have been capable of household tasks for atleast 2 decades.

Here's PR1 cleaning up a room,

https://www.youtube.com/watch?v=o7JH3UWO6I0

The issue is not even teleop as a product. The issue none of these companies talk about is one of state-reset. Even a teleop-ed robot comes nowhere near the dexterity of a human - as the Joanna Stern review of 1x shows: 10 mins to load a dishwasher, 5 mins to get a glass of water, body coming the way of a fridge door, irrecoverable breakdowns every 30 mins...

Consider what happens if it drops some glassware or spills liquids on a carpet in addition (or worse does something stupid with the kitchen appliances). The teleop guy in Phillipines or India can't hop on a plane to fix this.

This 'environment reset' problem is at the core of RL - there are no solutions for this yet, only workarounds.

akssri··on OpenCV 5 Is Here: The Biggest Leap in Years for Computer Vision
Yup, it's basically the ROS of computer-vision.
akssri··on Why China got rich and India didn't
The article has the "rough" idea correct - how could it not be- but is quite stupid in a sort of cliched Chrisitian-missionary / colonialism sort of way.

It talks about how Chinese society was completely destroyed and instantly "modernized" (read, liberal, secular-Christian etc.), and is one step removed from claiming that India too needs this "total destruction".

The article notes about "traditional evils like Dowry or Female Foeticide" like some cliched missionary in British India begging patrons for funding (also the tactic of many a NGOs) - but fails to mention that every one of these issues come from exactly this "societal smashing" created by the "Great" (TM) British civilizers, and their eugenics obsessed American counterparts [1][2]. The latter even talks about how obssesed with killing children the American elites were that they didn't even spare their allies China and South Korea (an unthinkable thing to today Yellow-Fevered zietgeist).

The article barely touches on how the colonial Indian state survived in nearly the same exact form, and pretty much implements the same old British policies to this day. Indeed, the constitution of India is a near facsimile of the 1935 Government of India Act. passed in the British Parliament to secure their vice-grip on the colony and choke it to death.

In India, education remains restricted to the 5-10% Anglophones, and everyone else is considered pretty much "not human". These policies come out from Indian-looking Anglo elites who hate the country to the very core, and don't face push back since even the counter-elites have to come from the same process of colonial education [3].

This is pretty much why India punches, in every field, as a country 1/10 the size. The Anglo-Americans don't complain, since they get slaves for cheap who willingly become part of the Anglo-American borg (like colonized Africa, Phillipines etc.), and it also satisfies their deep religio-cultural obsession with turning everything into be a mirror of themselves by "societal smashing".

This "societal-smashing" business and "lets turn everything American!" scheme of liberalism will die with the societies whom it exhausts into exhaustion and extinction. The breakdown of social-cohesion and drop of birth-rates, coupled without the necessary financial power to "marketize" society (Anglo-utilitarianism is obsessed with "marketizing" everything), this will "fix" itself in half-a-century.

The signs are quite obvious. I hope the Elephant remains a witness.

[1]. Oldenburg, Veena Talwar. Dowry murder: The imperial origins of a cultural crime. Oxford University Press, 2002.

[2]. Hvistendahl, Mara. Unnatural selection: Choosing boys over girls, and the consequences of a world full of men. Public Affairs, 2011.

[3]. Sanu, Sankrant. "The English class system." South Asian Language Review 17, no. 1 (2007): 69-85.

https://sankrant.org/wp-content/uploads/2011/03/The-English-...

akssri··on Random numbers, Persian code: A mysterious signal transfixes radio sleuths
More so if you know the etymology,

https://www.etymonline.com/word/cipher

(Al Jabr, the translator of Indian Mathematical texts was a Persian IIRC)

akssri··on XML is a cheap DSL
Obligatory,

https://www.schnada.de/grapt/eriknaggum-xmlrant.html

akssri··on NewPipe: YouTube client without vertical videos and algorithmic feed
Newpipe is awesome. If you're on firefox, you can block the main-page feed with the following filter in ublock-origin,

"www.youtube.com##ytd-browse[page-subtype="home"]"

Sadly, you can't do this on Chrome/Chromium anymore with manifest v3.

akssri··on iCloud Photos Downloader
For those of you on Android / PC-Mac - Syncthing is an excellent tool for P2P syncing between multiple devices (it works over NAT and IPV6 too!).
akssri··on ChkTag: x86 Memory Safety
The article seems sparse on details.

Would this imply an architecture similar to what Lisp-Machines once had ? That'd be a great addition IMO, and would speed up a lot of dynamic-ish languages without resorting to unsafe-routes for speed.

akssri··on A 3K-year-old copper smelting site could be key to understanding origins of iron
This discovery is only of interest because the Iron-Age, as per standard-theory, started around 1200 BC. in the Caucuses/Anatolia or the near-East - which fits with another theory which claims that this allowed the "Aryans" to invade India with their technological superiority around this same time and replace the (dark-skinned) natives genetically.

(Note: the above is obviously a caricature, but current versions of theory don't change the structure, only the emphasis on "race").

No one would care about a copper-smelt site from 500 BC.; nor would they care about this one if the Indian archaeological claims were accepted (but that one also destroys centuries of Western history-making about India, and all the social-theories that depend on it).

This is all a digression from the main claims, so I'd prefer that people don't pull on this thread. For more information on how 'race' was ingested into Indology, I'd refer the interested reader to the excellent book by Adluri/Bagchi [0].

[0] https://academic.oup.com/ahr/article-abstract/120/3/1132/197...

akssri··on A 3K-year-old copper smelting site could be key to understanding origins of iron
Note: there have been actual Iron-working sites discovered in India that are older than this, dated to 1600 BC [0]. A lot of this has been ignored (just like the Painted-Grey ware continuity from IVC), partly I imagine, because it calls into question a lot of the racial non-sense that passes for "Indology".

[0]https://www.jstage.jst.go.jp/article/isijinternational/54/5/...

[1]https://www.lkouniv.ac.in/site/writereaddata/siteContent/202...

Edit: Apparently Tamil Nadu state in South India has claimed to have found a site from 3500 BC (not yet peer-reviewed AFAICT),

https://www.bbc.com/news/articles/c62e36jm4jro

akssri··on De-Googling TOTP Authenticator Codes
If you use Emacs on GNU-Linux, you can have it run oathtool and copy the code to the clipboard which you can straightaway middle-click-paste.

https://gist.github.com/akssri/92a3b240c89212815a66e86c60eab...

akssri··on God created the real numbers
The set of computable numbers is actually countable (see ref. linked above). It has to be by definition because the set of finite computer-programs is itself countable.

This is the whole point of the un-reality of "real" numbers: "all" of it (= measure 1) is uncomputable except a "tiny" measure-0 set.

akssri··on God created the real numbers
Theory of Computation wasn't around when all this "exciting" stuff was developed in Mathematics. Given their non-constructive nature "real" numbers are unsurprisingly totally incompatible with computation.

Chaitin has a great paper on this and shows how Cantor's constructions were reflected a half-century later by Turing. https://arxiv.org/abs/math/0411418

Except of-course, while "hyper-Turing" machines that can do magic "post-Turing" "post-Halting" computation are seen as absurd fictions, real-numbers are seen as "normal" and "obvious" and "common-sensical"! It was amusing sometime back to see people pooh-pooh the likes of Hava Siegelmann for being funded for their "super-Turing" machines with "real-number" computation, without realizing that the core issue is the "real"-number itself!

I've always found this quite strange, but I've realized that this is almost blasphemy (people in STEM, and esp. their "allies", aren't as enlightened etc. as they pretend to be tbh).

Some historicans of mathematics claim (C. K. Raju for eg.) that this comes from the insertion of Greek-Christian theological bent in the development of modern mathematics.

Anyone who has taken measure theory etc. and then gone on to do "practical" numerical stuff, and then realizes the pointlessness of much of this hard/abstract construction dealing with "scary" monsters that can't even be computed, would perhaps wholeheartedly agree.

edit: The post has a great link to a note on Cantor's theology,

https://apeironcentre.org/theology-of-georg-cantor/

akssri··on Reloading Classes in Python
This doesn't work the moment the module you're importing something imports something else that you've changed.

Worse, you can't redine methods, because the classes get "redefined". This means that you need to first redefine classes, then "reload" (hoping it doesn't break for to silly implementation limitations mentioned above), then initialize objects, then retest.

Obviously this is quite painful which is why I use this decorator to mimic Lisp's defmethod to patch methods on "live" objects without class redefinition,

https://gist.github.com/akssri/431f2dfe037bbdbb3c8668872edfd...

akssri··on Moved a server from one building to another with zero downtime
Was it George Costanza ?

https://m.youtube.com/watch?v=a-FbktgqCqY

akssri··on How to Write a Video Player in Less Than 1000 Lines (2015)
Sadly, the code in this tutorial doesn't work anymore due to upstream changes in FFmpeg. There are quite a few attempts at keeping Dranger's tutorial up to date, but I found the repo below to be one of the better ones.

https://github.com/rambodrahmani/ffmpeg-video-player

akssri··on Ask HN: Production Lisp in 2020?
ITA software's account of using CL may also be of interest,

http://www.paulgraham.com/carl.html

akssri··on A unusual keyboard key switch
Very cool! Old keyboards and key-switches are an endless source of fun trivia.

I think Topre is the only one that manufactures keyboards with contactless key switches today. Topre key-switches measure the change in capacitance instead, and their keyboards (of the HHKB fame) sell for greater than $200.

https://www.keychatter.com/topre-switches/

akssri··on [dead]
Julia is great no doubt. However, all the additional complexity is not entirely 'free'.

For instance, Julia has a performant generational GC compared to Python's simple (but slow) refcount GC. This has the effect of not freeing up intermediate tensors immediately while doing backprop, thus leading to the premature exhaustion of GPU memory while training a deep neural net in Julia. This above issue was flagged with Flux.jl sometime back, and while I'm sure this has been fixed, it's also an illustration of how such low-level implementation details come back to bite.

Pytorch/Chainer etc. in contrast use a memory pool to manage GPU resources (the equivalent of malloc is quite slow), so that Python's 'slow' GC is actually a boon for deep learning workloads.

akssri··on GoPro cuts workforce, changes sales strategy
I heard that GoPro hasn't been doing well in the past couple years [1]. Did they ever transition out of their "badge re-engineering" approach to products ?

[1]. https://www.youtube.com/watch?v=1qa1tGmi5g4

akssri··on Ask HN: How do you backup your email?
isync and cron
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