The bouncing droplets imply having to drop the Bohmian approach?

If you are interested in the area of QM foundations, then may be you should drop everything at once, and go, check out the latest pop-sci news report: “Famous experiment dooms alternative to quantum weirdness” by Natalie Wolchover in the Quanta Magazine [^].

Remember the bouncing droplets experiments performed by Yves Couder and pals? In 2006, they had reported that they could get the famous interference pattern even if the bouncing droplets passed through the double slit arrangement only one at a time. … As the Quanta article now reports, it turns out that when other groups in the USA and France tried to reproduce this result (the single-particle double-slit interference), they could not.

“Repeat runs of the experiment, called the “double-slit experiment,” have contradicted Couder’s initial results and revealed the double-slit experiment to be the breaking point of both the bouncing-droplet analogy and de Broglie’s pilot-wave vision of quantum mechanics.”

Well, just an experimental failure or two in reproducing the interference, by itself, wouldn’t make for a “breaking point,”i.e., if the basic idea itself were to be sound. So the question now becomes whether the basic idea itself is sound enough or not.

Turns out that a new argument has been put forth, in the form of a thought experiment, which reportedly shows why and how the very basic idea itself must be regarded as faulty. This thought experiment has been proposed by a Danish professor of fluid dynamics, Prof. Tomas Bohr. (Yes, there is a relation: Prof. Tomas Bohr is a son of the Nobel laureate Aage Bohr, i.e., a grandson of the Nobel laureate Niels Bohr [^].)

Though related to QM foundations, this thought experiment is not very “philosophical” in nature; on the contrary, it is very, very “physics-like.” And the idea behind it also is “simple.” … It’s one of those ideas which make you exclaim “why didn’t I think of it before?”—at least the first time you run into it. Here is an excerpt (which actually is the caption for an immediately understandable diagram):

“Tomas Bohr’s variation on the famous double-slit experiment considers what would happen if a particle must go to one side or the other of a central dividing wall before passing through one of the slits. Quantum mechanics predicts that the wall will have no effect on the resulting double-slit interference pattern. Pilot-wave theory, however, predicts that the wall will prevent interference from happening.”

… Ummm… Not quite.

From whatever little I know about the pilot-wave theory, I think that the wall wouldn’t prevent the interference from occurring, even if you use this theory. … It all seems to depend on how you interpret (and/or extend) the pilot-wave theory. But if applied right (which means: in its own spirit), then I guess that the theory is just going to reproduce whatever it is that the mainstream QM predicts. Given this conclusion I have drawn about this approach, I did think that the above-quoted portion was a bit misleading.

The main text of the article then proceeds to more accurately point out the actual problem (i.e., the way Prof. Tomas Bohr apparently sees it):

“… the dividing-wall thought experiment highlights, in starkly simple form, the inherent problem with de Broglie’s idea. In a quantum reality driven by local interactions between a particle and a pilot wave, you lose the necessary symmetry to produce double-slit interference and other nonlocal quantum phenomena. An ethereal, nonlocal wave function is needed that can travel unimpeded on both sides of any wall. [snip] But with pilot waves, “since one of these sides in the experiment carries a particle and one doesn’t, you’ll never get that right. You’re breaking this very important symmetry in quantum mechanics.””

But isn’t the pilot wave precisely ethereal and nonlocal in nature, undergoing instantaneous changes to itself at all points of space? Doesn’t the pilot theory posit that this wave doesn’t consist of anything material that does the waving but is just a wave, all by itself?

…So, if you think it through, people seem to be mixing up two separate issues here:

  1. One issue is whether it will at all be possible for any real physical experiment done up with the bouncing droplets to be able to reproduce the predictions of QM or not.
  2. An entirely different issue is whether, in Bohr’s dividing-wall thought-experiment, the de Broglie-Bohm approach actually predicts something that is at a variance from what QM predicts or not.

These two indeed are separate issues, and I think that the critics are right on the first count, but not necessarily on the second.

Just to clarify: The interference pattern as predicted by the mainstream QM itself would undergo a change, a minor but a very definite change, once you introduce the middle dividing wall; it would be different from the pattern obtained for the “plain-vanilla” version of the interference chamber. And if what I understand about the Bohmian mechanics is correct, then it too would proceed to  produce exactly the same patterns in both these cases.

With that said, I would still like to remind you that my own understanding of the pilot-wave theory is only minimal, mostly at the level of browsing of the Wiki and a few home pages, and going through a few pop-sci level explanations by a few Bohmians. I have never actually sat down to actually go through even one paper on it fully (let alone systematically study an entire book or a whole series of articles on this topic).

For this reason, I would rather leave it to the “real” Bohmians to respond to this fresh argument by Prof. Tomas Bohr.

But yes, a new argument—or at least, an old argument but in a remarkably new settings—it sure seems to be.

How would the Bohmians respond?

If you ask me, from whatever I have gathered about the Bohmians and their approach, I think that they are simply going to be nonchalant about this new objection, too. I don’t think that you could possibly hope to pin them down with this argument either. They are simply going to bounce back, just like those drops. And the reason for that, in turn, is what I mentioned already here in this post: their pilot-wave is both ethereal and nonlocal in the first place.

So, yes, even if Wolchover’s report does seem to be misguided a bit, I still liked it, mainly because it was informative on both the sides: experimental as well as theoretical (viz., as related to the new thought-experiment).

In conclusion, even if the famous experiment does not doom this (Bohmian) alternative to the quantum weirdness, the basic reason for its unsinkability is this:

The Bohmian mechanics is just as weird as the mainstream QM is—even if the Bohmians habitually and routinely tell you otherwise.

When a Bohmian tells you that his theory is “sensible”/“realistic”/etc/, what he is talking about is: the nature of his original ambition—but not the actual nature of his actual theory.

To write anything further about QM is to begin dropping hints to my new approach. So let me stop right here.

[But yes, I am fully ready willing from my side to disclose all details about it at any time to a suitable audience. … Let physics professors in India respond to my requests to let me conduct an informal (but officially acknowledged) seminar on my new approach, and see if I get ready to deliver it right within a week’s time, or not!

[Keep waiting!]]

Regarding other things, as you know, the machine I am using right now is (very) slow. Even then, I have managed to run a couple of 10-line Python scripts, using VSCode.

I have immediately taken to liking this IDE “code-editor.” (Never had tried it before.) I like it a lot. … Just how much?

I think I can safely say that VSCode is the best thing to have happened to the programming world since VC++ 6 about two decades ago.

Yes, I have already stopped using PyCharm (which, IMHO, is now the second-best alternative, not the best).

No songs section this time, because I have already run a neat and beautiful song just yesterday. (Check out my previous post.) … OK, if some song strikes me in a day or two, I will return here to add it. Else, wait until the next time around. … Until then, take care and bye for now…

[Originally published on 16 October 2018 22:09 hrs IST. Minor editing (including to the title line) done by 17 October 2018 08:09 hrs IST.]


Back on the ‘net!

Hushshshsh… Finally I am back on the ‘net (I mean to say, in a real way—not via smartphone). But it’s not after having the broken laptop repaired. On the contrary, it seems as if it’s no longer viable to revive my broken laptop.

So, right now, I am writing this post using an even older laptop that I had. I dug it up from the cupboard, and revived it.

Actually, you can’t call it a laptop; even the manufacturer called it a notebook (the 2008 model Compaq Presario C700, 32-bit Intel Core Duo @ 1.83 GHz, 1 GB RAM). I used to use about a decade ago. All my PhD time programs and data were sitting on it. (The thesis had been written and submitted even earlier, even before I bought this notebook; it was written on a desktop I had back then. However, after submitting thesis, it took them 2 years to arrange for the defence. That’s how, it was on this machine that I had prepared my final defence slides.)

It was a dual boot machine, with one partition running XP, and the other, Vista. I had forgotten the password of the Vista, but fortunately, not of the XP.

The trouble with XP was that both the Mozilla and Internet Explorer installed on it had already become absolutely obsolete. Also Java. (The support for these software had vanished by 2014, I now gathered.) The browsers were so old that they couldn’t handle even simplest of today’s https requests—the SSL layer itself must have been too old. So, I couldn’t have used that OS even for just surfing on the ‘net.

So, what I did over the past couple of days was to first take a backup of my PhD-time data. Then, I proceeded to reformat the whole hard disk, and installed Lubuntu 18.04.1 on it.

Yes, Lubuntu does manage to run even on a 32-bit 1 GB machine. However, even with this comparatively light-weight OS, there is enormous disk-thrashing, particularly if I try to use a programming IDE. (After bootup, the OS by itself eats up something like 600–700 MB of RAM.) So far, I’ve tried installing and using PyCharm, Spyder and VSCode. They all do run, but very, very slowly. Sometimes, you have to even wait for a minute or so just for a context-switch between two processes (say, the browser and the IDE).

So, looks like despite all my valiant tries, this machine isn’t going to be useful for my ANN studies; it would be usable only for browsing. … May be I should borrow money and buy a new laptop….

But one way or the other, this decade-old machine still is better, much much better, than my new (late-2017 times) smart-phone. … As I said recently, the smart-phone is a bad idea. …

… Anyway, now that I am on the ‘net (can use a real keyboard), I should be back pretty soon, say tomorrow or the day after, with something which is much more exciting. That’s a promise. So, bye for now, but stay tuned.

A song I like:
(Marathi) “ekaach yaa janmi jaNu…”
Music: Sudhir Phadke
Lyrics: Sudhir Moghe
Singer: Asha Bhosale

[Usually, when you say “song,” what you usually mean is the basic tune. OK, sometimes, first the words and then the tune. However, this song is odd.

The real beauty of this song lies not in any one of its elements but in the way it unfolds—the way the music composer leads you through an interplay between various musical phrases and the lyrical ones. Especially noteworthy are the violin pieces which transition you from the stanza to the refrain and back. Also noteworthy is the interplay between the Western and the Indian instruments…

So, what rules here is not just the tune, not just the words, not just the orchestration, and not just the rendering in the voice by the singer. Instead, it is the skillfully arranged interplay between all these elements which truly gives the defining character to this song and makes it so beautiful.

So, it’s the music composer who really stands out here, even if the entire team is outstanding… Or so I believe. … Anyway, bye for now. ]

[May be a little streamlining, later on.]

The quantum mechanical features of my laptop…

My laptop has developed certain quantum mechanical features after its recent repairs [^]. In particular, if I press the “power on” button, it does not always get “measured” into the “power-on” state.

That’s right. In starting the machine, it is not possible to predict when the power-on button may work, when it may lead to an actual boot-up. Sometimes it does, sometimes it doesn’t.

For instance, the last time I shut it down was on the last night, just before dinner. Then, after dinner, when I tried to restart it, the quantum mechanical features kicked in and the associated randomness was such that it simply refused the request. Ditto, this morning. Ditto, early afternoon today. But now (at around 18:00 hrs on 09 October), it somehow got up and going!

Fortunately, I have taken backup of crucial data (though not all). So, I can afford to look at it with a sense of humour.

But still, if I don’t come back for a somewhat longer period of time than is usual (about 8–10 days), then know that, in all probability, I was just waiting helplessly in getting this thing repaired, once again. (I plan to take it to the repairsman tomorrow morning.) …

…The real bad part isn’t this forced break in browsing or blogging. The real bad part is: my inability to continue with my ANN studies. It’s not possible to maintain any tempo in studies in this now-on-now-off sort of a manner—i.e., when the latter is not chosen by you.

Yes, I do like browsing, but once I get into the mood of studying a new topic (and, BTW, just reading through pop-sci articles does not count as studies) and especially if the studies also involve programming, then having these forced breaks is really bad. …

Anyway, bye for now, and take care.

PS: I added that note on browsing and then it struck me. Check out a few resources while I am gone and following up with the laptop repairs (and no links because right while writing this postscript, the machine crashed, and so I am somehow completing it using smartphone—I hate this stuff, I mean typing using at most two fingers, modtly just one):

  1. As to Frauchiger and Renner’s controversial much-discussed result, Chris Lee’s account at ArsTechnica is the simplest to follow. Go through it before any other sources/commentaries, whether to the version published recently in Nature Comm. or the earlier ones, since 2016.
  2. Carver Mead’s interview in the American Spectator makes for an interesting read even after almost two decades.
  3. Vinod Khosla’s prediction in 2017 that AI will make radiologists obsolete in 5 years’ time. One year is down already. And that way, the first time he made remarks to that sort of an effect were some 6+ years ago, in 2012!
  4. As to AI’s actual status today, see the Quanta Magazine article: “Machine learning confronts the elephant in the room” by Kevin Hartnett. Both funny and illuminating (esp. if you have some idea about how ML works).
  5. And, finally, a pretty interesting coverage of something about which I didn’t have any idea beforehand whatsoever: “New AI strategy mimics how brains learn to smell” by Jordana Cepelwicz in Quanta Mag.

Ok. Bye, really, for now. See you after the laptop begins working.

A Song I Like:
Indian, instrumental: Theme song of “Malgudi Days”
Music: L. Vaidyanathan



I must not…

I must not ever let the wise counsel out of the eye.

And so, I add, for your personal pleasure, a song which I very much liked in my youth.

Well, not an issue if you don’t like it.



A song I like:

(Hindi/Urdu): “ishq mein ghairat-e-jazbaat nein…”
Music: Jagjit Singh
Singers: Chitra Singh. Also, Jagjit Singh. (Yes, sometimes, he exceeds her. But, I, still like her here better.)
Lyrics: You figure out. (An exercise once in a while is not so bad for you, I mean—and what do you think of that?)


Suspension of blogging

Earlier, within a day of my posting the last blog entry here, i.e. right by 26th September morning, my laptop developed a problem, which led to a series of problems, which meant that, for a while, I could not at all blog or even surf on the ‘net effectively.

The smartphone screen is too small for me to do any serious browsing very effectively, let alone doing any blogging / writing / coding.

Never did buy into that idiotic Steve Jobs’ ridiculous claims anyway; bought my smartphone only because it’s good for things like storing phone numbers and listening to songs—and, yes, also for browsing a bit on google maps, and for taking snaps once in a while. But that’s about it. Nothing more than that. In particular, no social media, no banking, no e-payments, no emails, no real browsing. And, as to that prized (actually wretched) thin-ness and/or the delicate-ness of this goddamn thing. It is annoying. Just hold the damn thing in your palm, and it seems as if it itself auto-punches a few buttons and proceeds to close all the windows you had kept active. Or, worse: it launches a new window all by itself, forcing you to take a hike into an ad-link or sundry news item.

A good 1 inch thick and sturdy instrument with goodly big buttons would have been a better design choice, far better—not those bloody thin slivers on the sides which pass for buttons.

Anyway, the troubles with the laptop were these:

(i) In 2014, the screen panel of the laptop had cracked near a corner a bit, and then, subsequently, over a period of years or so, the front and the back covering parts of the screen panel had come to split apart, though only just slightly, only partially. I had shown the problem to the authorized dealer. He had advised me to do nothing about it. (If the problem were to be worse, he would have advised me to replace the screen, he had said. This was about 2 years ago.)

(ii) Then, slowly, friction began developing in only one of the hinges of the screen panel, the hinge near the same (cracked) corner. Finally, came this day when this partial splitting suddenly led to the panel-studs breaking apart (with a clean, brittle fracture). How did it happen? Because—I figured out only after the fact—the friction in the hinges together with the partial split up meant that an interior part of the screen panel was getting excessively bent, near the broken panel corner. This excessive bending was putting enormous bending moment on the studs holding the two parts of the partially split up panel near the hinges. (The overall frame of the screen panel was effectively acting as a large lever arm serving to bend the small plastic studs.)

(iii) In getting the above-mentioned problem fixed (by 29th September), some short-circuiting also occurred, with the result that now the graphics chip conked up. (No, the authorized dealer didn’t accept the machine. He advised replacement of both the mother-board and the screen. So, I did a google search and went through two private repairs-men, one of them being much better than the other. He fixed it right.)

Fixing the graphics problem took time because a replacement chip was not readily available in the local market, and there was a national holiday in between (on 2nd October) which kept the concerned courier services closed on that day.

(iv) Then, after replacing the graphics chip, once the screen finally started working, now it was the turn of the USB ports to begin malfunctioning. I got the delivery of my laptop last evening, and noticed it only after coming home.

This is a problem which has not yet been fixed. Getting it fixed is important because only 1 out of the 3 USB ports is currently functioning, and if it too is gone, backups will become impossible. I am not willing to lose my data once again.

The problem with the machine meant that my studies (and programming) of ANNs too got interrupted.

They still remain interrupted.

I guess the remaining problem (regarding the malfunctioning USB ports) is relatively a minor issue.

What I mean to say is that I could have resumed my regular sort of blogging.

However, last night, at around 00:40 hrs IST on 05 October 2018 there was a psychic attack on me which woke me up from sleep. (Also note the update in my last post). In view of this attack, I have finally decided to say it clear and loud, (perhaps once again):

“To hell with you, LA!”

If you wonder why I was so confident about “LA,” check out the visits pattern for the earlier part of the day yesterday, and juxtapose them with the usual patterns of visits here, overall.

In case you don’t know, all local newspapers of all California towns have been full of advertisements for psychic “consultants” providing their “services” for a fee—which would be almost nothing when measured in US dollars.

I have had enough of these bitches and bastards. That’s why, I am temporarily suspending my blog. When the psychic attacks come to a definitive stop, I will resume my own blogging, as also my commenting on other blogs, and posting any research notes etc.

And, yes, one more point: No, don’t believe what Ayn Rand Institute tells you. Psychic attacks are for real (though they are much, much rarer, and they indeed are effected in far more controlled ways, than what folklore or your average street-side vendor of the “services” says.)

No songs section this time round, for obvious reasons.

PS: BTW, no, I still haven’t seen my approach to QM mentioned in any of the papers / books, or in any discussions of any papers anywhere (including some widely followed blogs / twitter feeds), as yet. Apparently, my judgment that my approach is indeed new, continues to hold.



Some running thoughts on ANNs and AI—1

Go, see if you want to have fun with the attached write-up on ANNs [^] (but please also note the version time carefully—the write-up could change without any separate announcement).

The write-up is more in the nature of a very informal blabber of the kind that goes when people work out something on a research blackboard (or while mentioning something about their research to friends, or during brain-storming session, or while jotting things on the back of the envelop, or something similar).


A “song” I don’t like:

(Marathi) “aawaaj waaDaw DJ…”
“Credits”: Go, figure [^]. E.g., here [^]. Yes, the video too is (very strongly) recommended.

Update on 05 October 2018 10:31 IST:

Psychic attack on 05 October 2018 at around 00:40 IST (i.e. the night between 4th and 5th October, IST).


Flames not so old…

The same picture, but two American interpretations, both partly misleading (to varying degrees):

NASA releases a photo [^] on the FaceBook, on 24 August at 14:24, with this note:

The visualization above highlights NASA Earth satellite data showing aerosols on August 23, 2018. On that day, huge plumes of smoke drifted over North America and Africa, three different tropical cyclones churned in the Pacific Ocean, and large clouds of dust blew over deserts in Africa and Asia. The storms are visible within giant swirls of sea salt aerosol (blue), which winds loft into the air as part of sea spray. Black carbon particles (red) are among the particles emitted by fires; vehicle and factory emissions are another common source. Particles the model classified as dust are shown in purple. The visualization includes a layer of night light data collected by the day-night band of the Visible Infrared Imaging Radiometer Suite (VIIRS) on Suomi NPP that shows the locations of towns and cities.

[Emphasis in bold added by me.]

For your convenience, I reproduce the picture here:

Aerosol data by NASA

Aerosol data by NASA. Red means: Carbon emissions. Blue means: Sea Salt. Purple means: Dust particles.

Nicole Sharp blogs [^] about it at her blog FYFD, on Aug 29, 2018 10:00 am, with this description:

Aerosols, micron-sized particles suspended in the atmosphere, impact our weather and air quality. This visualization shows several varieties of aerosol as measured August 23rd, 2018 by satellite. The blue streaks are sea salt suspended in the air; the brightest highlights show three tropical cyclones in the Pacific. Purple marks dust. Strong winds across the Sahara Desert send large plumes of dust wafting eastward. Finally, the red areas show black carbon emissions. Raging wildfires across western North America are releasing large amounts of carbon, but vehicle and factory emissions are also significant sources. (Image credit: NASA; via Katherine G.)

[Again, emphasis in bold is mine.]

As of today, Sharp’s post has collected some 281 notes, and almost all of them have “liked” it.

I liked it too—except for the last half of the last sentence, viz., the idea that vehicle and factory emissions are significant sources (cf. NASA’s characterization):

My comment:

NASA commits an error of omission. Dr. Sharp compounds it with an error of commission. Let’s see how.

NASA does find it important to mention that the man-made sources of carbon are “common.” However, the statement is ambiguous, perhaps deliberately so. It curiously omits to mention that the quantity of such “common” sources is so small that there is no choice but to regard it as “not critical.” We may not be in a position to call the “common” part an error of commission. But not explaining that the man-made sources play negligible (even vanishingly small) role in Global Warming, is sure an error of omission on NASA’s part.

Dr. Sharp compounds it with an error of commission. She calls man-made sources “significant.”

If I were to have an SE/TE student, I would assign a simple Python script to do a histogram and/or compute the densities of red pixels and have them juxtaposed with areas of high urban population/factory density.

This post may change in future:

BTW, I am only too well aware of the ugly political wars being waged by a lot of people in this area (of Global Warming). Since I do appreciate Dr. Sharp’s blog, I would be willing to delete all references to her writing from this post.

However, I am going to keep NASA’s description and the photo intact. It serves as a good example of how a good visualization can help in properly apprehending big data.

In case I delete references to Sharp’s blog, I will simply add another passage on my own, bringing out how man-made emissions are not the real cause for concern.

But in any case, I would refuse to be drawn into those ugly political wars surrounding the issue of Global Warming. I have neither the interest nor the bandwidth to get into it, and further, I find (though can’t off-hand quote) that several good modelers/scientists have come to offer very good, detailed, and comprehensive perspectives that justify my position (mentioned in the preceding paragraph). [Off-hand, I very vaguely remember an academic, a lady, perhaps from the state of Georgia in the US?]

The value of pictures:

One final point.

But, regardless of it all (related to Global Warming and its politics), this picture does serve to highlight a very important point: the undeniable strength of a good visualization.

Yes I do find that, in a proper context, a picture is worth a thousand words. The obvious validity of this conclusion is not affected by Aristotle’s erroneous epistemology, in particular, his wrong assertion that man thinks in terms of “images.” No, he does not.

So, sure, a picture is not an argument, as Peikoff argued in the late 90s (without using pictures, I believe). If Peikoff’s statement is taken in its context, you would agree with it, too.

But for a great variety of useful contexts, as the one above, I do think that a picture is worth a thousand words. Without such being the case, a post like this wouldn’t have been possible.

A Song I Like:
(Hindi) “dil sajan jalataa hai…”
Singer: Asha Bhosale
Music: R. D. Burman [actually, Bertha Egnos [^]]
Lyrics: Anand Bakshi

Copying it right:

“itwofs” very helpfully informs us [^] that this song was:

Inspired in the true sense, by the track, ‘Korbosha (Down by the river) from the South African stage musical, Ipi Ntombi (1974).”

However, unfortunately, he does not give the name of the original composer. It is: Bertha Egnos (apparently, a white woman from South Africa [^]).

“itwofs” further opines that:

Its the mere few initial bars that seem to have sparked Pancham create the totally awesome track [snip]. The actual tunes are completely different and as original as Pancham can get.

I disagree.

Listen to Korbosha and to this song, once again. You will sure find that it is far more than “mere few initial bars.” On the contrary, except for a minor twist here or there (and that too only in some parts of the “antaraa”/stanza), Burman’s song is almost completely lifted from Egnos’s, as far as the tune goes. And the tune is one of the most basic—and crucial—elements of a song, perhaps the most crucial one.

However, what Burman does here is to “customize” this song to “suit the Indian road conditions tastes.” This task also can be demanding; doing it right takes a very skillful and sensitive composer, and R. D. certainly shows his talents in this regard, too, here. Further, Asha not only makes it “totally, like, totally” Indian, she also adds a personal chutzpah. The combination of Egnos, RD and Asha is awesome.

If the Indian reader’s “pride” got hurt: For a reverse situation of “phoreenn” people customizing our songs, go see how well Paul Mauriat does it.

One final word: The video here is not recommended. It looks (and is!) too gaudy. So, even if you download a YouTube video, I recommend that you search for good Open Source tools and use it to extract just the audio track from this video. … If you are not well conversant with the music software, then Audacity would confuse you. However, as far as just converting MP4 to MP3 is concerned, VLC works just as great; use the menu: Media \ Convert/Save. This menu command works independently of the song playing in the “main” VLC window.

Bye for now… Some editing could be done later on.

Caste Brahmins, classification, and ANN

1. Caste Brahmins:

First, a clarification: No, I was not born in any one of the Brahmin castes, particularly, not at all in the Konkanastha Brahmins’ caste.

Second, a suggestion: Check out how many caste-Brahmins have made it to the top in the Indian and American IT industry, and what sort of money they have made—already.

No, really.

If you at all bother visiting this blog, then I do want you to take a very serious note of both these matters.

No. You don’t have to visit this blog. But, yes, if you are going to visit this blog, to repeat, I do want you to take  matters like these seriously.

Some time ago, perhaps a year ago or so, a certain caste-Brahmin in Pune from some place (but he didn’t reveal his shakha, sub-caste, gotra, pravar, etc.) had insulted me, while maintaining a perfectly cool demeanor for himself, saying how he had made so much more money than me. Point taken.

But my other caste-Brahmin “friends” kept quiet at that time; not a single soul from them interjected.

In my off-the-cuff replies, I didn’t raise this point (viz., why these other caste-Brahmins were keeping quiet), but I am sure that if I were to do that, then, their typical refrain would have been (Marathi) “tu kaa chiDatos evhaDa, to tar majene bolat hotaa.” … English translation: Why do you get so angry? He was just joking.

Note the usual caste-Brahmin trick: they skillfully insert an unjustified premise; here, that you are angry!

To be blind to the actual emotional states or reactions of the next person, if he comes from some other caste, is a caste-habit with the caste-Brahmins. The whole IT industry is full of them—whether here in India, or there in USA/UK/elsewhere.

And then, today, another Brahmin—a Konkanastha—insulted me. Knowing that I am single, he asked me if I for today had taken the charge of the kitchen, and then, proceeded to invite my father to a Ganesh Pooja—with all the outward signs of respect being duly shown to my father.

Well, coming back to the point which was really taken:

Why have caste-Brahmins made so much money—to the point that they in one generation have begun very casually insulting the “other” people, including people of my achievements?

Or has it been the case that the people of the Brahmin castes always were this third-class, in terms of their culturally induced convictions, but that we did not come to know of it from our childhood, because the elderly people around us kept such matters, such motivations, hidden from us? May be in the naive hope that we would thereby not get influenced in a bad manner? Possible.

And, of course, how come these caste-Brahmins have managed to attract as much money as they did (salaries in excess of Rs. 50 lakhs being averagely normal in Pune) even as I was consigned only to receive “attract” psychic attacks (mainly from abroad) and insults (mainly from those from this land) during the same time period?

Despite all my achievements?

Do take matters like these seriously, but, of course, as you must have gathered by now, that is not the only thing I would have, to talk about. And, the title of this post anyway makes this part amply clear.

2. The classification problem and the ANNs:

I have begun my studies of the artificial neural networks (ANNs for short). I have rapidly browsed through a lot of introductory articles (as also the beginning chapters of books) on the topic. (Yes, including those written by Indians who were born in the Brahmin castes.) I might have gone through 10+ such introductions. Many of these, I had browsed through a few years ago (I mean only the introductory parts). But this time round, of course, I picked them up for a more careful consideration.

And soon enough (i.e. over just the last 2–3 days), I realized that no one in the field (AI/ML) was talking about a good explanation of this question:

Why is it that the ANN really succeeds as well as it does, when it comes to the classification tasks, but not others?

If you are not familiar with Data Science, then let me note that it is known that ANN does not do well on all the AI tasks. It does well only on one kind of them, viz., the classification tasks. … Any time you mention the more general term Artificial Intelligence, the layman is likely to think of the ANN diagram. However, ANNs are just one type of a tool that the Data Scientist may use.

But the question here is this: why does the ANN do so well on these tasks?

I formulated this question, and then found an answer too, and I would sure like to share it with you (whether the answer I found is correct or not). However, before sharing my answer, I want you to give it a try.

It would be OK by me if you answer this question in reference to just one or two concrete classification tasks—whichever you find convenient. For instance, if you pick up OCR (optical character recognition, e.g., as explained in Michael Nielson’s free online book [^]), then you have to explain why an ANN-based OCR algorithm works in classifying those MNIST digits / alphabets.

Hint: Studies of Vedic literature won’t help. [I should know!] OTOH, studies of good books on epistemology, or even just good accounts covering methods of science, should certainly come in handy.

I will give you all some time before I come back on that question.

In the meanwhile, have fun—if you wish to, and of course, if you are able to. With questions of this kind. (Translating the emphasis in the italics into chaste Marathi: “laayaki asali tar.” Got it?)

A song I like:
(Marathi) “ooncha nicha kaahi neNe bhagawant”
Lyrics: Sant Tukaram
Music and Singer: Snehal Bhatkar



The title word of this post is Marathi for “phew!”—not for “hush hush.” (But, to me, the Marthi word is more expressive. [BTW, the “hu” is to be pronounced as “hoo”.])

The reason for this somewhat accentuated and prolonged exhalation is this: I am done with the version “0.1-beta” of my note on flux (see my last post). I need a break.

As of now, this note is about 27 pages, and with figures and some further (< 5%) additions, the final number of pages for the version 0.1 should easily go into the early 30s. … To be readable, it will have to brought down to about 15 pages or fewer, including diagrams. Preferably, < 10 pages. Some other day. For now, I find that I have grown plain sick and tired of working on that topic. I need to get away from it all. I am sure that I will return to it later on—may be after a month or so. But for the time being, I simply need a break—from it. I’ve had enough of this flux and vectors and tensors thing. … Which brings me to the next topic of this post.

There are also other announcements.

I think that I have also had enough of QM.

QM was interesting, very interesting, to me. It remained that way for some four decades. But now that I have cracked it (to my satisfaction), my interest in the topic has begun dwindling down very rapidly.

Sure I will conduct a few simulations, deliver the proposed seminar(s) I had mentioned in the past, and also write a paper or two about it. But I anticipate that I won’t go much farther than what I have already understood. The topic, now, simply has ceased to remain all that interesting.

But, yes, I have addressed all the essential QM riddles. That’s for certain.

And then, I was taking a stock of my current situation, and here are a few things that stood out:

  • I am not getting an academic job in Pune (because of the stupid / evil SPPU rules), and frankly, the time when a (full) Professor’s job could have meant something to me is already over. If I were to get such a job well in time—which means years ago—then I could have done some engineering research (especially in CFD), guided a few students (in general in computational science and engineering), taught courses, developed notes, etc. But after having lost a decade or so due to that stupid and/or evil Metallurgy-vs-Mechanical Branch Jumping issue, I don’t have the time to pursue all that sort of a thing, any more.
  • You would know this: All my savings are over; I am already in debts.
  • I do not wish to get into a typical IT job. It could be well paying, but it involves absolutely no creativity and originality—I mean creativity involving theoretical aspects. Deep down in my heart, I remain a “theoretician”—and a programmer. But not a manager. There is some scope for creativity in the Indian IT industry, but at my “seniority,” it is mostly limited, in one way or the other, only to “herd-management” (to use an expression I have often heard from my friends in the industry). And, I am least bothered about that. So, to say that by entering the typical Indian IT job, my best skills (even “gifts”) would go under-utilized, would be an understatement.
  • For someone like me, there is no more scope, in Pune, in the CFD field either. Consultants and others are already well established. I could keep my eyes and ears open. But it looks dicey to rely on this option. The best period for launching industrial careers in CFD here was, say, up to the early naughties. … I still could continue with some research in CFD. But guess it no longer is a viable career option for me. Not in Pune.
  • Etc.

However, all is not gloomy. Not at all. Au contraire.

I am excited that I am now entering a new field.

I will not ask you to take a guess. This career route for people with my background and skills is so well-established by now, that there aren’t any more surprises left in it. Even an ANN would be able to guess it right.

Yes, that’s right. From now on, I am going to pursue Data Science.

This field—Data Science—has a lot of attractive features, as far as I am concerned. The way I see it, the following two stand out:

  1. There is a very wide variety of application contexts; and
  2. There is a fairly wide range of mathematical skills that you have to bring to bear on these problems.

Notice, the emphasis is on the width, not on the depth.

The above-mentioned two features, in turn, lead to or help explain many other features, like:

  1. A certain open ended-ness of solutions—pretty much like what you have in engineering research and design. In particular, one size doesn’t fit all.
  2. A relatively higher premium on the individual thinking skills—unlike what your run-of-the-mill BE in CS does, these days [^].

Yes, Data Science, as a field, will come to mature, too. The first sign that it is reaching the first stage of maturity would be an appearance of a book like “Design Patterns.”

However, even this first stage is, I anticipate, distant in future. All in all, I anticipate that the field will not come to mature before some 7–10 years pass by. And that’s long enough a time for me to find some steady career option in the meanwhile.

There are also some other plus points that this field holds from my point of view.

I have coded extensively—more than 1 lakh (100,000) lines of C++ code in all, before I came to stop using C++, which happened especially after I entered academia. I am already well familiar with Python and its eco-system, though am not an expert when it comes to writing the fastest possible numerical code in Python.

I have handled a great variety of maths. The list of equations mentioned in my recent post [^] is not even nearly exhaustive. (For instance, it does not even mention whole topics like probability and statistics, stereology, and many such matters.) When it comes to Data Science, a prior experience with a wide variety of maths is a plus point.

I have not directly worked with topics like artificial neural networks, deep learning, the more advanced regression analysis, etc.

However, realize that for someone like me, i.e., someone who taught FEM, and had thought of accelerating solvers via stochastic means, the topic of constrained optimization would not be an entirely unknown animal. Some acquaintance has already been made with the conjugate gradient (though I can’t claim mastery of it). Martingales theory—the basic idea—is not a complete unknown. (I had mentioned a basic comparison of my approach vis-a-vis the simplest or the most basic martingales theory, in my PhD thesis.)

Other minor points are these. This field also (i) involves visualization abilities, (ii) encourages good model building at the right level of abstraction, and (iii) places premium on presentation. I am not sure if I am good on the third count, but I sure am confident that I do pretty well on the first two. The roots of all my new research ideas, in fact, can be traced back to having to understand physical principles in 3+1 D settings.

Conclusion 1: I should be very much comfortable with Data Science. (Not sure if Data Science itself (i.e., Data Scientists themselves) would be comfortable with me or not. But that’s something I could deal later on.)

Conclusion 2: Expect blogging here going towards Data Science in the future.

A Song I Like:

(Marathi) “uff, teri adaa…”
Music: Shankar-Ahsaan-Loy
Singer: Shankar Mahadevan
Lyrics: Javed Akhtar

[By any chance, was this tune at least inspired (if not plagiarized) from some Western song? Or is it through and through original? …In any case, I like it a lot. I find it wonderful. It’s upbeat, but not at all banging on the ears. (For contrast, attend any Ganapati procession, whether on the first day, the last day, or any other day in between. You will have ample opportunities to know what having your ears banged out to deafness means. Nay, these opportunities will be thrust upon you, whether you like it or not. It’s our “culture.”)]



General update: Will be away from blogging for a while

I won’t come back for some 2–3 weeks or more. The reason is this.

As you know, I had started writing some notes on FVM. I would then convert my earlier, simple, CFD code snippets, from FDM to FVM. Then, I would pursue modeling Schrodinger’s equation using FVM. That was the plan.

But before getting to the nitty-gritties of FVM itself, I thought of jotting down a note, once and for all, putting in writing my thoughts thus far on the concept of flux.

If you remember, it was several years ago that I had mentioned on this blog that I had sort of succeeded in deriving the Navier-Stokes equation in the Eulerian but differential form (d + E for short).

… Not an achievement by any stretch of imagination—there are tomes written on say, differentiable manifolds and whatnot. I feel sure that deriving the NS equations in the (d + E) form would be less than peanuts for them.

Yet, the fact of the matter is: They actually don’t do that!

Show me a single textbook or a paper that does that. If not at the UG level, then at least at the PG level, but one that is written using the language of only plain calculus, as used by engineers—not that of advanced analysis.

And as to the UG/PG books from engineering:

What people normally do is to derive these equations in its integral form, whether using the Lagrangian or the Eulerian approach. That is, they adopt either the (i + L) approach or the (i + D) approach.

At some rare times, if they at all begin fluid dynamics with a differential form of the NS equations, then they invariably follow the Lagrangian approach, never the Eulerian. That is, they invariably begin with only (d + L)—even in those cases when their objective is to obtain (d + E). Then, after having derived (d +L) , they simply invoke some arbitrary-looking vector calculus identities to “transform” those equations from (d + L) to (d +E).

And, worse:

They never discuss the context, meaning, or proofs of those identities. None from fluid dynamics or CFD side does that. And neither do the books on maths written for scientists and engineers.

The physical bases of the “transformation” process must remain a mystery.

When I started working through it a few years ago, I realized that the one probable reason why they don’t use the (d +E) form right from the beginning is because: forget the NS equations, no one understands even the much simpler idea of the flux—if it is to be couched entirely in the settings of (d+E). You see, the idea of the flux too always remains couched in the integral form, never the differential. For example, see Narasimhan [^]. Or, any other continuum mechanics books that impresses you.

It’s no accident that the Wiki article on Flux [^] says that it

needs attention from an expert in Physics.

And then, more important for us, the text of the article itself admits that the formula it notes, for a definition of flux in differential terms, is

an abuse of notation

See the section here [^].

Also, ask yourself, why is a formula that is free of the abuse of notation not being made available? In spite of all those tomes having been written on higher mathematics?

Further, there were also other related things I wanted to write about, like an easy pathway to the idea of tensors in general, and to that of the stress tensor in particular.

So, I thought of writing it down it for once and for all, in one note. I possibly could convert some parts of it into a paper later on, perhaps. For the time being though, the note would be more in the nature of a tutorial.

I started writing down the note, I guess, from 17 August 2018. However, it kept on growing, and with growth came reorganization of material for a better hierarchy or presentation. It has already gone through some 4–5 thorough re-orgs (meaning: discarding the earlier LaTeX file entirely and starting completely afresh), and it has already become more than 10 LaTeX pages. Even then, I am nowhere near finishing it. I may be just about half-way through—even though I have been working on it for some 7–8 hours every day for the past fortnight.

Yes, writing something in original is a lot of hard work. I mean “original” not in the sense of discovery, but in the sense of a lack of any directly citable material whatsoever, on the topic. Forget copy-pasting. You can’t even just gather a gist of the issue so that you could cite it.

And, the trouble here is, this topic is otherwise so very mature. (It is some 150+ years old.) So, you know that if you go even partly wrong, the whole world is going to pile on you.

And that way, in my experience, when you write originally, there is at least 5–10 pages of material you typically end up throwing away for every page that makes it to the final, published, version. Yes, the garbage thrown out is some 5–10 times the material retained in—no matter how “simple” and “straightforward” the published material might look.

Indeed, I could even make a case that the simpler and the more straight-forward the published material looks, if it also happens to be original, then the more strenuous it has been, on the part of the author.

Few come to grasp this simple an observation, ever, in their entire life.

As a case in point, I wish to recall here my conference paper on diffusion. [To be added here soon enough.]

I have many times silently watched people as they were going through this paper for the first time.

Typically, when engineers read it, they invariably come out with a mild expression which suggests that they probably were thinking of something like: “isn’t it all so simple and straight-forward?” Sometimes they even explicitly ask: “And, what do you say was the new contribution here?” [Even after having gone through both the abstract and the conclusion part of it, that is.]

On the other hand, on the four-five rare occasions when I have had the opportunity to watch professional mathematicians go through this paper of mine, in each case, the expression they invariably gave at the end of finishing it was as if they still were very intently absorbed in it. In particular, they never do ask me what was new about it—they just remain deeply engaged in what looks like an exercise in “fault-finding”, i.e., in checking if any proof, theorem or lemma they had ever had come across could be used in order to demolish the new idea that has been presented. Invariably, they give the same argument by way of an objection. Invariably, I explain why their argument does not address the issue I have raised in the paper. Invariably they chuckle and then go back to the paper and to their intent thinking mode, to see if there is any other weakness to my basic argument…

Till date (even after more than a decade), they haven’t come back.

But in all cases, they were very ready to admit that they were coming across this argument for the first time. I didn’t have to explain it to them that though the language and the tone of the paper looked simple enough, the argument itself was not easy to derive originally.

No, the notes which I am currently working on are nowhere near as original as that. [But yes, original, these are.]

Yet, let me confess, even as I keep prodding through it for the better part of the day the way I have done over the past fortnight or so, I find myself dealing with a certain doubt: wouldn’t they just dismiss it all as being too obvious? as if all the time and effort I spent on it was, more or less, ill spent? that it was all meaningless to begin with?

Anyway, I want to finish this task before resuming blogging—simply because I’ve got a groove about it by now… I am in a complete and pure state of anti-procrastination.

… Well, as they say: Make the hay while the Sun shines…

A Song I Like:
(Marathi) “dnyaandev baaL maajhaa…”
Singer: Asha Bhosale
Lyrics: P. Savalaram
Music: Vasant Prabhu