# What are the rules for hiring?—2

Last year in August, I had written a post of the title: “What are the rules for hiring?” [^]. In that post, I had pointed out that historically, the University of Pune (now called Savitribai Phule Pune University, or SPPU for short), in fact didn’t have this “Mechanical-vs-Metallurgy `Branch-Jumping’ Issue.” Though I have a BE in Metallurgy, I myself had taken admission, right in COEP, for an ME program in Mechanical Engineering.

In that post, I had also traced in some detail how COEP had thrown obstacles in my path at the time of my admission to the PhD program in Mechanical Engineering. (If you found (or now find) reading through all those details exasperating, then take a moment to realize what it might have been like for me to live through those artificially created struggles.)

Today, in this post, I once again return to the issue of the hiring rules. I want to provide the reader with copies of the relevant official documents, together with some discussion of the issues as well as my comments.

(I) The AICTE Norms:

If you do ‘net searches to find the AICTE norms document which governs the hiring of professors in the engineering colleges in this country, then you will find many documents floated by different colleges or universities. Most of the matter in such documents are similar to the actual AICTE document, though there often are some small and subtle differences. I don’t mind if different colleges/universities wish to follow policies that are at a slight variance from the norms issued by the AICTE. After all, these are norms, not hard-and-fast rules. To me, trouble begins only when they don’t explicitly note the points of departure. Go ahead, do ‘net searches, and you will find that not a single one of these unofficial documents has bothered to explicitly identify the changes they made from the original AICTE document.

For my purposes, I was looking for the original and authentic AICTE document. I found it faithfully uploaded at SPPU’s Web site, here [^]. Since the college/university Web sites sometimes fail to maintain all the documents or links in order, I have decided to keep a copy of this same document also on my Google Drive, here [^].

See Serial Number 3 on page 2 for Professor’s position in this document. It states:

“Ph.D  degree  with  first  class  degree  at  Bachelor’s  or  Master’s  level  in  the appropriate  branch  of  Engineering  /  Technology  with  10  years  experience in Teaching / Industry / Research out of which 5 years must be at the level of  Assistant  Professor  and  /  or  equivalent.”

True to the khaki register-style dumbness (or the (Marathi) “khaa kee!” type of “smart”ness), this wording is vague on multiple counts. (If there is someone intending to get bribes, let me state it, publicly, that I am refusing to give them any.)

You can interpret this wording in several different ways. The different interpretations can be had by mentally inserting braces “{}” to isolate the different blocks of the text together, and then working out whether these blocks of text apply multiplicatively (as in the Cartesian product) or not.

The two relevant and entirely different ways in which the wording can be interpreted is this:

Interpretation 1.0:

This interpretation says that: you should have a PhD degree in the appropriate branch + you should have a first class either at bachelor’s level or at the master’s level, but both the bachelor’s and the master’s degrees must have come only in the appropriate branch.

According to this interpretation, you are allowed to be dumb (you have to somehow manage a first class only once), so long as you have been conforming to the same branch throughout your life.

With this interpretation, the following issue arises: What does constitute an appropriate branch?

1.1 One sub-interpretation is: Only the Mechanical branch is the appropriate branch for the position of Professor of Mechanical Engineering.

1.2 The other sub-interpretation is: You may have the Mechanical branch either at the bachelor’s or the master’s level (just the way you can have a first class either at bachelor’s or master’s level) but not necessarily at both.

Since I didn’t have a Mechanical degree at either bachelor’s or master’s level, I couldn’t qualify, according to this interpretation 1.0 (whether you follow 1.1 or 1.2).

Interpretation 2.0:

This interpretation says that: You should have a PhD degree in the appropriate branch + you should have a first class either at bachelor’s level or at the master’s level, and further, that either bachelor’s or master’s degrees should have come from an appropriate branch.

Once again, you have to decide what constitutes an appropriate branch.

2.1 One sub-interpretation is: Only the Mechanical branch is the appropriate branch for a position of Professor of Mechanical Engineering.

2.1 The other sub-interpretation is: There can be choices for the appropriate branch at any of the degrees. For instance, to become a Professor of Mechanical Engineering, all the following are OK:
BE (Mech) + ME (Mech) + PhD (Met.)
BE (Mech) + ME (Prod) + PhD (Prod)
BE (Prod) + ME (Prod) + PhD (Prod)
BE (Met) + MTech (Met) + PhD (Mech)—my combination
BE (Aero) + ME (Met) + PhD (Met.)
Etc.

This was my interpretation. It makes sense, because: (i) the wording is: “Bachelor’s or Master’s level in the appropriate branch,” and (ii) the word used is: “the appropriate branch,” not “the same branch.”

The Malady: The interpretation 1.0 was what was adopted by the former Dean of Faculty of Engineering at SPPU, i.e., Dr. G. K. Kharate.

End of (this part of the) story.

(II) The Mumbai University Norms (2012):

The Mumbai University historically had always followed the interpretation 2.2, and never had major issues.

However, in view of the tightening of the government controls, they had held detailed discussions, and then had arrived at an explicit document that clearly states what all constitute the appropriate branches. They published this decision via a document called “Circular No. CONCOL/ICC/04/ of 2012”. I once again link to a copy that I have stored on my Google Drive, here [^].

See page 2 of this document, for the statement qualifications for an Assistant Professor:

“BE/ B Tech and ME /M Tech in relevant subject with First Class or equivalent either in BE / B Tech or ME / M Tech OR ME/M TECH in relevant Subject with First Class”

See page 3 of the same document for additional qualifications for an Associate Professor:

“Qualification as above that is for the post of Assistant Professor, as applicable and PHD or equivalent, in appropriate Discipline”

On the same page, certain additional qualifications expected for a Professor’s position are noted.

See page 9, Serial No. 2 of this document. For a position of Professor in Mechanical Engineering, Metallurgy is included as an equivalent/relevant/appropriate branch, even though only at the master’s level.

However, the drafting is extraordinarily clear here—there are two “or”s—one in the lowercase letters, and another in the capitals. The existence of the capital “OR” makes it abundantly clear that having only a master’s in a relevant subject with First Class is good enough. [Little wonder that the University of Mumbai always cuts ahead of the SPPU on rankings.]

As such, Interpretation 2.2 applies, and I qualify.

I anyway met with their Dean, had it clarified that I indeed do qualify, and eventually, was offered jobs as a Professor of Mechanical Engineering. See my resume regarding these jobs. (The particular link to my resume may change as I update the resume, but it is always accessible from the home page of my personal Web site [^].)

But then, of course, the University of Pune (now SPPU) believes that they are the best and the most conscientious (or least licentious) in the world. So, they were never going to be taken in by the mere fact that the University next door (one which has always been ranked higher by every agency in the world) did easily allow me to function as an employed Professor of Mechanical Engineering. (I anyway do function as a professor of engineering. The only question is: whether they allow me to get employed as one, or not. The lower-ranked SPPU’s geniuses don’t.)

III The Maharashtra State GR (May 2014):

Sorry, on two counts: (i) I cannot give you a direct link to this document at the Web sites of the Maharashtra State Government. I found this document at the Recruitments section of COEP’s Web site, in June 2015, but the document is no longer to be found even at the COEP Web site. (ii) The document is in Marathi, so, my English readers would have to trust me when it comes to the titles of the columns of the relevant table.

Though the GR had come in effect in May 2014, I came to know of it only in June of 2015. The utmost benevolent Mechanical Engineering Professors (and the authorities) at SPPU are still napping dozing off, still getting annoyed when I mention the GR, and still asking me for a copy of this document (with a “knowing” certainty that they would be able to disqualify me in reference even to this GR).

I have once again uploaded my copy of the document to Google Drive, here [^].

Refer to page 13, Serial Number 2. (Fortunately, the Arabic numerals in English and in Marathi are quite similar, because the so-called Arabic numerals had originated in India anyway.)

At the master’s level, the GR expands on even the Mumbai Universities’ list of the equivalent/relevant/appropriate branches (though it cuts down on the Aerospace engineering at the bachelor’s level).

Showing this document, my last employers did offer me a position of Professor in Mechanical Engineering. (No, they didn’t give me the UGC scale. But they did offer me a full Professor’s position—and later on, treated me with full organizational respect that goes with a full Professor’s position.) I even uploaded the internal marks to SPPU’s BCUD Web site, using my own official account.)

Even then, even this year, the Mechanical Engineering geniuses and other employers at the utmost conscientious SPPU are still telling me that I don’t qualify.

As to my last employers, though their college is in Pune and is affiliated to SPPU, their headquarters are in Nagpur, not in Pune. But then, my point is, you don’t have to go so far away as to Nagpur. Go just 75 kms from this filthy place, and as soon as you climb down the Khandala ghat (and with that, also shed your obnoxious conformism of a mindless sort), and you reach a better place.

The Rules for the Maharashtra State Government’s Autonomous Institutes (November, 2014):

These are the latest rules. They apply only to the State Goverment’s Autonomous Institutes—not to the engineering colleges affiliated to SPPU.

But bear in mind that in the view of the State Government (and most every one else), these Autonomous Institutes are supposed to be in the leadership positions; they are supposed to be guide-lamps to the other colleges. It is in this context that their rules become relevant.

I found the document at COEP’s Web site, this year, here [^]. Once again, I have uploaded a copy at my Google Drive, here [^].

See page 3, Paragraph Serial Number 3.2. It says:

“PROFESSOR: Essential: (i)  Ph.D.  Degree  or  equivalent  in  the  concerned  discipline  from  a reputed  institution, preceded  by a UG/PG  Degree in the  relevant  discipline in First Class (or equivalent) with consistently good academic record; ” etc.

Much better (though not as good as the University of Mumbai’s).

Note that the PhD ought to come in the concerned discipline, whereas either the UG or the PG degree should have come from a relevant discipline.

This document thus settles the issue that the Interpretations 1.1 and 2.1 are NOT valid; only the Interpretations 1.2 and 2.2 can be. However, unlike the broadest interpretation in 2.2, here, the requirements are a bit restrictive: your PhD must be in the concerned discipline.

Thus, for the position of Professor in Mechanical Engineering, the following combination is allowed:

BE (Met) + M Tech (Met) + PhD (Mech).

On the other hand, as far as I can make it out (and I can be wrong here), both of the following come in doubt:

BE (Mech) + M Tech (Mech) + PhD (Aero)
BE (Mech) + M Tech (Mech) + PhD (Met)

Looks like they should hire people with better drafting abilities at both COEP as well as in the DTE—and most certainly, and first and foremost, at the AICTE. (Yeah, right. Keep hoping. (AICTE sits in New Delhi.))

I assert that the University of Mumbai’s draft is the best (among those considered above). If you differ, drop me a line.

For obvious reasons, for this post, there won’t be the usual section on a song I like.

I may come back and edit this post, but only for correcting typos/links, or to streamline the write-up.

Since the issues are both legal and important, I may also come back to edit this post any time in a distant future. If so, I will note those (more serious) updates explicitly. (In contrast, the immediate updates merely for streamlining and all, will not be noted explicitly.)

Update 1 on 2016.06.21: Added the detailed rules for Assistant and Associate Professor’s positions at the University of Mumbai. [The link to original document was given even earlier, but now the text of the main post also quotes the detailed requirements.]

[E&OE]

# QM: The physical view it takes—1

So, what exactly is quantum physics like? What is the QM theory all about?

You can approach this question at many levels and from many angles. However, if an engineer were to ask me this question (i.e., an engineer with sufficiently good grasp of mathematics such as differential equations and linear algebra), today, I would answer it in the following way. (I mean only the non-relativistic QM here; relativistic QM is totally beyond me, at least as of today):

Each physics theory takes a certain physical view of the universe, and unless that view can be spelt out in a brief and illuminating manner, anything else that you talk about it (e.g. the maths of the theory) tends to become floating, even meaningless.

So, when we speak of QM, we have to look for a physical view that is at once both sufficiently accurate and highly meaningful intuitively.

But what do I mean by a physical view? Let me spell it out first in the context of classical mechanics so that you get a sense of that term.

Personally, I like to think of separate stages even within classical mechanics.

Consider first the Newtonian mechanics. We can say that the Newtonian mechanics is all about matter and motion. (Maxwell it was, I think, who characterized it in this beautifully illuminating a way.) Newton’s original mechanics was all about the classical bodies. These were primarily discrete—not quite point particles, but finite ones, with each body confined to a finite and isolated region of space. They had no electrical attributes or features (such as charge, current, or magnetic field strength). But they did possess certain dynamical properties, e.g., location, size, density, mass, speed, and most importantly, momentum—which was, using modern terminology, a vector quantity. The continuum (e.g. a fluid) was seen as an extension of the idea of the discrete bodies, and could be studied by regarding an infinitesimal part of the continuum as if it were a discrete body. The freshly invented tools of calculus allowed Newton to take the transition from the discrete bodies (billiard balls) to both: the point-particles (via the shells-argument) as well as to the continuum (e.g. the drag force on a submerged body.)

The next stage was the Euler-Lagrange mechanics. This stage represents no new physics—only a new physical view. The E-L mechanics essentially was about the same kind of physical bodies, but now a number (often somewhat wrongly called a scalar) called energy being taken as the truly fundamental dynamical attribute. The maths involved the so-called variations in a global integral expression involving an energy-function (or other expressions similar to energy), but the crucial dynamic variable in the end would be a mere number; the number would be the outcome of evaluating a definite integral. (Historically, the formalism was developed and applied decades before the term energy could be rigorously isolated, and so, the original writings don’t use the expression “energy-function.” In fact, even today, the general practice is to put the theory using only the mathematical and abstract terms of the “Lagrangian” or the “Hamiltonian.”) While Newton’s own mechanics was necessarily about two (or more) discrete bodies locally interacting with each other (think collisions, friction), the Euler-Lagrange mechanics now was about one discrete body interacting with a global field. This global field could be taken to be mass-less. The idea of a global something (it only later on came to be called a field) was already a sharp departure from the original Newtonian mechanics. The motion of the massive body could be predicted using this kind of a formalism—a formalism that probed certain hypothetical variations in the global field (or, more accurately, in the interactions that the global field had with the given body). The body itself was, however, exactly as in the original Newtonian mechanics: discrete (or spread over definite and delimited region of space), massive, and without any electrical attributes or features.

The next stage, that of the classical electrodynamics, was about the Newtonian massive bodies but now these were also seen as endowed with the electrical attributes in addition to the older dynamical attributes of momentum or energy. The global field now became more complicated than the older gravitational field. The magnetic features, initially regarded as attributes primarily different from the electrical ones, later on came to be understood as a mere consequence of the electrical ones. The field concept was now firmly entrenched in physics, even though not always very well understood for what it actually was: as a mathematical abstraction. Hence the proliferation in the number of physical aethers. People rightly sought the physical referents for the mathematical abstraction of the field, but they wrongly made hasty concretizations, and that’s how there was a number of aethers: an aether of light, an aether of heat, an aether of EM, and so on. Eventually, when the contradictions inherent in the hasty concretizations became apparent, people threw the baby with the water, and it was not long before Einstein (and perhaps Poincare before him) would wrongly declare the universe to be devoid of any form of aether.

I need to check the original writings by Newton, but from whatever I gather (or compile, perhaps erroneously), I think that Newton had no idea of the field. He did originate the idea of the universal gravitation, but not that of the field of gravity. I think he would have always taken gravity to be a force that was directly operating between two discrete massive bodies, in isolation to anything else—i.e., without anything intervening between them (including any kind of a field). Gravity, a force (instantaneously) operating at a distance, would be regarded as a mere extension of the idea of the force by the direct physical contact. Gravity thus would be an effect of some sort of a stretched spring to Newton, a linear element that existed and operated between only two bodies at its two ends. (The idea of a linear element would become explicit in the lines of force in Faraday’s theorization.) It was just that with gravity, the line-like spring was to be taken as invisible. I don’t know, but that seems like a reasonable implicit view that Newton must have adopted. Thus, the idea of the field, even in its most rudimentary form, probably began only with the advent of the Euler-Lagrange mechanics. It anyway reached its full development in Maxwell’s synthesis of electricity and magnetism into electromagnetism. Remove the notion of the field from Maxwell’s theory, and it is impossible for the theory to even get going. Maxwellian EM cannot at all operate without having a field as an intermediate agency transmitting forces between the interacting massive bodies. On the other hand, Newtonian gravity (at least in its original form and at least for simpler problems) can. In Maxwellian EM, if two bodies suddenly change their relative positions, the rest of the universe comes to feel the change because the field which connects them all has changed. In Newtonian gravity, if two bodies suddenly change their relative positions, each of the other bodies in the universe comes to feel it only because its distances from the two bodies have changed—not because there is a field to mediate that change. Thus, there occurs a very definite change in the underlying physical view in this progression from Newton’s mechanics to Euler-Lagrange-Hamilton’s to Maxwell’s.

So, that’s what I mean by the term: a physical view. It is a view of what kind of objects and interactions are first assumed to exist in the universe, before a physics theory can even begin to describe them—i.e., before any postulates can even begin to be formulated. Let me hasten to add that it is a physical view, and not a philosophical view, even though physicists, and worse, mathematicians, often do confuse the issue and call it a (mere) philosophical discussion (if not a digression). (What better can you expect from mathematicians anyway? Or even from physicists?)

Now, what about quantum mechanics? What kind of objects does it deal with, and what kind of a physical view is required in order to appreciate the theory best?

What kind of objects does QM deal with?

QM once again deals with bodies that do have electromagnetic attributes or features—not just the dynamical ones. However, it now seeks to understand and explain how these features come to operate so that certain experimentally observed phenomena such as the cavity radiation and the gas spectra (i.e., the atomic absorption- and emission-spectra) can be predicted with a quantitative accuracy. In the process, QM keeps the idea of the field more or less intact. (No, strictly speaking it doesn’t, but that’s what physicists think anyway). However, the development of the theory was such that it had to bring the idea of the spatially delimited massive body, occupying a definite place and traveling via definite paths, into question. (In fact, quantum physicists went overboard and threw it out quite gleefully, without a thought.) So, that is the kind of “objects” it must assume before its theorization can at all begin. Physicists didn’t exactly understand what they were dealing with, and that’s how arose all its mysteries.

Now, how about its physical view?

In my (by now revised) opinion, quantum mechanics basically is all about the electronic orbitals and their evolutions (i.e., changes in the orbitals, with time).

(I am deliberately using the term “electronic” orbital, and not “atomic” orbital. When you say “atom,” you must mean something that is localized—else, you couldn’t possibly distinguish this object from that at the gross scale. But not so when it is the electronic orbitals. The atomic nucleus, at least in the non-relativistic QM, can be taken to be a localized and discrete “particle,” but the orbitals cannot be. Since the orbitals are necessarily global, since they are necessarily spread everywhere, there is no point in associating something local with them, something like the atom. Hence the usage: electronic orbitals, not atomic orbitals.)

The electronic orbital is a field whose governing equation is the second-order linear PDE that is Schrodinger’s equation, and the problems in the theory involve the usual kind of IVBV problems. But a further complexity arises in QM, because the real-valued orbital density isn’t the primary unknown in Schrodinger’s equation; the primary unknown is the complex-valued wavefunction.

The Schrodinger equation itself is basically like the diffusion equation, but since the primary unknown is complex-valued, it ends up showing some of the features of the wave equation. (That’s one reason. The other reason is, the presence of the potential term. But then, the potential here is the electric potential, and so, once again, indirectly, it has got to do with the complex nature of the wavefunction.) Hence the name “wave equation,” and the term “wavefunction.” (The “wavefunction” could very well have been called the “diffusionfunction,” but Schrodinger chose to call it the wavefunction, anyway.) Check it out:

Here is the diffusion equation:

$\dfrac{\partial}{\partial t} \phi = D \nabla^2 \phi$
Here is the Schrodinger equation:
$\dfrac{\partial}{\partial t} \Psi = \dfrac{i\hbar}{2\mu} \nabla^2 \Psi + V \Psi$

You can always work with two coupled real-valued equations instead of the single, complex-valued, Schrodinger’s equation, but it is mathematically more convenient to deal with it in the complex-valued form. If you were instead to work with the two coupled real-valued  equations, they would still end up giving you exactly the same results as the Schrodinger equation. You will still get the Maxwellian EM after conducting suitable grossing out processes. Yes, Schrodinger’s equation must give rise to the Maxwell’s equations. The two coupled real-valued equations would give you that (and also everything else that the complex-valued Schrodinger’s equation does). Now, Maxwell’s equations do have an inherent  coupling between the electric and magnetic fields. This, incidentally, is the simplest way to understand why the wavefunction must be complex-valued. [From now on, don’t entertain the descriptions like: “Why do the amplitudes have to be complex? I don’t know. No one knows. No one can know.” etc.]

But yes, speaking in overall terms, QM is, basically, all about the electronic orbitals and the changes in them. That is the physical view QM takes.

Hold that line in your mind any time you hit QM, and it will save you a lot of trouble.

When it comes to the basics or the core (or the “heart”) of QM, physicists will never give you the above answer. They will give you a lot many other answers, but never this one. For instance, Richard Feynman thought that the wave-particle duality (as illustrated by the single-particle double-slit interference arrangement) was the real key to understanding the QM theory. Bohr and Heisenberg instead believed that the primacy of the observables and the principle of the uncertainty formed the necessary key. Einstein believed that entanglement was the key—and therefore spent his time using this feature of the QM to deny completeness to the QM theory. (He was right; QM is not complete. He was not on the target, however; entanglement is merely an outcome, not a primary feature of the QM theory.)

They were all (at least partly) correct, but none of their approaches is truly illuminating—not to an engineer anyway.

They were correct in the sense, these indeed are valid features of QM—and they do form some of the most mystifying aspects of the theory. But they are mystifying only to an intuition that is developed in the classical mechanical mould. In any case, don’t mistake these mystifying features for the basic nature of the core of the theory. Discussions couched in terms of the more mysterious-appearing features in fact have come to complicate the quantum story unnecessarily; not helped simplify it. The actual nature of the theory is much more simple than what physicists have told you.

Just the way the field in the EM theory is not exactly the same kind of a continuum as in the original Newtonian mechanics (e.g., in EM it is mass-less, unlike water), similarly, neither the field nor the massive object of the QM is exactly as in their classical EM descriptions. It can’t be expected to be.

QM is about some new kinds of the ultimate theoretical objects (or building blocks) that especially (but not exclusively) make their peculiarities felt at the microscopic (or atomic) scale. These theoretical objects carry certain properties such that the theoretical objects go on to constitute the observed classical bodies, and their interactions go on to produce the observed classical EM phenomena. However, the new theoretical objects are such that they themselves do not (and cannot be expected to) possess all the features of the classical objects. These new theoretical objects are to be taken as more fundamental than the objects theorized in the classical mechanics. (The physical entities in the classical mechanics are: the classical massive objects and the classical EM field).

Now, this description is quite handful; it’s not easy to keep in mind. One needs a simpler view so that it can be held and recalled easily. And that simpler view is what I’ve told you already:

To repeat: QM is all about the electronic orbital and the changes it undergoes over time.

Today, most any physics professor would find this view objectionable. He would feel that it is not even a physics-based view, it is a chemistry-based one, even if the unsteady or the transient aspect is present in the formulation. He would feel that the unsteady aspect in the formulation is artificial; it is more or less slapped externally on to the picture of the steady-state orbitals given in the chemistry textbooks, almost as an afterthought of sorts. In any case, it is not physics—that’s what he would be sure of. By that, he would also be sure to mean that this view is not sufficiently mathematical. He might even find it amusing that a physical view of QM can be this intuitively understandable. And then, if you ask him for a sufficiently physics-like view of QM, he would tell you that a certain set of postulates is what constitutes the real core of the QM theory.

Well, the QM postulates indeed are the starting points of QM theory. But they are too abstract to give you an overall feel for what the theory is about. I assert that keeping the orbitals always at the back of your mind helps give you that necessary physical feel.

OK, so, keeping orbitals at the back of the mind, how do we now explain the wave-particle duality in the single-photon double-slit interference experiment?

Let me stop here for this post; I will open my next post on this topic precisely with that question.

A Song I Like:

(Hindi) “ik ajeeb udaasi hai, meraa man_ banawaasi hai…”
Music: Salil Chowdhury
Singer: Sayontoni Mazumdar
Lyrics: (??)

[No, you (very probably) never heard this song before. It comes not from a regular film, but supposedly from a tele-film that goes by the name “Vijaya,” which was produced/directed by one Krishna Raaghav. (I haven’t seen it, but gather that it was based on a novel of the same name by Sharat Chandra Chattopadhyaya. (Bongs, I think, over-estimate this novelist. His other novel is Devadaas. Yes, Devadaas. … Now you know. About the Chattopadhyaya.)) Anyway, as to this song itself, well, Salil-daa’s stamp is absolutely unmistakable. (If the Marathi listener feels that the flute piece appearing at the very beginning somehow sounds familiar, and then recalls the flute in Hridayanath Mangeshkar’s “mogaraa phulalaa,” then I want to point out that it was Hridayanath who once assisted Salil-daa, not the other way around.) IMO, this song is just great. The tune may perhaps sound like the usual ghazal-like tune, but the orchestration—it’s just extraordinary, sensitive, and overall, absolutely superb. This song in fact is one of Salil-daa’s all-time bests, IMO. … I don’t know who penned the lyrics, but they too are great. … Hint: Listen to this song on high-quality head-phones, not on the loud-speakers, and only when you are all alone, all by yourself—and especially as you are nursing your favorite Sundowner—and especially during the times when you are going jobless. … Try it, some such a time…. Take care, and bye for now]

[E&OE]

# Monsoon—it’s officially here!

Yes, the monsoon has arrived! Even in the mainland peninsular India!

… Yes, even the government says so, now! [^].

The news was expected for quite some time, may be a week or so by now. … I have been tracking not just the IMD but also SkyMetWeather [^], and in fact, also the blogging by the latter’s CEO. Here is the latest from him [^].

As to the IMD, well, none at IMD blogs. … But still, you have to give them some credit. One would have thought that they would wait for Modi’s address to the joint session of the US Congress to get over before “notorizing” the arrival of the monsoon. … No, the quoted phrase is not mine; it comes from a blog post by Jatin Singh, the CEO of SkyMetWeather. [Sorry, can’t locate that post of his so readily; will insert the link later, if I get it.] That post by Singh had appeared about a week ago, and the author had rightly shown in it why and how the arrival of the Monsoon could be announced right back then—a week ago. … Anyway, apparently, in forming the subjective judgment of the objective criteria [once again, the characterization comes from Jatin Singh], the IMD, it seems, followed the rains more than the PM.

All the same, it’s a huge (and hugely welcome) a piece of news.

… If you are an American (or come from any advanced country) you just cannot in your entire lifetime imagine just what the phrase “Monsoon arrival” means to an Indian.

Yes, I am an Indian. Naturally, my memory (and/or attention-span) is short. Naturally, I’ve already forgotten how fast I had consumed my Internet data-pack limit last month (as was mentioned in my last post). The fact of the matter is, the data pack got renewed just a few days ago. And that’s all that matters to me, right now.

Naturally, I have watched quite a few satellite animation videos, and in fact also want to strongly recommend that you, too, go and watch them. Check out here [^] and here [^]. (As to the EuMetSat site, I have no idea why they have a blank atmosphere on 7th June until about 20:00 UTC.)

For the same reason—of being an Indian all the way to my core—I do not, and would never ever in my life, associate any of the following with the word “monsoon”:

• Random interruptions in the electricity supply (in the cities where there at all is an electricity supply)
• Overflowing gutters, drainages, nullahs and minor rivers in the cities; also the blocked roads, the broken down buses, the cancelled trains
• News of people in the cities being evacuated, but only after a few have already drowned because of the “sudden” increase in the water levels in the areas down-stream of dams, because of a “sudden” and very heavy downpour, even though every one owns a cell phone these days, including those in the slums in the cities and the villages in the rural areas.
• News of bus getting washed away in the floods in the rural areas because the driver thought that the waters overflowing on the low-lying bridge was not deep enough or fast enough
• News of young, educated, sleek people from Mumbai and Pune (including those employed in the IT industry, including young women) drowning at Alibag or Murud or Ganapati Pule beach, despite the local people urging them again and again not to go swimming in the seas at a time they themselves don’t dare doing so, because the sea is so rough
• News of young, educated, sleek people from Pune and Mumbai (including those employed in the IT industry, including young women) drowning at the Bushy dam at Lonavala, despite police yelling at them, using even loudspeakers, not to go and play in the rough waters
• And, oh, yes, add the Bhandardara lake near Nasik too.  Also the waterfalls near Mahabaleshwar. …

Yes, you have to be an Indian to have this kind of a sense of “humour,” too.

… Yes, we Indians are like that only.

… If we weren’t, life would immediately become far too depressing for even us to handle.

But, any way, we the Indians really feel good when we see the kind of reception our PM receives abroad.

… All of us do. Including those of us in the S. F. Bay Area. (Including those who have become American citizens.) It’s one of those few, few things which makes our lives acquire some luminosity, some rich splashes of the rainbow hues, even if only temporarily. Life becomes interesting then. Magnificent. Majestic. We feel proud then. … We can. Yes, we can. We can feel proud. At such moments.

Our movie-makers know all about it, all too well—the feel good factor. Not just the Hindi cinema, but, now-a-days, also the Marathi cinema.

The Marathi cinema, too, has by now become technically rich. And sleek. As sleek as those young crowds who must flock to the Sinhgad fort on their super-macho motorbikes (or in their massive SUVs) on every week-end during the Monsoons, despite knowing very well in advance that all roads to and near Sinhgad would be overflowing with vehicles, resulting in 5+ hours of traffic jams.

Hey, every one needs to feel better, at  least once in a while, OK?

OK. So, let me, too, join them all, and share a recent Marathi movie song with you.

A Song I Like:

Regardless of what all I wrote above, I actually like this song.

About this song: There is something a bit strange about this song. … Sometimes, a song excels in only a few departments: great tune, great voice, great singing, great orchestration, great acting, great-looking actors, great location, great picturization, or just a great overall theme. Etc. This song is strange in the sense that it is good on many such counts—when the factors are taken individually. The thing is: There is no complete integration of these elements. That’s the strange part about this song… I mean to say, for example, that the words mention rains, but the picturization doesn’t show any. The words, phrases and even metaphors are authentic (even traditional) Marathi, but the orchestration is Western. Etc. And even then, even if a complete consistency is not there, the song, somehow, comes out good. That’s strange.

Anyway, it indeed is a good song. (It certainly is better integrated than the movie in which it appears.) And, yes, I like it.

[As you must have guessed by now, yes, for this time round, I do mean to refer not just the audio, but also to the video of this song. [Yes, I realized that I have the bandwidth to go watch it right now, and that’s all that mattered to me, right now. … Remember, I am an Indian?]]

Anyway, here is the song:

(Marathi) “kadhee too, rimjhim zaraNaari barasaat…”
Lyrics: Shrirang Godbole
Music: Avinash-Vishwajeet

[Perhaps a minor editing pass may be done 2–3 days later. [Done, right away.]  … My stint at the previous college got over in late-April, and so, these days, I am busy applying for jobs, attending interviews and all. … The research has taken a back-seat for the time being. Implication: I will be busy attending interviews or traveling in the near future, and so, it may be 2–3 days (perhaps 3–4 days) before I am able to come back and think of improving this blog post or check the comments queue here. … But then, probably, even minor editing isn’t required for this post anyway; so regard this version as more or less the final version. [Yes, that’s right. The editing is now done.] … Take care and bye for now.]

[E&OE]

Even while enjoying my writer’s block, I still won’t disappoint you. … My browsing has yielded some material, and I am going to share it with you.

It all began with googling for some notes on CFD. One thing led to another, and soon enough, I was at this page [^] maintained by Prof. Praveen Chandrashekhar of TIFR Bangalore.

Do go through the aforementioned link; highly recommended. It tells you about the nature of my trade [CFD]…

As that page notes, this article had first appeared in the AIAA Student Journal. Looking at the particulars of the anachronisms, I wanted to know the precise date of the writing. Googling on the title of the article led me to a PDF document which was hidden under a “webpage-old” sub-directory, for the web pages for the ME608 course offered by Prof. Jayathi Murthy at Purdue [^]. At the bottom of this PDF document is a note that the AIAA article had appeared in the Summer of 1985. … Hmm…. Sounds right.

If you enjoy your writer’s block [the way I do], one sure way to continue having it intact is to continue googling. You are guaranteed never to come out it. I mean to say, at least as far as I know, there is no equivalent of Godwin’s law [^] on the browsing side.

Anyway, so, what I next googled on was: “wind tunnels.” I was expecting to see the Wright brothers as the inventors of the idea. Well, I was proved wrong. The history section on the Wiki page [^] mentions Benjamin Robins and his “whirling arm” apparatus to determine drag. The reference for this fact goes to a book bearing the title “Mathematical Tracts of the late Benjamin Robins, Esq,” published, I gathered, in 1761. The description of the reference adds the sub-title (or the chapter title): “An account of the experiments, relating to the resistance of the air, exhibited at different times before the Royal Society, in the year 1746.” [The emphasis in the italics is mine, of course! [Couldn’t you have just guessed it?]]

Since I didn’t know anything about the “whirling arm,” and since the Wiki article didn’t explain it either, a continuation of googling was entirely in order. [The other reason was what I’ve told you already: I was enjoying my writer’s block, and didn’t want it to go away—not so soon, anyway.] The fallout of the search was one k-12 level page maintained by NASA [^]. Typical of the government-run NASA, there was no diagram to illustrate the text. … So I quickly closed the tab, came back to the next entries in the search results, and landed on this blog post [^] by “Gina.” The name of the blog was “Fluids in motion.”

… Interesting…. You know, I knew about, you know, “Fuck Yeah Fluid Dynamics” [^] (which is a major time- and bandwidth-sink) but not about “Fluids in motion.” So I had to browse the new blog, too. [As to the FYFD, I only today discovered the origin of the peculiar name; it is given in the Science mag story here [^].]

Anyway, coming back to Gina’s blog, I then clicked on the “fluids” category, and landed here [^]… Turns out that Gina’s is a less demanding on the bandwidth, as compared to FYFD. [… I happen to have nearly exhausted my monthly data limit of 10 GB, and the monthly renewal is on the 5th June. …. Sigh!…]

Anyway, so here I was, at Gina’s blog, and the first post in the “fluids” category was on “murmuration of starlings,” [^]. There was a link to a video… Video… Video? … Intermediate Conclusion: Writer’s blocks are costly. … Soon after, a quiet temptation thought: I must get to know what the phrase “murmuration of starlings” means. … A weighing in of the options, and the final conclusion: what the hell! [what else], I will buy an extra 1 or 2 GB add-on pack, but I gotta see that video. [Writer’s block, I told you, is enjoyable.] … Anyway, go, watch that video. It’s awesome. Also, Gina’s book “Modeling Ships and Space Craft.” It too seems to be awesome: [^] and [^].

The only way to avoid further spending on the bandwidth was to get out of my writer’s block. Somehow.

So, I browsed a bit on the term [^], and took the links on the first page of this search. To my dismay, I found that not even a single piece was helpful to me, because none was relevant to my situation: every piece of advice there was obviously written only after assuming that you are not enjoying your writer’s block. But what if you do? …

Anyway, I had to avoid any further expenditure on the bandwidth—my expenditure—and so, I had to get out of my writer’s block.

So, I wrote something—this post!

[Blogging will continue to remain sparse. … Humor apart, I am in the middle of writing some C++ code, and it is enjoyable but demanding on my time. I will remain busy with this code until at least the middle of June. So, expect the next post only around that time.]

[May be one more editing pass tomorrow… Done.]

[E&OE]

/

# Papers must fall out…

Over the past couple of weeks or so, I’ve been going over SPH (smoothed particle hydrodynamics).

I once again went through the beginning references noted in my earlier post, here [^]. However, instead of rewriting my notes (which I lost in the last HDD crash), this time round, I went straight to programming. … In this post, let me recap recall what all I did.

First, I went through the great post “Why my fluids don’t flow” [^] by Tom Madams. … His blog has the title: “I am doing it wrong,” with the sub-text: “most of the time.” [Me too, Tom, me too!] This post gave a listing of what looked like a fully working C++ code. Seeing this code listing (even if the videos are no longer accessible), I had to try it.

So, I installed the Eclipse CDT. [Remember my HDD crash?—the OS on the new HDD had no IDEs/C++ compilers installed till now; I had thus far installed only Python and PyCharm]. I also installed MinGW, freeglut, Java JRE, but not all of them in the correct order. [Remember, I too do it wrong, most of the time.] I then created a “Hello World” project, and copy-pasted Tom’s code.

Tom’s program not only compiled well, but it also worked beautifully. Quite naturally, I had to change something about it.

So I removed his call to glDrawArrays(), and replaced the related code with the even older glBegin(GL_POINTS), glVertex2d(), glEnd() sort of a code. As I had anticipated,  there indeed was no noticeable performance difference. If the fluid in the original code required something like a minute (of computer’s physical time) to settle down to a certain quiescent state, then so did the one with the oldest-style usage of OpenGL. The FPS in the two cases were identical in almost all of the release runs, and they differed by less than 5–7% for the debug runs as well, when the trials were conducted on absolutely fresh cold-starts (i.e. with no ready-to-access memory pages in either physical or virtual memory).

Happy with my change, I then came to study Tom’s SPH code proper. I didn’t like the emitters. True to my core engineering background, what I wanted to simulate was the dam break. That means, all the 3000 particles would be present in the system right from the word go, thereby also having a slower performance throughout, including in the beginning. But Tom’s code was too tied up with the emitters. True to my software engineering background, rather than search and remove the emitters-related portion and thus waste my time fixing the resulting compiler errors, I felt like writing my own code. [Which true programmer doesn’t?]

So I did that, writing only stubs for the functions involving the calculations of the kernels and the accelerations. … I, however, did implement the grid-based nearest-neighbor search. Due to laziness, I simply reused the STL lists, rather than implementing the more basic (and perhaps slightly more efficient) “p->next” idiom.

Then I once again came back to Tom’s code, and began looking more carefully at his SPH-specific computations.

What I now didn’t like was the variables defined for the near-density and the near-pressure. These quantities didn’t fit very well into my preconceived notions of how a decent SPH code ought to look like.

So, I decided to deprove [which word is defined as an antonym of “improve”] this part, by taking this 2010 code from its 2007 (Becker et al.) theoretical basis, to a 2003 basis (Muller et al., Eurographics).

Further following my preconceived notions, I also decided to keep the values of the physical constants (density, gas stiffness, viscosity, surface tension) the same as those for the actual water.

The code, of course, wouldn’t work. The fluid would explode as if it were a gas, not water.

I then turned my learner’s attention to David Bindel’s code (see the “Resources” section at the bottom of his page here [^]).

Visiting Bindel’s pages once again, this time round, I noticed that he had apparently written this code only as a background material for a (mere) course-assignment! It was not even an MS thesis! And here I was, still struggling with SPH, even after having spent something like two weeks of full-time effort on it! [The difference was caused by the use of the realistic physical constants, of course. But I didn’t want to simply copy-paste Tom’s or Bindel’s parameter values; I wanted to understand where they came from—what kind of physical and computational contexts made those specific values give reasonable results.]

I of course liked some of the aspects of Bindel’s code better—e.g. kernels—and so, I happily changed my code here and there to incorporate them.

But I didn’t want to follow Bindel’s normalize_mass routine. Two reasons: (i) Once again according to my preconceived notions, I wanted to first set aside a sub-region of the overall domain for the fluid; then decide with how many particles to populate it, and what lattice arrangement to follow (square? body centered-cubic? hexagonal close-packed?); based on that, calculate each particle’s radius; then compute the volume of each particle; and only then set its mass using the gross physical density of the material from which it is composed (using the volume the particle would occupy if it were to be isolated from all others, as an intermediate step). The mass of a particle, thus computed (and not assumed) would remain fixed for all the time-steps in the program. (ii) I eventually wanted a multi-phase dam-break, and so wasn’t going to assume a global constant for the mass. Naturally, my code wouldn’t be able to blindly follow Bindel on all counts.

I also didn’t like the version of the leapfrog he has implemented. His version requires you to maintain additional quantities of the velocities at the half time-steps (I didn’t mind that), and also to implement a separate leapfrog_start() function (which I did mind—an additional sequence of very similar-looking function calls becomes tricky to modify and maintain). So, I implemented the other version of the leapfrog, viz., the “velocity Verlet.” It has exactly the same computational properties (of being symplectic and time-reversible), the same error/convergence properties (it too is second-order accurate), but it comes with the advantage that the quantities are defined only at the integer time-steps—no half-time business, and no tricky initialization sequence to be maintained.

My code, of course, still  didn’t work. The fluid would still explode. The reason, still, was: the parameter values. But the rest of the code now was satisfactory. How do I know this last part? Simple. Because, I commented out the calls to all the functions involving all other accelerations, and retained only the acceleration due to gravity. I could then see the balls experiencing the correct free-fall under gravity, with the correct bouncing-back from the floor of the domain. Both the time for the ball to hit the floor as well as the height reached after bouncing were in line with what physics predicts. Thus I knew that my time integration routines would be bug-free. Using some debug tracings, I also checked that the nearest-neighbour routines were working correctly.

I then wrote a couple of Python scripts to understand the different kernels better; I even plotted them using MatPlotLib. I felt better. A program I wrote was finally producing some output that I could in principle show someone else (rather than having just randomly exploding fluid particles). Even if it was doing only kernel calculations and not the actual SPH simulation. I had to feel [slightly] better, and I did.

At this stage, I stopped writing programs. I began thinking. [Yes, I do that, too.]

To cut a long story short, I ended up formulating two main research ideas concerning SPH. Both these ideas are unlike my usual ones.

Usually, when I formulate some new research idea, it is way too conceptual—at least as compared to the typical research reported in the engineering journals. Typically, at that stage (of my formulation of a new research idea), I am totally unable to see even an outline of what kind of a sequence of journal papers could possibly follow from it.

For instance, in the case of my diffusion equation-related result, it took me years before an outline for a good conference paper—almost like really speaking, at par with a journal paper—could at all evolve. I did have the essential argument ready. But I didn’t know what all context—the specifically mathematical context—would be expected in a paper based on that idea. I (and all the mathematicians I contacted) also had no idea as to how (or where) to go hunting for that context. And I certainly didn’t have any concrete idea as to how I would pull it all together to build a concrete and sufficiently rigorous argument. I knew nothing of that; I only knew that the instantaneous action-at-a-distance (IAD) was now dead; summarily dead. Similarly, in case of QM, I do have some new ideas, but I am still light-years away from deciding on a specific sequence of what kind of papers could be written about it, let alone have a good, detailed idea for the outline of the next journal paper to write on the topic.

However, in this case—this research on SPH—my ideas happen to be more like what [other] people typically use when they write papers for [even very high impact] journals those which lie behind the routine journal papers. So, papers should follow easily, once I work on these ideas.

Indeed, papers must follow those ideas. …There is another reason to it, too.

… Recently, I’ve come to develop an appreciation, a very deep kind of an appreciation, of the idea of having one’s own Google Scholar page, complete with a [fairly] recent photo, a verified email account at an educational institution (preferably with a .edu, or a .ac.in (.in for India) domain, rather than a .org or a .com domain), and a listing of one’s own h-index. [Yes, my own Google Scholar page, even if the h-Index be zero, initially. [Time heals all wounds.] I have come to develop that—an appreciation of this idea of having a Google Scholar page. … One could provide a link to it from one’s personal Web site, one could even cite the page in one’s CV, it could impress UGC/NBA/funding folks…. There are many uses to having a Google Scholar page.

…That is another reason why [journal] papers must come out, at least now.

And I expect that the couple of ideas regarding SPH should lead to at least a couple of journal papers.

Since these ideas are more like the usual/routine research, it would be possible to even plan for their development execution. Accordingly, let me say (as of today) that I should be able to finish both these papers within the next 4–5 months. [That would be the time-frame even if I have no student assistant. [Having a student assistant—even a very brilliant student studying at an IIT, say at IIT Bombay—would still not shorten the time to submission, neither would it reduce my own work-load any more than by about 10–20% or so. That’s the reason I am not planning on a student assistant on these ideas.]

But, yes, with all this activity in the recent past, and with all the planned activity, it is inevitable that papers would fall out. Papers must, in fact, fall out. …. Journal papers! [Remember Google Scholar?]

Of course, when it comes to execution, it’s a different story that even before I begin any serious work on them, I still have to first complete writing my CFD notes, and also have to write a few FDM, FVM and VoF/LevelSet programs scripts or OpenFOAM cases. Whatever I had written in the past, most of it was lost in my last HDD crash. I thus have a lot of territory to recover first.

Of course, rewriting notes/codes is fast. I could so rapidly progress on SPH this year—a full working C++ code in barely 2–3 weeks flat—only because I had implemented some MD (molecular dynamics) code in 2014, no matter how simple MD it was. The algorithms for collision detection and reflections at boundaries remain the same for all particles approaches: MD with hard disks, MD with LJ potential, and SPH. Even if I don’t have the previously written code, the algorithms are no longer completely new to me. As I begin to write code, the detailed considerations and all come back very easily, making the progress very swift, as far as programming is concerned.

When it comes to notes, I somehow find that writing them down once again takes almost the same length of time—just because you had taken out your notes earlier, it doesn’t make writing them down afresh takes any less time.

Thus, overall, recovering the lost territory would still take quite some effort and time.

My blogging would therefore continue to remain sparse even in the near future; expect at the most one more post this month (May 2016).

The work on the journal papers itself should begin in the late-June/early-July, and it should end by mid-December. It could. Nay, it must. … Yes, it must!

Papers must come out of all these activities, else it’s no research at all—it’s nothing. It’s a zero, a naught, a nothing, if there are no papers to show that you did research.

Papers must fall out! … Journal papers!!

A Song I Like:

(Western, Instrumental) “The rain must fall”
Composer: Yanni

[May be one quick editing pass later today, and I will be done with this post. Done on 12th May 2016.]

[E&OE]