Hacker News Reader

ubasuon A Supermarket in California (1955)

The Trader Joe's at University and MLK is very recent, only since 2010 [1]. It used to be an auto-parts store before. Perhaps it used to be a grocery store back in 1955?

[1] https://www.sfgate.com/bayarea/place/article/Complex-houses-...

ubasuon Why the United States has the best research universities

Because WWI and Nazi Germany drove the best scientists from Europe to the US?

ubasuon What’s Wrong with “Multiplication Is Repeated Addition”? (2008)

To put it in terms of what the audience here can relate to:

multiplication is an overloaded operation, or in more modern terms, it is doing multiple dispatch, depending on whether the input is a whole number or integer or rational or real or complex

ubasuon Gauss’s “Remarkable Theorem” and the best way to hold a pizza slice (2014)

It's not about curvature, it's moment of inertia that stops it from bending, see:

https://news.ycombinator.com/item?id=8275112

ubasuon My Personal Journey from MIT to GPL

Here's my rant of the day:

The meme that the GPL is "less free" sounds very Orwellian.

What it really means is that I cannot freely use someone else's creation without restriction, and that I have to respect the wishes of the original author about how their work should be used.

That is because GPL was intended to be a hack on the copyright system (hence "copyleft"), but it always respected the idea of copyright - it does not call for the abolition of copyright.

This talk of GPL being "not free" smells of propaganda so that people (big corporations?) can reuse and repackage others' valuable work for free without any kind of compensation or acknowledgement. (TFA says the same thing)

Feel free not to use GPL'ed code if you find it too restrictive, but please don't contribute to spreading propaganda against it (and get off my lawn while you're at it)

[For the record, I work on proprietary software myself and haven't written any FOSS code, but I use GPL software daily - Linux, gcc, emacs etc]

ubasuon Notes on Resonance

"Resonance occurs when two sources of excitation fall completely in sync, and reinforce one another endlessly."

This is incorrect, even according to the wikipedia article it links to.

Resonance occurs when the excitation frequency matches a natural frequency of the system being excited, causing it to vibrate at larger amplitudes, even perhaps uncontrollably.

It seems that the author misunderstands mixing also - the graph that he presents for the mixed signal seems to be incorrect according to the other wikipedia article he links to.

ubasuon Ask HN: I just discovered a new algorithm. What should I do?

In my experience, the method described here works very well in practice:

http://wwwf.imperial.ac.uk/~rn/distance2ellipse.pdf

(this is linked to from the stackoverflow post)

Finding the closest point for an ellipsoid is more challenging in practice, because one needs to take a different parametrization near a pole, and sometimes conjugate gradient is necessary to get convergence.

ubasuon iPhone SE

Never mind, found them all here:

http://www.apple.com/ios/carplay/available-models/

ubasuon iPhone SE

I couldn't identify all the car company logos. Specifically, in 1-based (row, column) format:

(1,3), (3,2), (3,6), (4,4), (4,6), (4,7), (5,9)

Can people please chime in with the correct identifications?

(There seems to be a logo behind the speaker, which I am not counting)

ubasuon Julia: A Fast Language for Numerical Computing

You seem to be conflating "numerical computing" with machine learning. However, numerical computing typically involves solving PDEs via e.g. finite elements or finite differences, or solving large systems of linear equations associated with such methods.

The difference between the two is that when solving PDEs, accuracy is paramount, so even using single precision is a bit of a compromise, whereas in machine learning, the trend seems to be to use half-precision or lower, sacrificing accuracy for speed.

For classical numerical computing, e.g. solving PDEs or linear equations, Java may not be the best choice, e.g. see the following paper:

How Java's Floating Point Hurts Everyone Everywhere:

https://www.cs.berkeley.edu/~wkahan/JAVAhurt.pdf

ubasuon Academic Drivel Report: Confessing my sins and exposing my academic hoax

You can read Sokal's various commentaries on this topic. His point was that many philosophers tried to make grandiose statements about science and mathematics that did not make sense at all. The philosophers were making statements based on their imagination of what certain terms meant, and not on the actual meaning of those terms.

See the links here:

https://news.ycombinator.com/item?id=10715872

ubasuon Philosophy of science books every computer scientist should read

Please keep in mind that the book by Bruno Latour referenced here (Science in Action) and another of his articles was lampooned in the Sokal Affair because Latour was confused about relativity:

https://en.wikipedia.org/wiki/Sokal_affair

http://www.physics.nyu.edu/faculty/sokal/transgress_v2/trans...

http://www.physics.nyu.edu/sokal/le_monde_english.html

http://www.physics.nyu.edu/sokal/noretta.html

ubasuon Too much of the research process is now shrouded by the opaque use of computers

Modern compilers should, but there is a lot of legacy code.

ubasuon Too much of the research process is now shrouded by the opaque use of computers

I don't disagree that badly-written scientific code exists (both in academia and in the industry), but I want to point out a couple of things for people who have only a software engineering background.

1. Keep in mind that most scientific code for numerical analysis, being based in mathematics, follows the convention for using algebraic symbols, e.g. even in physics, we write

F=m*a

instead of the wordy version, which we overcame a couple of centuries ago. So using shortened variable names [1] comes from that background, and using longer names as in Java-world seems like a regression.

2. Writing code like [2]

    Ax_1 += Bx_1 + Cx_1 # Add Bx_1 to Cx_1
    Ax_2 += Bx_2 + Cx_2 # Same thing, but for Ax_2
    Ax_3 += Bx_3 + Cx_3 # "
    Ay_1 += By_1 + Cy_1 # "

is known as loop unrolling [3,4] and is used for optimization.

[1] https://news.ycombinator.com/item?id=10539078

[2] https://news.ycombinator.com/item?id=10540446

[3] https://en.wikipedia.org/wiki/Loop_unrolling

[4] http://stackoverflow.com/questions/2349211/when-if-ever-is-l...

ubasuon I killed my startup hours before closing a seed round

I made my first offer to a full-time employee, who could add necessary medical expertise to the team. She chose us over an existing offer and gave notice to her current employer.

What happened to this employee? Just curious...

ubasuon What is Concrete?

See the concrete canoe competition:

https://en.wikipedia.org/wiki/Concrete_canoe http://www.asce.org/concrete-canoe-photo-gallery/

ubasuon Feynman's concept of scientific integrity

Here's Krugman's commentary on this discussion:

http://krugman.blogs.nytimes.com/2015/08/02/freshwaters-wron...

ubasuon What Was the Venus de Milo Doing with Her Arms?

According to the Wikipedia entry [1] and other pages mentioned in another comment [2], the statue was found with a fragment of a left hand holding an apple, and a right hand with a draped sash. This was taken to understand that the statue represented the Judgement of Paris [3].

So apparently it is known what the hands held, which seems to make this speculation unnecessary.

[1] https://en.wikipedia.org/wiki/Venus_de_Milo [2] https://news.ycombinator.com/item?id=9474238 [3] http://en.wikipedia.org/wiki/Judgement_of_Paris

ubasuon What is it like to be poor at an Ivy League school?

I would recommend reading these books by one Ruby Payne which explore such differences in detail:

A framework for understanding poverty: http://www.amazon.com/gp/product/1929229488/

Crossing the Tracks for Love: http://www.amazon.com/gp/product/192922933X/

Hidden Rules of Class at Work: http://www.amazon.com/gp/product/1929229070/

In particular, she goes in to these very concerns about how on has to change their identity and mindset from their old world to be in the new world.

ubasuon Visualizing matrix multiplication as a linear combination

Here's how you can apply this interpretation of matrix multiplication:

Think of the columns of the matrix A as basis vectors of a coordinate system represented in global coordinates, and the vector v as the components of a vector in that coordinate system. Then the product A * v transforms the vector v into the global coordinate system.

Carrying this forward, matrix multiplication A * B gives the combined representation of two coordinate transformations.

ubasuon Sam Altman: Why Hardware Could Yield the Next $10B Startups

Just curious: what software do you use for you FEA simulations?

ubasuon I Can’t Write My Name in Unicode

I am referring to the first line of Bengali text.

I have viewed it in Acrobat Reader, epdfview, Chrome's PDF Reader, Firefox's pdf reader and my iPhone's pdf reader.

The problems are that joint-letter ligatures are not used, and several vowels signs are placed after the consonant when they should have been placed before them.

ubasuon I Can’t Write My Name in Unicode

It has to do with how the text is rendered. For example, if you see the Bengali text on page 3 of this PDF:

http://www.unicode.org/L2/L2004/04252-khanda-ta-review.pdf

it is unreadable and incorrect Bengali. ;-)

ubasuon I Can’t Write My Name in Unicode

Native Bengali here. The ligature used for the last letter of "haTaat" (suddenly) is not the same as the last ligature in "aditya" - the latter doesn't have the circle at the top.

More generally, using the vowel silencing diacritic (hasanta) along with a separate ligature for the vowel ending - while theoretically correct - does not work because no one writes that way! Not using the proper ligatures makes the test essentially unreadable.

ubasuon Housing markets: The spectre haunting San Francisco

Previous discussion:

https://news.ycombinator.com/item?id=7602740

Article is from 2014

ubasuon Do Orchestras Really Need Conductors? (2012)

The conductor is the musician, and the orchestra is his instrument, so yes.

ubasuon War and Peace in the Bhagavad Gita

It is the subtext that is anti-Hindu here (i.e. you have to read between the lines). Doniger seems to be forwarding the narrative that Hindus are violent Others, driven by their holy text. This is similar to the established(?) narrative that Muslims are terrorists, being motivated by the Quran, never mind that it is not true. You may say that it is only my interpretation here, but this sort of narrative-building is all too common - in the past, the word "savages" would have been used.

Words are the tools of Doniger's trade. It is extremely unlikely that her choice of words is inadvertent.

ubasuon War and Peace in the Bhagavad Gita

Are there alternate versions of the Mahabharat where Krishna does not go to the Kauravas with a peace treaty and where the war happens before such a peace effort?

To whoever downvoted this: note that I was trying to highlight the logical fallacy in the parent comment, which was using the existence of different versions of the Ramayana to make a sweeping generalization about the Mahabharata without providing proof specific about the latter.

ubasuon War and Peace in the Bhagavad Gita

While such generic calls to decorum are always welcome, the specific issue here is that Doniger seems to be selectively and willfully misinterpreting the text to advance her own agenda. Most prominently, she declaims the Gita as a warlike-text, ignoring the clear context of the Mahabharata that war is inevitable in this situation when all attempts at a peaceful resolution have been rebuffed. (see https://news.ycombinator.com/item?id=8664662)

One may adopt a position of Gandhian non-violence and say that war is not justified even in that context, thus disagreeing with the philosophy of the Mahabharata, and that is OK, but misrepresenting the text is not.

ubasuon War and Peace in the Bhagavad Gita

Wendy Doniger is known to have an interpretation of Hindu texts that is hostile to traditional understanding of the texts [1]. Some specific examples in this particular article are:

1. The Bhagvad Gita is commonly understood to be a discussion of appropriate duty. In this case, Krishna's argument was it is Arjuna's duty to go to war, considering that all other peaceful solutions had been explored and rejected by the Kauravas (Arjuna's opponents)[2]. In fact, Krishna himself had acted as peacemaker, and asked Arjuna to take take up arms only when that failed. The use of the Gita by Indian Nationalists fighting for Indian independence from the British has to be understood in this context.

2. Doniger says that the war was "lawless", but the Mahabharata war was an attempt at a "just" war, as understood in its contemporary context. Deviations from just behaviour are noted and held up as examples of unjust behaviour.

3. The so-called "Doomsday" manifestation of Krishna is in fact him showing his universal form, which is supposed to be beyond the capacity of ordinary humans to visualize, which is why Krishna had to grant Arjuna divine vision to be able to comprehend it. Doniger's use of the Abrahamic term "Doomsday" is loaded, because the understanding of comprehensive destruction or "Pralay" [3] in Hinduism is very different. Sure Doniger understands the difference, since she is a professor of Religious Studies.

4. She seems to be applying guilt-by-association by tying the Gita to the RSS and the assassination of Gandhi, and she criticizes Richard Davis for being too respectful of Hindu understanding of the Gita. Overall, the impression is that her anti-Hindutva agenda is spilling over into being an anti-Hindu agenda.

[1] http://creative.sulekha.com/risa-lila-1-wendy-s-child-syndro... [2] http://en.wikipedia.org/wiki/Kurukshetra_War#Krishna.27s_pea... [3] http://en.wikipedia.org/wiki/Pralaya