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dchapp

48 karma · joined October 14, 2013

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dchapp··on Demystifying bitwise operations, a gentle C tutorial
I see several people sharing the Stanford bithacks link, so I'll throw in a slightly-less well-known resource that I found particularly instructive. Basically, a collection of the lemmata we can prove about fixed-length sequences of bits and the fun algorithms that can be built atop those results.

https://www.jjj.de/fxt/

And for the non-pdf-phobic: https://www.jjj.de/fxt/fxtbook.pdf

dchapp··on What I learned working with a senior engineer as a new grad
That may be a fair criticism in some cases.

For my toy example I don't think it is because it's generally easy (in the languages I work in) to overload arithmetic operators on types that are basically constrained scalars so there's no explicit wrapping/unwrapping to do when you want to operate on them as if they were plain scalars.

Maybe you could give me an example of the kind of pathological situation you're alluding to?

dchapp··on What I learned working with a senior engineer as a new grad
Readability. In particular, an increase in the rate at which long, verbose names which are mostly the same are confused with one another.
dchapp··on What I learned working with a senior engineer as a new grad
I have. I prefer statically typed languages.
dchapp··on What I learned working with a senior engineer as a new grad
> Long verbose names don't cost anything

They absolutely do have a cost. The question is whether the benefit they bring in implicit documentation is worth their cost.

> Even beyond the DX of readable names, it also acts like a type-checker. By reading the code, you can verify at least the semantics make sense.

I would strongly prefer that the actual type system do this job instead. As a toy example, if a function is only meant to operate on "lengths" (i.e., non-negative scalar values) then that should be modeled in the types of its arguments, not in its name.

dchapp··on Semantle: guess words based on Word2vec similarity scores
> the semantics it learns sometimes have significant artifacts resulting from associations that are common in news coverage

I think this is largely the point. The game is significantly easier (for me at least) when I limit myself to thinking about what words would have high co-occurrence in English print journalism.

dchapp··on Ask HN: What to do about ‘Good at programming Bad at Leetcode’
| It tests my anxiety levels at least 5x more than my skillset.

I'm not so convinced that these are two distinct things. I want coworkers who can maintain their level of skill under extremely hostile, stressful conditions. I'm not going impose those conditions on them, but I can't necessarily control the myriad third parties or circumstances that might.

dchapp··on MIT graduate students vote to unionize
Would you have been willing to hire this person without them graduating?
dchapp··on Ask HN: Are most of us developers lying about how much work we do?
First, I claim there exist disasters that are not simple to mitigate against collectively. Civil unrest (the full spectrum, from vigorous protest to outright governmental collapse) being the big one I have in mind.

Second, I claim that the wealthy character in the story above has significantly greater ability than the non-wealthy character to: (1) have accurate situational awareness about disasters (e.g., can distinguish shit actually hitting the fan from shit narrowly missing the fan (possibly via superior sensing apparati, more likely, just by delegating the task)); and (2) have well-equipped (read: expensive) bug-in/out plans in place. Thus, even in cases where disasters are mitigated against collectively as you claim is possible, the wealthy character will be in a better position to maintain their pre-disaster quality of life than the non-wealthy character.

That said, this is all a little too removed from a concrete comparison for my liking. Maybe you have one in mind? Ideally, an example where collective efforts at disaster mitigation basically made outcomes for individuals insensitive to the wealth of those individuals.

dchapp··on Ask HN: Are most of us developers lying about how much work we do?
Exactly one of the characters in that story can weather disasters.
dchapp··on U.S. house prices are rising exponentially faster than income
IME, when people say this, they mean that the difference between two quantities varies exponentially with time.
dchapp··on “Static Linking Considered Harmful” Considered Harmful
> Yeah, there are reasons to use dynamic linking, but I'm still not sure why dynamic linking gives you better profiling and tracing.

It's not so much that the tracing becomes better, but that it becomes feasible at all. Two specific situations come to mind, both MPI-adjacent. (1) Running a PMPI-based tool on code you can't recompile yourself (e.g., you need a Q clearance to see the source, but not to actually execute it--weird I know, but not that uncommon in the DOE labs.); and (2) running multiple PMPI-based tools simultaneously which are composed at runtime via PnMPI.

dchapp··on Climate change risk assessment 2021 [pdf]
Thanks! Since this was not obvious to me (and maybe isn't to others) here's a summary that cleared things up for me: https://blogs.nicholas.duke.edu/citizenscientist/oxygen-in-t...
dchapp··on Climate change risk assessment 2021 [pdf]
Suppose all of those mitigations in your second paragraph are true. If phytoplankton die off in meaningful amounts, where will we get our oxygen?
dchapp··on Intermediate Algebra
Landau's "Foundations of Analysis"
dchapp··on William Gibson is a literary genius
Agreed. I remember reading Hinterlands as a high school student and being depressed for the following decade.
dchapp··on Australia Joins the Race for Supersonic Flight
Consider a meeting in which you are attempting to read the body language of an adversary. Video chat may not be sufficient. For a concrete example, consider poker. Note that I am taking a fairly broad definition of "meeting" here.
dchapp··on Choosing Java instead of C++ for low-latency systems
What does OpenMP (the shared memory parallel runtime) have to do with optimizing away less-used branches? Am I missing something here or did you mean something else instead of OpenMP?
dchapp··on Toward an API for the Real Numbers
> I'm sorry addition isn't commutative...

My understanding is that in IEEE 754 compliant implementations of floating-point arithmetic, commutativity over "+" holds but not associativity. (With the possible exception to commutativity for the NaNs, though I don't remember offhand whether this caveat is necessary).

dchapp··on The Case Against Octopus Farming
If you're interested in schools of thought that argue on the side of "better off not having been born at all", take a look at negative utilitarianism.
dchapp··on Employers are monitoring computers, toilet breaks, even emotions
I suspect that tattoo/piercing artists are simply an affordable set of professionals with the right experience for implanting various body mods.
dchapp··on A coworker stole my spicy food, got sick, and is blaming me (2016)
I certainly understand that it's not legal to turn your house, nor your lunch, into a deathtrap. Nor at any point did I claim that any particular kind of action was legal. I said that Americans generally feel that we're collectively justified in harming certain kinds of people. That's not a claim about legality. That's a claim about how a subset of the population feels.

My use of "we" was merely meant to indicate that our society, through the apparatus of our legislators, has decided that our society is justified in doing harm to certain classes of people and has set up mechanisms for doing this. I was not using "we" in the "me and my immediate peers" sense.

dchapp··on A coworker stole my spicy food, got sick, and is blaming me (2016)
Maybe it is "always wrong" given a particularly rigid and simplistic code of ethics, but in American society at least we are very comfortable with the notion of causing deserved harm (whether physical, financial, or merely emotional) to wrongdoers as a deterrent to others.
dchapp··on Advanced Data Analysis from an Elementary Point of View (2017) [pdf]
I don't think the author gains anything. On the contrary, as a reader I gain something from this statement. It's not "now would be an excellent time to leave and you should feel bad you stupid person", it's "now would be an excellent time to leave so that you don't waste your time trying to build a house on a junk foundation". If anything, it's courteous.
dchapp··on How Strength Training Changes Your Body for Good
Elite track cyclists--i.e., the ones who ride at 40+ kmph on velodromes--definitely do squat. I wouldn't be surprised if they also incorporated power cleans and deadlifts.

Example: https://m.youtube.com/watch?v=aOImvJOaGiY

dchapp··on Fast exact summation using small and large superaccumulators
You might be interested in ReproBLAS too.(http://bebop.cs.berkeley.edu/reproblas/)

It uses a different approach than superaccumulators, which as far as I know was first explored for the purpose of determinizing parallel floating-point sums by the folks working on ExBLAS (https://exblas.lip6.fr/)

dchapp··on How to Become a Good Theoretical Physicist
I agree that use of "good" is questionable here. One would think that without the skills mentioned, one wouldn't be a theoretical physicist at all. (Is every person who lacks these skills a "bad theoretical physicist"? Only in a vacuous sense.)

That said, I think we should interpret "how to become a good theoretical physicist" as "how to gain the competencies that are expected of s theoretical physicist."

dchapp··on Trading Meat for Tires as Bartering Economy Grows in Greece
Alcohol. Both disinfecting-strength and recreating-strength.
dchapp··on The Supervolcano Under Yellowstone Is Alive and Kicking
I'm not convinced wind farms wouldn't be affected as well.

With an ash cloud large and dense enough to restrict that much sunlight, wouldn't we also get a different distribution of warmed land and therefore different wind patterns?

dchapp··on I barely graduated college, and that's okay
His parent edited his comment. Previously it ended with the parent hinting at a "politically incorrect" theory as to why he was not admitted to the Foreign Service while Mr. Paruchuri was.

Edit: That said, I'd be disheartened too and I don't really think your parent's "dig" was justified.

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