5 ms·

What do you mean by projections? Do you have another example?

Jtsummers 6y ago
Map the problem into other domains. In this case, he could work with the original (hard to understand) source code. Or he could use a tool that would translate it (or the binary) into a more sensible language. In other tasks, consider different data structures or representations that fundamentally represent the same data, but in different ways that offer different guarantees. Representing a graph with a matrix may let you answer some questions very quickly, but it may make others harder to answer, for example.
tclancy 6y ago
Back up and consider if all of the turns you made to get down this particular blind alley actually made sense. “First principles” and all that.
aneutron 6y ago
He means mathematical projections. For example, calculating rotation velocities in a cartesian projection is harder than using cylindrical projection.
- notretarded 6y ago
  Nope you're giving him too much credit. He meant projections as in to a different view on the problem. Not anything more well defined than that. Your manner of explaining it is much better.
  - dllthomas 6y ago
    I very much meant mathematical projections, but also (by analogy) other kinds of perspective shift where they have enough of the same properties.
tenken 6y ago
Its an eastern mode if thinking. When faced by a problem, walk around the problem and examine all avenues of approach. Much like scaling a mountain. Seek the path of least resistance. To often we simply reach for our trusty hammer, and it's not always an efficient or usable tool.
- sidlls 6y ago
  How is this an "eastern" mode of thinking. It's a pretty typical way we'd approach solving problems in physics anyway, and this was all in very western university here in the US.
  - tenken 6y ago
    It may be prevalent in niche industries. But it's largely not culturally apart of historically western culture. And would you apply that problem approach prior to becoming a physics expert, did they teach that in kindergarten? Eg in school we learn as kids derivatives, rote routines to solve a type of problem, and we plug and chug, but we are not shown (necessarily) by govt education the underlying theories that may create a solution. This/my opinion is of course dependant on how expert an instructor is ... The best anecdotal example I can give off the net offhand would be: https://www.google.com/amp/ask.metafilter.com/105309/Tao-thinking-and-problem-solving/amp https://www.google.com/amp/ask.metafilter.com/105309/Tao-thi... Thanks for your feedback Edit: Also in the usa we're taught do your own homework for example. In asian cultures often students band together to succeed in classes (I work in higherEd and this is culturally visible in peers in classes). This is another example of this philosophy being different between cultures.
    - bouncycastle 6y ago
      Creative/critical thinking is taught heavily from kindergarten in western schools. In contrast to eastern education which tends to greatly focus on memorization through repetition.. (i.e https://en.m.wikipedia.org/wiki/Rote_learning https://en.m.wikipedia.org/wiki/Rote_learning) The quote you have included is based on Taoism. Is that common? I was under the impression that Confucianism has the more dominant influence on values and thought. Anyways, at least that's one thing we can agree on - Taoism's philosophy encourages an open mind and awareness.
josephg 6y ago
More examples: When debugging a web app, you can debug the code (and add print statements / breakpoints). Or look at the HTTP queries its making in the inspector. Or debug the server - look at what queries its receiving and returning. Or experiment with different values in the database. Last year I was trying to track down a memory leak in some wasm code. The tooling for that sort of thing in wasm was/is quite primitive, so I did some work to compile the module natively then ran valgrind on the resulting executable. That didn't work - the C code executed differently from the wasm and didn't exhibit the bug! So I added print statements randomly through the program and ran it both natively and through wasm, then diffed the text output to track down when the execution traces diverged. (It wasn't a compiler bug, fwiw.) I wanted more information about the memory leak. So I wrapped all the malloc/free calls with a replacement that stored all outstanding allocations in a list, with the stack trace when malloc was called. When the leak happened, I could ask for the stack trace of all outstanding allocated objects[1]. That was fast and effective, and I added a memory leak check in my CI. At one of my first programming jobs we were using visual source safe (oh god, kill it with fire). I ended up losing some changes I'd made in a ~3000 line java class that we'd already deployed to production. I didn't want to do my work over again (or admit the mistake to my boss!). So I ran a decompiler against the class file we deployed to production - but it was huge and unreadable. To find the changes I'd made I took the current version of the java file, then compiled it and decompiled it again. So then I had two ugly files - but I could diff them, and that highlighted immediately the dozen or so changes I'd made. Then I just manually rewrote each change back into the original source file. Importantly, I had complete confidence that I didn't miss any of my changes. [1] Its not pretty, but the code looks like this if anyone's curious: https://github.com/josephg/mime-to-jmap/blob/2a7429f7b805cb00a5b94272564f46ad5c3a63d7/src/xmalloc.c https://github.com/josephg/mime-to-jmap/blob/2a7429f7b805cb0...
- HexagonalKitten 6y ago
  > visual source safe (oh god, kill it with fire) Did you have merge week too? Often stretching into a second?
  - josephg 6y ago
CRConrad 6y ago
> What do you mean by projections? @Jtsummers puts it as “Map the problem into other domains”; another interpretation (or a variation on the same) is “look at it from a different angle” or “look at it in a different light”. Do both -- move around with your light source, shine a torch/flashlight at your problem, and different shapes will be “projected” onto the wall behind it. Kind of like, if you are familiar with Hofstadter's _Gödel, Escher, Bach_ -- remember that “G,E,B” cube pictured on the cover of many editions? A more or less abstract “thing” or idea can be “projected” into different practical views depending on perspective. In actual practical work talking about “projections” can of course feel a little highfalutin’; to me it's a bit like always talking about your RDBMS tables or views as “relations”. But in a more philosophical sense it is of course perfectly valid. And AFAICS it's an age-old idea in Western philosophy; what I described above is essentially precisely what is known as _Plato's Cave_. (Which incidentally is why @tenken’s identifying it as “Eastern” feels quite peculiar to me.)
dllthomas 6y ago
Two classic examples (Cartesian vs polar coordinates, frequency vs time domain) are mentioned in other comments. I would certainly add "looking at values vs looking at differences" and "looking at the generator vs looking at what's generated" (which the top level story is an example of). It may take a little squinting, but we can see the common mathematical practice of reducing one problem to an example of another as an instance of this. There are also tweakier math examples where treating something as topology or something makes it easy to solve.

Map the problem into other domains. In this case, he could work with the original (hard to understand) source code. Or he could use a tool that would translate it (or the binary) into a more sensible language. In other tasks, consider different data structures or representations that fundamentally represent the same data, but in different ways that offer different guarantees. Representing a graph with a matrix may let you answer some questions very quickly, but it may make others harder to answer, for example.

tclancy 6y ago

Back up and consider if all of the turns you made to get down this particular blind alley actually made sense. “First principles” and all that.

aneutron 6y ago

He means mathematical projections. For example, calculating rotation velocities in a cartesian projection is harder than using cylindrical projection.

notretarded 6y ago
Nope you're giving him too much credit. He meant projections as in to a different view on the problem. Not anything more well defined than that. Your manner of explaining it is much better.
- dllthomas 6y ago
  I very much meant mathematical projections, but also (by analogy) other kinds of perspective shift where they have enough of the same properties.

tenken 6y ago

Its an eastern mode if thinking. When faced by a problem, walk around the problem and examine all avenues of approach. Much like scaling a mountain. Seek the path of least resistance. To often we simply reach for our trusty hammer, and it's not always an efficient or usable tool.

sidlls 6y ago
How is this an "eastern" mode of thinking. It's a pretty typical way we'd approach solving problems in physics anyway, and this was all in very western university here in the US.
- tenken 6y ago
  It may be prevalent in niche industries. But it's largely not culturally apart of historically western culture. And would you apply that problem approach prior to becoming a physics expert, did they teach that in kindergarten? Eg in school we learn as kids derivatives, rote routines to solve a type of problem, and we plug and chug, but we are not shown (necessarily) by govt education the underlying theories that may create a solution. This/my opinion is of course dependant on how expert an instructor is ... The best anecdotal example I can give off the net offhand would be: https://www.google.com/amp/ask.metafilter.com/105309/Tao-thinking-and-problem-solving/amp https://www.google.com/amp/ask.metafilter.com/105309/Tao-thi... Thanks for your feedback Edit: Also in the usa we're taught do your own homework for example. In asian cultures often students band together to succeed in classes (I work in higherEd and this is culturally visible in peers in classes). This is another example of this philosophy being different between cultures.
  - bouncycastle 6y ago
    Creative/critical thinking is taught heavily from kindergarten in western schools. In contrast to eastern education which tends to greatly focus on memorization through repetition.. (i.e https://en.m.wikipedia.org/wiki/Rote_learning https://en.m.wikipedia.org/wiki/Rote_learning) The quote you have included is based on Taoism. Is that common? I was under the impression that Confucianism has the more dominant influence on values and thought. Anyways, at least that's one thing we can agree on - Taoism's philosophy encourages an open mind and awareness.

josephg 6y ago

More examples: When debugging a web app, you can debug the code (and add print statements / breakpoints). Or look at the HTTP queries its making in the inspector. Or debug the server - look at what queries its receiving and returning. Or experiment with different values in the database. Last year I was trying to track down a memory leak in some wasm code. The tooling for that sort of thing in wasm was/is quite primitive, so I did some work to compile the module natively then ran valgrind on the resulting executable. That didn't work - the C code executed differently from the wasm and didn't exhibit the bug! So I added print statements randomly through the program and ran it both natively and through wasm, then diffed the text output to track down when the execution traces diverged. (It wasn't a compiler bug, fwiw.) I wanted more information about the memory leak. So I wrapped all the malloc/free calls with a replacement that stored all outstanding allocations in a list, with the stack trace when malloc was called. When the leak happened, I could ask for the stack trace of all outstanding allocated objects[1]. That was fast and effective, and I added a memory leak check in my CI. At one of my first programming jobs we were using visual source safe (oh god, kill it with fire). I ended up losing some changes I'd made in a ~3000 line java class that we'd already deployed to production. I didn't want to do my work over again (or admit the mistake to my boss!). So I ran a decompiler against the class file we deployed to production - but it was huge and unreadable. To find the changes I'd made I took the current version of the java file, then compiled it and decompiled it again. So then I had two ugly files - but I could diff them, and that highlighted immediately the dozen or so changes I'd made. Then I just manually rewrote each change back into the original source file. Importantly, I had complete confidence that I didn't miss any of my changes. [1] Its not pretty, but the code looks like this if anyone's curious: https://github.com/josephg/mime-to-jmap/blob/2a7429f7b805cb00a5b94272564f46ad5c3a63d7/src/xmalloc.c https://github.com/josephg/mime-to-jmap/blob/2a7429f7b805cb0...

HexagonalKitten 6y ago
> visual source safe (oh god, kill it with fire) Did you have merge week too? Often stretching into a second?
- josephg 6y ago

CRConrad 6y ago

> What do you mean by projections? @Jtsummers puts it as “Map the problem into other domains”; another interpretation (or a variation on the same) is “look at it from a different angle” or “look at it in a different light”. Do both -- move around with your light source, shine a torch/flashlight at your problem, and different shapes will be “projected” onto the wall behind it. Kind of like, if you are familiar with Hofstadter's _Gödel, Escher, Bach_ -- remember that “G,E,B” cube pictured on the cover of many editions? A more or less abstract “thing” or idea can be “projected” into different practical views depending on perspective. In actual practical work talking about “projections” can of course feel a little highfalutin’; to me it's a bit like always talking about your RDBMS tables or views as “relations”. But in a more philosophical sense it is of course perfectly valid. And AFAICS it's an age-old idea in Western philosophy; what I described above is essentially precisely what is known as _Plato's Cave_. (Which incidentally is why @tenken’s identifying it as “Eastern” feels quite peculiar to me.)

dllthomas 6y ago

Two classic examples (Cartesian vs polar coordinates, frequency vs time domain) are mentioned in other comments. I would certainly add "looking at values vs looking at differences" and "looking at the generator vs looking at what's generated" (which the top level story is an example of). It may take a little squinting, but we can see the common mathematical practice of reducing one problem to an example of another as an instance of this. There are also tweakier math examples where treating something as topology or something makes it easy to solve.