bloomer · HackerTrans

6 лет назадdiscuss

This is really cool. Have you looked at all at the constant Q transform https://en.m.wikipedia.org/wiki/Constant-Q_transform which is basically a Fourier Transform with logarithmically spaces bins so that it can be aligned with traditional musical notes. Miller Puckette (Max/Pure Data) among others, has a fast algorithm for its calculation.

bloomer

6 лет назадdiscuss

Well according to Cuomo’s March 26 briefing the ventilator situation maybe nearly that bad. https://www.bloomberg.com/news/articles/2020-03-26/n-y-death... 3-4 days for non-covid versus 11-21 days for covid.

bloomer

6 лет назадdiscuss

Yeah I think this terminology is odd because I think that the computable numbers are much more “useful” than the definable numbers.

bloomer

6 лет назадdiscuss

For an alternate empirical take:

https://weis2019.econinfosec.org/wp-content/uploads/sites/6/...

They find publishers only have a 4% premium on programatic ads that involve behavioral targeting.

bloomer

6 лет назадdiscuss

The test they use to select employees correlates with their rating of employees is pretty circular. Any arbitrary test will do that.

bloomer

6 лет назадdiscuss

I haven’t read this in detail, but a few things stand out. In the write up, you say it compares better than bitwise radix sort. You need to compare against an optimized byte-wise radix sort which is by far the fastest sort for decent sized arrays of integers. The second claim that skyline sort somehow sorts an array of size a faster than two arrays of size n does not make sense. That implies that the time per element goes to zero as the size goes to infinity. That would be faster than O(n), which is what radix sort is, i.e. constant time per element for larger arrays.

It sounds like this is just a variation of counting sort or bucket sort optimized for a small number of unique values.

bloomer

6 лет назадdiscuss

Somewhat, in that it doesn’t use more precision than needed, but the real issue is you can’t just pick some arbitrarily large precision and round at the end. For some calculations, even 400 digits during intermediate steps would not be enough due to catastrophic cancellation and you would need to go even higher precision to get the right answer. It really is about solving an accuracy issue and not an optimization. And determining that you are using sufficient precision to get an accurate answer is an extra cost, so it is always more expensive than just plowing ahead and calculating an inaccurate answer.

bloomer

6 лет назадdiscuss

The default Android calculator app by Hans Boehm (developer of the Boehm Garbage Collector as well) does this by using the computable real numbers.

https://dl.acm.org/doi/10.1145/2911981

Provides a good overview of how it works and perms website has more information.

What’s cool about the computable reals implementation is you can increase the precision after the fact and it will recalculate up to that precision. Basically it memoizes the steps of the calculation and how they affect the precision.

bloomer

6 лет назадdiscuss

This isn’t a performance optimization but rather an accuracy optimization. Even if the requested output is a double (64-bits) the intermediate calculations often need to be done to higher precision to get fully accurate answers. Note that the desktop calculator on Android does the same analysis by using computable numbers.

https://dl.acm.org/doi/10.1145/2911981

Is a nice overview.

bloomer

6 лет назадdiscuss

I would also like to not that encoding the the Option<char> using the unused bits of the return value is a perfectly valid implementation. But that is exactly what it is, an implementation detail. It could work exactly the same way as today but the programmer wouldn’t have to care about how it was implemented, just whether they got a char or None.

bloomer

6 лет назадdiscuss

http://c-faq.com/decl/spiral.anderson.html Is the rule I learned to understand C declarations and while the rule there is described as simple I think the examples even without argument types are actually fairly complex.

It also seems telling that no recent language has followed C’s example for declaration style, which is more implicit than explicit.

bloomer

6 лет назадdiscuss

Actually this is quite a bit different. This is more a columnar-store version of SQLite, basically an embedded OLAP database, which is pretty cool. I’m not aware of other column-stores in this niche, most are distributed systems meant for big data and so are much more complicated to setup and manage.

bloomer

6 лет назадdiscuss

Smoke C by several orders of magnitude? Citation needed.

bloomer

6 лет назадdiscuss

https://en.m.wikipedia.org/wiki/Blackbird_(land_yacht) Was built to demonstrate that you can sail directly downwind faster than the wind as well.

bloomer

6 лет назадdiscuss

> Many people think donating 3% of their income is a lot, let alone the 10%

Except of course for many mainstream religions https://en.m.wikipedia.org/wiki/Tithe “weirdness” is very relative to your local view.

bloomer

6 лет назадdiscuss

NULL is similar to floating point NaN (aka not a number) which also has the same comparison operation NaN != NaN.

bloomer

6 лет назадdiscuss

Would not even require difference in circumstances, seems like the other defendants would be likely to just pin the blame on her if she isn’t going to defend herself.

bloomer

7 лет назадdiscuss

It’s downside is that it is computationally very expensive. All of the other NIST candidates are not very computationally demanding, but have much larger keys. So the trade off with SIDH is that it spends a lot of time calculating while the others are transmitting bytes over the network. There are trade offs with all the proposed schemes. a

bloomer

7 лет назадdiscuss

It’s missing the fungibility where it is produced by multiple suppliers and can be treated equivalently by the end buyer. Large grade A eggs are a commodity as it doesn’t matter which farm produced them. A specific set of processors from Intel are not a commodity since there are no fungible equivalents. Widely available would probably be a better description in this case.

bloomer

7 лет назадdiscuss

Weird that this is being downvoted because Uber has shown no interest in acquiring and managing assets (self-driving cars or even their own cars) which is a completely different business than being a marketer for independent taxis. If self-driving cars become a business it seems like rental car companies would be ideally positioned to take advantage of them.

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