willdearden

3 年前議論

People have different risk exposures and different risk appetites. If you're a corn farmer then your entire livelihood is tied to the price of corn. You're willing to give up expected value to reduce risk by selling futures and there are others who are less exposed to corn prices who are willing to take the other side of that trade.

willdearden

3 年前議論

FWIW for my comment I essentially used your code and cleaned up compiler-generated imperative code.

So yes it used the fact that it only recursed to n-1 but did not use any optimizations related to booleans. And looking at other examples can see general principles. You store a data structure for each function which acts as a cache. For example, suppose you said even(0) = True, even(1) = False, and even(n) = even(n - 2), then one way would to unroll it would be to use a size 2 ring buffer as a cache.

willdearden

3 年前議論

Here's how I would write the loop version of this. It does involve an optimization since we know parity only depends on n - 1.

  #include <algorithm>
  
  template <typename T>
  bool even(T n)
  {
      bool is_even{true}, is_odd{false};
      for (; n--;)
      {
          std::swap(is_even, is_odd);
      }
      return is_even;
  }

willdearden

4 年前議論

I was there until the end. It was definitely fading into obscurity but still had >50% of peak numbers. And we were switching to C++ in the last year or so.

willdearden

4 年前議論

There is actually already a Scheme interpreter implemented in Rust (https://github.com/mattwparas/steel) which has the same name for the exact reasons you stated.

willdearden

4 年前議論

Veterans Affairs? Virginia?

willdearden

4 年前議論

There is a professor who was at Wisconsin, Charles Manski, who developed partial identification, which uses tons of these decompositions.

Idea is let's say you have a binary survey question where 80% respond and 90% of them respond "yes". What can we say about population "yes" rate (assume sample size is huge for simplicity)?

P(Yes) = P(Yes | response) * P(response) + P(Yes | no response) * P(no response) = 0.9 * 0.8 + P(Yes | no response) * 0.2 = 0.72 + P(Yes | no response) * 0.2

Then 0 <= P(Yes | no response) <= 1, so 0.72 <= P(Yes) <= 0.92. This example is somewhat trivial but it's a useful technique for showing exactly how your assumptions map to inferences.

willdearden

4 年前議論

https://www.sec.gov/news/press-release/2021-155

You absolutely can get charged for trading in a similar company.

willdearden

5 年前議論

Reminds me of the Kairos retreats popular in Catholic high schools. I went to one and it was pretty intense and not in a forced way. Basically 4 day group therapy.

willdearden

5 年前議論

Ah cool, are the internalized orders reported publicly anywhere or are they just sent to the SEC/FINRA?

willdearden

5 年前議論

Most trades through a brokerage don't make it on an exchange. They're internalized by a wholesaler like Citadel Securities. Which is the reason for the question.

willdearden

5 年前議論

https://www.uptake.com/blog/good-data-scientist-bad-data-sci...

done here too

willdearden

5 年前議論

Probably comes from the first and second theorems of welfare economics:

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

willdearden

6 年前議論

More like broker 1 offered it to me for 95 and to pay Robinhood 1. Broker 2 offered it to me for 97 and to pay Robinhood 2. Robinhood took the offer from broker 2. No collusion necessary but they weren’t acting in the best interests of their customers according to stated offers.

コメント