Jupyter Experiment

I know all the cool kids have been using it for years. I thought I should give it a try. Currently working through Applied Data Science with Python and Jupyter, but this is not from the book.

The desired output of this is the line graph showing the relationship between average weekly deaths in England and Wales, and weekly deaths this year. This is it:

Deaths per Week, England and Wales

 

So you’re going to be a Penalty Box Timer?

A couple of weeks ago I worked as a penalty box timer for the Fab Slav roller derby sevens tournament. If you don’t know what roller derby is, this post is not for you. Instead, you should find out!
 
This post is about what I learned of penalty box timing after doing it for the first time. It’s not a substitute for reading the WFTDA docs, being familiar with the sheets you’ll fill in, watching Brain of Terror’s videos, or taking any training that is offered to you.

Read more

Riddler Classic, January 24 2020

EDIT: Nope! Not far wrong, but definitely wrong.

My strategy of starting with the easy cases and building out to more complex cases was used successfully by other solvers. My analysis of the easy cases was correct, but there was a mistake in the way I built out. My diagram probably didn’t help; the one drawn by the winner didn’t distinguish between the larger and smaller piles, and I think that’s where my error crept in.

For example, when I considered (9, 5), I thought it was a losing position because I didn’t see that taking six coins from the larger pile produced (5, 3), since the larger pile became the smaller pile in that move. So the “simplification” I introduced, of specifying one pile as larger, while not wrong, made it easier for me to make a mistake. It helped to break my mental model by suggesting an identity for the piles (“larger” or “smaller”) that isn’t persistent, but depends on the progress of the game. Will try not to do that again!

EDIT 2: Revised the original spread sheet showing the rows that I had calculated wrongly, and producing a correct game state table.


 

Another week of being fairly confident about this week’s Riddler Classic. (Bolstered by getting exactly the right answer for the last one I did, if by a slightly inefficient method.)

The puzzle is a coin-picking game, with the usual aim of taking the last coins, but the unusual condition of having two coin stacks:

Read more

Understanding Cash-Settled Futures

What is This?

This spread sheet is my own attempt to show how the collateral flow to or from a clearing house works. I created it about five years ago when I was working at a bank, and needed to explain the relationships between different quantities, and how they are calculated.

If you have a rough idea of how futures work, and want to see a detailed example, this post might help. If you don’t know what futures are, this won’t help, but Wikipedia’s intro might.

Read more

Choosing to do a Project: Three Gates

I’ve had this mental model for a while, but it solidified a year ago after explaining it at work, and I wanted to use it again in a Twitter debate shortly afterwards. Twitter’s the wrong place for real explanations though, so here it is.

This model will not solve your disagreements for you, and it’s not a substitute for calculating the NPV of your possible projects. Instead, it’s a quick shorthand that might make discussions more useful, and show you something about your team.

Read more