Viewing posts by christian

Following on from this post about the simple double pendulum, (two bobs connected by light, rigid rods), this post animates the double *compound* pendulum (also called a double complex or physical pendulum): two rods connected to each other, with their mass distributed along their length. The analysis on Wikipedia provides the dynamical equations for the case of equal-mass and equal-length rods. Here, the more general case of rods with lengths $l_1$ and $l_2$ and masses $m_1$ and $m_2$ is considered.

To find your Hollywood Walk of Fame Quarantine house, use this script on the command line, providing your latitude and longitude:

The Padovan sequence is a cousin of the more famous Fibonacci sequence defined by the initial values $P(1)=P(2)=P(3)=1$ and the recurrence relation $P(n) = P(n-2) + P(n-3)$. That is, the next value is obtained not by summing the previous two values but by summing the two values before the last one. The first few values are:

Following on from this previous post, here is a short tutorial on creating this and similar charts using pandas by automatically downloading data from Johns Hopkins University's CSSE GitHub repository (the "JHU/CSSE dataset").

The Centre for Systems Science and Engineering (CSSE) at Johns Hopkins University publishes daily statistics of the number of confirmed cases of COVID-19 by country on its GitHub page. The short script below pulls data from this page to plot a bar chart of cases and growth in cases as a function of time for a given country. For example: