There is a very old “disappearing cyclist” puzzle, by Sam Loyd, you may have seen or seen a variation upon the theme. In Ben Sparks‘ video he gives a great overview:

Continue reading “Optical Illusions and Considering Minimal Examples to Explain”## Matt Parker’s new Video on Math Beeing Interesting

In Matt Parker’s recent video he looks into some interesting properties of the shapes commonly found in nature in bee’s hives:

Continue reading “Matt Parker’s new Video on Math Beeing Interesting”## Sum/product of consecutive numbers and other math shortcuts

If you have studied some of the old SAT questions at some point you may have gone through questions like –

4 consecutive numbers sum to 166. What is the product of the numbers? or…

3 consecutive even numbers sum to X. What is their product?

The way the tutors and the online tutorials show seems to always be to algebraically solve this – for example 4 consecutive numbers would solve x+x+1+x+2+x+3 = 166, collect terms and solve…

However there is another way that works for this and works for other similar problems.

Continue reading “Sum/product of consecutive numbers and other math shortcuts”## PyImageSearch Review

If you have been doing OpenCV or Python machine learning, you have most likely come across PyImageSearch. If you come across a sale for this service I would recommend trying it out if you are learning some machine learning. This past week they have run a free promo 7 day trial, which gave me an opportunity to browse these.

Continue reading “PyImageSearch Review”## In search of the best scientific calculator for Librem Phone/Pinephone

While many apps do run on Librem 5 phone, there are many yet to be fully working on the small screen. In this post we explore the various calculator apps for Linux and see which might best work as a student/engineer’s go-to calculator:

Continue reading “In search of the best scientific calculator for Librem Phone/Pinephone”## Mathematicians submit proof of Erdős Coloring Conjecture

Fifty years ago, several mathematicians at a dinner party were discussing graphs (points and lines, not chart graphs), and the generalization if you make the edges connecting a point (vertex) with another, able to connect multiple points. While working out the minimal number of colors in general, they found it to be an interesting problem, to test out and prove the next day… Well, that solution, to Erdős, Faber, and Lovász’ problem was delayed for years and years!

Continue reading “Mathematicians submit proof of Erdős Coloring Conjecture”## Happy Pi day 2021!

Happy Pi day! Hope you are enjoying making pie (within your household/pod) and learning some new math stuff today! Matt Parker has an interesting video up on an attempting to calculate pi from a diameter of one-molecule thick droplet spreading on water:

Continue reading “Happy Pi day 2021!”## Injecting commands and debugging a running Python program, with Project Euler example

How often has it happened to you… you build a simple script to calculate something, run some bulk process, and coming back after an hour or so it just hangs with no output. Is it doing something or stuck? You could debug it, using WinPdb or Visual Studio Code debugger or GDB to run it step by step, but that would lose the time that it has been processing. Instead, you can use Pyrasite, a program for looking in to a running Python script!

Continue reading “Injecting commands and debugging a running Python program, with Project Euler example”## Machine learning SVM – the usefulness of kernels

If you’ve read through how Support Vector Machines work, you probably know the linear simple SVM might not work in all cases… but how does it fail? Let’s take a look at an example I tried like to my simple example… but change it to be a larger space than just 4, and separated with a region in the middle, and the region around it (positive, negative labelled areas to learn):

Continue reading “Machine learning SVM – the usefulness of kernels”## Human pose estimation with Python and Gluoncv

Human pose estimation is something useful for robotics/programming as you can see what position a person is in a picture. For last weekend’s Hackrithmitic I did an experiment for fun using computer vision pose estimation. To start with I found several possibilities with available libraries:

- Tensorflow js has been used to say, don’t touch your face, but it takes a massive amount of cpu.
- Openpose is a popular one, only licensed for noncommercial research use, and there is a Opencv example for it that doesn’t quite show how to use it.
- AlphaPose is supposedly faster and has a more clear license and possibility for commercial use – if you want that as a possibility. I checked out the install instructions and worked but for “python3” instead of “python”. It also misses obvious step of installing cuda for your Nvidia system before running.
**GluonCV**is another, which seems more user friendly. This one I was able to get running in a few minutes with their example: