3Blue1Brown did an excellent video explaining exponential growth. He took the opportunity to explain Covid-19, growth, trajectory and more importantly pressing question on when this growth will stop using mathematical equations. I was highly impressed. It helped to make sense of the situation, and help with dealing with the situation.

Please watch this video

The video deals with the questions explained in the slide.

Exponential growth means as you go from one day to the next, it involves multiplying by a constant.

In terms of an Equation the exponential growth is represented mathematically like this.

3Blue1Brown says that this data fits in a linear regression model.

Linear regression calculates an equation that minimizes the distance between the fitted line and all of the data points. And if want to find the equation that minimizes the distance between a line and the data point, the most common way is to find "least square regression" .

We will notice that the least square regression ends up with an equation of line \(y = m \dot x + b\) Where m is same as the multiplying factor the exponential growth.

So he uses the data point to track the growth for linear regression.

And finds out \(R^2\) which is a coefficient of determination, a statistical measure of how close the data are to the fitted regression line. We notice that \(R^2\) is close to 1.0 which is a straight line, increasing by a factor, \(m\) each day.

He is making a point with logistic regression that, when a country has 100 times lower cases than another country, the country is not 100 times better, but just 30 days behind!

And following the numbers, if we extrapolate, we will hit a 1 billion cases in 81 days. But that's hardly desirable, and everyone wants to know when we do stop growing linearly and hit a plateau. He notes that "Linear Growth" is a theoretical phenomenon, not a realistic one. Just like, if you were not married last year, and you got married this yea, it does not mean, will you marry every year from now. (Explain XKCD)

But unlike marriage, we are seeing an exponential growth here. We will have to find out the factors that reduce the exponential growth.

So, in reality what we are expecting is a logistic curve where the exponential growth includes damping factor contributed by people who are not infected.

Our whole idea, then becomes to increase this damping factor, that is not get infected by this virus.

What makes the growth factor go down other than maxing out at the total population?

• Decrease the number of people getting exposed - aka social distancing

• Decrease the probability of exposure - aka wash your hands completely, maintain hygiene amongst other things.

And important point to remember in this damping factor is, the output decreases exponentially too

For instance with the growth factor of 1.15, we have the first number and reduces significantly, only by 10% decrease in the damping factor.

3Blue1Brown has tried to quantify our worry factor, and give us hope that by social distancing, good hygiene we can reduce the damping factor and control the growth. However, "If we are not worried, that's only thing to worry about".

Related Articles / Simulations

• Why outbreaks like coronavirus spread exponentially, and how to flatten the curve by Harry Stevens

Happy Pi Day

I celebrated the Pi day during Covid-19 times with these activities.

• Learning AWS ML Modelling

• Solving an Easy Brilliant.org quiz but getting it wrong.

• Reading a little about Thales Theorem from the Timeline of Mathematics at Mathigon

• I also did a leetcode weekly contest

Blown to Bits: Your Life, Liberty, and Happiness After the Digital Explosion by Hal Abelson
My rating: 5 of 5 stars

Bits are Bit. Even if they are transmitted through electrons in copper wires or light in fiber optical cables or via modulation in radio waves. All of these carry bits and run the world. This book covers the intersection between technology, society, the justice system, policies, and politics. It is highly approachable and helps you appreciate technology, not just from a technical standpoint but from a societal standpoint. I really appreciate the concern for fellow human beings put forefront in this book. It opens the reader's mind to care a lot about the political process and be aware that any technology we design is going to have a wide societal impact.

The entire book is available free online: http://www.bitsbook.com/excerpts/

This is from Masterminds of programming. Person sharing the story and the perspective is Thomas Kurtz

I cleared the CKAD exam.

I took 3 attempts to clear this exam. In my first attemp, I had forgotten the concepts. I was not very confident during 2nd, and prepared well for the 3rd attempt to clear it.

I read "Kubernetes from Ground Up" again. Practised and "understood" the concepts better. With all these, the tests were actually very enjoyable.

I had setup a raspberry pi cluster, and suddenly the master became non-operational. The cluster was able to see itself, but if I login to master node, I noticed it was not able communicate externally.

The DNS Resolution for any site from master was failing.

Then I figured that Ubuntu had made some changes to resolve.conf protocol

Ubuntu requested users not to edit /etc/resolv.conf, and it's content on my cluster was not something that I wanted.

I had setup pihole, and my devices had started to see the internet through this. I noticed that Ubuntu since 18.04 had not set my router as the first nameserver and thus after pi-hole experiment, my master node lost its resolution capability

Fixing the Ubuntu DNS resolution was easy. I followed this post from datawookie

1. resolvconf package was already installed.

2. Edit /etc/resolvconf/resolv.conf.d/head

nameserver <pi-hole-server>
nameserver 8.8.4.4
nameserver 8.8.8.8

3. Restart the resolvconf server

sudo service resolvconf restart

I had supported this project called "Modeling Is Key to Understand Processes, Structures and Scales!" by Mrs. Sexton of Montevideo Elementary School for the fifth graders. They had this project going on for the family science night in the winter of 2019.

On my birthday this year, I received a ton of thank you notes for the supporting this project. It felt amazing to see so many handwritten cards!

Thanks to students, and the teacher for this gesture. I will support your science efforts anytime! :)

Siddhartha and I built a Modern House in Minecraft.

We got the idea and followed this Youtube video https://www.youtube.com/watch?v=-LcdpQ2LLK0 for building the house.

It was a fun project!

I setup a kubernetes cluster using Raspberry pi. It was much easier than I had imagined.

I used a Raspberry 4 for the master, and an agent. And I used two Raspberry B for two agents.

I setup using mhausenblas tutorial, which uses k3s for setting up of kubernetes on raspberry pis. I used k3sup tool for installation of packages, which worked well.

My overall goal ran into some challenges.

• I was not able to setup the kubernetes dashboard via helm package, and I had to use instructions from github.

• I was not able to setup minecraft using the available helm package: https://github.com/itzg/docker-minecraft-server/issues/433

• I used k3sup to install packages, but I do not know how to uninstall the package using k3sup https://github.com/alexellis/k3sup/issues/179

Givem all these, I still have the my local kubernetes cluster up and running and I am excited about the possiblities of using kubernetes on raspberry pis.

The Manga Guide to Calculus by Hiroyuki Kojima
My rating: 2 of 5 stars

I tried to pick up some high-level intuition on the basics of calculus with this book, but I failed. Unlike, other Manga guides on electricity, and linear algebra, I found this book not very strong on the plot and I felt it did not present the story in a cohesive manner.

The concepts were introduced randomly, and I could not see how one built upon the previously introduced concept.

On the positive note, it did introduce very basics of calculus well, and I am eager to pick up other books on calculus with that foundation.

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