Hello everyone.I hope you all are doing well.

Here are my GATE 2021 credentials:

Name-Akshat Kumar

GATE Paper:CS/IT

Rank-206

Score-798

Category-Non EWS General

B.E/B.Tech branch-Printing Engineering

Since I had less chances of getting CDS coursework and was anyway somewhat more inclined towards research, I decided to apply for MTech research.

Firstly,candidates where shortlisted based on their GATE scores for the written test which would be used to shortlist for interviews.Unlike 2020 where cutoff was an astonishingly high 845 GATE score for written test, this year the cut off was a generous 700.

I don’t exactly remember the questions but there were 9 MCQ questions,7 Mathematics(Linear algebra,Probability,Graphs) and 2 Programming.

7^{th} May,2021: Written test:

1 question was on graph plotting,1 question on Baye’s theorem, 2 questions based on Eigen values, 1 question on general probability and 2 questions had all options incorrect as far as I remember. For programming, there was 1 question on spiral traversal of matrix and another was called Dominant Matrix in which we had to find number of rows in which magnitude of diagonal element was greater than magnitude of all other elements in the row.

The test was conducted on HackerEarth Platform and was 1 hr 15 mins in duration.I attempted all questions except spiral matrix as I didn’t have much time left.

I was shortlisted for interviews after which we had to fill our lab preferences.I filled VCL AND BCL(Visual computing and Biomolecular computation labs). We also had to give Statement of Purpose for each of the labs we wanted to join.

17^{th} May,2021:Interview:

The interview was conducted over Microsoft teams.There were 4 professors in the call.Here is my interview (Ix=interviewer x):

I1:Read out my application form details like GATE score, B.E degree and Labs preferences.

Me:Confirmed

I1:What topics have you come prepared for Akshat?

Me:Sir, linear algebra,probability,DSA and image processing basics.

I1:Starting with linear algebra.Can 2 matrices with different elements have same eigen values?

Me:(after thinking for a moment)Yes sir,

I1:Can you give me an example?

Me: Gave example by keeping major diagonal elements same and using favorable minor diagonal elements,sometimes making Minor diagonal product zero and sometimes making one of the elements as 1.

I1:That is a pretty good example.This is a property of matrix. We write it as A=PBP^(-1).

Me:Oh yes.Isn’t this condition for diagonalizable matrices, sir?

I1:Yes,good observation.Now can you prove that the two matrices A and PBP^(-1) have the same eigen values?

Me:Asked permission for using pen and paper and started thing along the equation A.X=lambda.X

After few minutes I was able to prove this and showed the solution on camera.

I1:(quite impressed)That is a really good proof. I2 now you can ask him questions.

I2:Are you comfortable with probability?

Me:Yes sir.

I2:Ok,suppose you are in a class of 30 students,what is the probability of having a birthday common with atleast 1 student in the class?

Me:Again used pen and paper.Thought in terms of discrete random variables.Say X represents number of students with whom I have a birthday in common.So basically I need to find P(X>=1) which is same as 1-P(X=0).

P(X=0)=(364/365)^29

So P(X>=1)=1-(364/365)^29.

I was also narrating my steps to I2 while solving.So I gave answer like this.

I2:Good.So what will your answer be approximately.

Me:Sir its a difficult calculation but would be close to 0.99.(Realized my mistake immediately and corrected)Sir actually 364/365^29 is close to 0.99 so probability would be something like 0.01 .

I2:Ok.So now suppose we have 400 students instead of 30.Would the probability increase or decrease?

Me:(A bit confused)Sir i think it would decrease.

I2:Are you sure?

Me:(Realized)No sir, actually since the number of students have increased, there is higher chance of having a common birthday and also 364/365^399 would yield a smaller value so 1-364/365^399 would have a larger value.

I2:Ok good.I3,would you like to ask some programming question(probably because my B.E was in printing XD).

I3:Yes.So can you write a program to find largest and second largest numbers in a given matrix.

Me:Yes sir.First I wrote a code finding largest in one pass and second largest in another pass and narrated the logic to I3.

I3:Ok that’s fine,can you optimize it, like try to do this in one pass.

Me:Did that.And showed the psuedo code on camera.

I3:Ok good.I4 do you have any questions?

I4:No I am fine.

I3:Ok Akshat.Your interview is over.We will now disconnect the call.

Me:Thank you sir.

My interview lasted only about 18 mins including introductions and salutations, which was relatively short,probably because I didn’t struggle much with any of the questions(not boasting).Overall, interview was great and it felt great to be interviewed by the best minds fro one of the best research universities in the world. The professors were very friendly and as far as i felt, will always guide you through if you are stuck with some question.I would definitely recommend Gilbert Strang’s MIT OCW lectures on linear algebra to be thorough with theoretical understanding of the same.First 15 lectures should suffice.

26^{th} May,2021:The provisional shortlist was released and my application number was on the list.I was really happy but still had some fears since there is always some chance that you may not make it to the final list although such chances are less if your interview went quite well like mine.

10^{th} June,2021:Received offer letter in mail at 7:09PM. My happiness knew no bounds.From B.E in Printing Engineering to AIR 206 in GATE CS/IT followed by M.Tech Research at IISc CDS, what a journey this has been, I imagined as I watched my parents shed tears of happiness :’) .Thank you all. I hope I helped you somewhat and hope to see many of you at IISc next year.Cheers. :D

Btw,which lab did you get into finally ?