Archive for the ‘Uncategorized’ Category

Sanskrit Text: “Arjuna uvacha : senayor ubhayor madhye ratham sthapaya me acchutha”

Meaning: Arjuna requests Lord Krishna to drive his chariot into center of the two armies

Senayo: – Of the armies  – referring to the armies of Pandavas and Kauravas
Ubhayo – of both
Madhye – in the middle
Ratham – chariot
Sthapaya – stop
Me – My
Acchutha – the infallible

Interpretation:
With no intention of fighting against his own kins, Arjuna requests his Sarathi to take him into the center of two armies. But, the question here is why he wants to move into the center of the army?

May be he wants to be a spectator and see what is going on against Pandavas or he is so curious to see the kins and relatives who turned against them.

In this world, we come across the same situation many times, when we have to make a decision and we are so confused on which side we should fall. Only way we can get clarity on situation is by standing in the middle and weighing with the pros and cons of the situation. May be thats what Arjuna is trying to do.

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Learning L shaped OLL

Posted: July 24, 2017 in Uncategorized

There are 6 L shaped OLLs . In that first two can be easily memorized as one is mirror case of another . 

For the faster recognition I always write oll algorithm in notebook with a 2D notation.

First case is pretty easy to recognize. The hyphen in the outer layer denotes the yellow color . And “T” is RUR’U’.

Second case is easy to execute . But for faster recognition it would be easy to memorize it as third diagram. 

Double pawn in Ruy Lopez

Posted: July 24, 2017 in Uncategorized

Learning of the day :

This is the tactics that I learnt today to eliminate double pawn position while playing as black against Spanish Opening( screenshot given below)

img_0196
We need to play the move Nge7(knight e7) after white plays bishop b5.

img_0192
If white decides to capture the knight ,we can win back using the other knight. But , what if white doesnt trade and decides to castle ? By moving knight to e7 we blocked our dark square Bishop and king couldn’t castle.

We can play the move a6 which will threaten white bishop to move back. Now bishop moves back to A4. black plays b5 to put more pressure. White bishop settles in the square B3

img_0193
As the threat against the knight is eliminated, we can move Knight g6. However , black needs to keep in mind that white is eying on the f7 pawn.

img_0194
Now black can think about moving his dark square bishop and castle on kings side. And then place light squared bishop to b7.

img_0195
Played couple of games today with this position and felt comfortable than having double pawn .

Good luck !!!

Many of us would have encountered this situation where we need to run some script which takes hours together to complete.

And most of the time the shell goes inactive and it becomes really hard to track what has happened.

One simple solution for that is to run the script in background.\

For example:

./run_my_script.sh &

Oh.. But where are my logs.. Yes, its difficult for us to track what has happened, unless we redirect our output to some specific file .

Anyhow, we have a posix command in linux which can do this stuff. Its nohub.

Checkout the wikipedia link for it here

https://en.wikipedia.org/wiki/Nohup

all you need is to add nohup parameter before your script

nohup run_my_script.sh

Even if the shell goes down, doesnt matter.. We will have the process running in the background. And we can track the logs from nohub.out file . This file will be autocreated in the directory where we ran the script.

For installing python releated packages we need to use pip. Hence installing pip in our server is our first task.

the package name for pip is “python-pip”. Hence the straight forward approach to install pip would be

apt-get install python-pip

But, if the source list is not updated properly , we will end up with older version of pip (in my case i got 1.5.3 however, 8.1.1 is the latest one). Hence to avoid this issue , we need to follow the approach given in wikipedia

i.e  to download the package from internet via this url . Hence we use the curl command

curl https://bootstrap.pypa.io/get-pip.py

Once get-pip.py gets downloaded. run the python file to install pip

python get-pip.py

Even beyond this, if we need to install pip package without internet .

Download the source from https://pypi.python.org/pypi/pip

wget https://pypi.python.org/pypi?:action=show_md5&digest=6b86f11841e89c8241d689956ba99ed7

extract the folder

tar -xvzf pip-8.1.1.tar.gz

Move inside the folder and install it

cd pip-8.1.1; python setup.py install

Square Root Algorithm

Posted: March 17, 2016 in Uncategorized

There are N number of ways to compute square root of a number

we can use the existing library (math) in python to compute the square root

However, there is a constrain in number of decimal digits . Hence, we need an algorithm which can compute a square root and provide n decimal digits .

The following algorithm uses Digit by digit calculation from this wikipedia link

Square Root Computation Algorithms

I have created a python script which will compute square root of 2 with 100 decimal digits .

And i verified the digits from this link

First 100 Digits for SQRT of 2 – Verification

The algorithm is not optimized. However, it gives me the result quickly for first 100 digits

For multiple irrational number , populate the irr list (by default contains 2)

To control number of digits after decimal change decimal variable (by default set to 100)

<br data-mce-bogus="1">
import time
import math

starttime = time.time()

global flag, start, end, decimal
flag = True
start = 0
end = 1
decimal = 100


def main():

answer = 0
irr = [2]

# for each irrational number
for num in irr:

# Step - 1 : Converting number to string and appending 200 zeros
str_num = str(num)
for i in range(0, 210):
str_num = str_num + "0"

# Step - 2: Setting Flag : if lenght of the number is odd we need to take one digit or else two digits
if len(str_num) % 2 != 0:
flag = True
else:
flag = False

start = 0
end = 0
ap_new_dig = 0

# Step - 3: Logic to take one or 2 digits
if flag:
start = 0
end = 1

else:
start = 0
end = 2

temp_num = str_num[start:end]
temp_int_num = int(temp_num)

# Step - 4 : Calculate the initial quotiend and remainder

quo = int(math.sqrt(temp_int_num))
rem = temp_int_num - int(quo ** 2)

# Step - 5 : Here is the main logic to iterate the steps
counter = 0
while counter < decimal - 1 :

# Step - 6 : Bring down the digits
if flag:
start = start + 1
end = start + 2
flag = False
else:
start = start + 2
end = start + 2
new_dig = str_num[start:end]

# Step -7 : Add the digits with previous remainder
ap_new_dig = str(rem) + new_dig

# Step - 8 : Compute a number less than max ap_new_digit
double_num = quo * 2
max_val = 0
t = 0
for i in range(1, 10):
if int( str(double_num) + str(i) ) * i <= int(ap_new_dig):
t = int( str(double_num) + str(i) ) * i
max_val = i
else:
break

# Step - 9 : Find new quotient and remainder
quo = int ( str(quo) + str(max_val) )
rem = int(ap_new_dig) - t

counter = counter + 1

# Final Quotient will be the answer
print "Square Root of N is" , quo



main()

print "Time taken ", time.time() - starttime

Excecution:
 

>>>
Square Root of N is 1414213562373095048801688724209698078569671875376948073176679737990732478462107038850387534327641572
Time taken  0.0269999504089

 

 

Learning Year – 2014 !!!!

Posted: December 31, 2014 in Uncategorized

Started of the year with lot of resolutions ….. 

 

resolution

Speed Cubing

rubiks

In Feb, i entered into a new world called speedcubing. Never heard it before. Never solved a rubik cube before. Feb 18, 2014 was a start. Initially, i just started off with “how to solve rubik cube” video in you tube. When i started practicing it , things started to be serious and fun as well.
badmephisto.com- took me from 8 minutes to 28 seconds. Thanks and salute to badmephisto.

 

How to Solve Rubik’s Cube Blindfolded

blindfold

 

 Everytime, when i see a blindfolded solve in internet , it always looked like a magic. I thought , i would never make it. But, this link made me understand that i was wrong. Memos, formulas and other stuff .. Ufff.. Nov 18, 2014 i got my first rubik blindfold solve.

Coursera 

mooc

 

One of the interesting medium to learn about softwares and related stuff is coursera. Enrolled in many courses , but didnt finish even one with certificate :P.
however, it was a very good learning experience . R programming was new to me. STarted with the basics of data analytics and also some python stuff.

 

Jquery

jquery

Everytime when i take javascript , i could not move more than 5 pages in book . Jquery changed that interest. Started watching my favorite programmer – Alex’s video in youtube for jquery and completed till 40/200. It was a wonderful start for basics and was very helpful while programming front end stuffs.

 

Project Euler Problems

 

projecteuler

 In early december, moved back to that old black console (c++) and started solving problems on project euler. Initially , the problems were easier and simillar. But, when i moved on things were getting complex and there were lot of Project Euler Problemsthinking and learning involved. Got more ideas on sieves, searching, sorting, dynamics and other stuff. solved 50 problems on it and ranked less than 500 in india out of 8k odd people.

 

Creating Android App

  android

 

Is that very difficult to create an android app ? Wanted an alarm and remainder app in my own way. And i designed it with online help.

 Learn German

 

germasn

 

 

 Duolingo made it as a routine and learnt it for 30 days . Few words in German got set into my mind .

Chess Cube 

chesscube

One more addictive website.. chesscube.. Hmmm.. what to say.. Restricted myself to one game a day.. Very interesting to play with unknown persons. But, it eats lot of time. Also, went thro some videos of Akobian (French Defense, Ruy Lopez) just to maintain my cubits in chesscube. and also used chess android app level 4. 4/12 was too low .. but i wanted to play level 4 until i gain good confidence on it.

Blogging  

blog

And at last, blogging.. Couldn’t post much.. Thats gonna be my new year resolution. Will try to share as much as i can . !!!

 

newyear

Happy Learning !!!