How to disable caps lock in Linux
August 3rd, 2008 by Daniel Høyer Iversen
If you want to disable the caps lock. Open the ~/.bashrc file and add:
# Disables the caps lock button
xmodmap -e "remove lock = Caps_Lock"
How to install Code::Blocks
July 24th, 2008 by Daniel Høyer Iversen
Code::Blocks is a great IDE for C++. Here is a guide to install Code::Blocks in Linux.
Open a Terminal (Applications -> Accessories), and wright:
sudo gedit /etc/apt/sources.list
add these lines to the end of the file:
deb http://lgp203.free.fr/ubuntu/ gutsy universe
deb http://apt.wxwidgets.org/ gutsy-wx main
In the Terminal:
wget -q http://lgp203.free.fr/public.key -O- | sudo apt-key add -
wget -q http://apt.wxwidgets.org/key.asc -O- | sudo apt-key add -
Installing the packages:
sudo apt-get install libcodeblocks0 codeblocks libwxsmithlib0 codeblocks-contrib
You will now receive updates automatically.
You will find Code::Blocks at Applications -> Programming.
My .emacs file
June 26th, 2008 by Daniel Høyer Iversen
Here is my .emacs file. Copy it to ~/ and it will modify your emacs.
Numerical solution of the stationary advection diffusion equation.
June 23rd, 2008 by Daniel Høyer Iversen
The stationary advection diffusion equation solved with the finite difference method.
Continue reading ‘Numerical solution of the stationary advection diffusion equation.’
Bash script for SFV and uncompressing of .r00 files
June 14th, 2008 by Daniel Høyer Iversen
A bash script to verify the integrity of files on Linux. Simple file verification (SFV) is file format to store CRC32 checksums. If the checksums is correct, then the script will uncompress the files. The script can be used of files of format .rar, .r00, .r01 etc and with a .sfv file.
Continue reading ‘Bash script for SFV and uncompressing of .r00 files’
Steepest Descent Iteration
June 7th, 2008 by Daniel Høyer Iversen
Steepest Descent Iteration , written in Matlab to solve the Advection-diffusion equation. The matrix A (in A x= b) is a block pentadiagonal matrix.
Successive over-relaxation
June 2nd, 2008 by Daniel Høyer Iversen
Successive over-relaxation (SOR), written in Matlab to solve the Advection-diffusion equation. The matrix A (in A x= b) is a block pentadiagonal matrix.
Quick sort
September 29th, 2007 by Daniel Høyer Iversen
Quick sort in Python
def sort(A):
if len(A) <= 1:
return A
small = []
middle = []
big = []
temp = int((A[0][0]+A[len(A)-1][0])/2)
for x in A:
if x[0] < temp:
small.append(x)
elif x[0] == temp:
middle.append(x)
elif x[0] > temp:
big.append(x)
A = sort(small)
A.extend(middle)
A.extend(sort(big))
return A
Nim
September 2nd, 2007 by Daniel Høyer Iversen
Nim is a two-player game in which players take turns removing objects from distinct heaps. On each turn, a player must remove at least one object. The player who take the last object loses.
Project Euler - problem 092
August 1st, 2007 by Daniel Høyer Iversen
A number chain is created by continuously adding the square of the digits in a number to form a new number until it has been seen before.
For example,
44 -> 32 -> 13 -> 10 -> 1 -> 1
85 -> 89 -> 145 -> 42 -> 20 -> 4 -> 16 -> 37 -> 58 -> 89
Therefore any chain that arrives at 1 or 89 will become stuck in an endless loop. What is most amazing is that EVERY starting number will eventually arrive at 1 or 89.
How many starting numbers below ten million will arrive at 89?
Project Euler - problem 030
August 1st, 2007 by Daniel Høyer Iversen
Surprisingly there are only three numbers that can be written as the sum of fourth powers of their digits:
1634 = 14 + 64 + 34 + 44
8208 = 84 + 24 + 04 + 84
9474 = 94 + 44 + 74 + 44
As 1 = 14 is not a sum it is not included.
The sum of these numbers is 1634 + 8208 + 9474 = 19316.
Find the sum of all the numbers that can be written as the sum of fifth powers of their digits.
Project Euler - problem 015
August 1st, 2007 by Daniel Høyer Iversen
Starting in the top left corner of a 2*2 grid, there are 6 routes (without backtracking) to the bottom right corner.
How many routes are there through a 20*20 grid?
Project Euler - problem 014
August 1st, 2007 by Daniel Høyer Iversen
The following iterative sequence is defined for the set of positive integers:
n ->n/2 (n is even)
n ->3n + 1 (n is odd)
Using the rule above and starting with 13, we generate the following sequence:
13 -> 40 -> 20 -> 10 -> 5 -> 16 -> 8 -> 4 -> 2 -> 1
It can be seen that this sequence (starting at 13 and finishing at 1) contains 10 terms. Although it has not been proved yet (Collatz Problem), it is thought that all starting numbers finish at 1.
Which starting number, under one million, produces the longest chain?
NOTE: Once the chain starts the terms are allowed to go above one million.
Project Euler - problem 012
August 1st, 2007 by Daniel Høyer Iversen
The sequence of triangle numbers is generated by adding the natural numbers. So the 7th triangle number would be 1 + 2 + 3 + 4 + 5 + 6 + 7 = 28. The first ten terms would be:
1, 3, 6, 10, 15, 21, 28, 36, 45, 55, …
Let us list the factors of the first seven triangle numbers:
1: 1
3: 1,3
6: 1,2,3,6
10: 1,2,5,10
15: 1,3,5,15
21: 1,3,7,21
28: 1,2,4,7,14,28
We can see that the 7th triangle number, 28, is the first triangle number to have over five divisors.
Which is the first triangle number to have over five-hundred divisors?
Project Euler - problem 010
August 1st, 2007 by Daniel Høyer Iversen
The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17.
Find the sum of all the primes below one million.
Project Euler - problem 009
August 1st, 2007 by Daniel Høyer Iversen
A Pythagorean triplet is a set of three natural numbers, a<b<c, for which,
a² + b² = c²
For example, 3² + 4² = 9 + 16 = 25 = 5².
There exists exactly one Pythagorean triplet for which a + b + c = 1000.
Find the product abc.
Project Euler - problem 007
August 1st, 2007 by Daniel Høyer Iversen
By listing the first six prime numbers: 2, 3, 5, 7, 11, and 13, we can see that the 6th prime is 13.
What is the 10001st prime number?
Project Euler - problem 006
August 1st, 2007 by Daniel Høyer Iversen
The sum of the squares of the first ten natural numbers is,
1² + 2² + … + 10² = 385
The square of the sum of the first ten natural numbers is,
(1 + 2 + … + 10)² = 55² = 3025
Hence the difference between the sum of the squares of the first ten natural numbers and the square of the sum is 3025 - 385 = 2640.
Find the difference between the sum of the squares of the first one hundred natural numbers and the square of the sum.
Project Euler - problem 005
August 1st, 2007 by Daniel Høyer Iversen
2520 is the smallest number that can be divided by each of the numbers from 1 to 10 without any remainder.
What is the smallest number that is evenly divisible by all of the numbers from 1 to 20?
Project Euler - problem 004
August 1st, 2007 by Daniel Høyer Iversen
A palindromic number reads the same both ways. The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 * 99.
Find the largest palindrome made from the product of two 3-digit numbers.
Project Euler - Problem 003
August 1st, 2007 by Daniel Høyer Iversen
The prime factors of 13195 are 5, 7, 13 and 29.
What is the largest prime factor of the number 317584931803?
Project Euler - Problem 002
August 1st, 2007 by Daniel Høyer Iversen
Each new term in the Fibonacci sequence
is generated by adding the previous two terms.
By starting with 1 and 2, the first 10 terms will be:
1, 2, 3, 5, 8, 13, 21, 34, 55, 89, …
Find the sum of all the even-valued
terms in the sequence which do not exceed one million.
Project Euler - Problem 001
August 1st, 2007 by Daniel Høyer Iversen
If we list all the natural numbers below
10 that are multiples of 3 or 5, we get 3, 5,
6 and 9. The sum of these multiples is 23.
Find the sum of all the multiples of 3 or 5 below 1000.
Continue reading ‘Project Euler - Problem 001′
To tankser som har brutt sammen, og det eneste som fungerer er kanonene
August 1st, 2007 by Daniel Høyer Iversen
Opprinnelig skrevet 03.05.2007:
Ja, da var endelig javaspillet vårt ferdig. Etter mye jobbing er det morsomt å se et resultat i hvert fall jeg er fornøyd med.
Continue reading ‘To tankser som har brutt sammen, og det eneste som fungerer er kanonene’
