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Flip the main diagonal of a matrix
Given a n x n matrix, M, flip its main diagonal. Example: >> M=magic(5); >> flipDiagonal(M) 9 24 1 ...

2 years ago

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Reverse the elements of an array
Reverse the order of elements in an array: eg: input X = [ 1 2 3 ; 4 5 6 ; 7 8 9 ] o...

2 years ago

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Back to basics 21 - Matrix replicating
Covering some basic topics I haven't seen elsewhere on Cody. Given an input matrix, generate an output matrix that consists o...

2 years ago

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Remove NaN ?
input -> matrix (n*m) with at least one element equal to NaN; output -> matrix(p*m), the same matrix where we deleted the enti...

2 years ago

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Sophie Germain prime
In number theory, a prime number p is a *Sophie Germain prime* if 2p + 1 is also prime. For example, 23 is a Sophie Germain prim...

2 years ago

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Find nearest prime number less than input number
Find nearest prime number less than input number. For example: if the input number is 125, then the nearest prime number whi...

2 years ago

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Largest Twin Primes
<http://en.wikipedia.org/wiki/Twin_prime Twin primes> are primes p1, p2 = p1 + 2 such that both p1 and p2 are prime numbers. Giv...

2 years ago

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Find the next prime number
Find the next prime number or numbers for given n. For example: n = 1; out = 2; or n = [5 7]; out = [7 11]; ...

2 years ago

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Make a vector of prime numbers
Input(n) - length of vector with prime numbers Output(v) - vector of prime numbers Example: * n=1; v=2 * n=3; v=[2 3 5...

2 years ago

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Mersenne Primes
A Mersenne prime is a prime number of the form M = 2^p - 1, where p is another prime number. For example, 31 is a Mersenne prim...

2 years ago

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Fibonacci-Sum of Squares
Given the Fibonacci sequence defined by the following recursive relation, * F(n) = F(n-1) + F(n-2) * where F(1) = 1 and F(1)...

2 years ago

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Longest run of consecutive numbers
Given a vector a, find the number(s) that is/are repeated consecutively most often. For example, if you have a = [1 2 2 2 1 ...

2 years ago

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Rescale Scores
Each column (except last) of matrix X contains students' scores in a course assignment or a test. The last column has a weighted...

2 years ago

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2 years ago

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Plot Damped Sinusoid
Given two vectors |t| and |y|, make a plot containing a blue ( |b| ) dashed ( |--| ) line of |y| versus |t|. Mark the minimum...

2 years ago

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Calculate a Damped Sinusoid
The equation of a damped sinusoid can be written as |y = A.ⅇ^(-λt)*cos(2πft)| where |A|, |λ|, and |f| ...

2 years ago

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Verify Law of Large Numbers
If a large number of fair N-sided dice are rolled, the average of the simulated rolls is likely to be close to the mean of 1,2,....

2 years ago

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Natural numbers in string form
Create a cell array of strings containing the first n natural numbers. _Slightly_ harder than it seems like it should be. Ex...

2 years ago

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Fix the last element of a cell array
Note: this is lifted directly from <http://www.mathworks.com/matlabcentral/answers/82825-puzzler-for-a-monday Puzzler for a Mond...

2 years ago

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String Array Basics, Part 1: Convert Cell Array to String Array; No Missing Values
<http://www.mathworks.com/help/matlab/characters-and-strings.html String array> and cell array are two types of containers for s...

2 years ago

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Remove element(s) from cell array
You can easily remove an element (or a column in any dimension) from a normal matrix, but assigning that value (or range) empty....

2 years ago

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Convert a Cell Array into an Array
Given a square cell array: x = {'01', '56'; '234', '789'}; return a single character array: y = '0123456789'

2 years ago

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Split a string into chunks of specified length
Given a string and a vector of integers, break the string into chunks whose lengths are given by the elements of the vector. Ex...

2 years ago

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Convert a numerical matrix into a cell array of strings
Given a numerical matrix, output a *cell array of string*. For example: if input = 1:3 output is {'1','2','3'} whic...

2 years ago

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Create a cell array out of a struct
Create a cell array out of a (single) struct with the fieldname in the first column and the value in the second column: in: ...

2 years ago

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There are 10 types of people in the world
Those who know binary, and those who don't. The number 2015 is a palindrome in binary (11111011111 to be exact) Given a year...

2 years ago

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Binary code (array)
Write a function which calculates the binary code of a number 'n' and gives the result as an array(vector). Example: Inpu...

2 years ago

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Relative ratio of "1" in binary number
Input(n) is positive integer number Output(r) is (number of "1" in binary input) / (number of bits). Example: * n=0; r=...

2 years ago

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Bit Reversal
Given an unsigned integer _x_, convert it to binary with _n_ bits, reverse the order of the bits, and convert it back to an inte...

2 years ago

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Given an unsigned integer x, find the largest y by rearranging the bits in x
Given an unsigned integer x, find the largest y by rearranging the bits in x. Example: Input x = 10 Output y is 12 ...

2 years ago