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Put two time series onto the same time basis

Use interpolation to align two time series onto the same time vector. This is a problem that comes up in <http://www.mathwork...

1 year ago

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Create logical matrix with a specific row and column sums

Given two numbers *|n|* and *|s|*, build an |n-by-n| logical matrix (of only zeros and ones), such that both the row sums and th...

1 year ago

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Reindex a vector

You are given two vectors of equal length. Vector N has numeric values (no Inf or NaN) while vector IDX has integers. Place th...

1 year ago

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Getting logical indexes

This is a basic MATLAB operation. It is for instructional purposes. --- Logical indexing works like this. thresh = 4...

1 year ago

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Remove the two elements next to NaN value

The aim is to *remove the two elements next to NaN values* inside a vector. For example: x = [6 10 5 8 9 NaN 23 9 7 3 21 ...

1 year ago

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Return a list sorted by number of consecutive occurrences

Inspired by Problem 38 by Cody Team. Given a vector x, return a vector y of the values in x sorted by the number of CONSECUTIVE...

1 year ago

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Set the array elements whose value is 13 to 0

Input A either an array or a vector (which can be empty) Output B will be the same size as A . All elements of A equal to 13...

1 year ago

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Joining Ranges

You are given a n-by-2 matrix. Each row represents a numeric range, e.g. x = [0 5; 10 3; 20 15; 16 19; 25 25] contains...

1 year ago

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Find the largest value in the 3D matrix

Given a 3D matrix A, find the largest value. Example >> A = 1:9; >> A = reshape(A,[3 1 3]); >> islargest(A) a...

1 year ago

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Get the elements of diagonal and antidiagonal for any m-by-n matrix

In the problem <http://www.mathworks.com/matlabcentral/cody/problems/858-permute-diagonal-and-antidiagonal Problem 858. Permute ...

1 year ago

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Replicate elements in vectors

Replicate each element of a row vector (with NaN) a constant number of times. Examples n=2, A=[1 2 3] -> [1 1 2 2 3 3] ...

1 year ago

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Morse Code Generator! Try it!

.... . .-.. .-.. --- . ...- . .-. -.-- --- -. . -.-.-- .-.. . - ... -.. --- ... --- -- . -- --...

1 year ago

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Recurring Cycle Length (Inspired by Project Euler Problem 26)

Preface: This problem is inspired by <http://projecteuler.net/problem=26 Project Euler Problem 26> and uses text from that quest...

1 year ago

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P-smooth numbers

This Challenge is to find <https://en.wikipedia.org/wiki/Smooth_number P-smooth number> partial sets given P and a max series va...

1 year ago

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Fermat's Last Theorem - Fermat's conjecture

Fermat's Last Theorem (sometimes called Fermat's conjecture, especially in older texts) states that no three positive integers a...

1 year 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...

1 year ago

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Is it an Armstrong number?

An Armstrong number of three digits is an integer such that the sum of the cubes of its digits is equal to the number itself. Fo...

1 year ago

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Champernowne Constant

The <http://en.wikipedia.org/wiki/Champernowne_constant Champernowne constant> is a real number whose digits in decimal represen...

1 year ago

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Lychrel Number Test (Inspired by Project Euler Problem 55)

The task for this problem is to create a function that takes a number _n_ and tests if it might be a Lychrel number. This is, re...

1 year ago

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First N Perfect Squares

*Description* Return the first N perfect squares *Example* input = 4; output = [ 1 4 9 16 ];

1 year ago

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Numbers with prime factors 2, 3 and 5.

Make a function which takes one positive integer n and returns a matrix with the numbers of the form (2^i)*(3^j)*(5^k) which are...

1 year ago

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Happy 2013...

Happy 2013, everyone! An interesting tidbit about 2013 is that it is the first year since 1987 to contain four different digits...

1 year ago

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Determine if input is a perfect number

A <http://en.wikipedia.org/wiki/Perfect_number/ perfect number> occurs whent the sum of all divisors of a positive integer, exce...

1 year ago

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Project Euler: Problem 9, Pythagorean numbers

A Pythagorean triplet is a set of three natural numbers, a b c, for which, a^2 + b^2 = c^2 For example, 3^2 + 4^2 =...

1 year ago

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Determine if input is a Narcissistic number

<http://en.wikipedia.org/wiki/Narcissistic_number Narcissistic number> is a number that is the sum of its own digits each raised...

1 year 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...

1 year ago

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arithmetic progression

I've written a program to generate the first few terms of <https://en.wikipedia.org/wiki/Arithmetic_progression arithmetic progr...

1 year ago

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Find similar sequences

Another problem inspired by a question on the <http://www.mathworks.com/matlabcentral/answers answers> forum. Given a matrix ...

1 year ago

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Sum of series VII

What is the sum of the following sequence: Σ(km^k)/(k+m)! for k=1...n for different n and m?

1 year ago

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Sum of series VI

What is the sum of the following sequence: Σk⋅k! for k=1...n for different n?

1 year ago