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Matrix which contains the values of an other matrix A at the given locations.
If you have two matrices, which together give xc and yc coordinates into another matrix, eg : xc = [1 1 1; 2 2 1]; ...

13 years ago

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Volume difference between Ellipsoid and Sphere
Given an ellipsoid of semi principal axis (a,b,c) find the volume of the difference between this ellipsoid and the sphere with...

13 years ago

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Solving a quadratic equation
Given a, b and c, Return the solution of the following quadratic equation: a*x^2 + b*x + c = 0.

13 years ago

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Find the elements of a matrix according to a defined property.
From A = [5,2,3] and B = [1,2,3,4,5,6,7,8,9,10] produce a vector C where : C(1) is the sum of the first A(1) elements of B, ...

13 years ago

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Wrapping the Tower of Pisa
The famous artist Christo Vladimirov Javacheff, who likes pizza, wants to wrap the well-known Italian tower in paper. It is a ci...

13 years ago

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Detect a number and replace with two NaN's
Write code which replaces the number 1 with two NaNs. Example X = [ 1 2 NaN 4 1 3 7 NaN 1 4 NaN 2] ...

13 years ago

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Create a recurrence matrix for a vector of data
In <https://en.wikipedia.org/wiki/Conversation_analysis conversation analysis>, it's often useful to track the contributions fro...

13 years ago

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Functional inputs
Return an n-dimensional array whose elements are the results of a function over a set of vectors. The (i,j,k, ...n)th element...

13 years ago

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Find the list of all open files
In the test suite, I use <http://www.mathworks.com/help/matlab/ref/fopen.html fopen> to create new files. The task is to find th...

13 years ago

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Guess the Coefficients!
Given a polynomial _p_ known to have positive integer coefficients, deduce the values of the coefficients. For example: ...

13 years ago

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Community Problem 500!
In honor of this being the 500th Community problem, see if you can create a function that has a Cody size of 500. It can do any...

13 years ago

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Change a specific color in an image
The ability to change colors can be a useful tool in image processing. Given an m x n x 3 array (much like CData in images), fin...

13 years ago

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Create an 'arrow-head" matrix
Write a function that when given an odd number, produces an arrow-head function pointing to the right. Examples n = 3 ...

13 years ago

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Mann-Kendall Correlation
Write a function that returns the <http://en.wikipedia.org/wiki/Kendall_tau_rank_correlation_coefficient Mann-Kendall> correlati...

13 years ago

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Count up then down
Create a function that produces counting up from 0 up to n then down to 0 n=2 --> 0 1 2 1 0 n=3 --> ...

13 years ago

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Given a matrix, return the last eigen value
Given a matrix, return the first eigen value For example: x = magic(5) 17 24 1 8 15 23 5 7 14 ...

13 years ago

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Two-output anonymous function?
Return a function handle that when applied to an input, it produces two outputs: the first is the same as the input, and the sec...

13 years ago

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Circular Primes (based on Project Euler, problem 35)
The number, 197, is called a circular prime because all rotations of the digits: 197, 971, and 719, are themselves prime. The...

13 years ago

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Eliminate Polysyllabics: Long live short words!
Given a string s1, return s2 in which all the words with more than one syllable have been removed. To make things simple, we ...

13 years ago

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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...

13 years ago

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Twist 'n' Match
Given n and m, construct an n-by-n matrix a such that a, when rotated 90 degrees and compared with itself, matches itself in exa...

13 years ago

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Give a matrix that matches itself when rotated
Given n and s, return a n-by-n matrix a of integers such that sum(sum(a == rot90(a))) is equal to exactly s. The integer...

13 years ago

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Crossing to Kissing - Untangle the Lines
Turn lines that cross into lines that kiss. You will be given two lines that cross at some point. Your job is to untangle the...

13 years ago

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Prime Time
All you need to do here is submit your solution a prime number of seconds after the top of the hour. Any hour at all... Easy, ...

13 years ago

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Cell Source Index
Suppose that C is a cell array whose elements consist of row vectors of elements of the same type. For example, C could be a ce...

13 years ago

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Construct an index vector from two input vectors in vectorized fashion
Create an index vector defined by two input vectors, one defining the beginnings of one or more index ranges, and the other defi...

13 years ago

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Reference Index Number
Given a reference set R of elements (each unique but identical in type), and a list V of elements drawn from the set R, possibly...

13 years ago

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Book Club
A book club that has _K_ members, as a group, have to read _N_ books. Return how many different ways the members could read the ...

13 years ago

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intersection of matrices
Given two matrices filled with ones and zeros, determine if they share a common row, column entry. These matrices are of identi...

13 years ago

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Find third Side of a right triangle given hypotenuse and a side. No * - or other functions allowed
Find the remaining side of a triangle given the hypotenuse and a side. However, the normal functions and symbols are not allowe...

13 years ago