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Permute diagonal and antidiagonal
Permute diagonal and antidiagonal For example [1 2 3;4 5 6;7 8 9] -> [3 2 1;4 5 6;9 8 7] WITHOUT diag function (and variable n...

1 year ago

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Rotate input square matrix 90 degrees CCW without rot90
Rotate input matrix (which will be square) 90 degrees counter-clockwise without using rot90,flipud,fliplr, or flipdim (or eval)....

1 year ago

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Removing rows from a matrix is easy - but what about inserting rows?
Assume A is a 5-by-5 matrix. A([2,4],:) = [] is a quick way to remove rows 2 and 4. Can you find a quick way to insert rows into...

1 year ago

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Matrix with different incremental runs
Given a vector of positive integers a = [ 3 2 4 ]; create the matrix where the *i* th column contains the vector *1:a(i)...

1 year ago

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surrounded matrix
With a given matrix A (size m x n) create a matrix B (size m+2 x n+2) so that the matrix A is surrounded by ones: A = [1 2 ...

1 year ago

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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 ...

1 year ago

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Make an awesome ramp for a tiny motorcycle stuntman
Okay, given a vector, say v=[1 3 6 9 11], turn it into a matrix 'ramp' like so: m=[1 3 6 9 11; 3 6 9 11 0; 6 9 ...

1 year ago

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Back to basics 23 - Triangular matrix
Covering some basic topics I haven't seen elsewhere on Cody. Given an input matrix, return a matrix with all elements above a...

1 year 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...

1 year 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...

1 year ago

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A matrix of extroverts
Now that the introverts have had their script, the extroverts spoke up (naturally!) and demanded one as well. You will be given...

1 year ago

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Convert matrix to 3D array of triangular matrices
Given a 2D numeric array x in which each column represents the vectorized form of an upper triangular matrix, return a 3D array ...

1 year ago

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Write a function man that takes a row vector v and returns a matrix H as follows..
Write a function called man that takes a row vector v as an input and returns a matrix H whose first column consist of the eleme...

1 year ago

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Toeplitize a matrix
Similar to <http://www.mathworks.com/matlabcentral/cody/problems/3094-hankelize-a-matrix Problem 3094. Hankelize a matrix>, now ...

1 year ago

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Hankelize a matrix
Similar to <http://www.mathworks.com/matlabcentral/cody/problems/42501-toeplitize-a-matrix Problem 42501. Toeplitize a matrix>, ...

1 year ago

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Matrix of Multiplication Facts
This is James's daughter again, sneaking into his Cody account. Thanks to your help in my math class last year, I did great! But...

1 year ago

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Go to the head of the class!
You're given a matrix and a single number. If that number is in the matrix, reorder the matrix so that number is in the first r...

1 year ago

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Must be in the front row...
You are given a matrix followed by a single number. Your object is to write a script that will shift the matrix around so that ...

1 year ago

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Replace Nonzero Numbers with 1
Given the matrix x, return the matrix y with non zero elements replaced with 1. Example: Input x = [ 1 2 0 0 0 ...

1 year ago

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Matrix multiplication across rows
Given matrix m, return matrix n such that, rows of n are result of multiplication of the rows of the input matrix Example ...

1 year ago

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Too Many Zeros, Dump Them!
Sometimes when I create a matrix, I use this syntax: a = zeros(1000,1000); But when the function ends, I find that I don'...

1 year ago

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Enlarge array
Given an m-by-n numeric array (A) and a 1-by-2 vector (sz) indicating the dimensions [p q] to enlarge each element, return an (m...

1 year ago

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Remove entire row and column in the matrix containing the input values
Remove the entire row and column from the matrix containing specific values. The specified value can be a scalar or a vector. Fo...

1 year ago

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frame of the matrix
Given the matrix M, return M without the external frame.

1 year ago

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subtract central cross
Given an n-by-n square matrix, where n is an odd number, return the matrix without the central row and the central column.

1 year ago

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MatCAT - Reconstruct X from Its X-rays
Consider a matrix x x = [ 1 2 0 0 5 0 3 0 8 ] If we sum x along the rows we get row_sums = [3 5 11] ...

1 year ago

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Given a matrix, swap the 2nd & 3rd columns
If a = [1 2 3 4; 1 2 3 4; 1 2 3 4; 1 2 3 4]; then the result is ans = 1 3 2 4 1 3 2...

1 year ago

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matrix zigzag
Unfold a 2-D matrix to a 1-D array in zig-zag order, e.g., for matrix [ 1 2 3 ; 4 5 6 ; 7 8 9 ] the resulting 1-...

1 year ago

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Pascal's pyramid
In Pascal's triangle each number is the sum of the two nearest numbers in the line above: 1 1 1 ...

1 year ago

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Diagonal of a Spiral Matrix
Write a function that will return same output as diag(spiral(n)). The only exception is that spiral and diag functions are not a...

1 year ago