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Is A the inverse of B?
Given a matrix A and a matrix B, is A the inverse of B? >>A=[2,4;3,5]; >>B=[-2.5,2;1.5,-1]; >>isInverse...

13 years ago

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Least common multiple of many numbers
1:6 -> 60

13 years ago

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Hackathon: the beginnings
I am thinking of a number between 1 and 10000... can you guess what this number is? *Description* The test suite has rando...

13 years ago

Solved

Matrix indexing with two vectors of indices
Given a matrix M and two index vectors a and b, return a row vector x where x(i) = M(a(i),b(i)).

13 years ago

Solved

Replace Vector Elements
Replace all elements in a vector which are equal to or smaller than zero with 0.1. Example: A = [1 2 3 -1 0 2 -3 -80]; ...

13 years ago

Solved

Geometric series
Find the sum, given the first term t1, the common ratio r, and number of terms n. Examples If input t1=1, r=1, n=7 the...

13 years ago

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Vectorize the digits of an Integer
Create a vector of length N for an integer of N digits. x=123045; x_vec=[1 2 3 0 4 5]; I happened upon a trick to do ...

13 years ago

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Half?
If you toss an even number (x) of coins, what is the probability (y) of 50% head and 50% tail?

13 years ago

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Project Euler: Problem 5, Smallest multiple
2520 is the smallest number that can be divided by each of the numbers from 1 to 10 without any remainder. What is the smalle...

13 years ago

Solved

Make a random, non-repeating vector.
This is a basic MATLAB operation. It is for instructional purposes. --- If you want to get a random permutation of integer...

13 years ago

Solved

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: ...

13 years ago

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No Twins?
Write a function that accepts as input a vector and returns the same vector, but retaining only the first occurrence of an eleme...

13 years ago

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Create a square matrix of multiples
Given an input, N, output a matrix N x N with each row containing multiples of the first element of each row. This also applies...

13 years ago

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Getting the indices from a vector
This is a basic MATLAB operation. It is for instructional purposes. --- You may already know how to <http://www.mathworks....

13 years ago

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Angle between two vectors
You have two vectors , determine the angle between these two vectors For example: u = [0 0 1]; v = [1 0 0]; The a...

13 years ago

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Project Euler: Problem 2, Sum of even Fibonacci
Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 te...

13 years ago

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Back to basics 26 - Keywords
Covering some basic topics I haven't seen elsewhere on Cody. Return a cell array of strings of all MATLAB keywords.

13 years 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 ...

13 years ago

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High school cafeteria
Given an input vector of positive integers, return a row vector with the primes first (in increasing order) and the composites n...

13 years ago

Solved

Read a Soroban Abacus
*Description* The Soroban is the name of the modern Japanese abacus. Information on reading a Soroban can be found <http://we...

13 years ago

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Remove the air bubbles
Given a matrix a, return a matrix b in which all the zeros have "bubbled" to the top. That is, any zeros in a given column shoul...

13 years ago

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Project Euler: Problem 7, Nth prime
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 Nth prime nu...

13 years ago

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Count from 0 to N^M in base N.
Return an array of numbers which (effectively) count from 0 to N^M-1 in base N. The result should be returned in a matrix, with ...

13 years ago

Solved

Back to basics 15 - Benchmark
Covering some basic topics I haven't seen elsewhere on Cody. Return an array of the benchmark values for MATLAB.

13 years ago

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Compute a dot product of two vectors x and y
x and y are input vectors, d is a number and contains their dot product

13 years ago

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Rotate a Matrix by 90 degrees
Rotate a Matrix by 90 degrees Example: If the input is: X = 1 2 3 4 5 6 7 8 9 ...

13 years ago

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Sorting
Assume that x is an n-by-2 matrix. The aim is to return the first column of x, but sorted according to the second column. Exa...

13 years 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...

13 years ago

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give nth decimal place of pi
max 15th place after the decimal point is ok for now

13 years ago

Solved

Return the 'Size' of a String of Code
One of the most 'mysterious' parts of playing Cody is the sizing system. Given a string of commands, return the size that Cody w...

13 years ago