Matlab

Matrices

Basics

See Introduction to Matlab

Special matrices/vectors

Name (matrix type)	Matlab syntax	Result
Ones	>> ones(3,2);	$ \left[ \begin{array}{cc} 1 & 1 \\ 1 & 1 \\ 1 & 1 \end{array} \right] $
Zeros	>> zeros(3,1);	$ \left[ \begin{array}{cc} 0 \\ 0 \\ 0 \end{array} \right] $
Eye (identity)	>> eye(3);	$ \left[ \begin{array}{ccc} 1 & 0 & 0 \\ 0 & 1 & 0 \\ 0 & 0 & 1 \end{array} \right] $
Rand (random numbers)	>> rand(3,2);	$ \left[ \begin{array}{cc} 0.21955 & 0.27560\\ 0.42385 & 0.62212\\ 0.53343 & 0.69182 \end{array} \right] $
Meshgrid	>> [x,y] = meshgrid(1:4,1:4);	$ x = \left[ \begin{array}{cccc} 1& 2& 3& 4\\ 1& 2& 3& 4\\ 1& 2& 3& 4\\ 1& 2& 3& 4 \end{array} \right] $ $ y = \left[ \begin{array}{cccc} 1& 1& 1& 1\\ 2& 2& 2& 2\\ 3& 3& 3& 3\\ 4& 4& 4& 4 \end{array} \right] $
Magic (magic square matrix) (The sum of each row and column is equal to the same value)	>> magic(4);	$ \left[ \begin{array}{cccc} 16& 2& 3& 13\\ 5& 11& 10& 8\\ 9& 7& 6& 12\\ 4& 14& 15& 1 \end{array} \right] $

Functions

det

This function returns the determinant of a matrix:

>> A=magic(4)
A =

   16    2    3   13
    5   11   10    8
    9    7    6   12
    4   14   15    1

>> det(A)
ans = -1.4495e-12

repmat

This function creates a new matrix consisting of several copies of an existing matrix.

>> A = magic(3)
A =

   8   1   6
   3   5   7
   4   9   2

>> repmat(A,2,2)
ans =

   8   1   6   8   1   6
   3   5   7   3   5   7
   4   9   2   4   9   2
   8   1   6   8   1   6
   3   5   7   3   5   7
   4   9   2   4   9   2

linspace

logspace

length

det

x(end)

sort

find

max

min

diag

size

flipud

fliplr

See also

• Octave

• Introduction to Matlab (lecture)