MatricesArrays of numbers can also compose matrices. To create a matrix, spaces or commas separate the elements in columns, semicolons separate rows. >> g = [1 2 3 4; 5 6 7 8] g = 1 2 3 4 5 6 7 8 In this case g is a matrix of 2 rows and 4 columns (2x4). Naturally, all of the rows must have the same number of columns. Math with matrices and scalars To an array or matrix, arithmetic with scalars equal to perform the operation of every element with the scalar. >> g+3 ans = 4 5 6 7 8 9 10 11 >> 2*g-2 ans = 0 2 4 6 8 10 12 14 Math between matrices When two arrays have the same dimensions, you can add or subtract one to/from the other element by element, like this: >> A = [1 2 3 4; 5 6 7 8; 9 10 11 12] A = 1 2 3 4 5 6 7 8 9 10 11 12 >> B = [1 1 1 1; 2 2 2 2; 2 2 2 2] B = 1 1 1 1 2 2 2 2 2 2 2 2 >> A + B ans = 2 3 4 5 7 8 9 10 11 12 13 14 >> 2*A - B ans = 1 3 5 7 8 10 12 14 16 18 20 22 For multiplication, division or power operations, you use the 'element-wise' operators (with '.*', './', or '.^'). >> A.*B ans = 1 2 3 4 10 12 14 16 18 20 22 24 >> A./B ans = 1.0000 2.0000 3.0000 4.0000 2.5000 3.0000 3.5000 4.0000 4.5000 5.0000 5.5000 6.0000 >> A.^2 ans = 1 4 9 16 25 36 49 64 81 100 121 144 Matrix Addressing This notation refers to the element of row r and column c within matrix A. A(r,c) This notation refers to all of the elements of row r in matrix A. A(r,:) This notation refers to all of the elements of column c in matrix A. A(:,c) Matrix Functions
Special Matrices
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