MATLAB matrix operations

1: Find the number of rows nrow=size (matrix,1);

2: The number of columns ncol=size (matrix,2);

3: Matrix merge c1=[m1,m2] horizontal merge c2=[m1;m2] vertical merge

m1= [5 2 3]; M2=[1 2 3];

C1 =[5 2 3 1 2 3];

C2 =[

5 2 3
1 2 3

]

MATLAB subscript starting from 1, take the elements of Matlab directly with M[index] can

Take a sub-matrix

M[r1:rn,:] R1-rn row, all columns

M[:,C1-CN] C1-CN column, all rows

Number of elements in the statistical matrix that are equal to Q (ii)

OO (1,ii) =length (Find (H (:, i+1) ==q (ii));

4: Matrix transpose transpose (matrix) matrix ';

Matalab Logic Judgment

<, <=, >, >=, = =, ~=, &, |, ~

Decimal rounding

Ound (x): rounded to nearest integer
  Fix (x): the decimal to the nearest integer, whether positive or negative
  Floor (x): Rounding down, that is, rounding the positive decimal to the nearest integer
  Ceil (x): Rounding up, that is, adding positive decimals to the nearest integer

Matlab sorting by rows
Sortrows (M, nrow);
Sortcols (M,ncol);

matlab Matrix Establishment : http://www.cnblogs.com/whxiyi/archive/2009/12/08/1619500.html

Diagonal matrix eye (n);

Empty Matrix []

Nan (' Double ') is the same as Nan with no parameters. Nan (' single ') is an Nannan (n) of the mono-precision expression (representation) that returns a n*n-composed matrix of Nan. Nan (m,n) or Nan ([m,n]) returns a m*n matrix that is composed of Nan.

MATLAB matrix operations

A (:, j) denotes column J of Matrix A

A (i,:) Represents the line I of matrix A

A+b: Matrix addition

A-B: Matrix subtraction

A*b: Matrix multiplication

a\b: Left divide of Matrix

A/b: right-of-matrix removal

Transpose (m) or M ' Matrix transpose

A (:, j) denotes column J of Matrix A.

A (i,:) Represents the line I of matrix A.

A (I,J) represents the first row of column J of the matrix A element.

A (i) represents the first element of matrix A (:).

Each element of the m.^2 matrix is evaluated two times

Logical judgment

while (Iter<iter_max) && (Err>err_max)

MATLAB matrix operations