Machine-learning Course Study Summary Octave

Quick reference: Http://10.236.6.14/enacit1.epfl.ch/octave_doc/refcard/refcard-a4.pdf

1. Arithmetic operations:

A+b, A-A, a*b, A/b, a^b

Logical Operation:

A==b, a~=b (Not equal), A&&b, a| | B, Xor (A/b)

2. Assignment statement:

A=3;

A= ' Hi ';

A= 1>=3;

3. Output display:

A=pi

Disp (a)

Disp (sprintf (' 2 decimals:%0.2f ', a))

Disp (sprintf (' 6 decimals:%0.6f ', a))

Format Long

Format short

4. Vectors and matrices:

A=[1 2;3 4;5 6]

A=[1 2 3]

A=[1:0.1:2] %1-2 constructs a row vector in 0.1 units

A=1:6 %1-6 Line Vector

A=ones (3,4) % 3 Rows 4 columns Each element is 1 matrix

A=zeros (1,3) % 1 Rows 3 columns Each element is 0 matrix

A=randn (1,3) % normal distribution

A=7+SQRT (+) * (RANDN (1,10000)) % mean is 7, variance is square root

hist (A) % with 10bins column chart

hist (a,50) % with 50bins column chart

A=eye (5) % of the unit matrix with a order of 5

5. Data processing:

Load Abc.dat % Read File

who% lists variables in the working space

Whos % list details of variables in the workspace

Clear ABC % empty file

V=ABC (1:10) % read the first 10 data of the file

Save File.mat v; % save V to file

Save File.txt V-ascii; % save V to file in ASCII code

Size (A) % returns two values of the [Number of row series] vectors

Size (a,1) % number of rows

Size (a,2) % number of columns

Length (A) % maximum dimensions

A (:) %a all elements into a single column vector

A (3,2) % gets 3 rows of 2 columns of elements

A (2,:) % get line vector of line 2nd

A (2,:) =[2 3 4] % assigns A value to the 2nd row element

A=[A,[1;2;3]] % adds a column vector to the left of a

A ([1 3],:) % get all elements of a 1-3 line

C=[a B] % splicing matrix

C=[A,B]

C=[a; B

6. Data operation:

Set a=3*2 matrix, b=3*2 matrix, c=2*1 matrix

A*c

A.*b

A.^2

1./a

Log (A)

Exp (A)

ABS (A)

-A

A+1

A

Max (a) % returns a row vector with each value being the largest of each column, and if a is a row vector, only the maximum value is returned

Prod (A) % Ibid, just product

SUM (A) % Ibid, just and

SUM (a,1) % ibid .

SUM (a,2) % Ibid, return column vector

A<3 % Returns a homogeneous matrix, the value of <3 is 0 and vice versa is 1

Find (a<3) % returns the element position less than 3, which is a column vector

[R,c]=find (a<3) %ri,ci to conform to element coordinates

Flipud (A) % row reversal

PINV (a) inverse matrix of%a

7. Drawing

T=[0:0.01:0.98]

Y1=sin (2*pi*t)

Plot (t,y1) % drawing

On

Y2=cos (2*pi*t)

Plot (T,y2, ' R ')

Xlabel (' time ')

Ylabel (' value ')

Legend (' Sin ', ' cos ') % legend

Title (' My Plot ')

Print-dpng ' myplot.png ' % saved as picture file

Close % Closes the current diagram

Figure (1) % Create a diagram

CLF % Empty chart Current Contents

Subplot (1,2,2) % graph cut to 1*2 grid, draw 2nd grid

Axis ([0.5 1-1 1]) % axis changed to x belongs to [0.5,1],y belonging to [ -1,1]

Imagesc (The Magic ()), Colorbar,colormap Gray;

8. Loop condition Statements

For I=1:10,

V (i) =2^i;

End

------------------

While I<=5,

V (i) = 100;

i=i+1;

End

-------------------

If

ElseIf

Else

End

9. Functions:

function Y=fun (x)

y=x+2;

function [Y1,y2]=fun2 (x)

Y1=x*x;

Y2=x+x;

Called when the CD-to-function directory is then called directly

Ans=fun (args)

[A,b]=fun2 (args)

Machine-learning Course Study Summary Octave