1. MATLAB 해설
전자공학과

2. Number and Basic variables
Ans %답
Eps % 가장 작은수
pi = π
Flops % 부동연산의 횟수
i or j = sqrt(-1)
inf = 무한대
NaN=숫자가 아님
Realmin, realmax % 가장 작은(큰) 양의 실수

3. Array & Matrices x=[1, 2, 3]; x=[1 2 3] %1x3 vector
k=[1;2;3] %3x1 vector
y=[1+j, 2+pi*i, -sqrt(-1)]
A=[1 2 3; 4 5 6; 7 8 9] or A=[1,2,3;4,5,6;7,8,9] % 3x3 matrix
t=[0:0.1:10] % generates a row vector t that increases from 0
% to 10 in increments of 0.1

4. Matrices length(x) % returns the dimension of a vector x
Size(A) % compute the row & column of A
x(3)
A(2,3)
x(2:3)
A(1:2, 3)

5. M-files: Scripts and Function Files
Script m-file
test1.m
Function m-file
function [out1,out2, ...]=filename(in1,in2, ...)
test2.m
nargin, nargout

6. example File1.m ---- Script m-file Addiff.m---- function m-file
[a,b]=addiff(2,4);
save result.dat a b –ascii %저장
sprintf(‘sum =%d\ndiff=%d’,a,b) %화면에 표시
Addiff.m---- function m-file
function [isum, idiff] = addiff(a,b)
%이 프로그램은 두수의 합과 차를
%구하는 프로그램입니다.
if nargin ~= 2 error; end
if nargout ~=2 error; end
isum=a+b;
idiff=abs(a-b);

7. Mathematical Operations and Functions:
Lower Case letter
+, -, *, /, \, ^ (power), ' (transpose)
5^2, 22/2, 2\22
log, log10, exp, sqrt, det (determinant)
inv, eig, rank
real, imag, abs, conj

8. Basic Functions sin, cos, tan, asin : arcsine
acos, atan, sinh, cosh, tanh, asinh
abs : 절대치, sqrt : 제곱근, real : 실수부
imag : 허수부, conj : 공액복소수
round : 반올림, fix : 버림
sign : signum, rem : 나머지
exp : 밑이 e인 지수, log : 자연로그
log10 : 상용로그

9. Relational Operators < less than <= less than or equal == equal
> greater than
>= greater than or equal
~= not equal
xor

10. Logical Operators
& % AND
| % OR
~ % NOT

11. Loops and Conditional Structures
for
While
If~else
Switch ~ Case

12. For loop
for variable=expression
statement;
...
end

13. Example
For k=1:20
x(k) = sin(k*2*pi/20);
End x

14. WHILE Loop
while expression
statement;
...
end

15. Example
N! 구하기
N=5;i=1;
R=1;
while i<=N
R=i*R
i=i+1;
end R

16. IF, ELSE, ELSEIF if expression, statement, ... , statement, ...
elseif expression2, statement, ... , statement, ... ,
else statement, ... .
end

17. Example while 1 disp('*********Menu***************') disp('* A: *')
disp('* B: *')
disp('* C: *')
disp('****************************')
n=input('Type string : ','s');
if n == 'A' disp('You typed A')
elseif n == 'B' disp('You typed A')
elseif n == 'C' disp('You typed C')
else
disp('Please type character in the menu')
end

18. example while 1 n=input('Type any number(99:exit) : ');
if n==99 break; end
sprintf('You typed number %d',n)
end
sprintf('You typed number %d, Bye!',n)

19. CASE SWITCH statement
CASE is part of the SWITCH statement syntax, whose
general form is:
SWITCH switch_expr
CASE case_expr,
statement, ..., statement
CASE {case_expr1, case_expr2, case_expr3,...}
...
OTHERWISE,
END

20. example aaa =4; switch aaa case 1, disp('Number is 1')
otherwise, disp('Number is out of 1-9')
end

21. Plotting and Graphics plot, loglog, semilogx, semilogy, polar
t=0:2*pi*2/50:2*pi*2*2;
Y=sin(t);
Plot(t,Y)
Subplot(232);plot(t,Y)
legend(‘sine(t)’)
legend off

22. 4. Plot (계속) title('Title of the Figure'), xlabel('X-axis Label')
ylabel('Y-axis Label')
gtext('Text for annotation') % for mouse positioned text
text(x, y, 'Text for annotation'), grid

23. Matlab Workspace Who Whos Clear variables Help clear
Diary filename: 입력 및 명령창 출력을 파일로 저장
Diary off Cd
Dir
!dos command

24. Matlab Workspace (내장 명령어)
what
Type
Clock
Date
lookfor

25. 데이터의 저장과 복원 File/save workspace as… File/load workspace as… Save
Save file1 a b c
Save file2 a b c -ascii
Load
Load file1
Load file2 -ascii

26. Strings
Str = ‘Suwon univ’;
Size(Str)
U=Str(4:7)
U=Str(9:-1: 5)
disp('text string')
disp(Str)

27. String Functions
Base2dec
Bin2dec
Char
Dec2base
Dec2bin
Dec2hex
double

28. String Functions Fprintf Hex2dec Hex2num Int2str Sprintf Sscanf
str2num

29. File I/O(FPRINTF, SSCANF, FGETL, FGETS, FREAD, INPUT)
Opening and closing files
example : fid =fopen('pen.dat','r')
'r' : reading
'w' : wrighting
'a' : appending
'r+' : reading and wrighting
status = fclose(fid);
status = fclose('all');
( 0 : successful, -1 : unsuccessful )

30. File I/O Reading Binary Data Files fread : reads binary data files
example : fid = fopen('penny.dat', 'r');
A = fread(fid);
status = fclose(fid);

31. Controlling Position in a File
Writing Formatted Text Files and Strings
%e for exponential notation
%f for fixed point notation
%g which automatically selects the shorter of %e and %f
Reading Formatted Text Files and Strings
%s to match a string
%d to match a decimal number
%f to match a floating point value

32. Matlab Debugger dbstop : set breakpoint dbclear : remove breakpoint
dbcont : resume execution
dbstack : list who called whom
dbstatus : list all break point
dbstep : execute one or more lines
dbtype : list M-file with line numbers
dbup : change local workspace context
dbquit : quit debug mode

33. control system signal processing neural network Communications …….
Toolboxes
control system
signal processing
neural network
Communications
…….