1. CIVL 5320 Thomas Ng 1

2.  What is Matlab? MATrix LABoratory A high-performance language for technical computing An easy-to-use interactive environment for computation, visualization and programming 2

3.  Interactive: Direct key in command after “>>” >> help >> lookfor CCChang  Off-line: Put all commands into a m-file (name.m) and execute the file as follows >> name (without suffix.m) All commands in the file will be executed sequentially The m-file has to be in the current directory or directories set by “pathtool” 3

4.  mat-file (name.mat): Contains pre-defined variables, vectors and matrices >> save name Save all variables into a file called name.mat >> save name CCChang is wonderful Save variables, vectors or matrices “CCChang”, “is” and “wonderful” into a file called name.mat >> load name Load all variables in the name.mat to the MATLAB registry 4

5.  Do the followings >> help help >> help lookfor >> help plot >> lookfor plot  Put sdof.m and elcen.mat into the current directory >> sdof >> whos >> save temp >> clear all >> whos >> load temp >> whos  Create a m-file that contains the above commands and run the m-file 5

6.  Sequence of operations >> CCChang Is CCChang a variable? If not, next Is CCChang a built-in function? If not, next Is CCChang a m-file? If not, next ??? Undefined function or variable 'CCChang‘  Some useful commands Interrupting running the program: Ctrl+c Long command: … >> x=sin(1)+1+cos(2)+sin(2)+ sin(2)+... sin(4)+ sin(5)+ sin(6)+ sin(7) Suppress echo: ; Comment: % 6

7.  Some useful commands >> Clear >> Close  Scalar, vector and matrix >> A=123>> a=321 % >> Rowvector = [12 14 63] >> Colvector= [13; 45; -2] >> Matrix= [1 2 3; 4 5 6; 7 8 9] >> sub_matrix= Matrix( 1:2, 2:3) 7

8.  Do the followings >> A=123 >> A=123%This is fun! >> A=123; >> x=sin(1)+1+cos(2)+sin(2)+ sin(2)+... sin(4)+ sin(5)+ sin(6)+ sin(7) >> ColA=[1 ; 2 ; 3] >> RowA=[1 2 3] >> GuessA=[1:10] >> GuessB=[1:3:10] >> GuessC=[1:10]’ 8

9. >> CC=[1 2 3; 4 5 6; 7 8 9] >> CC=[1:3; 4:6; 7:9] >> subCC1=CC(1:2, 2:3)% what do you expect? >> subCC2=CC(:, 2:3)% what do you expect? >> subCC3=CC(1:2, :)% what do you expect? >> clear all 9

10. 10 Element by element operation Matrix operation

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12. CommandDescription eyeIdentity matrix zerosZeros array normNorm of vector or matrix detMatrix determinant eigEigenvalues and eigenvectors lsimSimulate response of LTI models for … endRepeat statements (do loop) demoRun demonstrations Many many more! Toolboxes contain specialized commands 12

13.  Do the followings >> RowA=[1 2 3]; ColA=[1 ; 2 ; 3]; >> RowA*ColA >> ColA*RowA >> ColA.*RowA >> ColA.*RowA’ >> RowA.*ColA >> RowA.*ColA’ >> RowA./ColA >> RowA./ColA’ 13

14. >> CC=[1 2; 3 4] >> det(CC) >> eye(2) >> zeros(2,2) >> DD=[CC zeros(2,2); zeros(2,2) eye(2)] 14

15.  Figure control >> figure(x)% Create/go to figure x >> clf(x)% Clear figure x >> close(x)% Close figure x >> title(‘I love MATLAB’)% Figure caption  Plotting >> plot(y)% Plot y versus index >> plot(x,y)% Plot y versus x >> semilogx(x,y)>> semilogy(x,y) >> loglog(x,y)>> plot3(x,y,z) >> subplot(m,n,p) % Create tiled plots 15

16. 16  Plotting control >> axis([xmin xmax ymin ymax]) >> xlabel(‘This is x-axis label’) >> ylabel(‘This is y-axis label’) >> text(x, y, ‘This is a label’) % Add text to (x,y)

17.  Open sdof.m file  Go through the codes  Run sdof.m file  Modify the file  Re-run 17

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