1MATLAB Tutorial1Based on IPLab@SUTMatlab TutorialContents¾ What is Matlab?¾ Matrices Numerical Arrays String Arrays¾ Elementary Math Logical Operators Math Functions¾ Importing and Exporting Data2Contents Continued¾ Graphics Fundamentals 2D plotting Subplots 3D plotting¾ Editing and Debugging M-files¾ Script and Function Files¾ Basic Parts of an M-file¾ Flow Control Statements¾ M-file Programming¾ Data Types3What is MATLAB? high-performance software Computation Visualization Easy-to-use environment. high-level language Data types Functions Control flow statements Input/output Graphics Object-oriented programming capabilities 5Calculations at the Command Line» a = 2;» b = 5;» a^bans = 32» x = 5/2*pi;» y = sin(x)y = 1» z = asin(y)z = 1.5708» a = 2;» b = 5;» a^bans = 32» x = 5/2*pi;» y = sin(x)y = 1» z = asin(y)z = 1.5708Results assigned to “ans” if name not specified() parentheses for function inputsSemicolon suppresses screen outputMATLAB as a calculatorAssigning VariablesA Note about Workspace:Numbers stored in double-precision floating point format» -5/(4.8+5.32)^2ans =-0.0488» (3+4i)*(3-4i)ans =25» cos(pi/2)ans =6.1230e-017» exp(acos(0.3))ans =3.5470» -5/(4.8+5.32)^2ans =-0.0488» (3+4i)*(3-4i)ans =25» cos(pi/2)ans =6.1230e-017» exp(acos(0.3))ans =3.54709General Functions whos: List current variables clear: Clear variables and functions from memory cd: Change current working directory ls: List files in directory102Getting helphelp command (>>help)lookfor command (>>lookfor)Printable Documents “Matlabroot\help\pdf_doc\”11Matrices Entering and Generating Matrices Subscripts Scalar Expansion Concatenation Deleting Rows and Columns Array Extraction Matrix and Array Multiplication12» a=[1 2;3 4]a = 1 23 4» b=[-2.8, sqrt(-7), (3+5+6)*3/4]b =-2.8000 0 + 2.6458i 10.5000» b(2,5) = 23b =-2.8000 0 + 2.6458i 10.5000 0 00 0 0 0 23.0000» a=[1 2;3 4]a = 1 23 4» b=[-2.8, sqrt(-7), (3+5+6)*3/4]b =-2.8000 0 + 2.6458i 10.5000» b(2,5) = 23b =-2.8000 0 + 2.6458i 10.5000 0 00 0 0 0 23.0000• Any MATLAB expression can be entered as a matrix element• Matrices must be rectangular. (Set undefined elements to zero)Entering Numeric ArraysRow separatorsemicolon (;)Column separatorspace / comma (,)Use square brackets [ ]13The Matrix in MATLAB4101 6 281.29 4 257.2 5 7 1 1100.54 5 5623 83 13 0 1012Rows (m) 345Columns(n)1 2 3 4 51 6 11 16 212 7 12 17 223 8 13 18 234 9 14 19 24510152025A =A (2,4)A (17)Rectangular Matrix:Scalar: 1-by-1 arrayVector: m-by-1 array1-by-n arrayMatrix: m-by-n array14» w=[1 2;3 4] + 5w =6 78 9» x = 1:5x =1 2 3 4 5» y = 2:-0.5:0y = 2.0000 1.5000 1.0000 0.5000 0 » z = rand(2,4)z =0.9501 0.6068 0.8913 0.45650.2311 0.4860 0.7621 0.0185» w=[1 2;3 4] + 5w =6 78 9» x = 1:5x =1 2 3 4 5» y = 2:-0.5:0y = 2.0000 1.5000 1.0000 0.5000 0 » z = rand(2,4)z =0.9501 0.6068 0.8913 0.45650.2311 0.4860 0.7621 0.0185Scalar expansionCreating sequences:colon operator (:)Utility functions for creating matrices.Entering Numeric Arrays15Numerical Array Concatenation» a=[1 2;3 4]a = 1 23 4» cat_a=[a, 2*a; 3*a, 4*a; 5*a, 6*a]cat_a =1 2 2 43 4 6 83 6 4 89 12 12 165 10 6 1215 20 18 24» a=[1 2;3 4]a = 1 23 4» cat_a=[a, 2*a; 3*a, 4*a; 5*a, 6*a]cat_a =1 2 2 43 4 6 83 6 4 89 12 12 165 10 6 1215 20 18 24Use [ ] to combine existing arrays as matrix “elements”Row separator:semicolon (;)Column separator:space / comma (,)Use square brackets [ ]Note:The resulting matrix must be rectangular 4*a163Deleting Rows and Columns » A=[1 5 9;4 3 2.5; 0.1 10 3i+1]A =1.0000 5.0000 9.0000 4.0000 3.0000 2.5000 0.1000 10.0000 1.0000+3.0000i» A(:,2)=[]A =1.0000 9.0000 4.0000 2.5000 0.1000 1.0000 + 3.0000i» A(2,2)=[]??? Indexed empty matrix assignment is not allowed.» A=[1 5 9;4 3 2.5; 0.1 10 3i+1]A =1.0000 5.0000 9.0000 4.0000 3.0000 2.5000 0.1000 10.0000 1.0000+3.0000i» A(:,2)=[]A =1.0000 9.0000 4.0000 2.5000 0.1000 1.0000 + 3.0000i» A(2,2)=[]??? Indexed empty matrix assignment is not allowed.17Array Subscripting / Indexing41016281.29 4 257.2 5 7 1 1100.54 5 5623 83 13 0 10123451 2 3 4 51 6 11 16 212 7 12 17 223 8 13 18 234 9 14 19 24510152025A =A(3,1)A(3)A(1:5,5)A(:,5) A(21:25)A(4:5,2:3)A([9 14;10 15])A(1:end,end)A(:,end)A(21:end)’18Matrix Multiplication» a = [1 2 3 4; 5 6 7 8];» b = ones(4,3);» c = a*bc =10 10 1026 26 26» a = [1 2 3 4; 5 6 7 8];» b = ones(4,3);» c = a*bc =10 10 1026 26 26[2x4][4x3][2x4]*[4x3] [2x3]a(2nd row).b(3rd column)» a = [1 2 3 4; 5 6 7 8];» b = [1:4; 1:4];» c = a.*bc =1 4 9 165 12 21 32» a = [1 2 3 4; 5 6 7 8];» b = [1:4; 1:4];» c = a.*bc =1 4 9 165 12 21 32c(2,4) = a(2,4)*b(2,4)Array Multiplication19Matrix Manipulation Functions• zeros: Create an array of all zeros• ones: Create an array of all ones• eye: Identity Matrix• rand: Uniformly distributed random numbers• diag: Diagonal matrices and diagonal of a matrix• size: Return array dimensions• repmat: Replicate and tile a matrix20Matrix Manipulation Functions• det: Matrix determinant• inv: Matrix inverse • eig: Evaluate eigenvalues and eigenvectors• rank: Rank of matrix21Elementary MathLogical OperatorsMath FunctionsPolynomial and Interpolation254Logical Operations» Mass = [-2 10 NaN 30 -11 Inf 31];» each_pos = Mass>=0each_pos =0 1 0 1 0 1 1» all_pos = all(Mass>=0)all_pos =0» all_pos = any(Mass>=0)all_pos =1» pos_fin = (Mass>=0)&(isfinite(Mass))pos_fin =0 1 0 1 0 0 1» Mass = [-2 10 NaN 30 -11 Inf 31];» each_pos = Mass>=0each_pos =0 1 0 1 0 1 1» all_pos = all(Mass>=0)all_pos =0» all_pos = any(Mass>=0)all_pos =1» pos_fin =
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