??????????????? MATLAB ?????????

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??????????????? MATLAB ?????????

• ??.???????? ???????????
• charturong.ee.engr.tu.ac.th/CN208
• ??????????????????????????????????
• ?????????????????????

????????????????????????????? ??.????? ??????????
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What is MATLAB?

• MATLAB ???????? MATrix LABoratory
  ???????????????????????????????????????????
  ???????????
• Math and computation
• Algorithm development
• Data acquisition
• Modeling, simulation, and prototyping
• Data analysis, exploration, and visualization
• Scientific and engineering graphics
• Application development, including graphic user
  interface building

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???????? MATLAB
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1
2
4

• The Command Window
• ?????????? commands ??????????????????????????????
  ?????? gtgt (the command prompt) ???????????????????
  ??????????? commands ????????????????? Enter
  ????????????
• 2. The Command History Window
• ?????????? the command history ???????????????????
  ???????????????????????????????? (The Command
  History) ?????????????????????????? MATLAB
• 3. The Current Directory
• ?????????????????????????????????? MATLAB
  ?????????????????? (Directory) ??????? ????????
  MATLAB ???????????????? Directory ??????????????
  ???????????????????????? (Browse) ????
  ???????????????? the Current Directory ???

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To get Help

• MATLAB ?????????? Help ???????????????????????????
  ????????? ????????????????????????????????????????
  ?? ????
• ?????????? ? ??????? Current Directory
• ???? 2. ????? helpdesk ???? helpwin ??? command
  prompt (gtgt) ?????????? Command ?????? Enter

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???????? Help
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• ?????????? Help ??????????????????????????????????
  4 ??????????????
• Contents ?????????????????????????????????? ???
  ????? Toolbox ?????
• Index ????????????? Function ??? MATLAB
  ???????????? A-Z
• Search ?????????????? Function ??????? MATLAB
• Demos ???????????????????????????????????? MATLAB
• ??? MATLAB
• ?????????????? MATLAB ??????????????????? exit
  ???? quit ??? command prompt ?????????? command

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Simple Math

• MATLAB ????????????????????????????????????????
  ???????????????????????????????????????
• ??????????????????????
• ???????? (2525-93)/2 ???? command prompt (gtgt)
• ??????????????????? 15

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Special Symbols
Operation Symbol
Addition Subtraction Multiplication Division Exponentation - /
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?????? ???? Variable

• ?????? (variable) ????????????????????????????????
  ?????? ???????????????????????????????????????????
  ????????????????????????????? command
  ????????????
• ??????????????? var ???????? 15 ????????????????
  gtgtvar 15 ??? command window

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??????????????????????

• ???????? MATLAB ????????????????????????????????
  ???????????????????????? ??? ????
  ????????????????????? ( _ ) ????????
  ?????????????????????????? 63 ????????
• ???????????????????????????????????????? index,
  year, growth_rate, a1, a2 ???????
• ???????????????????????????? growth rate
  (???????????????), 2r (?????????????????????)
• ???????? ???????? MATLAB ???? case-sensitive
  ??????? MATLAB ?????????????? Growth
  ???????????????????? growth
• ??????? ????????????????????????????????????????
  (lower-case letters) ??????????????????????

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Assignment Statements

• ???????????????????????????????????????
• var expression
• ??????? ??????????????????????????????????????
  ???? ??? MATLAB ???????????? expression
  ????????????????????? ????????????????????????????
  ?????? var
• ????????
• gtgt gas 29 ? ?????? gas ???? 29
• gtgt gas gas 1 ? ?????? gas ??????????? 30
  
• gtgt gas 1 30 ? ERROR

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Data Type

• ??????????????? MATLAB ????????????? double ????
  char
• ?????????? double ?????????????????????? (scalar)
  ????????????? 64 bits ????????????????????????????
  ???????????????????? 10-308 ??? 10308
  ???????????????????????????? 15
• MATLAB ???????????????????????? double
  ???????????????????????????
• ?????????? char ????????? 16 bits
  ???????????????????????????????????
  ??????????????????????????? MATLAB
  ?????????????????????? array ??? char
  ??????????????
• gtgtcomment 'This is a character string'
• ???????????????? comment ??????? array ???
  character 26 ???

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MATLAB Matrices 1

• ??????????????????????????????????????????????????
  
• 1. ?????????? element ???????????????????????????
  
• 2. ???????????(space)??????????(comma)???????????
  ????????????? (row)
• 3. ?????????????? semicolon ()
  ????????????????????????????
• 4. ????????????????????????????????
• ??????????????

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MATLAB Matrices 2

• ???????????????? MATLAB ??????????????????????????
  ?????? Enter ???? ?????? semicolon
  ??????????????????????????
• ?????? MATLAB ????????????????????????????????????
  ????????????? ????????????????????????????????????
  ???????????????????? (debug) ??????????????????

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???????????????????????????

• ????????????????? a ???
• ???????????????????? a ?? row ??? 2 ??? column
  ??? 4 ????????????????????
• ??????????????????????????????????????????????????
  ? ?????????????????????????????????????
  ?????????????????? comma ????????????????????
  column
• ??????????????????? a ?? row ??? 3 ??? column ???
  5 ??????????? gtgt a(3,5) ???????

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?????????????????????????????

• ????????????????????????????? ????????????????????
  ??????????????????????????????????????????? 12
  ???????????????????????????????????????????? ???
  ??????????????????????????????????????????? ()
  ?????????????? ???????????????????????????????? 2
  ?????????? 3 ??????????? a ???????????????????????
  ?? 0 ???????????????????????
• ???????????????????????? a ???????? 2 ??????????
  3 ????????????? 8 ???? 0

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The Colon () Operator

• The colon operator ???????????????? list
  ?????????????????????????????????????????????
  ????????????????????????????????????????
  ????????????????? colon ????????
• firstincrlast
• ?????? first ??????????????????????? incr
  ?????????????????????? ??? last
  ??????????????????????? ??????????????
• gtgt 129
• MATLAB ???????????
• ans 1 3 5 7 9
• ??????? ???????????????? 1 ????????????? 2
  ???????? 9
• ????????? incr ??? 1 ?????????????????????????????
  ??????? ???????????????????????????
• gtgt 58
• MATLAB ???????????
• ans 5 6 7 8

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?????? colon ???????????????????

• ???????? a ???
• ???????????????? b ??????????????????????????? a
  ??? row ??? 2 ??? column ??? 3 ?????????
  ?????????
• ???? 23 ????????????????????? 2 ????????? 3 ???
  35 ????????????? 3, 4, ??? 5
• ??????????????????????????? gtgt b a(2 3,3 4
  5) ????????????????????????

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• ??????????????????????????????????????????????????
  ????? ????????????????? colon ?????????????
  ??????????????
• gtgt a(2, ) 5 ??????????????????????????
  ? row 2 ?????????? a ???? 5
• ??????????????? ????????????????????????????
  1 ????????????????? ??????? ????????? a ?????? 2
  ?????????? 1 ?????????????????????????? 5
• gtgt a(, 3) -1 ??????????????????????????
  ? column 3 ?????????? a ???? -1
• ??????????? ?????????????????????? 1
  ????????????? ??????? ????????? a ?????? 1
  ????????????? ?????????? 3 ??????????? -1

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The end Function

• MATLAB ???????????????????? end
  ?????????????????????????????????? ????????? end
  ???????????????????????????????????????????????
  ??????????????
• ???
• gtgt b a(2end, 3end)
• ???????????????????????????????????????? 19
  ?????? end ????????????????? 3 ???????????????????
  ???????????? a ???? end ???????????????????? 5
  ??????????????????????????????????? a

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Vector

• ???????? (vector) ????????????? subset
  ??????????? ?????????????????????????????? 1
• ??????????????
• ????? row vector c ????????? array ???? 1x3
  ??????????? 3 ???????? 1.0, 2.5, ??? 3.0
  ????????
• 
  ?????????????? column vector d ????????? array
• 
  ???? 3x1 ??????????? 3 ????? ???????

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????????????????????????

• ??????????????????????????????????????????????????
  ???????????????????????? ??????????????
• gtgta 1 3 5 8 9
• ?????????????????????????? 3 ??????????? a
  ???????????????
• gtgta(3) ???? gtgta(1, 3)
• ??????????????????? ans 5
• ??????????????????????????? a ????????????????
• gtgta(end) ???? gtgt a(5) ???? gtgta(1, 5)
• ??????????????????? ans 9

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Transpose Operator (')

• Transpose operator (') ???????????????????????????
  ??????????????????? ??????????????
• gtgt f 14 ???? MATLAB ???????? f
  ???? row vector ???? 1x4
• f 1 2 3 4
• ???? transpose ???????? f ???????????????????????
• ????????
  column vector ???? 4x1

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?????????????????????????????????

• ??????????????????????????????????????????????????
  ???(????????????)??????????? ???????????
• gtgt g 1 3 2 7
• gtgt b 4 9
• gtgt h g b
• ???????????????
• gtgt m b' g
• ???????????????

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????????????????????????????????

• ?????????????????????????????????????????????? an
  empty array ????????????
• ????????????????????????? 2 ???????????
  ????????????????????
• gtgt h(, 2)
• ???? MATLAB ???????????????????? h ????????
• ????????????????? h ??????????????? 2x2
• ??????????????????????????????????? ??????????? a
  ?? 5 ?????????????????
• gtgta 3 9 0 1 5
• ??????????????????????????? 1 ???????????????????
  
• gtgta(1)
• ???? MATLAB ???????????????????? h ???????? a
  9 0 1 5

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MATLAB Functions for Initializing Variables
Function Purpose
zeros(n) zeros(n,m) zeros(size(arr)) ones(n) ones(n,m) ones(size(arr)) eye(n) eye(n,m) length(arr) size(arr) Generates an n n matrix of zeros Generates an n m matrix of zeros Generates a matrix of zeros of the same size as arr Generates an n n matrix of ones Generates an n m matrix of ones Generates a matrix of ones of the same size as arr Generates an n n identity matrix Generates an n m identity matrix Returns the length of a vector, or the longest dimension of a 2-D array Returns two values specifying the number of rows and columns in arr