Matlab Training Session 1: Introduction to Matlab for Graduate Research

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Matlab Training Session 1Introduction to Matlab
for Graduate Research
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• Non-Accredited Matlab Tutorial Sessions for
  beginner to intermediate level users
• Beginner SessionsSession Dates January 13,
  2009 February 4, 2009 Session times  Tuesday
  and Wednesday 300pm-500pmSession Location
  Bracken Library Computer Lab
• Intermediate SessionSession Dates February 10,
  2009 March 4, 2009 Session times  Tuesday and
  Wednesday 300pm-500pmSession Location Bracken
  Library Computer Lab
• Instructors
• Robert Marino rmarino_at_biomed.queensu.ca,
  (Beginner Sessions)
• Andrew Pruszynski 4jap1_at_qlink.queensu.ca
  (Intermediate Sessions)
• Course Website
• http//www.queensu.ca/neurosci/matlab.php

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• Non-Accredited Matlab Tutorial Sessions for
  beginner to intermediate level users
• Purpose To teach essential skills necessary for
  the acquisition, analysis, and graphical display
  of research data

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• Non-Accredited Matlab Tutorial Sessions for
  beginner to intermediate level users
• Purpose To teach essential skills necessary for
  the acquisition, analysis, and graphical display
  of research data
• Promote Self Sufficiency and Independence

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• Course Outline
• Each weekly session will independently cover a
  new and progressively more advanced Matlab topic
• Weeks
• Introduction to Matlab and its Interface
• Fundamentals (Operators)
• Fundamentals (Flow)
• Importing Data
• Functions and M-Files
• Plotting (2D and 3D)
• Statistical Tools in Matlab
• Analysis and Data Structures

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• Week 1 Lecture Outline
• An Introduction to Matlab and its Interface
• A. Why Matlab?
• Some Common Uses for Matlab in Research

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• Week 1 Lecture Outline
• An Introduction to Matlab and its Interface
• A. Why Matlab?
• Some Common Uses for Matlab in Research
• B. Understanding the Matlab Environment
• Navigating the Matlab Desktop
• Commonly used Toolbox Components
• Executing Commands
• Help and Documentation

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• Week 1 Lecture Outline
• An Introduction to Matlab and its Interface
• A. Why Matlab?
• Some Common Uses for Matlab in Research
• B. Understanding the Matlab Environment
• Navigating the Matlab Desktop
• Commonly used Toolbox Components
• Executing Commands
• Help and Documentation
• C. Using Matlab
• Matrices, Scalars and Arrays
• Useful Commands
• Searching and Indexing
• Saving and Reloading Work

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• Week 1 Lecture Outline
• An Introduction to Matlab and its Interface
• A. Why Matlab?
• Some Common Uses for Matlab in Research
• B. Understanding the Matlab Environment
• Navigating the Matlab Desktop
• Commonly used Toolbox Components
• Executing Commands
• Help and Documentation
• C. Using Matlab
• Matrices, Scalars and Arrays
• Useful Commands
• Searching and Indexing
• Saving and Reloading Work
• D. Exercises

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Why Matlab?

• Matrix Labratory
• Created in late 1970s
• Intended for used in courses in matrix theory,
  linear algebra and numerical analysis

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Why Matlab?

• Matrix Labratory
• Created in late 1970s
• Intended for used in courses in matrix theory,
  linear algebra and numerical analysis
• Currently has grown into an interactive system
  and high level programming language for general
  scientific and technical computation

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Why Matlab?

• Common Uses for Matlab in Research
• Data Acquisition
• Multi-platform, Multi Format data importing
• Analysis Tools (Existing,Custom)
• Statistics
• Graphing
• Modeling

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Why Matlab?

• Data Acquisition
• A framework for bringing live, measured data into
  MATLAB using PC-compatible, plug-in data
  acquisition hardware

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Why Matlab?

• Multi-platform, Multi Format data importing
• Data can be loaded into Matlab from almost any
  format and platform
• Binary data files (eg. REX, PLEXON etc.)
• Ascii Text (eg. Eyelink I, II)
• Analog/Digital Data files

PC
100101010
UNIX
Subject 1 143 Subject 2 982 Subject 3 87
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Why Matlab?

• Analysis Tools
• A Considerable library of analysis tools exist
  for data analysis
• Provides a framework for the design, creation,
  and implementation of any custom analysis tool
  imaginable

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Why Matlab?

• Statistical Analysis
• A considerable variety of statistical tests
  available including
• TTEST
• Mann-Whitney Test
• Rank Sum Test
• ANOVAs
• Linear Regressions
• Curve Fitting

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Why Matlab?

• Graphing
• A Comprehensive array of plotting options
  available from 2 to 4 dimensions
• Full control of formatting, axes, and other
  visual representational elements

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Why Matlab?

• Modeling
• Models of complex dynamic system interactions can
  be designed to test experimental data

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Understanding the Matlab Environment

• Navigating the Matlab Desktop

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Understanding the Matlab Environment

• Navigating the Matlab Desktop
• Commonly Used Toolboxes

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Understanding the Matlab Environment

• Navigating the Matlab Desktop
• Commonly Used Toolboxes
• Executing Commands
• Basic Calculation Operators
• Addition
• - Subtraction
• Multiplication
• / Division
• Exponentiation

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Using Matlab

• Solving equations using variables
• Expression language
• Expressions typed by the user are interpreted and
  evaluated by the Matlab system
• Variables are names used to store values
• Variable names allow stored values to be
  retrieved for calculations or permanently saved
• Variable Expression
• Or
• Expression
• Variable Names are Case Sensitive!

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Using Matlab

• Solving equations using variables
• Expression language
• Expressions typed by the user are interpreted and
  evaluated by the Matlab system
• Variables are names used to store values
• Variable names allow stored values to be
  retrieved for calculations or permanently saved
• Variable Expression
• Or
• Expression
• Variable Names are Case Sensitive!

gtgt x y Ans 12 gtgt x / y Ans 3 gtgt x y
Ans 36
gtgt x 6 x 6 gtgt y 2 y 2 gtgt x y Ans 8
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Using Matlab

• Working with Matrices
• Matlab works with essentially only one kind of
  object, a rectangular numerical matrix
• A matrix is a collection of numerical values
  that are organized into a specific configuration
  of rows and columns.
• The number of rows and columns can be any number
• Example
• 3 rows and 4 columns define a 3 x 4 matrix
  having 12 elements

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Using Matlab

• Working with Matrices
• Matlab works with essentially only one kind of
  object, a rectangular numerical matrix
• A matrix is a collection of numerical values
  that are organized into a specific configuration
  of rows and columns.
• The number of rows and columns can be any number
• Example
• 3 rows and 4 columns define a 3 x 4 matrix
  having 12 elements
• A scalar is a single number and is represented by
  a 1 x 1 matrix in matlab.
• A vector is a one dimensional array of numbers
  and is represented by an n x 1 column vector or a
  1 x n row vector of n elements

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Using Matlab
Working with Matrices c 5.66 or c 5.66
c is a scalar or a 1 x 1 matrix 
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Using Matlab
Working with Matrices c 5.66 or c 5.66
c is a scalar or a 1 x 1 matrix  x
3.5, 33.22, 24.5 x is a row vector or a
1 x 3 matrix 
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Using Matlab
Working with Matrices c 5.66 or c 5.66
c is a scalar or a 1 x 1 matrix  x
3.5, 33.22, 24.5 x is a row vector or a
1 x 3 matrix  x1 2 5 3
-1 x1 is
column vector or a 4 x 1 matrix
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Using Matlab
Working with Matrices c 5.66 or c 5.66
c is a scalar or a 1 x 1 matrix  x
3.5, 33.22, 24.5 x is a row vector or a
1 x 3 matrix  x1 2 5 3
-1 x1 is
column vector or a 4 x 1 matrix A 1 2 4
2 -2 2 0 3 5 5 4 9
A is a 4 x 3 matrix
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Using Matlab

• Working with Matrices
• Spaces, commas, and semicolons are used to
  separate elements of a matrix

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Using Matlab

• Working with Matrices
• Spaces, commas, and semicolons are used to
  separate elements of a matrix
• Spaces or commas separate elements of a row
• 1 2 3 4 or 1,2,3,4

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Using Matlab

• Working with Matrices
• Spaces, commas, and semicolons are used to
  separate elements of a matrix
• Spaces or commas separate elements of a row
• 1 2 3 4 or 1,2,3,4
• Semicolons separate columns
• 1,2,3,45,6,7,89,8,7,6 1 2 3 4
• 5 6 7 8
• 9 8 7 6

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Using Matlab

• Indexing Matrices
• A m x n matrix is defined by the number of m rows
  and number of n columns
• An individual element of a matrix can be
  specified with the notation A(i,j) or Ai,j for
  the generalized element, or by A(4,1)5 for a
  specific element.

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Using Matlab

• Indexing Matrices
• A m x n matrix is defined by the number of m rows
  and number of n columns
• An individual element of a matrix can be
  specified with the notation A(i,j) or Ai,j for
  the generalized element, or by A(4,1)5 for a
  specific element.
• Example
• gtgt A 1 2 4 56 3 8 2 A is a
  4 x 2 matrix
• gtgt A(1,2)
• Ans 6
• The colon operator can be used to index a range
  of elements
• gtgt A(13,2)
• Ans 1 2 4

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Using Matlab

• Indexing Matrices
• Specific elements of any matrix can be
  overwritten using the matrix index
• Example
• A 1 2 4 5
• 6 3 8 2
• gtgt A(1,2) 9
• Ans
• A 1 2 4 5
• 9 3 8 2

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Using Matlab

• Matrix Shortcuts
• The ones and zeros functions can be used to
  create any m x n matrices composed entirely of
  ones or zeros
• Example
• a ones(2,3)
• a 1 1
• 1 1
• 1 1

b zeros(1,5) b 0 0 0 0 0
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Using Matlab

• Data Types and Formats
• The semicolon operator determines whether the
  result of an expression is displayed
• who lists all of the variables in your
  matlab workspace
• whos list the variables and describes their
  matrix size

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Using Matlab
Saving your Work To save data to a .mat
file Typing save filename at the gtgt prompt and
the file filename.mat will be saved to the
working directory Select Save from the file pull
down menu To reload a .mat file 1. Type
load filename at the gtgt prompt to load
filename.mat (ensure the filename is located
in the current working directory) 2. Select
Open from the file pull down menu and manually
find the datafile
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Getting Help

• Help and Documentation
• Digital
• Updated online help from the Matlab Mathworks
  website
• www.mathworks.com/access/helpdesk/help/techdoc/mat
  lab.html
• Matlab command prompt function lookup
• Built in Demos
• Websites
• Hard Copy
• Books, Guides, Reference
• The Student Edition of Matlab pub. Mathworks Inc.

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Exercises
Enter the following Matrices in matlab using
spaces, commas, and semicolons to separate rows
and columns
A
B
D
D
C
E a 5 x 9 matrix of 1s
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Exercises
Use the who and whos functions to confirm all of
the variables and matrices in the work space are
present and correct
A
B
D
D
C
E a 5 x 9 matrix of 1s
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Exercises
Change the following elements in each matrix
76
76
0
A
B
0
D
76
0
D
C
76
E a 5 x 9 matrix of 1s
76
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