Informetric methods seminar

Tutorial 1: Matlab basicsErjia Yan

Getting started Install and use Matlab Data format in Matlab Export and import data in Matlab Useful functions and commands Programming in Matlab Resources

Contents

Getting started Install and use Matlab Data format in Matlab Export and import data in Matlab Useful functions and commands Programming in Matlab Resources

Contents

Some screenshots are taken from www.mathworks.com

High-level language for numerical computation, visualization, and application development

Built-in mathematical functions for linear algebra, statistics, matrix manipulation, etc.

Extensive tool-boxes (e.g., accounting, bioinformatics, etc.)

Built-in graphics for visualizing data and tools for creating custom plots

Functions for integrating MATLAB based algorithms with external applications and languages such as C, Java, .NET, and Microsoft® Excel®

Matlab key features

http://www.mathworks.com/products/matlab/description1.html

Getting started Install and use Matlab Data format in Matlab Export and import data in Matlab Useful functions and commands Programming in Matlab Resources

Contents

Desktop installation

Access Matlab in IU

Per yearOnly available on university-owned computersStudents can purchase directly from Mathworks.com

For students

https://iuanyware.iu.edu/vpn/index.html

Free IU Anyware access

East and west tower desktops And most UITS desktops on campus,

except for stand-alone informstations

Free UITS desktop access

http://racinfo.indiana.edu/hps/quarry For large data processing; batch file-

based Need to register an account before

using Windows users can use WinSCP and

Putty to upload/download files and send commands

Quarry…

Interface

http://www.tufts.edu/~rwhite07/Matlab_files/image017.jpg

Image interface

http://www.aquaphoenix.com/lecture/matlab10/images-large/matlab_audio_funky_plot_spectrogram_detail.jpg

Getting started Install and use Matlab Data format in Matlab Export and import data in Matlab Useful functions and commands Programming in Matlab Resources

Contents

Number: 4.34 Character: ‘variable_name’ Do not need to state variable types

a=4.34 cellname=‘networks’

Built-in variable (do not use them) pi, Inf, -Inf, ans, NaN

Variables

row=[1,2,3,4,5] a 1*5 matrix

column=[1;2;3;4;5] a 5*1 matrix

a=[1,2;3,4] a 2*2 matrix

Arrays and matrix

You can give any variable names to row and column.

a=

Getting started Install and use Matlab Data format in Matlab Export and import data in Matlab Useful functions and commands Programming in Matlab Resources

Contents

a=xlsread(filename) a=xlsread(filename,sheet) a=xlsread(filename,xlRange) a=xlsread(filename,sheet,xlRange)

Full matrix read

For other import and export functions in Matlab, such as textual data, XML, etc., you can find relevant information here: http://www.mathworks.com/help/matlab/data-import-and-export.html

xlswrite(filename,A) xlswrite(filename,A,sheet) xlswrite(filename,A,xlRange) xlswrite(filename,A,sheet,xlRange)

Full matrix write

a = csvread(filename,row,col) csvwrite(filename,a,row,col)

CSV files

row and col are zero based, meaning that they start from 0 but not 1

S = spconvert(D) Sparse matrix format

row_id col_id value First use load to upload the data into

Matlab and then use spconvert to convert the data into a matrix load datasample.txt M = spconvert(datasample)

Sparse matrix import

You can use mmwrite(filename,M) http://math.nist.gov/MatrixMarket/m

mio/matlab/mmiomatlab.html

Sparse matrix export

Getting started Install and use Matlab Data format in Matlab Export and import data in Matlab Useful functions and commands Programming in Matlab Resources

Contents

Arithmetic operations (+,-,*,/) 4+5*7-2

Exponentiation (^) 2^3=8

Operators

sqrt(2) log(2), log10(0.23) cos(1.2), atan(-.8) exp(2+4*i) round(1.4)=1, floor(3.9)=3,

ceil(4.23)=5 plot(x,y)

And countless more…

Built-in functions

Transpose transpose(M) M’

Addition and subtraction M-M’=

M+M’=

For matrices

M= M’=

=

=

For element-wise operations, use the dot: .(.*, ./, .^) M.*M’=

M./M’=

Matrix operations M*M’=

Multiplication and division

=

=

=

M(1,1)=1; M(1,2)=2 M(1,:)=[1 2] M(1:2,2)=

Indexing

M=

[ 24 ]

Getting started Install and use Matlab Data format in Matlab Export and import data in Matlab Useful functions and commands Programming in Matlab Resources

Contents

Command line

M file

Compiler http://www.mathworks.com/products/co

mpiler/

Object-Oriented Programming http://

www.mathworks.com/discovery/object-oriented-programming.html

Advanced programming

Getting started Install and use Matlab Data format in Matlab Export and import data in Matlab Useful functions and commands Programming in Matlab Resources

Contents

help command in Matlab…the most useful

Matlab Central http://www.mathworks.com/matlabcentr

al/

MIT Open Course http://ocw.mit.edu/courses/electrical-eng

ineering-and-computer-science/6-094-introduction-to-matlab-january-iap-2010/lecture-notes/

Google “matlab + keywords”

Free resources