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General Computer Science for Engineers CISC 106 Lecture 03. James Atlas Computer and Information Sciences 9/9/2009. Objectives. Use Matlab remotely Use Basic Unix Commands Document Functions Use Conditions If statement Input/Output variables. Using Matlab Remotely (text). - PowerPoint PPT Presentation
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General Computer Science General Computer Science for Engineersfor Engineers
CISC 106CISC 106Lecture 03Lecture 03
James AtlasComputer and Information Sciences
9/9/2009
ObjectivesObjectivesUse Matlab remotelyUse Basic Unix CommandsDocument FunctionsUse Conditions
◦If statementInput/Output variables
Using Matlab Remotely (text)ssh [email protected]
◦requires an ssh program such as PuTTY◦see course website for installation details
at prompt type:matlab -nodesktop
Using Matlab Remotely (GUI)Mac users:
◦ You already have an X-Windows environmentPC users:
◦ You must setup Cygwin-X◦ Download Cygwin setup.exe from:
http://www.cygwin.com/◦ Run setup.exe and select additional packages
for: xauth xinit openssh
Running Matlab RemotelyOnce the X-Windows environment is
setup, open a terminal window and login to strauss:◦ssh -c arcfour,blowfish-cbc -YC
[email protected] start Matlab:
◦matlab &
What does the & do?
EmacsEmacsTo start emacs
◦ emacs Graphical version◦ emacs –nw Text version
To open a file◦ emacs <filename>◦ emacs … then Ctrl-x Ctrl-f◦ Menu: File then “Open File…”
To save file◦ Ctrl-x Ctrl-s◦ Menu: File then “Save (current buffer)”
Exit◦ Ctrl-x Ctrl-c
Unix CommandsUnix CommandsWhen you log into a UNIX terminal
◦ You are in your home directory.◦ To see the files in your directory.
ls
◦ To make an new folder/directory. mkdir exampledir
◦ To change directories. cd exampledir
◦ To go back one directory. cd ..
◦ To go back to your home directory. cd
Handling filesHandling filescp file1 file2
◦ copy file1 and call it file2 mv file1 file2
◦ move or rename file1 to file2 rm file
◦ remove a file rmdir exampledir
◦ remove a directory cat file
◦ display contents of a file less file
◦ display a file a page at a time
Function documentationContractDescriptionExamples
Sample function circleArea.mSample function circleArea.m%circleArea(number) -> number
%Authors: James Atlas
%CISC106 Lab Section 45 TA: Scott Ivanka
%Description:
% This function computes the area of a circle
% given the radius.
%Examples:
% circleArea(3) -> 28
% circleArea(5) -> 78
% circleArea(45) -> 6362
function output = circleArea(radius)
output = pi * radius * radius;
Sample function circleArea.mSample function circleArea.m%circleArea(number) -> number
%Authors: James Atlas
%CISC106 Lab Section 45 TA: Scott Ivanka
%Description:
% This function computes the area of a circle
% given the radius.
%Examples:
% circleArea(3) -> 28
% circleArea(5) -> 78
% circleArea(45) -> 6362
function output = circleArea(radius)
output = pi * radius * radius;
Contract
Write one for function Write one for function ringArea.mringArea.mContractDescriptionExamples
ConditionsWhen you want to make a decision
based on data“If traffic light is red, stop”
ConditionsWhen you want to make a decision
based on data“If traffic light is red, stop”
◦Involves some comparison operator between data and a known value
◦known value = red◦data = current state of the traffic light◦comparison operator is “equals”
ConditionsWhen you want to make a decision
based on data“If traffic light is red, stop”
◦Involves some comparison operator between data and a known value
◦known value = red◦data = current state of the traffic light◦comparison operator is “equals”
“If current state of traffic light equals red, stop”
ConditionsIf statementOthers (will talk about later)
IF Statements in MatlabIF statements allow program to make
choices whether a condition is met or not
Basic if statement
if expression1 statements1
elseif expression2 statements2
else statements3
end
IF Statements in MatlabIF statements can be used with or
without the ELSEIF and ELSE parts
Traffic Light Examplefunction out = trafficLight(currentColor)
if (currentColor == 'R')
out = 'stop';
elseif (currentColor == 'Y')
out = 'slow';
else
out = 'go';
end
Condition operatorsequals
◦ ==not equals
◦ ~=greater than
◦ >◦ >=
less than◦ <◦ <=
Simple Input/Output
fav = input(‘Enter your favorite number\n’);
if (fav >= 0)disp(‘You like positive numbers’);
elsedisp(‘You like negative numbers’);
endfprintf(‘Your favorite number is %d’, fav);
Lab01Practice some unix commandsMatlab file sumIntsTest.m
◦an example of a “unit test”Create new functions