190 likes | 201 Views
General Computer Science for Engineers CISC 106 Lecture 02. James Atlas Computer and Information Sciences 9/4/2009. Objectives. Understand/explain how our Matlab program executes Use different types of Variables Use compound Expressions Access Matlab remotely. How does our program work?.
E N D
General Computer Science for EngineersCISC 106Lecture 02 James Atlas Computer and Information Sciences 9/4/2009
Objectives • Understand/explain how our Matlab program executes • Use different types of Variables • Use compound Expressions • Access Matlab remotely
How does our program work? • CPU • Disk • Memory
Our Program in Memory x86 instructions • ~~~~~~~~~~ • ~~~~~~~~~~ • ~~~~~~~~~~ • ~~~~~~~~~~ • ~~~~~~~~~~ • ~~~~~~~~~~ • ~~~~~~~~~~ • ~~~~~~~~~~ • . . .
Variables • var = expression • x = 2 * 2 • comment = ‘This is a string’ • area = circleArea(5) What type of data is stored in each variable?
How do computers store data? • Binary • Billions of tiny logic gates representing ON and OFF (1 and 0) • Video • http://www.youtube.com/watch?v=b6vHZ95XDwU
Data Types in Matlab • Floating point number by default • “double” precision = 64-bits of memory
Operations on Data Types • 5.5 • single(5.5) • int8(5) • int8(500) ? • int8(‘c’) ? • char(98) ? >> x = 5.5 >> whos x
Expressions • Data and Operator • 2 + 2 • circleArea(5)
Expressions • Data and Operator • 2 + 2 • circleArea(5) • Nested Expressions • circleArea(circleArea(5 + 2) + circleArea(3))
Expressions • Data and Operator • 2 + 2 • circleArea(5) • Nested Expressions • circleArea(circleArea(5 + 2) + circleArea(3)) • Expressions produce a value
Unix Commands • When 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 files • cp 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
Using Matlab Remotely (text) • ssh yourusername@strauss.udel.edu • 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 environment • PC 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 Remotely • Once the X-Windows environment is setup, open a terminal window and login to strauss: • ssh -c arcfour,blowfish-cbc -YC yourusername@strauss.udel.edu • Now start Matlab: • matlab & • What does the & do?