Getting started Quick demo of a couple of real-life uses: plotting sample data loading an image (+ playing around) image capture demo Diving straight in start Matlab by clicking the icon in the dock or log on to https://matlab.mathworks.com/ Rest of this session (1) We'll get you kick-started and explain how to: do simple maths with Matlab learn about + create variables change variables github.com/schluppeck/learningMatlab The Matlab environment Important Notation >> to illustrate the Matlab prompt. Don't type it again % is the symbol for comments. Things on the line after the symbol >> 1 + 1 % this is really silly maths numbers are written like you'd expect:: >> 129 % a simple "integer" >> -4.32 % negative number, with decimals >> 1.2e5 % engineering notation. The same as 1.2 * 10.^5 Some terminology Variables: a named placeholder for something Matlab commands or functions do stuff to inputs and return an outputs operators: really also just functions, but a convenient shortcut for very common jobs + - * / etc. much more on this later Doing some maths add, subtract, multiply, divide numbers like this: >> 1 + 1 - 1 % + and - >> 10 .* 5 % use .* and ./ to multiply and divide >> 2 .^ 0 >> 2 .^ 8 % use .^ to raise to power .* versus * (/ versus ./) note that the operators for multiply and divide are .* and ./ (more on the extra "dot" later) use parenthesess ( ) to make order of operations explicit: >> (10 + 1) .* 9 >> 10 + 1 .* 9 % not the same, WHY? 5 minutes practice Take 5-10 minutes to do simple maths exercises (first set in the last section of handout) and on next slide. If you get error messages, check your typing and try to understand what's gone wrong We'll move around the room to help if you are stuck Simple maths 3/2 value of pi (π\piπ). What do you think this could be called in Matlab? two times pi (π\piπ) 2 to the power of 8 4 to the power of 3 64 to the power of one third (bonus) the square root of 81 (not using the sqrt() function?!) Variables to store the results (and work on them), you can put data in a variable >> a = 10 % stores the number 10 in a variable called "a" >> b = 2+2 % stores the result of 2+2 in "b" you can now use the variables (or place holders):: >> a .* 2.3 % uses "a" >> c = a + b % stores result of a+b in "c" What's in my variables To get information about variables: interactive way in workspace explorer on command prompt >> c % enter variable name to display >> who % this command shows you variables in "workspace" >> whos % ... and with some additional information >> clear c % to get rid of c Vectors and Matrices Matlab is very good with dealing with vectors and matrices Vectors: lists of numbers: >> x = [1, 2, 3] % a ROW vector >> y = [4; 5; 6] % a COLUMN vector Matrices: tables of numbers:: >> u = [1, 2, 3 ; 4, 5, 6] % a 2 by 3 matrix Defining vectors, list of numbers Take some time to do the exercises on defining vectors and matrices. If you get unexpected error messages, take a note and we'll try to help you understand what's gone wrong We'll move around the room to help if you are stuck Creating Matrices fill a matrix with numbers:: >> ones(2,5) % 2-by-5 matrix full of 1 >> zeros(3,3) % 3-by-3 matrix full of 0 >> rand (100) % a 100-by-100 matrix of uniform random numbers many other useful commands:: >> randn(5) % gaussian random numbers (5-by-5 matrix) >> nan(10) % not-a-number ... useful in some cases