Variable names are an example of an identifier name: The name must begin with a letter of the alphabet Using mixed case can solve some problems with

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1 Chapter 1 Gui basically just a bunch of boxes that has been created by code % represents a comment. Does not actually do anything. Just helps you make more sense of the program Loop -when you do things repeatedly 1,2,3,4,repeat.. While command Sets up a loop Follow up by a true false statement. True repeats the loop False ends the loop Anything in a parenthesis represents a function can be named anything "function" does not actually do anything "disp" displays a message "mod" create a clock arithmetic 10,11,12,1,2.etc. No semicolon means an answer will be given =@ anonymous function ~ means not. Negates the function to mean the opposite "diary" starts a recording of the program "diary off" ends the recording "more" shows you more of a file Assignment statement Left side is the name of the variable Right side is the expression 'who' - lists out all of your variables Scripts - groups of commands that are executed sequentially >> = prompt Enter commands or expressions here and MATLAB will produce a result Programs - things contained in script files Commands: >>Demo - brings up examples in the Help browser >>Help - explains a function >>lookfor - searches help for specific words or phrases >>doc - brings up a documentation page in the help browser >>quit/exit - exits MATLAB Variable - a way to store a value in MATLAB Create variables using assignment statements Variable is on the left "=" = the assignment operator >> X = 6 X 6 >> ; at the end of the statement suppresses the output "ans" the variable that will be stored from the most recent arithmetic done Not a good idea to use "ans" as a defined variable Use the up arrow as a shortcut to retype commands

2 Variable names are an example of an identifier name: The name must begin with a letter of the alphabet Using mixed case can solve some problems with underscores Ex: TylerHahn Store variables as names that make sense as to what that variable is >>Who - shows the variables that have been assigned answers >>Clear - clears out all variables so they no longer exist >>Clear VariableName - clears out the specific variable Double click on a variable in the workspace to modify components Types Numbers Single precision - stores less numbers in a decimal place Double precision - stores more numbers in a decimal place Integer types Int8, int16, int32, int64 Represents the number of bits(characters in this case) that will be used Uint(8,16,32,64) Unsigned integer types(will always be positive) Char- used to store single characters or Strings - a sequence of characters Both characters and strings are in closed in single quotes '123 ' Logical - used to store true false values Changing format Numbers Short - the standard format for numbers, will display to four decimal places Long - display 15 decimal places Spacing Loose - empty lines between lines of code Compact - no empty lines For long commands use an ellipsis( ) to continue the command to the next line Operators Unary - operate on a single value Binary - operate on two values Operator precedence rules Same rules as you are used to in math remember PEMDAS In order of precedence: () parentheses ^ exponentiation - negation */\ multiplication and division +- addition and subtraction Calling a function The name of the function is given followed by the argument(s) in parenthesis Tab completion If you type the beginning characters in the name of a function and hit tab A list of functions that contain the letters will pop up Constants NaN - Not a Number

3 Random numbers >>rand(n,m) Gives a random number between the interval n to m The default interval for random numbers is (0,1) >>randn Normally distributed random real numbers >>randi Random integer Imin = integer min Imax = integer max >>Randi(n) Returns an integer in the interval (0,n) >>rng Sets the seed for Random number generator Characters and Strings Represented using single quotes ex: 'a' No quotes would denote a variable assignment '3' is a character 3 is a number Strings - sequences of numbers 128 different characters Relational expressions Expressions that are either true or false Sometimes called boolean expressions or logical expressions Regional operators - relate two expressions > < >= <= == ~= True = 1 = logical(1) False = 0 = logical(0) >>xor Exclusive or function Returns 'true' if one and only one of the statements are true >> Short circuit operations If the first statement it true it will respond with a true response without even looking at the second statement Type Ranges and Type Casting >>intmin Set the smallest possible integer >>intmax Sets the largest possible integer Casting Converts the type 'like' - changes one variable type to another variable type >>numequiv = ' '

4 Give the numerical equivalent of the character >>char Does the opposite and gives the character after inputting a number >>double Doubles the character value of everything put in as the assignment Built in numerical functions >>rem (#,#) Gives the remainder after dividing two numbers >>sign (#) Gives the sign of the number inputted >>round (#) Rounds a number to the specified number of digits >>nthroot (64, 3) Takes the cube root of 64 >>sqrt Square root >>log(x) Returns the natural logarithm >>log2(x) Returns the base 2 logarithm >>log10(x) Returns the base 10 logarithm >>exp(n) Returns the constant e^n >>deg2rad Converts degrees to radians >>rad2deg Converts radians to degrees Class notes >>rad = input('radius = '); >>area = pi * (rad^2) >>fprintf('the area of radius %f is %f \n', rad, area) The first %f refers to the first variable listed The second %f refers to the second variable listen Chapter 2 Vectors and matrices Row vector 1 x n Column vector N x 1 Elements The numbers inside of the matrix Array Will often be used interchangeably with the word matrix Creating row vectors

5 >>'name of matrix' = [ ] Colon operator(:) can be used to iterate through values >> v = 3:5 V = A step value can also be assigned using another colon >>v = 0:4:12 V = Matrix goes from 0-12 in increments of 4 Linspace Create a linearly spaced vector with n values Ls = linspace(x,y,n) X = min value Y = max value N = number of values in between Logspace Creates a logarithmically spaced vector >>logspace(x,y,n) X = 10^x Y = 10^y N = number of elements Vector variables can be created using existing variables >>newvec = [2 4 8 V] Newvec = >>newvec (n) Tells you the value in the n th element of the vector >>b = newvec(4:6) B = >>newvec([1 3 5]) This gives the first third and fifth elements in the matrix Changing an element >>b(1) = 2 The first element in b is now 2 Adding an element >>b(4) = 5 The new matrix is now If a element is skipped it will automatically get filled in with zeros Creating column vectors Use semicolons to separate rows >>c = [1; 2; 3; 4] C = 1 2 3

6 4 Any row vector can be transposed using an apostrophe >>r=1:3; >>c = r' C = Creating matrix variable >>mat = [4 3 1; 2 5 6] Mat = Random matrices can be created that are n x n >>rand(2) Creates a 2 x 2 matrix with random numbers >>rand(n,m) Creates a n X m matrix with random values >>randi ( [0, 10], 3, 3) Randi - random integer matrix [0, 10] - defines the range of popular integers 3, 3 - states it is a 3 x 3 matrix Can create a 0 matrix or a 1 matrix using the commands >>zeros(r, c) >>ones(r, c) Referring to and modifying elements of a matrix >>mat = [2:4; 3:5] Mat = >>mat(2,3) Ans = 5 >>mat(1:2, 2:3) Ans: :2 - calls the rows 1-2 2:3 - calls the columns 3-4 >>mat(1,:) Ans = calls the first row only : - calls all columns >>mat(1,2) = 11 Mat=

7 Changes one specific element >>mat (2,:) = 5:7 Mat= >>m = randi ([10 50], 3,5) M = %creating a random matrix% >>m(2:3, 3:5) = 3 M = This demonstrates how to change an entire subsection of a matric to a new value >>mat(:,4) = [9 2]' Mat = This demonstrates how to add a new column the same could be done with a row Dimensions Mat = >>length( ) Returns the number of rows or columns in a vector, whichever is largest >>size( ) Returns the size of the vector >>[r, c] = size(mat) R = 3 C = 2 This returned the Rows x Columns then saved those vectors as the variables R and C >>numel(mat) Ans= 6 Returns the total number of elements in the vector End - refers to the last element in either the row or column >>mat(end,1) Ans = 3 >>mat(1,end) Ans = 5 Changing dimensions

8 >>reshape(mat,r,c) Reshapes the matrix to the new column and row dimensions maintaining element position in that matrix >>fliplr(mat) Flips the matrix left and right. First column becomes last etc. >>flipup(mat) Flips the matrix up and down. First row becomes last etc. >>flip Used on vectors to switch >>rot90(mat) Rotates the vector 90 degrees clockwise >>repmat(mat,r,c) Replicates a matrix and plugs the old matrix into the new matrix >>repelem(mat,r,c) Replicates a matrix in the new dimensions specified Empty Vectors An empty vector can be created using square brackets >>evec = [] >>evec = [evec 4] This will add 4 to the empty vector >>evec = 4 >>evec = [evec 11] >>evec = 4 11 Three dimensional matrices Make sure you have the same rxc dimensions for the three dimensional layers >>layerone = reshape(1:15,3,5) Layerone = Most matrices are going to be two dimensional so don't worry about this too much Vectors and Matrices as function arguments An entire matrix can be passed to a function as an argument Vec = -2:1 Vec = >>absvec = abs(vec) Absvec= >>min Will return the smallest value in a vector(each column) >>max Returns the largest value in a vector( each column) >>sum

9 Adds up all the elements in a matrix >>prod Returns the product off all elements in a matrix >>cumsum Cumulative sum. Basically just shows all the steps it take to calculate >>sum >>cumprod Same as cumsum but for multiplication >>diff Returns the difference between consecutive elements of a vector Scalar and array operations on vectors and matrices >>v = [ ]; >>v = v * 3 V= [ ] "." is a way of saying to do operations on vectors term by term Logical vectors Logical vectors use rational expression that result in true/false values Relational expressions with vectors and matrices When using <,>,== the result will be a logical output True and false commands can be used to create 0 matrices and 1 matrices Matrix multiplication This is not multiplying term by term The columns of the first one must equal the rows of the second >>dot(vec1,vec2) How to code in a dot product >>cross(vec1,vec2) How to use the cross product on a set of vectors Chapter 3 Scripts - a chain of commands Algorithms - A sequence of steps used to solve the problem Top-down design - taking big tasks and breaking them down into small manageable tasks Prompting - telling the user they need to enter something For most programs the basic algorithm is a. Get the inputs b. Calculate the results c. Display the results Matlab Scripts Following a list of commands sequentially Compiler - the program that takes stuff from a high level language like MATLAB and convert it to a computer language Source code - the code you actually type Object code - the code that is used by the complier Creating a new script Click on "new script" under the home tab Moving from command window to a script Select commands in command window

10 Right click Click either script or live script % - allows you to enter comments on your matlab script and it will not be read when the program is executed Insert a space after the first line of the function to allow a 'help' command to make sense Input and Output Delimeters - general statement for punctuation marks %f is a string %d is a number >>Variable = input('some stuff') 's' allows you to enter strings into an input function Blank spaces before a character are stored as part of that string Serarate input statements are necessary if more than one input is desired >>disp(variable) Displays the variable without formating >>fprintf('words %f', variable) \n starts the command on the next line Use after the %f or %d in the fprintf command %d = integer %f = float real number %c = character %s = string of characters %#f The # is how many chracters it will be %5.3f Five digits with three decimal places Printing a vector Vec = 2:5; Fprintf('%d', vec) Fprintf('\n') Disp may work better for matrices because it displays it the way it should look and not with linear indexing Scripts to produce and customize simple plots Creating a plot is much easier in a script than from just the command window >>clf - clears everything from the figure window >>Figure - creates a new empty figure window >>hold - prevents creating a new plot. Points will continue to be placed on the current one >>legend - displays strings given to it that will be displayed on the plot >>grid - displays the gridlines on the graph Bar graphs are also able to be created Writing to a file - writing a file from the start Appending a file - adding to the end of a preexisting file >>save filename - saves the file Will always overwrite an existing file >>type FileName - displays the data in the file >>load FileName - loads the file and puts the data into a matrix User defined functions that return a single value Function header containts

11 the reserved word function The name of the output argument The name of the function The input arguments in parenthesis A comment the describes what the function does (%) The body of the function End - at the end of the function. This lets matlab know the function is over Function argument = functionname(input arguments) % the function does Statements here End Naming the file and the function the same thing is generally a good idea Function variables will not show up in the workspace like script variables Commands and functions >>type - types out the function for you to see >>load - creates a variable with the same name as the file Lecture Use a logical matrix and the sum function to be able to count how many of a certain letter are in a string && checks first statement then second & check both statements anyways or statement Chapter 4 >>if condition Action end '' double quotes like these are used inside printed statements to tell matlab to print only one apostrophe (') If-else statement if condition Action1 Else Action2 Error('error statement') Displaces the message in red If condition 1 Action 1 Elseif condition 2 Action 2 Elseif condition 3 Action 3 Else Action 4 End

12 The Switch Statement Switch Switch_Expression Case caseexp1 Action1 Case caseexp2 Action2 Case caseexp3 Action3 Otherwise Action4 End 'Switch_Expression' must be either a scalar or a string Combining multiple expressions can be done using { expression1, expression2} These will both result in the same action The "is" function in MatLab Many statements will have the word "is" in front of them and will return a logical answer >>isletter('h') Ans = 1 >>isempty Checks for an empty matrix >>isa(num, 'int16') Used to check a number to verify if it is a particular type >>iskeyword('xxx') Test to see if the word is a key word in matlab and can or can't be used as a variable Chapter 6 While If Or Switch Case For the project Sodoku Three functions One to check the rows One to check the columns One to check the compartments More types of user defined functions Functions that return or store variables Function [variables, calculated] = FunctionName(input) Functions that accomplish a task without returning values Function FunctionName(input) Cannot be inbedded in other statements and the outputs can not be stored as variables Functions that return values versus printing

13 It is good practice to separate the printing task from the function. The printing should be done in the script Passing arguments to functions Functions that don't need arguments like a function that returns a random number can completely leave the parenthesis out if desired If you're going to use input functions no parenthesis are needed either because the arguments will be asked for later in the function Matlab Program organization Modular programs - each program is broken down into their individual functions Main program - the main scrip that calls to the modular programs Primary function - the main function of the document Subfunction - the function that is called by the primary function Menu driven modular program Menu driven - matlab will display a menu of choices for the user to choose from Variable scope Scope - the workspace in which a variable is valid Base workspace - the workspace created in the command window of matlab Local variable - only used for a single function. Exists only inside that function Scripts interact with the variables in the workspace, however functions do not Persistent variables - variable that are not forgotten when the function is over Persistent 'variable' >>clear function Clears all the persistent variables >>clear func2 Clears the specific function's persistent variables Debugging techniques >>checkcode Function used to search for possible problems in the code Types of errors Syntax - an error in using the code Spelling errors Runtime (execution) errors - using incorrect matrix dimensions Logical error - a mistake in reasoning by the programmer >>echo functionname Lets the programmer know what function is being ran each time >>dbstop FunctionName # Stops the debug as the specified line number >>dbcont Continue the debugging >>dbquit Quits the debugging Breakpoint alley Denoted by a grey line in the code, use to set as a stopping point in the code to exam everything that has happened so far Function stubs Writing smaller functions that will eventually be combined to one script Live Scripts, Code Cells, and Publishing code Live scripts

14 Make the coding look nicer things such as: Different fonts Graphs next to code Equations Stored in.mlx files Code cells Allows each section of code to be run one at a time %% title of cell Click on the cell and hit run to run the specific section Chapter 11 Using objects with graphics and plot properties >>figure Returns the graphics handle Handle - basically the information about a graphic >>get(figure) Shows you all the information about the plot >>get(nameoffigure, 'Property') >>set(nameoffigure, 'PropertyName', property value) 'ui' = user interface Color is stored as the matrix [red green blue] [1 1 1] = white [0 0 0] = black 'gca' = get current axes 'gcf' = get current figure Chapter 5 Preface Counted loop - a loop that will repeat for a finite amount of times Conditional loops - repeats the loop for unknown amount of times until a condition is no longer met The for loop Counted loop >>For LoopVariable = range Action(s) End When using a running product, don't forget to initialize the variable as 1 >>subplot(r,c,n) Creates a matrix of plots with r rows c columns and n is the particular plot in the matrix While loops This is the conditional loop used in Matlab

15 >>while condition Action End The loop will eventually need to become false otherwise an infinite loop will be created Ctrl+C will get you out of this Use a variable to count how many times the loop is repeated. Var = var + 1 Put this inside the loop and it will count how many times the loop is done These can commonly be used to check for legal values being inputted to a function Loops with vectors and matrices; vectorizing Typically used with for loops >>for I = 1:length(vec) Action End To use this on a matrix a nested for loop would be best >>for col = 1:c For for = 1:c Do something with mat(row, Column) End End >>any >>all >>find 'is' functions return logicla values >>checkcode Lets you know if there are any style or function problems in the code Timing >>tic - starts a clock >>toc - ends a clock Chapter 12 Plot functions and customizing plots Plot - creates a 2D scatter plot Bar - creates a bar graph Clf - clears the figure window Xlable - sets the x label Ylable - sets the y label Title - sets the title Legend - creates a legend Sprintf - Chapter 7

16 String - any number of characters and is contained in single quotes Creating string variables Substring - a portion of an already created string Control characters - characters that cannot be printed, but accomplish a task (spaces) Leading blanks - a string that starts with a space Trailing blanks - a string that ends with a space Input('enter a string: ', 's') that makes the input a string and can be assigned to a variable from there Operations on strings String concatenation - combines 2 strings >>first = 'bird' >>last = 'house' >> [first last] Birdhouse >>strcat(1,2) horizontally combines two strings This removes all blanks while the bracket method does not >>char Along with converting numbers into characters This function will combine strings vertically and will add necessary spaces to even up the matrix >>blanks(#) Creates a blank string variable >>sprintf Creates a string instead of simply printing out the variables you originally wanted >>deblank Removes trailing blanks from a string >>strtrim Removes bother leading and trailing blanks from a function >>upper(string) Makes a string all uppercase >>lower(string) Makes a string all lowercase >>strcmp(str1, str2) Compares two strings and returns 1 or 0 depending on if the strings are identical or not >>strcmpi(str2, str2) Compares two strings, but ignores case >>strfind(string, substring) Finds places where the substring is in the main string and returns the positions using linear indexing >>strrep(string, substring1, substring2) Replaces substring 1 with substring 2 >>eval(string) Used to evaluate a function if there is a function inside a string 'is' function for strings Returns logical true or false functions >>isletter(string) 1's for letters 0's for anything else Isnumber

17 Isspace isempty >>ischar Test to see if it s a character Converting between string and number types Num2str Int2str Str2double Str2num Chapter 8 Cell arrays Elements of cell arrays can be of any type Use {} to denote a cell array The type of a cell array is always 'cell' Cell(r, c) Creates an empty cell array with r rows and c columns Cellvariable(cell number) Will tell you the type of the cell being referenced Cellvariable{cell number} Displays what is in the cell Strjoin Joins multiple strings together Strsplit Splits a string into its original elements Structures Structure name = struct(information and assignments) The class is stored as a struct Using the dot operator (.) allows you to navigate the structure Using an fprintf will only be able to display individual components. Not the whole structure Rmfield Removes a field from a structure Isstruct Checks if a variable is a structure Fieldnames Returns the names of all the fields in the structure This is returned as a cell array Enhanced data structures Categorial arrays Allows one to store a finite, countable number of different possible values Categories Returns the categories in alphabetical order Countcats or summary Counts how many time each category occurs They work in slightly different ways. Summary displays the names by the number of occurrences

18 Ordinal categorical arrays This can be used when there is a more logical order than simply alphabetical Variable = categorical(list, the, different, categories, in order, of, appearance, here) Tables Variable = table(c1, C2, 'RowNames' R1) Use {} to extract data from string assignments and get the numerical matrix Summary Will show you information about the categories Sorting Sort(data array) Fliplr or flipup can be used to change from ascending order to descending order Sortrows Will sort the function by row Index Vector End Cell2struct Changes a cell to a structure Struct2cell Changes a structure to a cell