MATLAB Programming/Print Version - Wikibooks, open books for an open world. Chapter 1: A Tutorial Introduction. Chapter 2: Basic MATLAB Concepts. The Current Directory and Defined Path. MATLAB Programming/Print Version. It's even possible to write loops and branches at the command line if you want to. Note that if you use j MATLAB still displays i on the screen. This makes it convenient to write things like 11 MATLAB does avoid copying a function argument. Similar to an error is a warning, which displays a message but allows. DISTMESH is a MATLAB program which generates and. General Public License along with this program; if not, write to the Free. Write a MATLAB program that determines sin(x) using the. As output the program displays the integer n and the corresponding sum. Write a program that accepts a year and determines whether or not the year. Write a MATLAB program to compute how much money will. It is necessary to declare a current directory before saving a file, loading a file, or running an M- file. By default, unless you edit the MATLAB shortcut, the current directory will be ../MATLAB/work. After you start MATLAB, change the current directory by either using the toolbar at the left- hand side of the screen, or entering the path in the bar at the top. The current directory is the directory MATLAB will look in first for a function you try to call. Therefore if you have multiple folders and each of them has an M- file of the same name, there will not be a discrepancy if you set the current directory beforehand. The current directory is also the directory in which MATLAB will first look for a data file. If you still want to call a function but it is not part of the current directory, you must define it using MATLAB's 'set path' utility. To access this utility, follow the path: file > set path.. Then look for and select the folder you want. 1.5 Input and Output; 1.6 Case Study: PageRank. Write a program Clock.java that displays an animation of the second. 172 Chapter 7: Programming in MATLAB. Write a program in a script file that calculates the pay to a worker. Solution The program in a script file is shown below. If you forget to do this and attempt to access a file that is not part of your defined path list, you will get an 'undefined function' error. Saving Files. There are many ways to save to files in MATLAB. The files are saved in your current directory, as seen on the top of the window. By default the current directory is ../MATLAB/work. Loading Files. Likewise, there are many ways to load files into the workspace. One way is to use the . To open a . m file click . Write A Matlab Program That Determines And Displays The ProgramWrite A Matlab Program That Determines And Displays The NameTo get the name of this and all other environment variables, type . The following characters cannot be used in filenames: ? You're not allowed to use the name of a reserved word as the name of a file. For example, while. MATLAB's reserved words. When you declare an m- file function, the m- file must be the same name as the function or MATLAB will not be able to run it. For example, if you declare a function called 'factorial'. Y = factorial(X). You must save it as . MATLAB will name it for you if you save it after typing the function declaration, but if you change the name of the function you must change the name of the file manually, and vice versa. Introduction. MATLAB is interesting in that it is dynamically compiled. In other words, when you're using it, you won't run all your code through a compiler, generate an executable, and then run the executable file to obtain a result. Instead, MATLAB simply goes line by line and performs the calculations without the need for an executable. Partly because of this, it is possible to do calculations one line at a time at the command line using the same syntax as would be used in a file. It's even possible to write loops and branches at the command line if you want to. Of course this would often lead to a lot of wasted efforts, so doing anything beyond very simple calculations, testing to see if a certain function, syntax, etc. Let us try to solve a simple problem: Sam's car's odometer reading was 3. Yesterday he checked his odometer and it read 3. He filled the tank and noticed that it took 1. If his car's gas tank holds 1. First let us compute the distance Sam's car has travelled in between the two gas fillings. Gas mileage of Sam's car is. With this, he can drive. Let us do the same example, now by creating named variables. The result will be stored in memory. You can then access the variable by calling its name. Example. > > projected. To call a function, the following general syntax is used. In the former case, it produces a noise and displays an error message in red. In the latter case, MATLAB will relinquish control to you, which you can see when the > > symbol is visible on the bottom of the workspace and the text next to . MATLAB has a large array of functions, and the help file as well as this wikibook are good places to look for help on what you need to provide as inputs and what you will get back. Be careful; the syntax for functions and for indexing arrays is the same. To avoid confusion, just make sure you don't name a variable the same as any function. To ensure this, type the name of the variable you want to define in the command prompt. If it tells you. Error using ==> (functionname). Not enough input arguments. Undefined function or variable '(functionname)'. OK. External Resources. Control. Theory. Pro. MATLAB File I/O: from the Command Line. Generic Importimportdata examines the extension and loads the data depending on the extension. The quickest means of saving and retrieving data is through the binary . MATLAB provides. This is the native format for MATLAB. Note: This author has had some problems with certain classes not being saved correctly when saving data using version 7 for use in version 6. Most data items will work just fine. Of particular interest was an issue with State- Space objects that were saved using version 7 to a version 6 compatible file. When the file was opend in MATLAB version 6+ the State- Space objects did not load. Spradlig (talk) 0. March 2. 00. 8 (UTC). Saving Data. The save command is used to save workspace data to a file. Save all workspace data to the file my. Save. mat in the current directory. I cover the command line first since it is often necessary to import the data while an m- function is being evaluated. Reading Excel Spreadsheets. MATLAB makes it easy to read from an Excel spreadsheet. It has the built in command . To use the xlsread function use the syntax. This line of code reads filename. MATLAB called g. You can then manipulate the array g any way you want. Make sure that the file you choose is in the same directory were you save your M- files (usually the work directory) otherwise you get an error. You can specify the path to a file but, this can get messy. Writing Excel Spreadsheets. To write data to an . The xlswrite command below creates a spreadsheet called filename. NOTE: if you are using MATLAB 6. There are several ways to write to a file. The simplest way I have found is. File. xls', 'w'). You can substitute new. File. xls with . txt. Also, there might be some issues with formatting in Excel. The formatting issues can usually be handled inside Excel but if they can't you might have to play around with the fopen command parameters. This is pretty similar (if not the same) way you would write to a file in C. Text files I/OReading Text Files. If a file is not an excel spreadsheet, it can still be read using . Otherwise you get an 'unrecognized character' error. The easiest way to write to a non- excel file, or using MATLAB 6. Usually there are no formatting difficulties with plain text files. For reading more general text files, MATLAB does not have a function to do it easily (unless you have excel), but you can read very general text files (with different delimiters for both cells and text within cells) using the . You can also try to use fscanf if the formatting is consistent enough (i. To use it, go to file > import data, and select the file you want. Then, choose what column separators are present (by selecting the appropriate radio button). Spaces are omitted, plusses and minuses are turned into other characters. To see the name MATLAB generated (and probably change it) type . MATLAB stores rational numbers as doubles by default, which is a measure of the number of decimal places that are stored in each variable and thus of how accurate the values are. Note that MATLAB represents irrational numbers such as pi with rational approximations, except when using the symbolic math toolbox. See that section for details. Boolean numbers are either . Boolean variables in MATLAB are actually interchangable with doubles, in that boolean operators can be performed with arrays of doubles and vice versa. Any non- zero number in this case is considered . Complex numbers; however, cannot be interchanged with boolean values like the real rationals can. Rational Operators on Single Values. MATLAB has all the standard rational operators. It is important to note, however, that Unless told otherwise, all rational operations are done on entire arrays, and use the matrix definitions. Thus, even though for now we're only talking about operations on a single value, when we get into arrays, it will be important to distinguish between matrix and componentwise multiplication, for example. Add, Subtract, multiply, divide, exponent operators: %additiona=1+2%subtractionb=2- 1%matrix multiplicationc=a*b%matrix division (pseudoinverse)d=a/b%exponentiatione=a ^ b. The modulo function returns the remainder when the arguments are divided together, so a modulo b means the remainder when a is divided by b.%moduloremainder=mod(a,b)All of these functions except for the modulus work for complex numbers as well. Relational Operators. Equality '==' returns the value . This must not be confused with the assignment operator '=' which assigns a value to a variable.> > %relational > > a=5; b=5; > > a==bans=1%Assignment> > a=5; b=3; > > a=ba=3. Note that in the first case, a value of 1 (true) is returned, however for the second case a gets assigned the value of b. Greater than, less than and greater than or equal to, less than or equal to are given by > , < , > =, < = respectively. All of them return a value of true or false. Example: > > a=3; b=5; > > a< =bans=1> > b< aans=0. Boolean Operators on Single Values. The boolean operators are & (boolean AND) . A value of zero means false, any non- zero value (usually 1) is considered true. Here's what they do: > > %boolean AND> > y=1& 0y=0> > y=1& 1y=1> > %boolean OR> > y=1. To see this, executing the following code: > > fstring='hello'; > > class(fstring)ans=char. Because strings are arrays, many array manipulation functions work including: size, transpose, and so on. Strings may be indexed to access specific elements. Program Logic and Indefinite Loops. Objectives. Use while statements. Use fencepost loops. Use the boolean type. Use while statements to handle user errors. Introduce assertions. Assignments. Read Chapter 5. Quiz 8 Available end of Week 1. Lab 6 Due beginning of Week 1. Quiz 9 Available end of Week 1. Lab 7 Due beginning of Week 1. Introduce Project 3 Contents. While Loops. Definite Loops. The for loops that we have been writing are definite loops. ALWAYS. In general you know nothing about values of parameters. NEVER. The above statement makes an assuption about the contents of the body of the loop.
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