Current directory, MATLAB

In the previous sections we have used MATLAB commands that were typed in on the desktop command line, as well as MATLAB commands that invoke special stored MATLAB files, called m files. When starting to work with MATLAB, we advise our users to create a special folder for their personal MATLAB m files once and to continue to use this folder to store personal m files. To access the stored m files from the MATLAB desktop, the user has to point the small desktop window called Current Directory to the personal m file folder. Then all stored m files, as well as all built in MATLAB functions can be accessed, called upon, and used from the command line. All stored personal... 

These files keep a record of a session. The simplest approach is not to use diary files but just to copy and paste the text of a Matlab session, but diary files can be useful because one can selectively save just certain commands. In order to start a diary file type diary (a default file called diary will be created in the current directory) or diary filename where filename is the name of the file. This automatically opens a file into which all subsequent commands used in a session, together with their results, are stored. To stop recording simply type diary off and to start again (in the same file) type diary on. 

Change the current directory in MATLAB (at the top of the command window) to a directory in which you wish to save your work and save it as f.m. 

Open Matlab and set the current directory to your directory. 

The icon is the command prompt. Anything entered after this is a MATLAB command. The Current Directory window displays folders and files associated with... 

If this function m file is stored as f unct. m in the current desktop working directory, it can be called and executed in MATLAB by typing funct(3,5,17) or x=3 z=5 k=17 [yy.sign] = f unct (x, z, k) for example. These calls will create the following sequence of outputs. 

MATLAB can keep a diary of a session or parts thereof via the commands diary or diary Junel2, for example, which collects all screen output in a file called diary or Junel2 , respectively, in the current working directory. The command diary off stops the collection of the on-screen information. If the diary on command is given later in the same session, the subsequent screen output will be appended to the previous diary and saved. Please read up on diary by entering help diag. 

A directory c matlabrxx work will be created where the results of your session will be stored unless you specify differently. There are several commands to manage directories. The cd command changes directory so that cd c changes the directory to c . If the new directory does not exist you must first create it with the mkdir command. It is best not to include a space in the name of the directory. The following code creates a directory called results on the c drive and makes this the current Matlab directory ... 

These files store the workspace or variables created during a session. All matrices, vectors and scalars with unique names are saved. Many chemometricians exchange data in this format. The command save places all this information into a file called matlab.mat in the current working directory. Alternatively, you can use the Save Workspace item on die File menu. Normally you wish to save the information as a named file, in which case you enter the filename after the save command. The following code saves the results of a session as a file called mydata in the directory c results, the first line being dependent on the current working directory and requires you to have created this first ... 

To demonstrate how to import data from another application into the MATLAB environment, let us assume that the experimental data exist in a file sheet such as Excel. The data represent the yearly incoming surface erythemal solar UV radiation dosage (J per cm ) for a clear sky, after modulation due to average cloud cover, as a function of earth latitude. The data were excerpted from M. Ilyas [Climate augmentation of er5 hemal UV-B radiation dose damage in the tropics and global change, Curr. Sci. 93(11) 1604-1608, 2007]. For simplicity, the file was copied to, or moved into, one of the MATLAB search path directories so that it will appear in the Current Folder Window of MATLAB (Fig. 5.1). 

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