MATLAB command format

It should be kept in mind that the format command does not affect how MATLAB computations are done. Computations on float variables, namely, single or double, are done in appropriate floating point precision, no matter how those variables are displayed. Computations on integer variables are done natively in integer. MATLAB uses double-precision floating point arithmetic, which is accurate to approximately 15 digits and can work with the following data types tTable 1.21. 

There is another easy way to "cheat." On UNIX/Linux workstations, open up a new text editor and enter your frequently used statements there. On Windows, you can use the really nice MATLAB Editor. You can copy-and-paste multiple commands back and forth between the text editor window and the MATLAB window easily. If you want to save the commands, you certainly can add comments and annotations. You can consider this text file as a "free-format notebook" without having to launch the Microsoft Word Notebook for MATLAB. 

The latter command will give the answer as 6.2832 in format short g, while the screen output will be 6.283185307179586e+00 in format long e. Powers of the base 10 are always displayed in MATLAB via the e-extension as be a in format e. Thus 400 = 4e+02 and 1/1000 = le-03 in MATLAB s exponential output and screen display. Format statements can be entered at any prompt such as format short, or inside MATLAB code where desired. Commanding format toggles the output format back to the previous format setting. 

In this book we shall use MATLAB codes and explain more involved features of MAT-LAB as we encounter them. MATLAB has a built-in help menu typing help format at the prompt, or help, for example, will show the syntax and variations of these two commands format and backslash . Whenever a student encounters a MATLAB command that is not self explanatory, we suggest using this built-in help function of MATLAB. 

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 ... 

Save in xxx.fi file format for re-start from FEMLAB stand-alone or in xxx.m file format for restart from either FEMLAB running under MATLAB or FEMLAB stand-alone. (Note m-Files save all your commands, including mistakes.)... 

MATLAB is a mathematical programme developed by the company called The MathWorks Inc. Examples in this chapter have been tested on MATLAB versions between 201 la and 2015b. It is expected that most of the commands presented will work with some earlier versions, as well as most later versions. It will be assumed that the reader has a basic understanding of MATLAB, can write MATLAB statements, understands basic MATLAB commands, and can plot a simple MATLAB graph. This chapter will examine in detail additional features, such as the different toolboxes and formatting features. In order to clearly distinguish between the code required for the MATLAB function and text, all MATLAB commands and variables are shown in bold Courier New. 

Hints Use the MATLAB MPC Toolbox, if desired, for this exercise. Two commands are used to produce a linear model of the plant in the representation needed for controller design. First, the dlinmod command obtains a state-space representation (A, B, C, D). To use this command, be sure that the Simuhnk diagram is drawn so that the process manipulated inputs and disturbances correspond to in ports on the top level of the Simulink flow sheet similarly, the outputs must correspond to out ports. Then the ss2mod command produces a model in MPC mod format, specifying inputs that are manipulated variables, measured disturbances, and unmeasured disturbances. The scmpc command simulates control of the hnearized plant with the MPC controller. 

In MATLAB all computations are done in double precision. However, the result of calculation is normally shown with only 5 digits. The/orwar command may be used to switch between different output display formats ... 

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