The MATLAB Help System Matlab Help

If all the MATLAB documentation were printed, it would fill a volume many times the size of this book. Therefore, it is impossible for us to describe all of the details of MATLAB. This book gives you in-depth coverage of the basic MATLAB language and an overview of the available tools to alert you to their existence. It gives you all the material you need to do the homework problems. If you need information about a topic covered in this book, remember to use the following special features that were designed as reference aids.

  • Throughout each margin notes identify where key terms are introduced.
  • Each contains tables summarizing the MATLAB commands introduced.
  • At the end of each  is a summary guide to the commands covered.
  • Appendix A contains tables of MATLAB commands, grouped by category, with the appropriate page references.
  • There are two indexes. The first lists MATLAB commands and symbols, while the second lists topics.

To explore the more advanced features of MATLAB not covered in this book, you will need to know how to use effectively the MATLAB Help System. MATLAB has these options 10 get help for using MathWorks products.

  1. Help Browser This graphical user interface helps you find information and view online documentation for your MathWorks products.
  2. Help Functions The functions help. look for, and doc can be used to display syntax information for a specified function.
  3. Other Resources For additional help, you can run demos, contact technical support, search documentation for other MathWorks products, view a list of other books, and participate in a newsgroup,

The Help Browser

The Help Browser enables you to search and view documentation for MATLAB and your other Math Works products. To open the Help Browser, select MATLAB Help from the Help menu, or click the question mark button in the tool bar. The Help Browser contains two window “panes”: the Help Navigator pane on the left and the Display pane on the right (see Figure 1.5-1). The Help Navigator contains four tabs:

  • Contents: a contents listing tab,
  • Index: a global index tab,
  • Search: a search tab having a find function and full text search features, and
  • Demos: a bookmarking tab to start built-in demonstrations.

Use the tabs in the Help Navigator to find documentation. You view documentation in the Display pane. To adjust the relative width of the two panes, drag the separator bar. between them. To close the Help Navigator pane, click the close box (x) in the

Figure 1.5-1 The MATLAB Help Browser

Figure 1.5-1 The MATLAB Help Browser

pane’s upper right comer. This is useful once you have found the documentation you wanted because it provides more screen space for the documentation itself. To open the Help Navigator pane from the display pane, click on Help Navigator in the View menu.

Viewing Documentation

After finding documentation with the Help Navigator, view the documentation in the Display pane. While viewing a page of documentation, you can:

  • Scroll to see contents not currently visible in the window.
  • View the previous-or next page in the document by clicking the left or right arrow at the top of the page.
  • View the previous or next item in the index by clicking the left or right arrow at the bottom of the page.
  • Reload a page by clicking the Refresh button (circular arrows) in the Help
    Browser tool bar.
  • Find a phrase in the currently displayed page by clicking on the binoculars icon and typing it in the Find what: box in the Help Browser tool bar and pressing the Enter key.
  • Add that page to your list of favorite documents by clicking Add to Favorites in the Help Browser tool bar.

The box above the Display pane contains the title of the help page currently displayed in the Display pane. Click on the arrow to the right of the box to see a list of the help pages you previously accessed. Then click on the name of a page, and it appears in the Display pane.

Using the Contents Tab

Click the Contents tab in the Help Navigator to list the titles and table of contents for all product documentation. To expand the listing for an item, click the + to the left of the item. To collapse the listings for an item, click the – to the left of the item, or double-click the item. Click on an item to select it. The first page of that document appears in the Display pane. Double-clicking an item in the contents listing expands the listing for that item and shows the first page of that document in the Display pane.

The Contents pane is synchronized with the Display pane. By default, the item selected in the Contents pane always matches the documentation appearing in the Display pane. Thus, the contents tree is synchronized with the displayed document. This feature is useful if you access documentation with a method other than the Contents pane, for example, using the back button in the Display pane. With synchronization, you always know to what section the displayed page belongs.

Using the Index Tab

Click the Index tab in the Help Navigator pane to find specific index entries (keywords) from all of your Math’Works documentation. Type a word or words in the “Search index for” box. As you type, the index highlights the matching entries. Scroll down in the Help Navigator pane to see more matching entries. Click on an entry to display the corresponding page. If you do no! find a matching index entry or if the corresponding page does not contain the information you seek. try a less specific topic by using only part of the wording, or use the Search tab.

Using the Search Tab

Click the Search tab in the Help Navigator pane to find all MATLAB documents containing a specified phrase. Type the phrase in the “Search for”box. Then click the Go button. The list of documents and the heading under which the phrase is found in that document then appear in the Help Navigator pane. Select an entry from the list of results to view that document in the Display pane.

Using the Favorites Menu

Click on the Favorites menu to add a page to the Favorites list, or to view a list of documents you previously designated as favorites. Select an entry and that document then appears in the Display pane. To remove a document from the list of favorites, right-click the document in the favorites list and select Delete from the pop-up menu. To designate a document page as a favorite, you can either:

  • Click Add to Favorites in the Help Browser toolbar while that document is open in the Display pane, or
  • Right-click the document name listed under the Contents tab and click the Add to Favorites button, or
  • Right-click the document name in the Help Browser search results list and click the Add to Favorites button.

Help Functions

Three MATLAB functions can be used for accessing online information about  MATLAB functions:

  • help funcname Displays in the Command window a description of the specified function funcname.
  • lookfor topic Displays in the Command window a brief description for all functions whose description includes the specified key word topic.
  • doc funcname Opens the Help Browser to the reference page for the specified function funcname, providing a description, additional remarks, and examples

The help Function The help function is the most basic way to determine the syntax and behavior of a particular function. Information is displayed directly in the Command window. For example, typing help log10 in the Command window produces the following display:

LOG10 Cornmon (base 10) logarithm.
LOG10(X) is the base 10 logarithm of the elements of X.
Complex results are produced if X is not positive.

            See also LOG, LOG2, EXP, LOGM.

Note that the display describes what the function does, warns about any unexpected results if nonstandard argument values are used, and directs the user to other related functions.

All the MATLAB functions are organized into logical groups, upon which the MATLAB direct,ay structure is based. For instance, all elementary mathematical functions such as log10 reside in the elfun directory, and the polynomial functions reside in the polyfun directory. To list the names of all the functions in that directory, with a brief description of each, type help poly fun.If you are unsure of what directory to search, type he 1p to obtain a list of all the directories, with a description of the function category each represents. Throughout this text we point out the appropriate directory name so that you can get more information if you need it.

Typing helpwin topic displays the help text for the specified topic inside the Desktop Help Browser window. Links are created to functions referenced in the “See Also” line of the help text. You can also access the Help window by selecting the Help option under the Help menu, or by clicking the question mark button on the tool bar.

The lookfor Function The lookfor function allows you to search for functions on the basis of a key word. It searches through the first line of help text, known as the HI line, for each MATLAB function, and returns all the HI lines containing a specified key word. For example, MATLAB does not have a function named sine. So the response from help sine is

sine.m not found

However, typing lookfor sine produces over a dozen matches, depending on which toolboxes you have installed. For example, you will see

ACOS        Inverse cosine.
ACOSH     Inverse hyperbolic cosine.
ASIN          Inverse sine.
ASINH       Inverse hyperbolic sine.
COS          Cosine.
COSH       Hyperbolic cosine.
SIN            Sine.
SINH         Hyperbolic sine.

Table 1.5-1 MATLAB Help functions

Table 1.5-1 MATLAB Help functions

From this list you can find the correct name for the sine function. Note that all words containing sine are returned, such as cosine. Adding -all to the lookfor function searches the entire help entry, not just the HI line.

The doc Function Typing doc displays the start page of the documentation in the Help Browser. Typing doc function displays the documentation for the MATLAB function function. Typing doc toolbox/function displays the documentation for the specified toolbox function. Typing doc toolbox displays the documentation road map page for the specified toolbox.
Table 1.5-1 summarizes the MATLAB Help functions.

The MathWorks Website

If your computer is connected to the Internet, you can access The MathWorks, Inc., the home of MATLAB. You can use electronic mail to ask questions, make . suggestions, and report possible bugs. You can also use a solution search engine at The Math Works website to query an up-to-date database of technical support information. The website address is

Posted on July 14, 2015 in An Overview of MATLAB

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