General purpose functions¶

The general purpose functions are used for managing variables and workspace, control of output, etc. The functions listed here are a subset of the general purpose functions described in the MATLAB manual. The functions can be divided into the following groups:

General functions¶

help¶

Purpose:

Display a description of purpose and syntax for a specific function.

Syntax:

help function_name

Description:

help provides an online documentation for the specified function.

Example:

Typing

>> help spring1e

yields

Ke=spring1e(ep)
-------------------------------------------------------------
PURPOSE
Compute element stiffness matrix for spring (analog) element.

INPUT:  ep = [k]; spring stiffness or analog quantity.

OUTPUT: Ke : stiffness matrix, dim(Ke)= 2 x 2
-------------------------------------------------------------

type¶

Purpose:

List file.

Syntax:

type filename

Description:

type filename lists the specified file. Use path names in the usual way for your operating system. If a filename extension is not given, .m is added by default. This makes it convenient to list the contents of .m-files on the screen.

what¶

Purpose:

Directory listing of .m-files, .mat-files and mex-files.

Syntax:

what
what dirname

Description:

what lists the .m-files, .mat-files and .mex-files in the current directory.

what dirname lists the files in directory dirname in the MATLAB search path. The syntax of the path depends on your operating system.

…¶

Purpose:

Continuation.

Syntax:

...

Description:

An expression can be continued on the next line by using ... .

%¶

Purpose:

Write a comment line.

Syntax:

% arbitrary text

Description:

An arbitrary text can be written after the symbol %.

Variables and workspace¶

clear¶

Purpose:

Remove variables from workspace.

Syntax:

clear
clear name1 name2 name3 ...

Description:

clear removes all variables from workspace.

clear name1 name2 name3 ... removes specified variables from workspace.

disp¶

Purpose:

Display a variable in matrix bank on display screen.

Syntax:

disp(A)

Description:

disp(A) displays the matrix A on the display screen.

load¶

Purpose:

Retrieve variable from disk and load in workspace.

Syntax:

load filename
load filename.ext

Description:

load filename retrieves the variables from the binary file filename.mat.

load filename.ext reads the ASCII file filename.ext with numeric data arranged in \(m\) rows and \(n\) columns. The result is an \(m \times n\) matrix residing in workspace with the name filename, i.e. with the extension stripped.

save¶

Purpose:

Save workspace variables on disk.

Syntax:

save filename
save filename variables
save filename variables -ascii

Description:

save filename writes all variables residing in workspace in a binary file named filename.mat.

save filename variables writes named variables, separated by blanks, in a binary file named filename.mat.

save filename variables -ascii writes named variables in an ASCII file named filename.

who, whos¶

Purpose:

List directory of variables in matrix bank.

Syntax:

who
whos

Description:

who lists the variables currently in memory.

whos lists the current variables and their size.

Examples:

who

Your variables are:

A       B       C       K       M       X       k       lambda

whos

Name         Size            Bytes  Class     Attributes

A            3x3                72  double
B            3x3                72  double
C            3x3                72  double
K           20x20             3200  double
M           20x20             3200  double
X           20x20             3200  double
k            1x1                 8  double
lambda      20x1               160  double

Files and command window¶

diary¶

Purpose:

Save session in a disk file.

Syntax:

diary filename
diary off
diary on

Description:

diary filename writes a copy of all subsequent keyboard input and most of the resulting output (but not graphs) on the named file. If the file filename already exists, the output is appended to the end of that file.

diary off stops storage of the output.

diary on turns it back on again, using the current filename or default filename diary if none has yet been specified.

The diary function may be used to store the current session for later runs. To make this possible, finish each command line with semicolon ‘;’ to avoid the storage of intermediate results on the named diary file.

echo¶

Purpose:

Control output on the display screen.

Syntax:

echo on
echo off
echo

Description:

echo on turns on echoing of commands inside Script-files.

echo off turns off echoing.

echo by itself toggles the echo state.

format¶

Purpose:

Control the output display format.

Syntax:

See the listing below.

Description:

format controls the output format. By default, MATLAB displays numbers in a short format with five decimal digits.

quit¶

Purpose:

Terminate CALFEM session.

Syntax:

quit

Description:

quit terminates CALFEM without saving the workspace.