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matlab\general – Команды общего назначения

General information

syntax - Help on MATLAB command syntax.

You can enter MATLAB commands using either a FUNCTION format or a

COMMAND format, as described below.

FUNCTION FORMAT

A command in this format consists of the function name followed by

one or more arguments separated by commas and enclosed in parentheses.

functionname(arg1, arg2, ..., argn)

You may assign the output of the function to one or more output values

separated by commas and enclosed in square brackets ([]).

[out1, out2, ..., outn] = functionname(arg1, arg2, ..., argn)

For example,

copyfile(srcfile, '..\mytests', 'writable')

[x1, x2, x3, x4] = deal(A{:})

Arguments are passed to the function by value. See the examples below,

under ARGUMENT PASSING.

COMMAND FORMAT

A command in this format consists of the function name followed by

one or more arguments separated by spaces.

functionname arg1 arg2 ... argn

Unlike the function format, you may not assign the output of the function

to a variable. Attempting to do so generates an error.

For example

save mydata.mat x y z

import java.awt.Button java.lang.String

Arguments are treated as string literals. See the examples below,

under ARGUMENT PASSING.

ARGUMENT PASSING

In the FUNCTION format, arguments are passed by value.

In the COMMAND format, arguments are treated as string literals.

In the following example,

disp(A) - passes the value of variable A to the disp function

disp A - passes the variable name, 'A'

A = pi;

disp(A) % Function format

3.1416

disp A % Command format

A

In the next example,

strcmp(str1, str2) - compares the strings 'one' and 'one'

strcmp str1 str2 - compares the strings 'str1' and 'str2'

str1 = 'one'; str2 = 'one';

strcmp(str1, str2) % Function format

ans =

1 (equal)

strcmp str1 str2 % Command format

ans =

0 (unequal)

PASSING STRINGS

When using the FUNCTION format to pass a string literal to a function,

you must enclose the string in single quotes, ('string').

For example, to create a new directory called MYAPPTESTS, use

mkdir('myapptests')

On the other hand, variables that contain strings do not need to be

enclosed in quotes.

dirname = 'myapptests';

mkdir(dirname)

See also mlint.

Reference page in Help browser

doc syntax

demo - Run demonstrations.

DEMO Access product demos via Help browser.

DEMO opens the Help browser and selects the MATLAB Demos

entry in the table of contents.

DEMO SUBTOPIC CATEGORY opens the Demos entry to the specified CATEGORY.

CATEGORY is a product or group within SUBTOPIC. SUBTOPIC is 'matlab',

'toolbox', 'simulink', 'blockset', or 'links and targets'. When

SUBTOPIC is 'matlab' or 'simulink', do not specify CATEGORY to show all

demos for the product.

Examples:

demo 'matlab'

demo 'toolbox' 'signal'

demo 'matlab' 'getting started'

See also echodemo, grabcode, help, helpbrowser.

Reference page in Help browser

doc demo

ver - MATLAB, Simulink and toolbox version information.

VER MATLAB, Simulink and toolbox version information.

VER displays MathWorks product family header information, followed by

the current MATLAB, Simulink and toolbox version information.

VER(TOOLBOX_DIR) displays the current version information for the

toolbox specified by the string TOOLBOX_DIR.

A = VER displays the general MATLAB version header and return in A the

sorted struct array of version information on all toolboxes on the

MATLAB path.

The definition of struct A is:

A.Name : toolbox name

A.Version : toolbox version number

A.Release : toolbox release string

A.Date : toolbox release date

For example,

ver control

displays the version info for the Control System Toolbox, sorted

alphabetically.

A = ver('control');

returns in A the version information for the Control System Toolbox,

sorted alphabetically.

For tips on how to get VER to display version information about

your toolbox, type at the MATLAB prompt

more on

type ver.m

and then type 'more off' when the display of ver.m has finished.

See also hostid, info, license, verLessThan, version, whatsnew.

Reference page in Help browser

doc ver

<version> - MATLAB version information.

VERSION Version information for MATLAB and libraries.

VERSION returns a string containing MathWorks product family version

information.

VERSION returns the full MathWorks product family

version string

VERSION('-date') returns the release date

VERSION('-release') returns the release number

VERSION('-description') returns the release description

VERSION('-java') returns Java version information

See also computer, ver, verLessThan, whatsnew.

Reference page in Help browser

doc version

< verLessThan> - Compare version of toolbox to specified version string.

verLessThan Compare version of toolbox to specified version string.

verLessThan(TOOLBOX_DIR, VERSION) returns true if the version of

the toolbox specified by the string TOOLBOX_DIR is older than the

version specified by the string VERSION, and false otherwise.

VERSION must be a string in the form 'major[.minor[.revision]]',

such as '7', '7.1', or '7.0.1'. If TOOLBOX_DIR cannot be found

on MATLAB's search path, an error is generated.

Examples:

if verLessThan('images', '4.1')

error('Image Processing Toolbox 4.1 or higher is required.');

end

if verLessThan('matlab', '7.0.1')

% Put code to run under MATLAB older than MATLAB 7.0.1 here

else

% Put code to run under MATLAB 7.0.1 and newer here

end

See also matlabpath, ver.

Reference page in Help browser

doc verLessThan

< logo > - Plot the L-shaped membrane logo with MATLAB lighting.

Logo

Plot the L-shaped membrane logo with MATLAB(R) lighting.

< membrane > - Generates the MATLAB logo.

MEMBRANE Generates the MATLAB logo.

L = MEMBRANE(k), for k <= 12, is the k-th eigenfunction of

the L-shaped membrane. The first three eigenfunctions have

been shown on the covers of various MathWorks publications.

MEMBRANE(k), with no output parameters, plots the k-th eigenfunction.

MEMBRANE, with no input or output parameters, plots MEMBRANE(1).

L = MEMBRANE(k,m,n,np) also sets some mesh and accuracy parameters:

k = index of eigenfunction, default k = 1.

m = number of points on 1/3 of boundary. The size of

the output is 2*m+1-by-2*m+1. The default m = 15.

n = number of terms in sum, default n = min(m,9).

np = number of terms in partial sum, default np = min(n,2).

With np = n, the eigenfunction is nearly zero on the boundary.

With np < n, like np = 2, the boundary is not tied down.

< bench > - MATLAB Benchmark.

BENCH MATLAB Benchmark

BENCH times six different MATLAB tasks and compares the execution

speed with the speed of several other computers. The six tasks are:

LU LAPACK. Floating point, regular memory access.

FFT Fast Fourier Transform. Floating point, irregular memory access.

ODE Ordinary diff. eqn. Data structures and functions.

Sparse Solve sparse system. Sparse linear algebra.

2-D plot(fft(eye)). 2-D line drawing graphics.

3-D MathWorks logo. 3-D animated OpenGL graphics.

A final bar chart shows speed, which is inversely proportional to

time. Here, longer bars are faster machines, shorter bars are slower.

BENCH runs each of the six tasks once.

BENCH(N) runs each of the six tasks N times.

BENCH(0) just displays the results from other machines.

T = BENCH(N) returns an N-by-6 array with the execution times.

The comparison data for other computers is stored in a text file:

fullfile(matlabroot, 'toolbox','matlab','general','bench.dat')

Updated versions of this file are available from MATLAB Central

Note the link above opens your system web browser as defined by WEB.

Fluctuations of five or 10 percent in the measured times of repeated

runs on a single machine are not uncommon. Your own mileage may vary.

This benchmark is intended to compare performance of one particular

Version of matlab on different machines. It does not offer direct

comparisons between different versions of MATLAB. The tasks and

problem sizes change from version to version.

The 2-D and 3-D tasks measure graphics performance, including software

or hardware support for OpenGL. The command

opengl info

describes the OpenGL support available on a particular machine.

Reference page in Help browser

doc bench

Managing the workspace

<who> - List current variables.

WHO List current variables.

WHO lists the variables in the current workspace.

In a nested function, variables are grouped into those in the nested

function and those in each of the containing functions. WHO displays

only the variables names, not the function to which each variable

belongs. For this information, use WHOS. In nested functions and

in functions containing nested functions, even unassigned variables

are listed.

WHOS lists more information about each variable.

WHO GLOBAL and WHOS GLOBAL list the variables in the global workspace.

WHO -FILE FILENAME lists the variables in the specified .MAT file.

WHO ... VAR1 VAR2 restricts the display to the variables specified. The

wildcard character '*' can be used to display variables that match a

pattern. For instance, WHO A* finds all variables in the current

workspace that start with A.

WHO -REGEXP PAT1 PAT2 can be used to display all variables matching the

specified patterns using regular expressions. For more information on

using regular expressions, type "doc regexp" at the command prompt.

Use the functional form of WHO, such as WHO('-file',FILE,V1,V2),

when the filename or variable names are stored in strings.

S = WHO(...) returns a cell array containing the names of the variables

In the workspace or file. You must use the functional form of who when

there is an output argument.

Examples for pattern matching:

who a* % Show variable names starting with "a"

who -regexp ^b\d{3}$ % Show variable names starting with "b"

% and followed by 3 digits

who -file fname -regexp \d % Show variable names containing any

% digits that exist in MAT-file fname

See also whos, clear, clearvars, save, load.

Overloaded methods:

Simulink.who

Reference page in Help browser

doc who

<whos> - List current variables, long form.

WHOS List current variables, long form.

WHOS is a long form of WHO. It lists all the variables in the current

workspace, together with information about their size, bytes, class,

etc.

In a nested function, variables are grouped into those in the nested

function and those in each of the containing functions, each group

separated by a line of dashes. In nested functions and in functions

containing nested functions, even uninitialized variables are listed.

WHOS GLOBAL lists the variables in the global workspace.

WHOS -FILE FILENAME lists the variables in the specified .MAT file.

WHOS ... VAR1 VAR2 restricts the display to the variables specified.

The wildcard character '*' can be used to display variables that match

a pattern. For instance, WHOS A* finds all variables in the current

workspace that start with A.

WHOS -REGEXP PAT1 PAT2 can be used to display all variables matching

the specified patterns using regular expressions. For more information

on using regular expressions, type "doc regexp" at the command prompt.

Use the functional form of WHOS, such as WHOS('-file',FILE,V1,V2), when

the filename or variable names are stored in strings.

S = WHOS(...) returns a structure with the fields:

name -- variable name

size -- variable size

bytes -- number of bytes allocated for the array

class -- class of variable

global -- logical indicating whether variable is global

sparse -- logical indicating whether value is sparse

complex -- logical indicating whether value is complex

nesting -- struct with the following two fields:

function -- name of function where variable is defined

level -- nesting level of the function

persistent -- logical indicating whether variable is persistent

You must use the functional form of WHOS when there is an output

argument.

Examples for pattern matching:

whos a* % Show variable names starting with "a"

whos -regexp ^b\d{3}$ % Show variable names starting with "b"

% and followed by 3 digits

whos -file fname -regexp \d % Show variable names containing any

% digits that exist in MAT-file fname

See also who, clear, clearvars, save, load.

Overloaded methods:

Simulink.whos

Reference page in Help browser

doc whos

<clear> - Clear variables and functions from memory.

CLEAR Clear variables and functions from memory.

CLEAR removes all variables from the workspace.

CLEAR VARIABLES does the same thing.

CLEAR GLOBAL removes all global variables.

CLEAR FUNCTIONS removes all compiled M- and MEX-functions.

CLEAR ALL removes all variables, globals, functions and MEX links.

CLEAR ALL at the command prompt also removes the Java packages import

list.

CLEAR IMPORT removes the Java packages import list at the command

prompt. It cannot be used in a function.

CLEAR CLASSES is the same as CLEAR ALL except that class definitions

are also cleared. If any objects exist outside the workspace (say in

userdata or persistent in a locked m-file) a warning will be issued and

the class definition will not be cleared. CLEAR CLASSES must be used if

the number or names of fields in a class are changed.

CLEAR JAVA is the same as CLEAR ALL except that java classes on the

dynamic java path (defined using JAVACLASSPATH) are also cleared.

CLEAR VAR1 VAR2 ... clears the variables specified. The wildcard

character '*' can be used to clear variables that match a pattern. For

instance, CLEAR X* clears all the variables in the current workspace

that start with X.

CLEAR -REGEXP PAT1 PAT2 can be used to match all patterns using regular

expressions. This option only clears variables. For more information on

using regular expressions, type "doc regexp" at the command prompt.

If X is global, CLEAR X removes X from the current workspace, but

leaves it accessible to any functions declaring it global.

CLEAR GLOBAL X completely removes the global variable X.

CLEAR GLOBAL -REGEXP PAT removes global variables that match regular

expression patterns.

Note that to clear specific global variables, the GLOBAL option must

come first. Otherwise, all global variables will be cleared.

CLEAR FUN clears the function specified. If FUN has been locked by

MLOCK it will remain in memory. Use a partial path (see PARTIALPATH) to

distinguish between different overloaded versions of FUN. For

instance, 'clear inline/display' clears only the INLINE method for

DISPLAY, leaving any other implementations in memory.

CLEAR ALL, CLEAR FUN, or CLEAR FUNCTIONS also have the side effect of

removing debugging breakpoints and reinitializing persistent variables

since the breakpoints for a function and persistent variables are

cleared whenever the m-file changes or is cleared.

Use the functional form of CLEAR, such as CLEAR('name'), when the

variable name or function name is stored in a string.

Examples for pattern matching:

clear a* % Clear variables starting with "a"

clear -regexp ^b\d{3}$ % Clear variables starting with "b" and

% followed by 3 digits

clear -regexp \d % Clear variables containing any digits

See also clearvars, who, whos, mlock, munlock, persistent.

Overloaded methods:

mbcstore/clear

cgrules/clear

cgoptimexprgroup/clear

xregdesign/clear

cgexprgroup/clear

xregtable/clear

Reference page in Help browser

doc clear

<onCleanup> - Specify cleanup work to be done on function completion.

onCleanup - Specify cleanup work to be done on function completion.

C = onCleanup(S), when called in function F, specifies any cleanup tasks

that need to be performed when F completes. S is a handle to a function

that performs necessary cleanup work when F exits (e.g., closing files that

have been opened by F). S will be called whether F exits normally or

because of an error.

onCleanup is a MATLAB class and C = onCleanup(S) constructs an instance C of

that class. Whenever an object of this class is explicitly or implicitly

cleared from the workspace, it runs the cleanup function, S. Objects that

are local variables in a function are implicitly cleared at the termination

of that function.

Example 1: Use onCleanup to close a file.

function fileOpenSafely(fileName)

fid = fopen(fileName, 'w');

c = onCleanup(@()fclose(fid));

functionThatMayError(fid);

end % c will execute fclose(fid) here

Example 2: Use onCleanup to restore the current directory.

function changeDirectorySafely(fileName)

currentDir = pwd;

c = onCleanup(@()cd(currentDir));

functionThatMayError;

end % c will execute cd(currentDir) here

See also: clear, clearvars

Reference page in Help browser

doc onCleanup

< pack> - Consolidate workspace memory.

PACK Consolidate workspace memory.

PACK performs memory garbage collection. Extended MATLAB

sessions may cause memory to become fragmented, preventing

large variables from being stored. PACK is a command that

saves all variables on disk, clears the memory, and then

reloads the variables.

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