% to define functions from expressions,
% we can use the inline
help 'inline'
 INLINE Construct INLINE object.
    INLINE(EXPR) constructs an inline function object from the
    MATLAB expression contained in the string EXPR.  The input
    arguments are automatically determined by searching EXPR
    for variable names (see SYMVAR). If no variable exists, 'x'
    is used.
 
    INLINE(EXPR, ARG1, ARG2, ...) constructs an inline
    function whose input arguments are specified by the
    strings ARG1, ARG2, ...  Multicharacter symbol names may
    be used.
 
    INLINE(EXPR, N), where N is a scalar, constructs an
    inline function whose input arguments are 'x', 'P1',
    'P2', ..., 'PN'.
 
    Examples:
      g = inline('t^2')
      g = inline('sin(2*pi*f + theta)')
      g = inline('sin(2*pi*f + theta)', 'f', 'theta')
      g = inline('x^P1', 1)
 
    See also <a href="matlab:help symvar">symvar</a>.


    Reference page in Help browser
       <a href="matlab:doc inline">doc inline</a>

% suppose we want to define an exponentional function
f = inline('70*exp(-0.2*t)')

f =

     Inline function:
     f(t) = 70*exp(-0.2*t)

f(0)

ans =

    70

f(3)

ans =

   38.4168

edit
% we just defined the script "cool.m"
% to check its existence, we can do help
help cool
  this function defines a simple
  model of a cooling off process

f3 = cool(3)

f3 =

   38.4168

% The next example is a function which returns
% more than one result.
edit
help sumavg
 
  [sum,avg] = sumavg(a,b)
  returns sum and average
  of the numbers a and b
 

[s,a] = sumavg(5,3)

s =

     8


a =

     4

a = rand(1,4);
b = rand(1,4);
[s,avg] = sumavg(a,b);
s

s =

    1.4471    1.0033    0.4055    1.4603

avg

avg =

    0.7235    0.5017    0.2027    0.7301

% we can make our scripts interactive
edit
help(areacircle)
??? Error using ==> areacircle
Too many output arguments.

help areacircle
 
  areacircle prompts the user for
  a radius and prints the area of
  the circle with that radius
 

areacircle
Give radius : 1.4
The area of circle with radius 1.40 is 6.157522
% we can define a piecewise linear function
% for example a hat function
edit
help hat
 
   y = hat(x) returns the value of
   a hat function:
    y = 0 for x < 0 and x > 1
    y = 1 for x >=0 and x <= 1.
 

hat(3)

ans =

     0

hat(0.1)

ans =

     1

hat(-3)

ans =

     0

edit
x = rand(1,4)

x =

  Columns 1 through 3

    0.9575    0.9649    0.1576

  Column 4

    0.9706

size(x,2)

ans =

     4

length(x)

ans =

     4

x(1)

ans =

    0.9575

x(1:length(x))

ans =

  Columns 1 through 3

    0.9575    0.9649    0.1576

  Column 4

    0.9706

findmax(x)

ans =

    0.9706

max(x)

ans =

    0.9706

% we can use functions inside other functions
edit
help traprule
 
  y = traprule(f,a,b) returns the value
  of the trapezoidal rule to approximate
  the integral of f over the interval [a,b].
 

traprule('cos',0,1)

ans =

    0.7702

traprule('cool',0,1)

ans =

   63.6556

help path
 PATH Get/set search path.
    PATH, by itself, prettyprints MATLAB's current search path. The initial
    search path list is set by PATHDEF, and is perhaps individualized by
    STARTUP.
 
    P = PATH returns a string containing the path in P. PATH(P) changes the
    path to P.  PATH(PATH) refreshes MATLAB's view of the directories on
    the path, ensuring that any changes to non-toolbox directories are
    visible.
 
    PATH(P1,P2) changes the path to the concatenation of the two path
    strings P1 and P2.  Thus PATH(PATH,P) appends a new directory to the
    current path and PATH(P,PATH) prepends a new directory.  If P is already 
    on the path, then PATH(PATH,P) moves P to the end of the path, 
    and similarly, PATH(P,PATH) moves P to the beginning of the path.
 
    For example, the following statements add another directory to MATLAB's
    search path on various operating systems:
 
      Unix:     path(path,'/home/myfriend/goodstuff')
      Windows:  path(path,'c:\tools\goodstuff')
 
    See also <a href="matlab:help what">what</a>, <a href="matlab:help cd">cd</a>, <a href="matlab:help dir">dir</a>, <a href="matlab:help addpath">addpath</a>, <a href="matlab:help rmpath">rmpath</a>, <a href="matlab:help genpath">genpath</a>, <a href="matlab:help pathtool">pathtool</a>, <a href="matlab:help savepath">savepath</a>, <a href="matlab:help rehash">rehash</a>.


    Reference page in Help browser
       <a href="matlab:doc path">doc path</a>

path

		MATLABPATH

	C:\Program Files\MATLAB\R2007a\toolbox\matlab\general
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\ops
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\lang
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\elmat
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\elfun
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\specfun
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\matfun
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\datafun
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\polyfun
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\funfun
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\sparfun
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\scribe
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\graph2d
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\graph3d
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\specgraph
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\graphics
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\uitools
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\strfun
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\imagesci
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\iofun
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\audiovideo
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\timefun
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\datatypes
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\verctrl
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\codetools
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\helptools
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\winfun
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\demos
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\timeseries
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\hds
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\guide
	C:\Program Files\MATLAB\R2007a\toolbox\matlab\plottools
	C:\Program Files\MATLAB\R2007a\toolbox\local
	C:\Program Files\MATLAB\R2007a\toolbox\shared\controllib
	C:\Program Files\MATLAB\R2007a\toolbox\simulink\simulink
	C:\Program Files\MATLAB\R2007a\toolbox\simulink\blocks
	C:\Program Files\MATLAB\R2007a\toolbox\simulink\components
	C:\Program Files\MATLAB\R2007a\toolbox\simulink\fixedandfloat
	C:\Program Files\MATLAB\R2007a\toolbox\simulink\fixedandfloat\fxpdemos
	C:\Program Files\MATLAB\R2007a\toolbox\simulink\fixedandfloat\obsolete
	C:\Program Files\MATLAB\R2007a\toolbox\simulink\simdemos
	C:\Program Files\MATLAB\R2007a\toolbox\simulink\simdemos\aerospace
	C:\Program Files\MATLAB\R2007a\toolbox\simulink\simdemos\automotive
	C:\Program Files\MATLAB\R2007a\toolbox\simulink\simdemos\simfeatures
	C:\Program Files\MATLAB\R2007a\toolbox\simulink\simdemos\simgeneral
	C:\Program Files\MATLAB\R2007a\toolbox\simulink\dee
	C:\Program Files\MATLAB\R2007a\toolbox\shared\dastudio
	C:\Program Files\MATLAB\R2007a\toolbox\shared\glue
	C:\Program Files\MATLAB\R2007a\toolbox\stateflow\stateflow
	C:\Program Files\MATLAB\R2007a\toolbox\rtw\rtw
	C:\Program Files\MATLAB\R2007a\toolbox\simulink\simulink\modeladvisor
	C:\Program Files\MATLAB\R2007a\toolbox\simulink\simulink\modeladvisor\fixpt
	C:\Program Files\MATLAB\R2007a\toolbox\simulink\simulink\MPlayIO
	C:\Program Files\MATLAB\R2007a\toolbox\simulink\simulink\dataobjectwizard
	C:\Program Files\MATLAB\R2007a\toolbox\shared\fixedpointlib
	C:\Program Files\MATLAB\R2007a\toolbox\simulink\dataimportexport
	C:\Program Files\MATLAB\R2007a\toolbox\shared\hdlshared
	C:\Program Files\MATLAB\R2007a\toolbox\stateflow\sfdemos
	C:\Program Files\MATLAB\R2007a\toolbox\stateflow\coder
	C:\Program Files\MATLAB\R2007a\toolbox\control\control
	C:\Program Files\MATLAB\R2007a\toolbox\control\ctrlguis
	C:\Program Files\MATLAB\R2007a\toolbox\control\ctrlobsolete
	C:\Program Files\MATLAB\R2007a\toolbox\control\ctrlutil
	C:\Program Files\MATLAB\R2007a\toolbox\control\ctrldemos
	C:\Program Files\MATLAB\R2007a\toolbox\shared\slcontrollib
	C:\Program Files\MATLAB\R2007a\toolbox\eml\eml
	C:\Program Files\MATLAB\R2007a\toolbox\emlcoder\emlcoder
	C:\Program Files\MATLAB\R2007a\toolbox\emlcoder\emlcodermex
	C:\Program Files\MATLAB\R2007a\toolbox\finance\finance
	C:\Program Files\MATLAB\R2007a\toolbox\finance\calendar
	C:\Program Files\MATLAB\R2007a\toolbox\finance\findemos
	C:\Program Files\MATLAB\R2007a\toolbox\finance\finsupport
	C:\Program Files\MATLAB\R2007a\toolbox\finance\ftseries
	C:\Program Files\MATLAB\R2007a\toolbox\finance\ftsdemos
	C:\Program Files\MATLAB\R2007a\toolbox\finance\ftsdata
	C:\Program Files\MATLAB\R2007a\toolbox\finance\ftstutorials
	C:\Program Files\MATLAB\R2007a\toolbox\fixedpoint\fixedpoint
	C:\Program Files\MATLAB\R2007a\toolbox\fixedpoint\fidemos
	C:\Program Files\MATLAB\R2007a\toolbox\ident\ident
	C:\Program Files\MATLAB\R2007a\toolbox\ident\nlident
	C:\Program Files\MATLAB\R2007a\toolbox\ident\idobsolete
	C:\Program Files\MATLAB\R2007a\toolbox\ident\idguis
	C:\Program Files\MATLAB\R2007a\toolbox\ident\idutils
	C:\Program Files\MATLAB\R2007a\toolbox\ident\iddemos
	C:\Program Files\MATLAB\R2007a\toolbox\ident\iddemos\examples
	C:\Program Files\MATLAB\R2007a\toolbox\ident\idhelp
	C:\Program Files\MATLAB\R2007a\toolbox\images\images
	C:\Program Files\MATLAB\R2007a\toolbox\images\imuitools
	C:\Program Files\MATLAB\R2007a\toolbox\images\imdemos
	C:\Program Files\MATLAB\R2007a\toolbox\images\iptutils
	C:\Program Files\MATLAB\R2007a\toolbox\shared\imageslib
	C:\Program Files\MATLAB\R2007a\toolbox\images\medformats
	C:\Program Files\MATLAB\R2007a\toolbox\slvnv\simcoverage
	C:\Program Files\MATLAB\R2007a\toolbox\nnet
	C:\Program Files\MATLAB\R2007a\toolbox\nnet\nncontrol
	C:\Program Files\MATLAB\R2007a\toolbox\nnet\nndemos
	C:\Program Files\MATLAB\R2007a\toolbox\nnet\nnet
	C:\Program Files\MATLAB\R2007a\toolbox\nnet\nnet\nnanalyze
	C:\Program Files\MATLAB\R2007a\toolbox\nnet\nnet\nncustom
	C:\Program Files\MATLAB\R2007a\toolbox\nnet\nnet\nndistance
	C:\Program Files\MATLAB\R2007a\toolbox\nnet\nnet\nnformat
	C:\Program Files\MATLAB\R2007a\toolbox\nnet\nnet\nninit
	C:\Program Files\MATLAB\R2007a\toolbox\nnet\nnet\nnlearn
	C:\Program Files\MATLAB\R2007a\toolbox\nnet\nnet\nnnetinput
	C:\Program Files\MATLAB\R2007a\toolbox\nnet\nnet\nnnetwork
	C:\Program Files\MATLAB\R2007a\toolbox\nnet\nnet\nnperformance
	C:\Program Files\MATLAB\R2007a\toolbox\nnet\nnet\nnplot
	C:\Program Files\MATLAB\R2007a\toolbox\nnet\nnet\nnprocess
	C:\Program Files\MATLAB\R2007a\toolbox\nnet\nnet\nnsearch
	C:\Program Files\MATLAB\R2007a\toolbox\nnet\nnet\nntopology
	C:\Program Files\MATLAB\R2007a\toolbox\nnet\nnet\nntrain
	C:\Program Files\MATLAB\R2007a\toolbox\nnet\nnet\nntransfer
	C:\Program Files\MATLAB\R2007a\toolbox\nnet\nnet\nnweight
	C:\Program Files\MATLAB\R2007a\toolbox\nnet\nnguis
	C:\Program Files\MATLAB\R2007a\toolbox\nnet\nnguis\nftool
	C:\Program Files\MATLAB\R2007a\toolbox\nnet\nnguis\nntool
	C:\Program Files\MATLAB\R2007a\toolbox\nnet\nnobsolete
	C:\Program Files\MATLAB\R2007a\toolbox\nnet\nnresource
	C:\Program Files\MATLAB\R2007a\toolbox\nnet\nnutils
	C:\Program Files\MATLAB\R2007a\toolbox\optim\optim
	C:\Program Files\MATLAB\R2007a\toolbox\optim\optimdemos
	C:\Program Files\MATLAB\R2007a\toolbox\shared\optimlib
	C:\Program Files\MATLAB\R2007a\toolbox\pde
	C:\Program Files\MATLAB\R2007a\toolbox\signal\signal
	C:\Program Files\MATLAB\R2007a\toolbox\signal\sigtools
	C:\Program Files\MATLAB\R2007a\toolbox\signal\sptoolgui
	C:\Program Files\MATLAB\R2007a\toolbox\signal\sigdemos
	C:\Program Files\MATLAB\R2007a\toolbox\shared\spcuilib
	C:\Program Files\MATLAB\R2007a\toolbox\stats
	C:\Program Files\MATLAB\R2007a\toolbox\symbolic
	C:\Program Files\MATLAB\R2007a\toolbox\vr\vr
	C:\Program Files\MATLAB\R2007a\toolbox\vr\vrdemos
	C:\Program Files\MATLAB\R2007a\toolbox\wavelet\wavelet
	C:\Program Files\MATLAB\R2007a\toolbox\wavelet\wmultisig1d
	C:\Program Files\MATLAB\R2007a\toolbox\wavelet\wavedemo
	C:\Program Files\MATLAB\R2007a\work
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