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19. Reference

There are many MATLAB features which cannot be included in these introductory notes. Listed below are some of the MATLAB functions and operators available, grouped by subject area. [Source: MATLAB User's Guide, version 3.5] Use the on-line help facility or consult the User's Guide for more detailed information on the functions.

There are many functions beyond these. There exist, in particular, several "toolboxes" of functions for specific areas; included among such are signal processing, control systems, robust-control, system identification, optimization, splines, chemometrics, mu-analysis and synthesis, state-space identification, and neural networks. [The toolboxes, which are optional, may not be installed on your system.] These can be explored via the command help.

[Note: Some of the following tables require a tables-aware browser, such as Netscape 1.1N or later. - Ed.] 

help help facility
demo run demonstrations
who list variables in memory
what list M-files on disk
size row and column dimensions
length vector length
clear clear workspace
computer type of computer
^C local abort
exit exit MATLAB
quit same as exit
Matrix Operators Array Operators
+ addition
- subtraction
* multiplication
/ division
\ left division
^ power
' conjugate transpose
+ addition
- subtraction
.* multiplication
./ division
.\ left division
.^ power
.' transpose
Relational and Logical Operators
< less than
<= less than or equal
> greater than
>= greater than or equal
== equal
~= not equal
& and
| or
~ not
Special Characters
= assignment statement
[ used to form vectors and matrices
] see [
( arithmetic expression precedence 
) see (
. decimal point
... continue statement to next line
, separate subscripts and function arguments
; end rows, suppress printing
% comments
: subscripting, vector generation
! execute operating system command
Special Values
ans answer when expression not assigned
eps floating point precision
pi 3.14159...
i, j sqrt(-1)
inf infinity
NaN Not-a-Number
clock wall clock
date date
flops floating point operation count
nargin number of function input arguments
nargout number of function output arguments
Disk Files
chdir change current directory
delete delete file
diary diary of the session
dir directory of files on disk
load load variables from file
save save variables to file
type list function or file
what show M-files on disk
fprintf write to a file
pack compact memory via save
Special Matrices
compan companion
diag diagonal
eye identity
gallery esoteric
hadamard Hadamard
hankel Hankel
hilb Hilbert
invhilb inverse Hilbert
linspace linearly spaced vectors
logspace logarithmically spaced vectors
magic magic square
meshdom domain for mesh points
ones constant
pascal Pascal
rand random elements
toeplitz Toeplitz
vander Vandermonde
zeros zero
Matrix Manipulation
rot90 rotation
fliplr flip matrix left-to-right
flipud flip matrix up-to-down
diag diagonal matrices
tril lower triangular part
triu upper triangular part
reshape reshape
.' transpose
: convert matrix to single column; A(:)
Relational and Logical Functions
any logical conditions
all logical conditions
find find array indices of logical values
isnan detect NaNs
finite detect infinities
isempty detect empty matrices
isstr detect string variables
strcmp compare string variables
Control Flow
if conditionally execute statements
elseif used with if
else used with if
end terminate if, for, while
for repeat statements a number of times
while do while
break break out of for and while loops
return return from functions
pause pause until key pressed
Programming and M-Files
input get numbers from keyboard
keyboard call keyboard as M-file
error display error message
function define function
eval interpret text in variables
feval evaluate function given by string
echo enable command echoing
exist check if variables exist
casesen set case sensitivity
global define global variables
startup startup M-file
getenv get environment string
menu select item from menu
etime elapsed time
Text and Strings
abs convert string to ASCII values
eval evaluate text macro
num2str convert number to string
int2str convert integer to string
setstr set flag indicating matrix is a string
sprintf convert number to string
isstr detect string variables
strcomp compare string variables
hex2num convert hex string to number
Command Window
clc  clear command screen
home  move cursor home
format  set output display format
disp  display matrix or text
fprintf print formatted number
echo  enable command echoing
Graph Paper
plot  linear X-Y plot
loglog  loglog X-Y plot
semilogx semi-log X-Y plot
semilogy semi-log X-Y plot
polar  polar plot
mesh  3-dimensional mesh surface
contour  contour plot
meshdom domain for mesh plots
bar  bar charts
stairs  stairstep graph
errorbar  add error bars
Graph Annotation
title  plot title
xlabel  x-axis label
ylabel  y-axis label
grid  draw grid lines
text  arbitrarily position text
gtext  mouse-positioned text
ginput  graphics input
Graph Window Control
axis  manual axis scaling
hold  hold plot on screen
shg  show graph window
clg  clear graph window
subplot split graph window
Graph Window Hardcopy
print  send graph to printer
prtsc  screen dump
meta  graphics metafile
Elementary Math Functions
abs  absolute value or complex magnitude
angle  phase angle
sqrt  square root
real  real part
imag  imaginary part
conj  complex conjugate
round  round to nearest integer
fix  round toward zero
floor  round toward $-\infty$
ceil  round toward $\infty$
sign  signum function
rem  remainder
exp  exponential base e
log  natural logarithm
log10  log base 10
Trigonometric Functions
sin  sine
cos  cosine
tan  tangent
asin  arcsine
acos  arccosine
atan  arctangent
atan2  four quadrant arctangent
sinh  hyperbolic sine
cosh  hyperbolic cosine
tanh  hyperbolic tangent
asinh  hyperbolic arcsine
acosh  hyperbolic arccosine
atanh  hyperbolic arctangent
Special Functions
bessel  bessel function
gamma  gamma function
rat  rational approximation
erf  error function
inverf inverse error function
ellipk complete elliptic integral of first kind
ellipj Jacobian elliptic integral
Decompositions and Factorizations
balance  balanced form
backsub  backsubstitution
cdf2rdf  convert complex-diagonal to real-diagonal
chol  Cholesky factorization
eig  eigenvalues and eigenvectors
hess  Hessenberg form
inv  inverse
lu  factors from Gaussian elimination
nnls  nonnegative least squares
null  null space
orth  orthogonalization
pinv  pseudoinverse
qr  orthogonal-triangular decomposition
qz  QZ algorithm
rref  reduced row echelon form
schur Schur decomposition
svd  singular value decomposition
Matrix Conditioning
cond  condition number in 2-norm
norm  1-norm,2-norm,F-norm,$\infty$-norm
rank  rank
rcond condition estimate (reciprocal)
Elementary Matrix Functions
expm  matrix exponential
logm  matrix logarithm
sqrtm matrix square root
funm  arbitrary matrix function
poly  characteristic polynomial
det  determinant
trace  trace
kron  Kronecker tensor product
poly  characteristic polynomial
roots  polynomial roots---companion matrix method
roots1  polynomial roots---Laguerre's method
polyval polynomial evaluation
polyvalm matrix polynomial evaluation
conv  multiplication
deconv  division
residue partial-fraction expansion
polyfit polynomial curve fitting
Column-wise Data Analysis
max  maximum value
min  minimum value
mean  mean value
median median value
std  standard deviation
sort  sorting
sum  sum of elements
prod  product of elements
cumsum cumulative sum of elements
cumprod cumulative product of elements
diff  approximate derivatives
hist  histograms
corrcoef  correlation coefficients
cov  covariance matrix
cplxpair  reorder into complex pairs
Signal Processing
abs  complex magnitude
angle  phase angle
conv  convolution
corrcoef  correlation coefficients
cov  covariance
deconv deconvolution
fft  radix-2 fast Fourier transform
fft2  two-dimensional FFT
ifft  inverse fast Fourier transform
ifft2  inverse 2-D FFT
fftshift FFT rearrangement
Numerical Integration
quad  numerical function integration
quad8  numerical function integration
Differential Equation Solution
ode23  2nd/3rd order Runge-Kutta method
ode45  4th/5th order Runge-Kutta-Fehlberg method
Nonlinear Equations and Optimization
fmin  minimum of a function of one variable
fmins  minimum of a multivariable function
fsolve  solution of a system of nonlinear equations
(zeros of a multivariable function)
fzero  zero of a function of one variable
spline  cubic spline
table1  1-D table look-up
table2  2-D table look-up

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