Control theory

Explanation of tables
*green Function exists in octave 2.0.x
Noted incompatibilities and missing features
+yellow Function exists in matcompat
Author and home for the function.
?orange Function doesn't exist
Explanation of what you can do instead.
xred Function doesn't exist, and no work-around

Octave 2.1.x has the control systems toolbox built in. Kai Mueller has a backport to Octave 2.0.x.

System construction
?filt
tf2sys
xfrd
xdss
?ss
ss2sys
?tf
tf2sys
?zpk
zp2sys
xfrdata
xdssdata
?ssdata
sys2ss
?tfdata
sys2tf
?zpkdata
sys2zp
xget
xset
xltimodels
xltiprops

System properties
xclass
xhasdelay
xisa
?isct
!is_digital, but what about mixed models?
?isdt
is_digital
xisempty
xisproper
?issiso
is_siso
xndims
xsize
xtotaldelay

System conversion
*c2d
*d2c
xd2d
xdelay2z
xchgunits
xpade

_
xbalreal
xminreal
xmodred
xsminreal

_
xcanon
*ctrb
*obsv
*gram
xctrbf
xobsvf
xss2ss
xssbal

Block diagram manipulations
?append
sysappend, strappend
xaugstate
?connect
sysconnect
xdrmodel
xdrss
xrmodel
xrss
xfeedback
?lft
starp
*ord2
*parallel
*series
xstack

Time domain analysis
xgensig
*impulse
xinitial
*lsim
*step
*damp
*dcgain
xcovar
xdsort
xesort
?norm
h2norm, hinfnorm, zgrownorm
xpole
*pzmap
?zero
tzero, tzero2

Frequency domain analysis
*bode
*nichols
*nyquist
*pzmap
*rlocus
xsigma
xevalfr
xfreqresp
xrlocfind
xmargin
xngrid
xsgrid
xzgrid

Controller design
*place
xacker
xestim
xreg
*lqr
*dlqr
xlqry
xlqrd
?kalman
lqe
?kalmd
dlqe
xlqgreg

Numerical functions
xcare
*dare
*lyap
*dlyap

GUI tools
xltiview
xrltool