matrices(1)

NAME
[] - empty matrix

DESCRIPTION
[] denotes the empty matrix. It is uniquely defined and has 0 row and 0 column, i.e. size([]) =[0,0] . The following convenient conventions are made:

[] * A = A * [] = []

[] + A = A + [] = A

[ [], A] = [A, []] = A inv([]) =[]

det([])=cond([])=rcond([])=1, rank([])=0

Matrix functions return [] or an error message when there is no obvious answer. Empty linear systems ( syslin lists) may have several rows or columns.

EXAMPLE
s=poly(0,'s'); A = [s, s+1];
A+[], A*[]
A=rand(2,2); AA=A([],1), size(AA)
svd([]) , norm([])
w=ssrand(2,2,2); wr=[]*w; size(wr), w1=ss2tf(wr), size(w1)

SEE ALSO
matrices, poly, string, boolean, rational, syslin.