empty

([]) 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.

Examples

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

See Also

• matrices Scilab object, matrices in Scilab
• poly polynomial definition
• string conversion to string
• boolean Scilab Objects, boolean variables and operators & | ~
• rational Scilab objects, rational in Scilab
• syslin linear system definition