Scilab Function
Last update : 12/01/2004
ereduc - computes matrix column echelon form by qz transformations
Calling Sequence
- [E,Q,Z [,stair [,rk]]]=ereduc(X,tol)
Parameters
-
X: m x n matrix with real entries.
-
tol: real positive scalar.
-
E: column echelon form matrix
-
Q: m x m unitary matrix
-
Z: n x n unitary matrix
-
stair: vector of indexes,
-
* ISTAIR(i) = + j if the boundary element E(i,j) is a corner point.
-
* ISTAIR(i) = - j if the boundary element E(i,j) is not a corner point.
(i=1,...,M)
-
rk: integer, estimated rank of the matrix
Description
Given an m x n matrix X (not necessarily regular) the function
ereduc computes a unitary transformed matrix E=Q*X*Z which is in
column echelon form (trapezoidal form). Furthermore the rank of
matrix X is determined.
Examples
X=[1 2 3;4 5 6]
[E,Q,Z ,stair ,rk]=ereduc(X,1.d-15)
See Also
fstair,
Author
Th.G.J. Beelen (Philips Glass Eindhoven). SLICOT