What is the difference between null(A) and null(A,'r') in Matlab ?
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Wayne King on 4 Jan 2014
Edited: Wayne King on 4 Jan 2014
null(A,'r') does not give an orthonormal basis for the nullspace of A.
The help has a good example of this.
Orthonormal basis for nullspace of A
A = [
1 2 3
1 2 3
1 2 3];
Z = null(A);
Zr = null(A,'r');
Note the above columns are not orthonormal, but
yields the zero matrix. So clearly both columns of Zr are elements of the nullspace of A. Note that the columns of Zr are linearly independent