rcond — inverse condition number
rcond(X)
rcond(X)
is an estimate for the reciprocal of the
condition of X
in the 1-norm.
If X
is well conditioned, rcond(X)
is close to 1.
If not, rcond(X)
is close to 0.
[r,z]=rcond(X)
sets r
to
rcond(X)
and returns z
such that
norm(X*z,1) = r*norm(X,1)*norm(z,1)
Thus, if rcond
is small z
is a vector in the kernel.