a character string. For method = "qr" the rank is
computed as qr(x)\$rank, or alternatively for
method="chol" the rank is
computed as attr(chol(x, pivot=TRUE), "rank").
Details
The function rk computes the rank of a matrix which is
the dimension of the range of the matrix corresponding to the number
of linearly independent rows or columns of the matrix, or to the
number of nonzero singular values.
The rank of a matrix is also named inear map.
References
Golub, van Loan, (1996);
Matrix Computations,
3rd edition. Johns Hopkins University Press.