qr:
	
Syntax:	qr ( A )
	qr ( A , "p" )

Description:

	Qr computes the QR decomposition of the input matrix A such
	that: 

		A = Q * R

	or

		A*p = Q * R

	Qr returns a list containing elements `q' and `r'. Optionally,
	qr can take a second argument ("p"), which tells qr to perform
	column pivoting when computing [q] and [r]. The permutation
	matrix `p' is returned in the same list as `q' and `r'.

	Qr utilizes LAPACK subroutines DGEQRF and DORGQR for REAL
	inputs, and ZGEQRF and ZUNGQR for COMPLEX inputs. When column
	pivoting is requested the LAPACK subroutines DGEQPF, and
	ZGEQPF are used.
