qr
Builtin Function
[1mSynopsis[0m
QR decomposition
[1mSyntax[0m
qr ( [4mA[24m )
qr ( [4mA[24m, "p" )
[1mDescription[0m
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 [4mq[24m and [4mr[24m. Optionally, qr can
take a second argument, "p" which tells qr to perform column
pivoting when computing [4mq[24m and [4mr[24m. The permutation matrix [4mp[24m is
returned in the same list as [4mq[24m and [4mr[24m.
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.