zqpt01.f - Man Page

double precision function zqpt01 (m, n, k, a, af, lda, tau, jpvt, work, lwork)
ZQPT01

ZQPT01

Purpose:

 ZQPT01 tests the QR-factorization with pivoting of a matrix A.  The
 array AF contains the (possibly partial) QR-factorization of A, where
 the upper triangle of AF(1:k,1:k) is a partial triangular factor,
 the entries below the diagonal in the first k columns are the
 Householder vectors, and the rest of AF contains a partially updated
 matrix.

 This function returns ||A*P - Q*R|| / ( ||norm(A)||*eps*max(M,N) )

Parameters

M

          M is INTEGER
          The number of rows of the matrices A and AF.

N

          N is INTEGER
          The number of columns of the matrices A and AF.

K

          K is INTEGER
          The number of columns of AF that have been reduced
          to upper triangular form.

A

          A is COMPLEX*16 array, dimension (LDA, N)
          The original matrix A.

AF

          AF is COMPLEX*16 array, dimension (LDA,N)
          The (possibly partial) output of ZGEQPF.  The upper triangle
          of AF(1:k,1:k) is a partial triangular factor, the entries
          below the diagonal in the first k columns are the Householder
          vectors, and the rest of AF contains a partially updated
          matrix.

LDA

          LDA is INTEGER
          The leading dimension of the arrays A and AF.

TAU

          TAU is COMPLEX*16 array, dimension (K)
          Details of the Householder transformations as returned by
          ZGEQPF.

JPVT

          JPVT is INTEGER array, dimension (N)
          Pivot information as returned by ZGEQPF.

WORK

          WORK is COMPLEX*16 array, dimension (LWORK)

LWORK

          LWORK is INTEGER
          The length of the array WORK.  LWORK >= M*N+N.

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Definition at line 118 of file zqpt01.f.