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zgeqpf.f(3) LAPACK zgeqpf.f(3)

zgeqpf.f -


subroutine zgeqpf (M, N, A, LDA, JPVT, TAU, WORK, RWORK, INFO)
 
ZGEQPF

ZGEQPF
Purpose:
 This routine is deprecated and has been replaced by routine ZGEQP3.
ZGEQPF computes a QR factorization with column pivoting of a complex M-by-N matrix A: A*P = Q*R.
Parameters:
M
          M is INTEGER
          The number of rows of the matrix A. M >= 0.
N
          N is INTEGER
          The number of columns of the matrix A. N >= 0
A
          A is COMPLEX*16 array, dimension (LDA,N)
          On entry, the M-by-N matrix A.
          On exit, the upper triangle of the array contains the
          min(M,N)-by-N upper triangular matrix R; the elements
          below the diagonal, together with the array TAU,
          represent the unitary matrix Q as a product of
          min(m,n) elementary reflectors.
LDA
          LDA is INTEGER
          The leading dimension of the array A. LDA >= max(1,M).
JPVT
          JPVT is INTEGER array, dimension (N)
          On entry, if JPVT(i) .ne. 0, the i-th column of A is permuted
          to the front of A*P (a leading column); if JPVT(i) = 0,
          the i-th column of A is a free column.
          On exit, if JPVT(i) = k, then the i-th column of A*P
          was the k-th column of A.
TAU
          TAU is COMPLEX*16 array, dimension (min(M,N))
          The scalar factors of the elementary reflectors.
WORK
          WORK is COMPLEX*16 array, dimension (N)
RWORK
          RWORK is DOUBLE PRECISION array, dimension (2*N)
INFO
          INFO is INTEGER
          = 0:  successful exit
          < 0:  if INFO = -i, the i-th argument had an illegal value
Author:
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
November 2011
Further Details:
  The matrix Q is represented as a product of elementary reflectors
Q = H(1) H(2) . . . H(n)
Each H(i) has the form
H = I - tau * v * v**H
where tau is a complex scalar, and v is a complex vector with v(1:i-1) = 0 and v(i) = 1; v(i+1:m) is stored on exit in A(i+1:m,i).
The matrix P is represented in jpvt as follows: If jpvt(j) = i then the jth column of P is the ith canonical unit vector.
Partial column norm updating strategy modified by Z. Drmac and Z. Bujanovic, Dept. of Mathematics, University of Zagreb, Croatia. -- April 2011 -- For more details see LAPACK Working Note 176.
Definition at line 149 of file zgeqpf.f.

Generated automatically by Doxygen for LAPACK from the source code.
Sat Nov 16 2013 Version 3.4.2

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