zgeqpf.f (3) - Linux Manuals
NAME
zgeqpf.f -
SYNOPSIS
Functions/Subroutines
subroutine zgeqpf (M, N, A, LDA, JPVT, TAU, WORK, RWORK, INFO)
ZGEQPF
Function/Subroutine Documentation
subroutine zgeqpf (integerM, integerN, complex*16, dimension( lda, * )A, integerLDA, integer, dimension( * )JPVT, complex*16, dimension( * )TAU, complex*16, dimension( * )WORK, double precision, dimension( * )RWORK, integerINFO)
ZGEQPF
Purpose:
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This routine is deprecated and has been replaced by routine ZGEQP3.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.
NN is INTEGER The number of columns of the matrix A. N >= 0
AA 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.
LDALDA is INTEGER The leading dimension of the array A. LDA >= max(1,M).
JPVTJPVT 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.
TAUTAU is COMPLEX*16 array, dimension (min(M,N)) The scalar factors of the elementary reflectors.
WORKWORK is COMPLEX*16 array, dimension (N)
RWORKRWORK is DOUBLE PRECISION array, dimension (2*N)
INFOINFO is INTEGER = 0: successful exit < 0: if INFO = -i, the i-th argument had an illegal value
Author:
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Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Date:
- November 2011
Further Details:
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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.
Author
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