SYNOPSIS
 SUBROUTINE SGEQPF(
 M, N, A, LDA, JPVT, TAU, WORK, INFO )
 INTEGER INFO, LDA, M, N
 INTEGER JPVT( * )
 REAL A( LDA, * ), TAU( * ), WORK( * )
PURPOSE
This routine is deprecated and has been replaced by routine SGEQP3. SGEQPF computes a QR factorization with column pivoting of a real MbyN matrix A: A*P = Q*R.ARGUMENTS
 M (input) INTEGER
 The number of rows of the matrix A. M >= 0.
 N (input) INTEGER
 The number of columns of the matrix A. N >= 0
 A (input/output) REAL array, dimension (LDA,N)
 On entry, the MbyN matrix A. On exit, the upper triangle of the array contains the min(M,N)byN upper triangular matrix R; the elements below the diagonal, together with the array TAU, represent the orthogonal matrix Q as a product of min(m,n) elementary reflectors.
 LDA (input) INTEGER
 The leading dimension of the array A. LDA >= max(1,M).
 JPVT (input/output) INTEGER array, dimension (N)
 On entry, if JPVT(i) .ne. 0, the ith column of A is permuted to the front of A*P (a leading column); if JPVT(i) = 0, the ith column of A is a free column. On exit, if JPVT(i) = k, then the ith column of A*P was the kth column of A.
 TAU (output) REAL array, dimension (min(M,N))
 The scalar factors of the elementary reflectors.
 WORK (workspace) REAL array, dimension (3*N)
 INFO (output) INTEGER

= 0: successful exit
< 0: if INFO = i, the ith argument had an illegal value
FURTHER DETAILS
The matrix Q is represented as a product of elementary reflectorsQ = H(1) H(2) . . . H(n)
Each H(i) has the form
H = I  tau * v * v'
where tau is a real scalar, and v is a real vector with
v(1:i1) = 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.
June 2006.
For more details see LAPACK Working Note 176.