1DGEQPF(1)       LAPACK deprecated driver routine (version 3.2)       DGEQPF(1)
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NAME

6       DGEQPF - routine i deprecated and has been replaced by routine DGEQP3
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SYNOPSIS

9       SUBROUTINE DGEQPF( M, N, A, LDA, JPVT, TAU, WORK, INFO )
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11           INTEGER        INFO, LDA, M, N
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13           INTEGER        JPVT( * )
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15           DOUBLE         PRECISION A( LDA, * ), TAU( * ), WORK( * )
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PURPOSE

18       This  routine  is  deprecated  and has been replaced by routine DGEQP3.
19       DGEQPF computes a QR factorization with column pivoting of a real M-by-
20       N matrix A: A*P = Q*R.
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ARGUMENTS

23       M       (input) INTEGER
24               The number of rows of the matrix A. M >= 0.
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26       N       (input) INTEGER
27               The number of columns of the matrix A. N >= 0
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29       A       (input/output) DOUBLE PRECISION array, dimension (LDA,N)
30               On  entry, the M-by-N matrix A.  On exit, the upper triangle of
31               the array contains the min(M,N)-by-N upper triangular matrix R;
32               the  elements  below the diagonal, together with the array TAU,
33               represent the orthogonal matrix Q as a product of min(m,n) ele‐
34               mentary reflectors.
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36       LDA     (input) INTEGER
37               The leading dimension of the array A. LDA >= max(1,M).
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39       JPVT    (input/output) INTEGER array, dimension (N)
40               On  entry,  if JPVT(i) .ne. 0, the i-th column of A is permuted
41               to the front of A*P (a leading column); if JPVT(i) = 0, the  i-
42               th column of A is a free column.  On exit, if JPVT(i) = k, then
43               the i-th column of A*P was the k-th column of A.
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45       TAU     (output) DOUBLE PRECISION array, dimension (min(M,N))
46               The scalar factors of the elementary reflectors.
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48       WORK    (workspace) DOUBLE PRECISION array, dimension (3*N)
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50       INFO    (output) INTEGER
51               = 0:  successful exit
52               < 0:  if INFO = -i, the i-th argument had an illegal value
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FURTHER DETAILS

55       The matrix Q is represented as a product of elementary reflectors
56          Q = H(1) H(2) . . . H(n)
57       Each H(i) has the form
58          H = I - tau * v * v'
59       where tau is a real scalar, and v is a real vector with
60       v(1:i-1) = 0 and v(i) = 1; v(i+1:m) is stored on  exit  in  A(i+1:m,i).
61       The matrix P is represented in jpvt as follows: If
62          jpvt(j) = i
63       then  the  jth  column  of P is the ith canonical unit vector.  Partial
64       column norm updating strategy modified by
65         Z. Drmac and Z. Bujanovic, Dept. of Mathematics,
66         University of Zagreb, Croatia.
67         June 2006.
68       For more details see LAPACK Working Note 176.
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72 LAPACK deprecated driver routineN(ovveermsbieorn230.028)                      DGEQPF(1)