Subroutine */
| 4880 | } /* dgeqr2_ */ |
| 4881 | |
| 4882 | /* Subroutine */ int dgeqrf_(integer *m, integer *n, doublereal *a, integer * |
| 4883 | lda, doublereal *tau, doublereal *work, integer *lwork, integer *info) |
| 4884 | { |
| 4885 | /* System generated locals */ |
| 4886 | integer a_dim1, a_offset, i__1, i__2, i__3, i__4; |
| 4887 | |
| 4888 | /* Local variables */ |
| 4889 | static integer i__, k, ib, nb, nx, iws, nbmin, iinfo; |
| 4890 | extern /* Subroutine */ int dgeqr2_(integer *, integer *, doublereal *, |
| 4891 | integer *, doublereal *, doublereal *, integer *), dlarfb_(char *, |
| 4892 | char *, char *, char *, integer *, integer *, integer *, |
| 4893 | doublereal *, integer *, doublereal *, integer *, doublereal *, |
| 4894 | integer *, doublereal *, integer *), dlarft_(char *, char *, integer *, integer *, doublereal |
| 4895 | *, integer *, doublereal *, doublereal *, integer *), xerbla_(char *, integer *); |
| 4896 | extern integer ilaenv_(integer *, char *, char *, integer *, integer *, |
| 4897 | integer *, integer *, ftnlen, ftnlen); |
| 4898 | static integer ldwork, lwkopt; |
| 4899 | static logical lquery; |
| 4900 | |
| 4901 | |
| 4902 | /* |
| 4903 | -- LAPACK routine (version 3.2) -- |
| 4904 | -- LAPACK is a software package provided by Univ. of Tennessee, -- |
| 4905 | -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- |
| 4906 | November 2006 |
| 4907 | |
| 4908 | |
| 4909 | Purpose |
| 4910 | ======= |
| 4911 | |
| 4912 | DGEQRF computes a QR factorization of a real M-by-N matrix A: |
| 4913 | A = Q * R. |
| 4914 | |
| 4915 | Arguments |
| 4916 | ========= |
| 4917 | |
| 4918 | M (input) INTEGER |
| 4919 | The number of rows of the matrix A. M >= 0. |
| 4920 | |
| 4921 | N (input) INTEGER |
| 4922 | The number of columns of the matrix A. N >= 0. |
| 4923 | |
| 4924 | A (input/output) DOUBLE PRECISION array, dimension (LDA,N) |
| 4925 | On entry, the M-by-N matrix A. |
| 4926 | On exit, the elements on and above the diagonal of the array |
| 4927 | contain the min(M,N)-by-N upper trapezoidal matrix R (R is |
| 4928 | upper triangular if m >= n); the elements below the diagonal, |
| 4929 | with the array TAU, represent the orthogonal matrix Q as a |
| 4930 | product of min(m,n) elementary reflectors (see Further |
| 4931 | Details). |
| 4932 | |
| 4933 | LDA (input) INTEGER |
| 4934 | The leading dimension of the array A. LDA >= max(1,M). |
| 4935 | |
| 4936 | TAU (output) DOUBLE PRECISION array, dimension (min(M,N)) |
| 4937 | The scalar factors of the elementary reflectors (see Further |
| 4938 | Details). |
| 4939 |