"atomic bomb" commit. Reorganized OpenCV directory structure
This commit is contained in:
Vadim Pisarevsky
238
3rdparty/lapack/sgelqf.c
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238
3rdparty/lapack/sgelqf.c
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#include "clapack.h"
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/* Table of constant values */
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static integer c__1 = 1;
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static integer c_n1 = -1;
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static integer c__3 = 3;
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static integer c__2 = 2;
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/* Subroutine */ int sgelqf_(integer *m, integer *n, real *a, integer *lda,
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real *tau, real *work, integer *lwork, integer *info)
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{
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/* System generated locals */
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integer a_dim1, a_offset, i__1, i__2, i__3, i__4;
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/* Local variables */
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integer i__, k, ib, nb, nx, iws, nbmin, iinfo;
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extern /* Subroutine */ int sgelq2_(integer *, integer *, real *, integer
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*, real *, real *, integer *), slarfb_(char *, char *, char *,
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char *, integer *, integer *, integer *, real *, integer *, real *
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, integer *, real *, integer *, real *, integer *), xerbla_(char *, integer *);
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extern integer ilaenv_(integer *, char *, char *, integer *, integer *,
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integer *, integer *);
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extern /* Subroutine */ int slarft_(char *, char *, integer *, integer *,
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real *, integer *, real *, real *, integer *);
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integer ldwork, lwkopt;
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logical lquery;
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/* -- LAPACK routine (version 3.1) -- */
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/* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. */
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/* November 2006 */
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/* .. Scalar Arguments .. */
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/* .. */
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/* .. Array Arguments .. */
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/* .. */
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/* Purpose */
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/* ======= */
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/* SGELQF computes an LQ factorization of a real M-by-N matrix A: */
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/* A = L * Q. */
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/* Arguments */
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/* ========= */
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/* M (input) INTEGER */
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/* The number of rows of the matrix A. M >= 0. */
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/* N (input) INTEGER */
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/* The number of columns of the matrix A. N >= 0. */
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/* A (input/output) REAL array, dimension (LDA,N) */
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/* On entry, the M-by-N matrix A. */
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/* On exit, the elements on and below the diagonal of the array */
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/* contain the m-by-min(m,n) lower trapezoidal matrix L (L is */
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/* lower triangular if m <= n); the elements above the diagonal, */
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/* with the array TAU, represent the orthogonal matrix Q as a */
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/* product of elementary reflectors (see Further Details). */
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/* LDA (input) INTEGER */
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/* The leading dimension of the array A. LDA >= max(1,M). */
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/* TAU (output) REAL array, dimension (min(M,N)) */
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/* The scalar factors of the elementary reflectors (see Further */
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/* Details). */
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/* WORK (workspace/output) REAL array, dimension (MAX(1,LWORK)) */
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/* On exit, if INFO = 0, WORK(1) returns the optimal LWORK. */
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/* LWORK (input) INTEGER */
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/* The dimension of the array WORK. LWORK >= max(1,M). */
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/* For optimum performance LWORK >= M*NB, where NB is the */
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/* optimal blocksize. */
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/* If LWORK = -1, then a workspace query is assumed; the routine */
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/* only calculates the optimal size of the WORK array, returns */
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/* this value as the first entry of the WORK array, and no error */
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/* message related to LWORK is issued by XERBLA. */
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/* INFO (output) INTEGER */
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/* = 0: successful exit */
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/* < 0: if INFO = -i, the i-th argument had an illegal value */
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/* Further Details */
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/* =============== */
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/* The matrix Q is represented as a product of elementary reflectors */
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/* Q = H(k) . . . H(2) H(1), where k = min(m,n). */
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/* Each H(i) has the form */
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/* H(i) = I - tau * v * v' */
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/* where tau is a real scalar, and v is a real vector with */
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/* v(1:i-1) = 0 and v(i) = 1; v(i+1:n) is stored on exit in A(i,i+1:n), */
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/* and tau in TAU(i). */
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/* ===================================================================== */
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/* .. Local Scalars .. */
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/* .. */
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/* .. External Subroutines .. */
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/* .. */
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/* .. Intrinsic Functions .. */
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/* .. */
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/* .. External Functions .. */
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/* .. */
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/* .. Executable Statements .. */
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/* Test the input arguments */
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/* Parameter adjustments */
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a_dim1 = *lda;
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a_offset = 1 + a_dim1;
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a -= a_offset;
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--tau;
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--work;
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/* Function Body */
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*info = 0;
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nb = ilaenv_(&c__1, "SGELQF", " ", m, n, &c_n1, &c_n1);
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lwkopt = *m * nb;
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work[1] = (real) lwkopt;
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lquery = *lwork == -1;
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if (*m < 0) {
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*info = -1;
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} else if (*n < 0) {
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*info = -2;
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} else if (*lda < max(1,*m)) {
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*info = -4;
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} else if (*lwork < max(1,*m) && ! lquery) {
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*info = -7;
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}
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if (*info != 0) {
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i__1 = -(*info);
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xerbla_("SGELQF", &i__1);
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return 0;
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} else if (lquery) {
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return 0;
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}
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/* Quick return if possible */
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k = min(*m,*n);
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if (k == 0) {
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work[1] = 1.f;
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return 0;
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}
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nbmin = 2;
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nx = 0;
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iws = *m;
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if (nb > 1 && nb < k) {
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/* Determine when to cross over from blocked to unblocked code. */
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/* Computing MAX */
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i__1 = 0, i__2 = ilaenv_(&c__3, "SGELQF", " ", m, n, &c_n1, &c_n1);
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nx = max(i__1,i__2);
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if (nx < k) {
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/* Determine if workspace is large enough for blocked code. */
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ldwork = *m;
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iws = ldwork * nb;
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if (*lwork < iws) {
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/* Not enough workspace to use optimal NB: reduce NB and */
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/* determine the minimum value of NB. */
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nb = *lwork / ldwork;
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/* Computing MAX */
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i__1 = 2, i__2 = ilaenv_(&c__2, "SGELQF", " ", m, n, &c_n1, &
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c_n1);
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nbmin = max(i__1,i__2);
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}
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}
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}
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if (nb >= nbmin && nb < k && nx < k) {
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/* Use blocked code initially */
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i__1 = k - nx;
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i__2 = nb;
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for (i__ = 1; i__2 < 0 ? i__ >= i__1 : i__ <= i__1; i__ += i__2) {
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/* Computing MIN */
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i__3 = k - i__ + 1;
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ib = min(i__3,nb);
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/* Compute the LQ factorization of the current block */
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/* A(i:i+ib-1,i:n) */
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i__3 = *n - i__ + 1;
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sgelq2_(&ib, &i__3, &a[i__ + i__ * a_dim1], lda, &tau[i__], &work[
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1], &iinfo);
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if (i__ + ib <= *m) {
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/* Form the triangular factor of the block reflector */
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/* H = H(i) H(i+1) . . . H(i+ib-1) */
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i__3 = *n - i__ + 1;
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slarft_("Forward", "Rowwise", &i__3, &ib, &a[i__ + i__ *
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a_dim1], lda, &tau[i__], &work[1], &ldwork);
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/* Apply H to A(i+ib:m,i:n) from the right */
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i__3 = *m - i__ - ib + 1;
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i__4 = *n - i__ + 1;
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slarfb_("Right", "No transpose", "Forward", "Rowwise", &i__3,
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&i__4, &ib, &a[i__ + i__ * a_dim1], lda, &work[1], &
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ldwork, &a[i__ + ib + i__ * a_dim1], lda, &work[ib +
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1], &ldwork);
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}
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/* L10: */
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}
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} else {
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i__ = 1;
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}
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/* Use unblocked code to factor the last or only block. */
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if (i__ <= k) {
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i__2 = *m - i__ + 1;
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i__1 = *n - i__ + 1;
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sgelq2_(&i__2, &i__1, &a[i__ + i__ * a_dim1], lda, &tau[i__], &work[1]
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, &iinfo);
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}
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work[1] = (real) iws;
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return 0;
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/* End of SGELQF */
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} /* sgelqf_ */
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