219 lines
5.5 KiB
C
219 lines
5.5 KiB
C
#include "clapack.h"
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/* Subroutine */ int dorml2_(char *side, char *trans, integer *m, integer *n,
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integer *k, doublereal *a, integer *lda, doublereal *tau, doublereal *
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c__, integer *ldc, doublereal *work, integer *info)
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{
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/* System generated locals */
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integer a_dim1, a_offset, c_dim1, c_offset, i__1, i__2;
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/* Local variables */
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integer i__, i1, i2, i3, ic, jc, mi, ni, nq;
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doublereal aii;
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logical left;
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extern /* Subroutine */ int dlarf_(char *, integer *, integer *,
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doublereal *, integer *, doublereal *, doublereal *, integer *,
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doublereal *);
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extern logical lsame_(char *, char *);
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extern /* Subroutine */ int xerbla_(char *, integer *);
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logical notran;
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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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/* DORML2 overwrites the general real m by n matrix C with */
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/* Q * C if SIDE = 'L' and TRANS = 'N', or */
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/* Q'* C if SIDE = 'L' and TRANS = 'T', or */
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/* C * Q if SIDE = 'R' and TRANS = 'N', or */
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/* C * Q' if SIDE = 'R' and TRANS = 'T', */
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/* where Q is a real orthogonal matrix defined as the product of k */
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/* elementary reflectors */
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/* Q = H(k) . . . H(2) H(1) */
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/* as returned by DGELQF. Q is of order m if SIDE = 'L' and of order n */
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/* if SIDE = 'R'. */
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/* Arguments */
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/* ========= */
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/* SIDE (input) CHARACTER*1 */
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/* = 'L': apply Q or Q' from the Left */
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/* = 'R': apply Q or Q' from the Right */
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/* TRANS (input) CHARACTER*1 */
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/* = 'N': apply Q (No transpose) */
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/* = 'T': apply Q' (Transpose) */
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/* M (input) INTEGER */
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/* The number of rows of the matrix C. M >= 0. */
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/* N (input) INTEGER */
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/* The number of columns of the matrix C. N >= 0. */
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/* K (input) INTEGER */
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/* The number of elementary reflectors whose product defines */
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/* the matrix Q. */
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/* If SIDE = 'L', M >= K >= 0; */
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/* if SIDE = 'R', N >= K >= 0. */
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/* A (input) DOUBLE PRECISION array, dimension */
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/* (LDA,M) if SIDE = 'L', */
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/* (LDA,N) if SIDE = 'R' */
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/* The i-th row must contain the vector which defines the */
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/* elementary reflector H(i), for i = 1,2,...,k, as returned by */
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/* DGELQF in the first k rows of its array argument A. */
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/* A is modified by the routine but restored on exit. */
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/* LDA (input) INTEGER */
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/* The leading dimension of the array A. LDA >= max(1,K). */
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/* TAU (input) DOUBLE PRECISION array, dimension (K) */
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/* TAU(i) must contain the scalar factor of the elementary */
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/* reflector H(i), as returned by DGELQF. */
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/* C (input/output) DOUBLE PRECISION array, dimension (LDC,N) */
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/* On entry, the m by n matrix C. */
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/* On exit, C is overwritten by Q*C or Q'*C or C*Q' or C*Q. */
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/* LDC (input) INTEGER */
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/* The leading dimension of the array C. LDC >= max(1,M). */
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/* WORK (workspace) DOUBLE PRECISION array, dimension */
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/* (N) if SIDE = 'L', */
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/* (M) if SIDE = 'R' */
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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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/* ===================================================================== */
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/* .. Parameters .. */
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/* .. */
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/* .. Local Scalars .. */
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/* .. */
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/* .. External Functions .. */
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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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/* .. 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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c_dim1 = *ldc;
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c_offset = 1 + c_dim1;
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c__ -= c_offset;
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--work;
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/* Function Body */
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*info = 0;
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left = lsame_(side, "L");
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notran = lsame_(trans, "N");
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/* NQ is the order of Q */
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if (left) {
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nq = *m;
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} else {
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nq = *n;
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}
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if (! left && ! lsame_(side, "R")) {
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*info = -1;
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} else if (! notran && ! lsame_(trans, "T")) {
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*info = -2;
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} else if (*m < 0) {
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*info = -3;
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} else if (*n < 0) {
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*info = -4;
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} else if (*k < 0 || *k > nq) {
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*info = -5;
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} else if (*lda < max(1,*k)) {
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*info = -7;
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} else if (*ldc < max(1,*m)) {
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*info = -10;
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}
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if (*info != 0) {
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i__1 = -(*info);
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xerbla_("DORML2", &i__1);
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return 0;
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}
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/* Quick return if possible */
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if (*m == 0 || *n == 0 || *k == 0) {
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return 0;
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}
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if (left && notran || ! left && ! notran) {
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i1 = 1;
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i2 = *k;
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i3 = 1;
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} else {
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i1 = *k;
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i2 = 1;
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i3 = -1;
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}
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if (left) {
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ni = *n;
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jc = 1;
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} else {
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mi = *m;
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ic = 1;
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}
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i__1 = i2;
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i__2 = i3;
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for (i__ = i1; i__2 < 0 ? i__ >= i__1 : i__ <= i__1; i__ += i__2) {
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if (left) {
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/* H(i) is applied to C(i:m,1:n) */
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mi = *m - i__ + 1;
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ic = i__;
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} else {
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/* H(i) is applied to C(1:m,i:n) */
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ni = *n - i__ + 1;
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jc = i__;
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}
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/* Apply H(i) */
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aii = a[i__ + i__ * a_dim1];
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a[i__ + i__ * a_dim1] = 1.;
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dlarf_(side, &mi, &ni, &a[i__ + i__ * a_dim1], lda, &tau[i__], &c__[
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ic + jc * c_dim1], ldc, &work[1]);
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a[i__ + i__ * a_dim1] = aii;
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/* L10: */
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}
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return 0;
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/* End of DORML2 */
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} /* dorml2_ */
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