283 lines
8.0 KiB
C
283 lines
8.0 KiB
C
#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__2 = 2;
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/* Subroutine */ int dormtr_(char *side, char *uplo, char *trans, integer *m,
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integer *n, doublereal *a, integer *lda, doublereal *tau, doublereal *
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c__, integer *ldc, doublereal *work, integer *lwork, integer *info)
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{
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/* System generated locals */
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address a__1[2];
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integer a_dim1, a_offset, c_dim1, c_offset, i__1[2], i__2, i__3;
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char ch__1[2];
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/* Builtin functions */
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/* Subroutine */ int s_cat(char *, char **, integer *, integer *, ftnlen);
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/* Local variables */
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integer i1, i2, nb, mi, ni, nq, nw;
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logical left;
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extern logical lsame_(char *, char *);
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integer iinfo;
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logical upper;
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extern /* Subroutine */ int 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 dormql_(char *, char *, integer *, integer *,
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integer *, doublereal *, integer *, doublereal *, doublereal *,
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integer *, doublereal *, integer *, integer *),
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dormqr_(char *, char *, integer *, integer *, integer *,
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doublereal *, integer *, doublereal *, doublereal *, integer *,
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doublereal *, integer *, integer *);
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integer 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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/* DORMTR overwrites the general real M-by-N matrix C with */
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/* SIDE = 'L' SIDE = 'R' */
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/* TRANS = 'N': Q * C C * Q */
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/* TRANS = 'T': Q**T * C C * Q**T */
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/* where Q is a real orthogonal matrix of order nq, with nq = m if */
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/* SIDE = 'L' and nq = n if SIDE = 'R'. Q is defined as the product of */
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/* nq-1 elementary reflectors, as returned by DSYTRD: */
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/* if UPLO = 'U', Q = H(nq-1) . . . H(2) H(1); */
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/* if UPLO = 'L', Q = H(1) H(2) . . . H(nq-1). */
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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**T from the Left; */
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/* = 'R': apply Q or Q**T from the Right. */
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/* UPLO (input) CHARACTER*1 */
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/* = 'U': Upper triangle of A contains elementary reflectors */
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/* from DSYTRD; */
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/* = 'L': Lower triangle of A contains elementary reflectors */
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/* from DSYTRD. */
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/* TRANS (input) CHARACTER*1 */
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/* = 'N': No transpose, apply Q; */
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/* = 'T': Transpose, apply Q**T. */
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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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/* 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 vectors which define the elementary reflectors, as */
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/* returned by DSYTRD. */
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/* LDA (input) INTEGER */
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/* The leading dimension of the array A. */
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/* LDA >= max(1,M) if SIDE = 'L'; LDA >= max(1,N) if SIDE = 'R'. */
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/* TAU (input) DOUBLE PRECISION array, dimension */
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/* (M-1) if SIDE = 'L' */
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/* (N-1) if SIDE = 'R' */
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/* TAU(i) must contain the scalar factor of the elementary */
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/* reflector H(i), as returned by DSYTRD. */
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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**T*C or C*Q**T 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/output) DOUBLE PRECISION 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. */
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/* If SIDE = 'L', LWORK >= max(1,N); */
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/* if SIDE = 'R', LWORK >= max(1,M). */
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/* For optimum performance LWORK >= N*NB if SIDE = 'L', and */
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/* LWORK >= M*NB if SIDE = 'R', where NB is the optimal */
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/* 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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/* ===================================================================== */
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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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upper = lsame_(uplo, "U");
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lquery = *lwork == -1;
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/* NQ is the order of Q and NW is the minimum dimension of WORK */
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if (left) {
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nq = *m;
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nw = *n;
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} else {
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nq = *n;
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nw = *m;
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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 (! upper && ! lsame_(uplo, "L")) {
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*info = -2;
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} else if (! lsame_(trans, "N") && ! lsame_(trans,
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"T")) {
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*info = -3;
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} else if (*m < 0) {
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*info = -4;
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} else if (*n < 0) {
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*info = -5;
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} else if (*lda < max(1,nq)) {
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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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} else if (*lwork < max(1,nw) && ! lquery) {
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*info = -12;
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}
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if (*info == 0) {
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if (upper) {
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if (left) {
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/* Writing concatenation */
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i__1[0] = 1, a__1[0] = side;
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i__1[1] = 1, a__1[1] = trans;
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s_cat(ch__1, a__1, i__1, &c__2, (ftnlen)2);
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i__2 = *m - 1;
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i__3 = *m - 1;
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nb = ilaenv_(&c__1, "DORMQL", ch__1, &i__2, n, &i__3, &c_n1);
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} else {
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/* Writing concatenation */
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i__1[0] = 1, a__1[0] = side;
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i__1[1] = 1, a__1[1] = trans;
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s_cat(ch__1, a__1, i__1, &c__2, (ftnlen)2);
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i__2 = *n - 1;
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i__3 = *n - 1;
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nb = ilaenv_(&c__1, "DORMQL", ch__1, m, &i__2, &i__3, &c_n1);
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}
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} else {
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if (left) {
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/* Writing concatenation */
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i__1[0] = 1, a__1[0] = side;
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i__1[1] = 1, a__1[1] = trans;
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s_cat(ch__1, a__1, i__1, &c__2, (ftnlen)2);
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i__2 = *m - 1;
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i__3 = *m - 1;
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nb = ilaenv_(&c__1, "DORMQR", ch__1, &i__2, n, &i__3, &c_n1);
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} else {
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/* Writing concatenation */
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i__1[0] = 1, a__1[0] = side;
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i__1[1] = 1, a__1[1] = trans;
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s_cat(ch__1, a__1, i__1, &c__2, (ftnlen)2);
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i__2 = *n - 1;
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i__3 = *n - 1;
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nb = ilaenv_(&c__1, "DORMQR", ch__1, m, &i__2, &i__3, &c_n1);
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}
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}
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lwkopt = max(1,nw) * nb;
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work[1] = (doublereal) lwkopt;
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}
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if (*info != 0) {
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i__2 = -(*info);
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xerbla_("DORMTR", &i__2);
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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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if (*m == 0 || *n == 0 || nq == 1) {
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work[1] = 1.;
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return 0;
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}
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if (left) {
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mi = *m - 1;
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ni = *n;
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} else {
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mi = *m;
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ni = *n - 1;
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}
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if (upper) {
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/* Q was determined by a call to DSYTRD with UPLO = 'U' */
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i__2 = nq - 1;
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dormql_(side, trans, &mi, &ni, &i__2, &a[(a_dim1 << 1) + 1], lda, &
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tau[1], &c__[c_offset], ldc, &work[1], lwork, &iinfo);
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} else {
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/* Q was determined by a call to DSYTRD with UPLO = 'L' */
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if (left) {
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i1 = 2;
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i2 = 1;
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} else {
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i1 = 1;
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i2 = 2;
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}
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i__2 = nq - 1;
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dormqr_(side, trans, &mi, &ni, &i__2, &a[a_dim1 + 2], lda, &tau[1], &
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c__[i1 + i2 * c_dim1], ldc, &work[1], lwork, &iinfo);
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}
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work[1] = (doublereal) lwkopt;
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return 0;
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/* End of DORMTR */
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} /* dormtr_ */
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