Ejemplo n.º 1
0
/* Subroutine */ int dlasda_(integer *icompq, integer *smlsiz, integer *n, 
	integer *sqre, doublereal *d__, doublereal *e, doublereal *u, integer 
	*ldu, doublereal *vt, integer *k, doublereal *difl, doublereal *difr, 
	doublereal *z__, doublereal *poles, integer *givptr, integer *givcol, 
	integer *ldgcol, integer *perm, doublereal *givnum, doublereal *c__, 
	doublereal *s, doublereal *work, integer *iwork, integer *info)
{
    /* System generated locals */
    integer givcol_dim1, givcol_offset, perm_dim1, perm_offset, difl_dim1, 
	    difl_offset, difr_dim1, difr_offset, givnum_dim1, givnum_offset, 
	    poles_dim1, poles_offset, u_dim1, u_offset, vt_dim1, vt_offset, 
	    z_dim1, z_offset, i__1, i__2;

    /* Builtin functions */
    integer pow_ii(integer *, integer *);

    /* Local variables */
    static doublereal beta;
    static integer idxq, nlvl, i__, j, m;
    static doublereal alpha;
    static integer inode, ndiml, ndimr, idxqi, itemp;
    extern /* Subroutine */ int dcopy_(integer *, doublereal *, integer *, 
	    doublereal *, integer *);
    static integer sqrei, i1;
    extern /* Subroutine */ int dlasd6_(integer *, integer *, integer *, 
	    integer *, doublereal *, doublereal *, doublereal *, doublereal *,
	     doublereal *, integer *, integer *, integer *, integer *, 
	    integer *, doublereal *, integer *, doublereal *, doublereal *, 
	    doublereal *, doublereal *, integer *, doublereal *, doublereal *,
	     doublereal *, integer *, integer *);
    static integer ic, nwork1, lf, nd, nwork2, ll, nl, vf, nr, vl;
    extern /* Subroutine */ int dlasdq_(char *, integer *, integer *, integer 
	    *, integer *, integer *, doublereal *, doublereal *, doublereal *,
	     integer *, doublereal *, integer *, doublereal *, integer *, 
	    doublereal *, integer *), dlasdt_(integer *, integer *, 
	    integer *, integer *, integer *, integer *, integer *), dlaset_(
	    char *, integer *, integer *, doublereal *, doublereal *, 
	    doublereal *, integer *), xerbla_(char *, integer *);
    static integer im1, smlszp, ncc, nlf, nrf, vfi, iwk, vli, lvl, nru, ndb1, 
	    nlp1, lvl2, nrp1;


#define difl_ref(a_1,a_2) difl[(a_2)*difl_dim1 + a_1]
#define difr_ref(a_1,a_2) difr[(a_2)*difr_dim1 + a_1]
#define perm_ref(a_1,a_2) perm[(a_2)*perm_dim1 + a_1]
#define u_ref(a_1,a_2) u[(a_2)*u_dim1 + a_1]
#define z___ref(a_1,a_2) z__[(a_2)*z_dim1 + a_1]
#define poles_ref(a_1,a_2) poles[(a_2)*poles_dim1 + a_1]
#define vt_ref(a_1,a_2) vt[(a_2)*vt_dim1 + a_1]
#define givcol_ref(a_1,a_2) givcol[(a_2)*givcol_dim1 + a_1]
#define givnum_ref(a_1,a_2) givnum[(a_2)*givnum_dim1 + a_1]


/*  -- LAPACK auxiliary routine (version 3.0) --   
       Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,   
       Courant Institute, Argonne National Lab, and Rice University   
       October 31, 1999   


    Purpose   
    =======   

    Using a divide and conquer approach, DLASDA computes the singular   
    value decomposition (SVD) of a real upper bidiagonal N-by-M matrix   
    B with diagonal D and offdiagonal E, where M = N + SQRE. The   
    algorithm computes the singular values in the SVD B = U * S * VT.   
    The orthogonal matrices U and VT are optionally computed in   
    compact form.   

    A related subroutine, DLASD0, computes the singular values and   
    the singular vectors in explicit form.   

    Arguments   
    =========   

    ICOMPQ (input) INTEGER   
           Specifies whether singular vectors are to be computed   
           in compact form, as follows   
           = 0: Compute singular values only.   
           = 1: Compute singular vectors of upper bidiagonal   
                matrix in compact form.   

    SMLSIZ (input) INTEGER   
           The maximum size of the subproblems at the bottom of the   
           computation tree.   

    N      (input) INTEGER   
           The row dimension of the upper bidiagonal matrix. This is   
           also the dimension of the main diagonal array D.   

    SQRE   (input) INTEGER   
           Specifies the column dimension of the bidiagonal matrix.   
           = 0: The bidiagonal matrix has column dimension M = N;   
           = 1: The bidiagonal matrix has column dimension M = N + 1.   

    D      (input/output) DOUBLE PRECISION array, dimension ( N )   
           On entry D contains the main diagonal of the bidiagonal   
           matrix. On exit D, if INFO = 0, contains its singular values.   

    E      (input) DOUBLE PRECISION array, dimension ( M-1 )   
           Contains the subdiagonal entries of the bidiagonal matrix.   
           On exit, E has been destroyed.   

    U      (output) DOUBLE PRECISION array,   
           dimension ( LDU, SMLSIZ ) if ICOMPQ = 1, and not referenced   
           if ICOMPQ = 0. If ICOMPQ = 1, on exit, U contains the left   
           singular vector matrices of all subproblems at the bottom   
           level.   

    LDU    (input) INTEGER, LDU = > N.   
           The leading dimension of arrays U, VT, DIFL, DIFR, POLES,   
           GIVNUM, and Z.   

    VT     (output) DOUBLE PRECISION array,   
           dimension ( LDU, SMLSIZ+1 ) if ICOMPQ = 1, and not referenced   
           if ICOMPQ = 0. If ICOMPQ = 1, on exit, VT' contains the right   
           singular vector matrices of all subproblems at the bottom   
           level.   

    K      (output) INTEGER array,   
           dimension ( N ) if ICOMPQ = 1 and dimension 1 if ICOMPQ = 0.   
           If ICOMPQ = 1, on exit, K(I) is the dimension of the I-th   
           secular equation on the computation tree.   

    DIFL   (output) DOUBLE PRECISION array, dimension ( LDU, NLVL ),   
           where NLVL = floor(log_2 (N/SMLSIZ))).   

    DIFR   (output) DOUBLE PRECISION array,   
                    dimension ( LDU, 2 * NLVL ) if ICOMPQ = 1 and   
                    dimension ( N ) if ICOMPQ = 0.   
           If ICOMPQ = 1, on exit, DIFL(1:N, I) and DIFR(1:N, 2 * I - 1)   
           record distances between singular values on the I-th   
           level and singular values on the (I -1)-th level, and   
           DIFR(1:N, 2 * I ) contains the normalizing factors for   
           the right singular vector matrix. See DLASD8 for details.   

    Z      (output) DOUBLE PRECISION array,   
                    dimension ( LDU, NLVL ) if ICOMPQ = 1 and   
                    dimension ( N ) if ICOMPQ = 0.   
           The first K elements of Z(1, I) contain the components of   
           the deflation-adjusted updating row vector for subproblems   
           on the I-th level.   

    POLES  (output) DOUBLE PRECISION array,   
           dimension ( LDU, 2 * NLVL ) if ICOMPQ = 1, and not referenced   
           if ICOMPQ = 0. If ICOMPQ = 1, on exit, POLES(1, 2*I - 1) and   
           POLES(1, 2*I) contain  the new and old singular values   
           involved in the secular equations on the I-th level.   

    GIVPTR (output) INTEGER array,   
           dimension ( N ) if ICOMPQ = 1, and not referenced if   
           ICOMPQ = 0. If ICOMPQ = 1, on exit, GIVPTR( I ) records   
           the number of Givens rotations performed on the I-th   
           problem on the computation tree.   

    GIVCOL (output) INTEGER array,   
           dimension ( LDGCOL, 2 * NLVL ) if ICOMPQ = 1, and not   
           referenced if ICOMPQ = 0. If ICOMPQ = 1, on exit, for each I,   
           GIVCOL(1, 2 *I - 1) and GIVCOL(1, 2 *I) record the locations   
           of Givens rotations performed on the I-th level on the   
           computation tree.   

    LDGCOL (input) INTEGER, LDGCOL = > N.   
           The leading dimension of arrays GIVCOL and PERM.   

    PERM   (output) INTEGER array,   
           dimension ( LDGCOL, NLVL ) if ICOMPQ = 1, and not referenced   
           if ICOMPQ = 0. If ICOMPQ = 1, on exit, PERM(1, I) records   
           permutations done on the I-th level of the computation tree.   

    GIVNUM (output) DOUBLE PRECISION array,   
           dimension ( LDU,  2 * NLVL ) if ICOMPQ = 1, and not   
           referenced if ICOMPQ = 0. If ICOMPQ = 1, on exit, for each I,   
           GIVNUM(1, 2 *I - 1) and GIVNUM(1, 2 *I) record the C- and S-   
           values of Givens rotations performed on the I-th level on   
           the computation tree.   

    C      (output) DOUBLE PRECISION array,   
           dimension ( N ) if ICOMPQ = 1, and dimension 1 if ICOMPQ = 0.   
           If ICOMPQ = 1 and the I-th subproblem is not square, on exit,   
           C( I ) contains the C-value of a Givens rotation related to   
           the right null space of the I-th subproblem.   

    S      (output) DOUBLE PRECISION array, dimension ( N ) if   
           ICOMPQ = 1, and dimension 1 if ICOMPQ = 0. If ICOMPQ = 1   
           and the I-th subproblem is not square, on exit, S( I )   
           contains the S-value of a Givens rotation related to   
           the right null space of the I-th subproblem.   

    WORK   (workspace) DOUBLE PRECISION array, dimension   
           (6 * N + (SMLSIZ + 1)*(SMLSIZ + 1)).   

    IWORK  (workspace) INTEGER array.   
           Dimension must be at least (7 * N).   

    INFO   (output) INTEGER   
            = 0:  successful exit.   
            < 0:  if INFO = -i, the i-th argument had an illegal value.   
            > 0:  if INFO = 1, an singular value did not converge   

    Further Details   
    ===============   

    Based on contributions by   
       Ming Gu and Huan Ren, Computer Science Division, University of   
       California at Berkeley, USA   

    =====================================================================   


       Test the input parameters.   

       Parameter adjustments */
    --d__;
    --e;
    givnum_dim1 = *ldu;
    givnum_offset = 1 + givnum_dim1 * 1;
    givnum -= givnum_offset;
    poles_dim1 = *ldu;
    poles_offset = 1 + poles_dim1 * 1;
    poles -= poles_offset;
    z_dim1 = *ldu;
    z_offset = 1 + z_dim1 * 1;
    z__ -= z_offset;
    difr_dim1 = *ldu;
    difr_offset = 1 + difr_dim1 * 1;
    difr -= difr_offset;
    difl_dim1 = *ldu;
    difl_offset = 1 + difl_dim1 * 1;
    difl -= difl_offset;
    vt_dim1 = *ldu;
    vt_offset = 1 + vt_dim1 * 1;
    vt -= vt_offset;
    u_dim1 = *ldu;
    u_offset = 1 + u_dim1 * 1;
    u -= u_offset;
    --k;
    --givptr;
    perm_dim1 = *ldgcol;
    perm_offset = 1 + perm_dim1 * 1;
    perm -= perm_offset;
    givcol_dim1 = *ldgcol;
    givcol_offset = 1 + givcol_dim1 * 1;
    givcol -= givcol_offset;
    --c__;
    --s;
    --work;
    --iwork;

    /* Function Body */
    *info = 0;

    if (*icompq < 0 || *icompq > 1) {
	*info = -1;
    } else if (*smlsiz < 3) {
	*info = -2;
    } else if (*n < 0) {
	*info = -3;
    } else if (*sqre < 0 || *sqre > 1) {
	*info = -4;
    } else if (*ldu < *n + *sqre) {
	*info = -8;
    } else if (*ldgcol < *n) {
	*info = -17;
    }
    if (*info != 0) {
	i__1 = -(*info);
	xerbla_("DLASDA", &i__1);
	return 0;
    }

    m = *n + *sqre;

/*     If the input matrix is too small, call DLASDQ to find the SVD. */

    if (*n <= *smlsiz) {
	if (*icompq == 0) {
	    dlasdq_("U", sqre, n, &c__0, &c__0, &c__0, &d__[1], &e[1], &vt[
		    vt_offset], ldu, &u[u_offset], ldu, &u[u_offset], ldu, &
		    work[1], info);
	} else {
	    dlasdq_("U", sqre, n, &m, n, &c__0, &d__[1], &e[1], &vt[vt_offset]
		    , ldu, &u[u_offset], ldu, &u[u_offset], ldu, &work[1], 
		    info);
	}
	return 0;
    }

/*     Book-keeping and  set up the computation tree. */

    inode = 1;
    ndiml = inode + *n;
    ndimr = ndiml + *n;
    idxq = ndimr + *n;
    iwk = idxq + *n;

    ncc = 0;
    nru = 0;

    smlszp = *smlsiz + 1;
    vf = 1;
    vl = vf + m;
    nwork1 = vl + m;
    nwork2 = nwork1 + smlszp * smlszp;

    dlasdt_(n, &nlvl, &nd, &iwork[inode], &iwork[ndiml], &iwork[ndimr], 
	    smlsiz);

/*     for the nodes on bottom level of the tree, solve   
       their subproblems by DLASDQ. */

    ndb1 = (nd + 1) / 2;
    i__1 = nd;
    for (i__ = ndb1; i__ <= i__1; ++i__) {

/*        IC : center row of each node   
          NL : number of rows of left  subproblem   
          NR : number of rows of right subproblem   
          NLF: starting row of the left   subproblem   
          NRF: starting row of the right  subproblem */

	i1 = i__ - 1;
	ic = iwork[inode + i1];
	nl = iwork[ndiml + i1];
	nlp1 = nl + 1;
	nr = iwork[ndimr + i1];
	nlf = ic - nl;
	nrf = ic + 1;
	idxqi = idxq + nlf - 2;
	vfi = vf + nlf - 1;
	vli = vl + nlf - 1;
	sqrei = 1;
	if (*icompq == 0) {
	    dlaset_("A", &nlp1, &nlp1, &c_b11, &c_b12, &work[nwork1], &smlszp);
	    dlasdq_("U", &sqrei, &nl, &nlp1, &nru, &ncc, &d__[nlf], &e[nlf], &
		    work[nwork1], &smlszp, &work[nwork2], &nl, &work[nwork2], 
		    &nl, &work[nwork2], info);
	    itemp = nwork1 + nl * smlszp;
	    dcopy_(&nlp1, &work[nwork1], &c__1, &work[vfi], &c__1);
	    dcopy_(&nlp1, &work[itemp], &c__1, &work[vli], &c__1);
	} else {
	    dlaset_("A", &nl, &nl, &c_b11, &c_b12, &u_ref(nlf, 1), ldu);
	    dlaset_("A", &nlp1, &nlp1, &c_b11, &c_b12, &vt_ref(nlf, 1), ldu);
	    dlasdq_("U", &sqrei, &nl, &nlp1, &nl, &ncc, &d__[nlf], &e[nlf], &
		    vt_ref(nlf, 1), ldu, &u_ref(nlf, 1), ldu, &u_ref(nlf, 1), 
		    ldu, &work[nwork1], info);
	    dcopy_(&nlp1, &vt_ref(nlf, 1), &c__1, &work[vfi], &c__1);
	    dcopy_(&nlp1, &vt_ref(nlf, nlp1), &c__1, &work[vli], &c__1);
	}
	if (*info != 0) {
	    return 0;
	}
	i__2 = nl;
	for (j = 1; j <= i__2; ++j) {
	    iwork[idxqi + j] = j;
/* L10: */
	}
	if (i__ == nd && *sqre == 0) {
	    sqrei = 0;
	} else {
	    sqrei = 1;
	}
	idxqi += nlp1;
	vfi += nlp1;
	vli += nlp1;
	nrp1 = nr + sqrei;
	if (*icompq == 0) {
	    dlaset_("A", &nrp1, &nrp1, &c_b11, &c_b12, &work[nwork1], &smlszp);
	    dlasdq_("U", &sqrei, &nr, &nrp1, &nru, &ncc, &d__[nrf], &e[nrf], &
		    work[nwork1], &smlszp, &work[nwork2], &nr, &work[nwork2], 
		    &nr, &work[nwork2], info);
	    itemp = nwork1 + (nrp1 - 1) * smlszp;
	    dcopy_(&nrp1, &work[nwork1], &c__1, &work[vfi], &c__1);
	    dcopy_(&nrp1, &work[itemp], &c__1, &work[vli], &c__1);
	} else {
	    dlaset_("A", &nr, &nr, &c_b11, &c_b12, &u_ref(nrf, 1), ldu);
	    dlaset_("A", &nrp1, &nrp1, &c_b11, &c_b12, &vt_ref(nrf, 1), ldu);
	    dlasdq_("U", &sqrei, &nr, &nrp1, &nr, &ncc, &d__[nrf], &e[nrf], &
		    vt_ref(nrf, 1), ldu, &u_ref(nrf, 1), ldu, &u_ref(nrf, 1), 
		    ldu, &work[nwork1], info);
	    dcopy_(&nrp1, &vt_ref(nrf, 1), &c__1, &work[vfi], &c__1);
	    dcopy_(&nrp1, &vt_ref(nrf, nrp1), &c__1, &work[vli], &c__1);
	}
	if (*info != 0) {
	    return 0;
	}
	i__2 = nr;
	for (j = 1; j <= i__2; ++j) {
	    iwork[idxqi + j] = j;
/* L20: */
	}
/* L30: */
    }

/*     Now conquer each subproblem bottom-up. */

    j = pow_ii(&c__2, &nlvl);
    for (lvl = nlvl; lvl >= 1; --lvl) {
	lvl2 = (lvl << 1) - 1;

/*        Find the first node LF and last node LL on   
          the current level LVL. */

	if (lvl == 1) {
	    lf = 1;
	    ll = 1;
	} else {
	    i__1 = lvl - 1;
	    lf = pow_ii(&c__2, &i__1);
	    ll = (lf << 1) - 1;
	}
	i__1 = ll;
	for (i__ = lf; i__ <= i__1; ++i__) {
	    im1 = i__ - 1;
	    ic = iwork[inode + im1];
	    nl = iwork[ndiml + im1];
	    nr = iwork[ndimr + im1];
	    nlf = ic - nl;
	    nrf = ic + 1;
	    if (i__ == ll) {
		sqrei = *sqre;
	    } else {
		sqrei = 1;
	    }
	    vfi = vf + nlf - 1;
	    vli = vl + nlf - 1;
	    idxqi = idxq + nlf - 1;
	    alpha = d__[ic];
	    beta = e[ic];
	    if (*icompq == 0) {
		dlasd6_(icompq, &nl, &nr, &sqrei, &d__[nlf], &work[vfi], &
			work[vli], &alpha, &beta, &iwork[idxqi], &perm[
			perm_offset], &givptr[1], &givcol[givcol_offset], 
			ldgcol, &givnum[givnum_offset], ldu, &poles[
			poles_offset], &difl[difl_offset], &difr[difr_offset],
			 &z__[z_offset], &k[1], &c__[1], &s[1], &work[nwork1],
			 &iwork[iwk], info);
	    } else {
		--j;
		dlasd6_(icompq, &nl, &nr, &sqrei, &d__[nlf], &work[vfi], &
			work[vli], &alpha, &beta, &iwork[idxqi], &perm_ref(
			nlf, lvl), &givptr[j], &givcol_ref(nlf, lvl2), ldgcol,
			 &givnum_ref(nlf, lvl2), ldu, &poles_ref(nlf, lvl2), &
			difl_ref(nlf, lvl), &difr_ref(nlf, lvl2), &z___ref(
			nlf, lvl), &k[j], &c__[j], &s[j], &work[nwork1], &
			iwork[iwk], info);
	    }
	    if (*info != 0) {
		return 0;
	    }
/* L40: */
	}
/* L50: */
    }

    return 0;

/*     End of DLASDA */

} /* dlasda_ */
Ejemplo n.º 2
0
/* Subroutine */ int clalsa_(integer *icompq, integer *smlsiz, integer *n, 
	integer *nrhs, complex *b, integer *ldb, complex *bx, integer *ldbx, 
	real *u, integer *ldu, real *vt, integer *k, real *difl, real *difr, 
	real *z__, real *poles, integer *givptr, integer *givcol, integer *
	ldgcol, integer *perm, real *givnum, real *c__, real *s, real *rwork, 
	integer *iwork, integer *info)
{
/*  -- LAPACK routine (version 3.0) --   
       Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,   
       Courant Institute, Argonne National Lab, and Rice University   
       June 30, 1999   


    Purpose   
    =======   

    CLALSA is an itermediate step in solving the least squares problem   
    by computing the SVD of the coefficient matrix in compact form (The   
    singular vectors are computed as products of simple orthorgonal   
    matrices.).   

    If ICOMPQ = 0, CLALSA applies the inverse of the left singular vector   
    matrix of an upper bidiagonal matrix to the right hand side; and if   
    ICOMPQ = 1, CLALSA applies the right singular vector matrix to the   
    right hand side. The singular vector matrices were generated in   
    compact form by CLALSA.   

    Arguments   
    =========   

    ICOMPQ (input) INTEGER   
           Specifies whether the left or the right singular vector   
           matrix is involved.   
           = 0: Left singular vector matrix   
           = 1: Right singular vector matrix   

    SMLSIZ (input) INTEGER   
           The maximum size of the subproblems at the bottom of the   
           computation tree.   

    N      (input) INTEGER   
           The row and column dimensions of the upper bidiagonal matrix.   

    NRHS   (input) INTEGER   
           The number of columns of B and BX. NRHS must be at least 1.   

    B      (input) COMPLEX array, dimension ( LDB, NRHS )   
           On input, B contains the right hand sides of the least   
           squares problem in rows 1 through M. On output, B contains   
           the solution X in rows 1 through N.   

    LDB    (input) INTEGER   
           The leading dimension of B in the calling subprogram.   
           LDB must be at least max(1,MAX( M, N ) ).   

    BX     (output) COMPLEX array, dimension ( LDBX, NRHS )   
           On exit, the result of applying the left or right singular   
           vector matrix to B.   

    LDBX   (input) INTEGER   
           The leading dimension of BX.   

    U      (input) REAL array, dimension ( LDU, SMLSIZ ).   
           On entry, U contains the left singular vector matrices of all   
           subproblems at the bottom level.   

    LDU    (input) INTEGER, LDU = > N.   
           The leading dimension of arrays U, VT, DIFL, DIFR,   
           POLES, GIVNUM, and Z.   

    VT     (input) REAL array, dimension ( LDU, SMLSIZ+1 ).   
           On entry, VT' contains the right singular vector matrices of   
           all subproblems at the bottom level.   

    K      (input) INTEGER array, dimension ( N ).   

    DIFL   (input) REAL array, dimension ( LDU, NLVL ).   
           where NLVL = INT(log_2 (N/(SMLSIZ+1))) + 1.   

    DIFR   (input) REAL array, dimension ( LDU, 2 * NLVL ).   
           On entry, DIFL(*, I) and DIFR(*, 2 * I -1) record   
           distances between singular values on the I-th level and   
           singular values on the (I -1)-th level, and DIFR(*, 2 * I)   
           record the normalizing factors of the right singular vectors   
           matrices of subproblems on I-th level.   

    Z      (input) REAL array, dimension ( LDU, NLVL ).   
           On entry, Z(1, I) contains the components of the deflation-   
           adjusted updating row vector for subproblems on the I-th   
           level.   

    POLES  (input) REAL array, dimension ( LDU, 2 * NLVL ).   
           On entry, POLES(*, 2 * I -1: 2 * I) contains the new and old   
           singular values involved in the secular equations on the I-th   
           level.   

    GIVPTR (input) INTEGER array, dimension ( N ).   
           On entry, GIVPTR( I ) records the number of Givens   
           rotations performed on the I-th problem on the computation   
           tree.   

    GIVCOL (input) INTEGER array, dimension ( LDGCOL, 2 * NLVL ).   
           On entry, for each I, GIVCOL(*, 2 * I - 1: 2 * I) records the   
           locations of Givens rotations performed on the I-th level on   
           the computation tree.   

    LDGCOL (input) INTEGER, LDGCOL = > N.   
           The leading dimension of arrays GIVCOL and PERM.   

    PERM   (input) INTEGER array, dimension ( LDGCOL, NLVL ).   
           On entry, PERM(*, I) records permutations done on the I-th   
           level of the computation tree.   

    GIVNUM (input) REAL array, dimension ( LDU, 2 * NLVL ).   
           On entry, GIVNUM(*, 2 *I -1 : 2 * I) records the C- and S-   
           values of Givens rotations performed on the I-th level on the   
           computation tree.   

    C      (input) REAL array, dimension ( N ).   
           On entry, if the I-th subproblem is not square,   
           C( I ) contains the C-value of a Givens rotation related to   
           the right null space of the I-th subproblem.   

    S      (input) REAL array, dimension ( N ).   
           On entry, if the I-th subproblem is not square,   
           S( I ) contains the S-value of a Givens rotation related to   
           the right null space of the I-th subproblem.   

    RWORK  (workspace) REAL array, dimension at least   
           max ( N, (SMLSZ+1)*NRHS*3 ).   

    IWORK  (workspace) INTEGER array.   
           The dimension must be at least 3 * N   

    INFO   (output) INTEGER   
            = 0:  successful exit.   
            < 0:  if INFO = -i, the i-th argument had an illegal value.   

    Further Details   
    ===============   

    Based on contributions by   
       Ming Gu and Ren-Cang Li, Computer Science Division, University of   
         California at Berkeley, USA   
       Osni Marques, LBNL/NERSC, USA   

    =====================================================================   


       Test the input parameters.   

       Parameter adjustments */
    /* Table of constant values */
    static real c_b9 = 1.f;
    static real c_b10 = 0.f;
    static integer c__2 = 2;
    
    /* System generated locals */
    integer givcol_dim1, givcol_offset, perm_dim1, perm_offset, difl_dim1, 
	    difl_offset, difr_dim1, difr_offset, givnum_dim1, givnum_offset, 
	    poles_dim1, poles_offset, u_dim1, u_offset, vt_dim1, vt_offset, 
	    z_dim1, z_offset, b_dim1, b_offset, bx_dim1, bx_offset, i__1, 
	    i__2, i__3, i__4, i__5, i__6;
    complex q__1;
    /* Builtin functions */
    double r_imag(complex *);
    integer pow_ii(integer *, integer *);
    /* Local variables */
    static integer jcol, nlvl, sqre, jrow, i__, j, jimag, jreal, inode, ndiml;
    extern /* Subroutine */ int sgemm_(char *, char *, integer *, integer *, 
	    integer *, real *, real *, integer *, real *, integer *, real *, 
	    real *, integer *);
    static integer ndimr;
    extern /* Subroutine */ int ccopy_(integer *, complex *, integer *, 
	    complex *, integer *);
    static integer i1;
    extern /* Subroutine */ int clals0_(integer *, integer *, integer *, 
	    integer *, integer *, complex *, integer *, complex *, integer *, 
	    integer *, integer *, integer *, integer *, real *, integer *, 
	    real *, real *, real *, real *, integer *, real *, real *, real *,
	     integer *);
    static integer ic, lf, nd, ll, nl, nr;
    extern /* Subroutine */ int xerbla_(char *, integer *), slasdt_(
	    integer *, integer *, integer *, integer *, integer *, integer *, 
	    integer *);
    static integer im1, nlf, nrf, lvl, ndb1, nlp1, lvl2, nrp1;
#define difl_ref(a_1,a_2) difl[(a_2)*difl_dim1 + a_1]
#define difr_ref(a_1,a_2) difr[(a_2)*difr_dim1 + a_1]
#define perm_ref(a_1,a_2) perm[(a_2)*perm_dim1 + a_1]
#define b_subscr(a_1,a_2) (a_2)*b_dim1 + a_1
#define b_ref(a_1,a_2) b[b_subscr(a_1,a_2)]
#define u_ref(a_1,a_2) u[(a_2)*u_dim1 + a_1]
#define z___ref(a_1,a_2) z__[(a_2)*z_dim1 + a_1]
#define poles_ref(a_1,a_2) poles[(a_2)*poles_dim1 + a_1]
#define bx_subscr(a_1,a_2) (a_2)*bx_dim1 + a_1
#define bx_ref(a_1,a_2) bx[bx_subscr(a_1,a_2)]
#define vt_ref(a_1,a_2) vt[(a_2)*vt_dim1 + a_1]
#define givcol_ref(a_1,a_2) givcol[(a_2)*givcol_dim1 + a_1]
#define givnum_ref(a_1,a_2) givnum[(a_2)*givnum_dim1 + a_1]


    b_dim1 = *ldb;
    b_offset = 1 + b_dim1 * 1;
    b -= b_offset;
    bx_dim1 = *ldbx;
    bx_offset = 1 + bx_dim1 * 1;
    bx -= bx_offset;
    givnum_dim1 = *ldu;
    givnum_offset = 1 + givnum_dim1 * 1;
    givnum -= givnum_offset;
    poles_dim1 = *ldu;
    poles_offset = 1 + poles_dim1 * 1;
    poles -= poles_offset;
    z_dim1 = *ldu;
    z_offset = 1 + z_dim1 * 1;
    z__ -= z_offset;
    difr_dim1 = *ldu;
    difr_offset = 1 + difr_dim1 * 1;
    difr -= difr_offset;
    difl_dim1 = *ldu;
    difl_offset = 1 + difl_dim1 * 1;
    difl -= difl_offset;
    vt_dim1 = *ldu;
    vt_offset = 1 + vt_dim1 * 1;
    vt -= vt_offset;
    u_dim1 = *ldu;
    u_offset = 1 + u_dim1 * 1;
    u -= u_offset;
    --k;
    --givptr;
    perm_dim1 = *ldgcol;
    perm_offset = 1 + perm_dim1 * 1;
    perm -= perm_offset;
    givcol_dim1 = *ldgcol;
    givcol_offset = 1 + givcol_dim1 * 1;
    givcol -= givcol_offset;
    --c__;
    --s;
    --rwork;
    --iwork;

    /* Function Body */
    *info = 0;

    if (*icompq < 0 || *icompq > 1) {
	*info = -1;
    } else if (*smlsiz < 3) {
	*info = -2;
    } else if (*n < *smlsiz) {
	*info = -3;
    } else if (*nrhs < 1) {
	*info = -4;
    } else if (*ldb < *n) {
	*info = -6;
    } else if (*ldbx < *n) {
	*info = -8;
    } else if (*ldu < *n) {
	*info = -10;
    } else if (*ldgcol < *n) {
	*info = -19;
    }
    if (*info != 0) {
	i__1 = -(*info);
	xerbla_("CLALSA", &i__1);
	return 0;
    }

/*     Book-keeping and  setting up the computation tree. */

    inode = 1;
    ndiml = inode + *n;
    ndimr = ndiml + *n;

    slasdt_(n, &nlvl, &nd, &iwork[inode], &iwork[ndiml], &iwork[ndimr], 
	    smlsiz);

/*     The following code applies back the left singular vector factors.   
       For applying back the right singular vector factors, go to 170. */

    if (*icompq == 1) {
	goto L170;
    }

/*     The nodes on the bottom level of the tree were solved   
       by SLASDQ. The corresponding left and right singular vector   
       matrices are in explicit form. First apply back the left   
       singular vector matrices. */

    ndb1 = (nd + 1) / 2;
    i__1 = nd;
    for (i__ = ndb1; i__ <= i__1; ++i__) {

/*        IC : center row of each node   
          NL : number of rows of left  subproblem   
          NR : number of rows of right subproblem   
          NLF: starting row of the left   subproblem   
          NRF: starting row of the right  subproblem */

	i1 = i__ - 1;
	ic = iwork[inode + i1];
	nl = iwork[ndiml + i1];
	nr = iwork[ndimr + i1];
	nlf = ic - nl;
	nrf = ic + 1;

/*        Since B and BX are complex, the following call to SGEMM   
          is performed in two steps (real and imaginary parts).   

          CALL SGEMM( 'T', 'N', NL, NRHS, NL, ONE, U( NLF, 1 ), LDU,   
       $               B( NLF, 1 ), LDB, ZERO, BX( NLF, 1 ), LDBX ) */

	j = nl * *nrhs << 1;
	i__2 = *nrhs;
	for (jcol = 1; jcol <= i__2; ++jcol) {
	    i__3 = nlf + nl - 1;
	    for (jrow = nlf; jrow <= i__3; ++jrow) {
		++j;
		i__4 = b_subscr(jrow, jcol);
		rwork[j] = b[i__4].r;
/* L10: */
	    }
/* L20: */
	}
	sgemm_("T", "N", &nl, nrhs, &nl, &c_b9, &u_ref(nlf, 1), ldu, &rwork[(
		nl * *nrhs << 1) + 1], &nl, &c_b10, &rwork[1], &nl);
	j = nl * *nrhs << 1;
	i__2 = *nrhs;
	for (jcol = 1; jcol <= i__2; ++jcol) {
	    i__3 = nlf + nl - 1;
	    for (jrow = nlf; jrow <= i__3; ++jrow) {
		++j;
		rwork[j] = r_imag(&b_ref(jrow, jcol));
/* L30: */
	    }
/* L40: */
	}
	sgemm_("T", "N", &nl, nrhs, &nl, &c_b9, &u_ref(nlf, 1), ldu, &rwork[(
		nl * *nrhs << 1) + 1], &nl, &c_b10, &rwork[nl * *nrhs + 1], &
		nl);
	jreal = 0;
	jimag = nl * *nrhs;
	i__2 = *nrhs;
	for (jcol = 1; jcol <= i__2; ++jcol) {
	    i__3 = nlf + nl - 1;
	    for (jrow = nlf; jrow <= i__3; ++jrow) {
		++jreal;
		++jimag;
		i__4 = bx_subscr(jrow, jcol);
		i__5 = jreal;
		i__6 = jimag;
		q__1.r = rwork[i__5], q__1.i = rwork[i__6];
		bx[i__4].r = q__1.r, bx[i__4].i = q__1.i;
/* L50: */
	    }
/* L60: */
	}

/*        Since B and BX are complex, the following call to SGEMM   
          is performed in two steps (real and imaginary parts).   

          CALL SGEMM( 'T', 'N', NR, NRHS, NR, ONE, U( NRF, 1 ), LDU,   
      $               B( NRF, 1 ), LDB, ZERO, BX( NRF, 1 ), LDBX ) */

	j = nr * *nrhs << 1;
	i__2 = *nrhs;
	for (jcol = 1; jcol <= i__2; ++jcol) {
	    i__3 = nrf + nr - 1;
	    for (jrow = nrf; jrow <= i__3; ++jrow) {
		++j;
		i__4 = b_subscr(jrow, jcol);
		rwork[j] = b[i__4].r;
/* L70: */
	    }
/* L80: */
	}
	sgemm_("T", "N", &nr, nrhs, &nr, &c_b9, &u_ref(nrf, 1), ldu, &rwork[(
		nr * *nrhs << 1) + 1], &nr, &c_b10, &rwork[1], &nr);
	j = nr * *nrhs << 1;
	i__2 = *nrhs;
	for (jcol = 1; jcol <= i__2; ++jcol) {
	    i__3 = nrf + nr - 1;
	    for (jrow = nrf; jrow <= i__3; ++jrow) {
		++j;
		rwork[j] = r_imag(&b_ref(jrow, jcol));
/* L90: */
	    }
/* L100: */
	}
	sgemm_("T", "N", &nr, nrhs, &nr, &c_b9, &u_ref(nrf, 1), ldu, &rwork[(
		nr * *nrhs << 1) + 1], &nr, &c_b10, &rwork[nr * *nrhs + 1], &
		nr);
	jreal = 0;
	jimag = nr * *nrhs;
	i__2 = *nrhs;
	for (jcol = 1; jcol <= i__2; ++jcol) {
	    i__3 = nrf + nr - 1;
	    for (jrow = nrf; jrow <= i__3; ++jrow) {
		++jreal;
		++jimag;
		i__4 = bx_subscr(jrow, jcol);
		i__5 = jreal;
		i__6 = jimag;
		q__1.r = rwork[i__5], q__1.i = rwork[i__6];
		bx[i__4].r = q__1.r, bx[i__4].i = q__1.i;
/* L110: */
	    }
/* L120: */
	}

/* L130: */
    }

/*     Next copy the rows of B that correspond to unchanged rows   
       in the bidiagonal matrix to BX. */

    i__1 = nd;
    for (i__ = 1; i__ <= i__1; ++i__) {
	ic = iwork[inode + i__ - 1];
	ccopy_(nrhs, &b_ref(ic, 1), ldb, &bx_ref(ic, 1), ldbx);
/* L140: */
    }

/*     Finally go through the left singular vector matrices of all   
       the other subproblems bottom-up on the tree. */

    j = pow_ii(&c__2, &nlvl);
    sqre = 0;

    for (lvl = nlvl; lvl >= 1; --lvl) {
	lvl2 = (lvl << 1) - 1;

/*        find the first node LF and last node LL on   
          the current level LVL */

	if (lvl == 1) {
	    lf = 1;
	    ll = 1;
	} else {
	    i__1 = lvl - 1;
	    lf = pow_ii(&c__2, &i__1);
	    ll = (lf << 1) - 1;
	}
	i__1 = ll;
	for (i__ = lf; i__ <= i__1; ++i__) {
	    im1 = i__ - 1;
	    ic = iwork[inode + im1];
	    nl = iwork[ndiml + im1];
	    nr = iwork[ndimr + im1];
	    nlf = ic - nl;
	    nrf = ic + 1;
	    --j;
	    clals0_(icompq, &nl, &nr, &sqre, nrhs, &bx_ref(nlf, 1), ldbx, &
		    b_ref(nlf, 1), ldb, &perm_ref(nlf, lvl), &givptr[j], &
		    givcol_ref(nlf, lvl2), ldgcol, &givnum_ref(nlf, lvl2), 
		    ldu, &poles_ref(nlf, lvl2), &difl_ref(nlf, lvl), &
		    difr_ref(nlf, lvl2), &z___ref(nlf, lvl), &k[j], &c__[j], &
		    s[j], &rwork[1], info);
/* L150: */
	}
/* L160: */
    }
    goto L330;

/*     ICOMPQ = 1: applying back the right singular vector factors. */

L170:

/*     First now go through the right singular vector matrices of all   
       the tree nodes top-down. */

    j = 0;
    i__1 = nlvl;
    for (lvl = 1; lvl <= i__1; ++lvl) {
	lvl2 = (lvl << 1) - 1;

/*        Find the first node LF and last node LL on   
          the current level LVL. */

	if (lvl == 1) {
	    lf = 1;
	    ll = 1;
	} else {
	    i__2 = lvl - 1;
	    lf = pow_ii(&c__2, &i__2);
	    ll = (lf << 1) - 1;
	}
	i__2 = lf;
	for (i__ = ll; i__ >= i__2; --i__) {
	    im1 = i__ - 1;
	    ic = iwork[inode + im1];
	    nl = iwork[ndiml + im1];
	    nr = iwork[ndimr + im1];
	    nlf = ic - nl;
	    nrf = ic + 1;
	    if (i__ == ll) {
		sqre = 0;
	    } else {
		sqre = 1;
	    }
	    ++j;
	    clals0_(icompq, &nl, &nr, &sqre, nrhs, &b_ref(nlf, 1), ldb, &
		    bx_ref(nlf, 1), ldbx, &perm_ref(nlf, lvl), &givptr[j], &
		    givcol_ref(nlf, lvl2), ldgcol, &givnum_ref(nlf, lvl2), 
		    ldu, &poles_ref(nlf, lvl2), &difl_ref(nlf, lvl), &
		    difr_ref(nlf, lvl2), &z___ref(nlf, lvl), &k[j], &c__[j], &
		    s[j], &rwork[1], info);
/* L180: */
	}
/* L190: */
    }

/*     The nodes on the bottom level of the tree were solved   
       by SLASDQ. The corresponding right singular vector   
       matrices are in explicit form. Apply them back. */

    ndb1 = (nd + 1) / 2;
    i__1 = nd;
    for (i__ = ndb1; i__ <= i__1; ++i__) {
	i1 = i__ - 1;
	ic = iwork[inode + i1];
	nl = iwork[ndiml + i1];
	nr = iwork[ndimr + i1];
	nlp1 = nl + 1;
	if (i__ == nd) {
	    nrp1 = nr;
	} else {
	    nrp1 = nr + 1;
	}
	nlf = ic - nl;
	nrf = ic + 1;

/*        Since B and BX are complex, the following call to SGEMM is   
          performed in two steps (real and imaginary parts).   

          CALL SGEMM( 'T', 'N', NLP1, NRHS, NLP1, ONE, VT( NLF, 1 ), LDU,   
      $               B( NLF, 1 ), LDB, ZERO, BX( NLF, 1 ), LDBX ) */

	j = nlp1 * *nrhs << 1;
	i__2 = *nrhs;
	for (jcol = 1; jcol <= i__2; ++jcol) {
	    i__3 = nlf + nlp1 - 1;
	    for (jrow = nlf; jrow <= i__3; ++jrow) {
		++j;
		i__4 = b_subscr(jrow, jcol);
		rwork[j] = b[i__4].r;
/* L200: */
	    }
/* L210: */
	}
	sgemm_("T", "N", &nlp1, nrhs, &nlp1, &c_b9, &vt_ref(nlf, 1), ldu, &
		rwork[(nlp1 * *nrhs << 1) + 1], &nlp1, &c_b10, &rwork[1], &
		nlp1);
	j = nlp1 * *nrhs << 1;
	i__2 = *nrhs;
	for (jcol = 1; jcol <= i__2; ++jcol) {
	    i__3 = nlf + nlp1 - 1;
	    for (jrow = nlf; jrow <= i__3; ++jrow) {
		++j;
		rwork[j] = r_imag(&b_ref(jrow, jcol));
/* L220: */
	    }
/* L230: */
	}
	sgemm_("T", "N", &nlp1, nrhs, &nlp1, &c_b9, &vt_ref(nlf, 1), ldu, &
		rwork[(nlp1 * *nrhs << 1) + 1], &nlp1, &c_b10, &rwork[nlp1 * *
		nrhs + 1], &nlp1);
	jreal = 0;
	jimag = nlp1 * *nrhs;
	i__2 = *nrhs;
	for (jcol = 1; jcol <= i__2; ++jcol) {
	    i__3 = nlf + nlp1 - 1;
	    for (jrow = nlf; jrow <= i__3; ++jrow) {
		++jreal;
		++jimag;
		i__4 = bx_subscr(jrow, jcol);
		i__5 = jreal;
		i__6 = jimag;
		q__1.r = rwork[i__5], q__1.i = rwork[i__6];
		bx[i__4].r = q__1.r, bx[i__4].i = q__1.i;
/* L240: */
	    }
/* L250: */
	}

/*        Since B and BX are complex, the following call to SGEMM is   
          performed in two steps (real and imaginary parts).   

          CALL SGEMM( 'T', 'N', NRP1, NRHS, NRP1, ONE, VT( NRF, 1 ), LDU,   
      $               B( NRF, 1 ), LDB, ZERO, BX( NRF, 1 ), LDBX ) */

	j = nrp1 * *nrhs << 1;
	i__2 = *nrhs;
	for (jcol = 1; jcol <= i__2; ++jcol) {
	    i__3 = nrf + nrp1 - 1;
	    for (jrow = nrf; jrow <= i__3; ++jrow) {
		++j;
		i__4 = b_subscr(jrow, jcol);
		rwork[j] = b[i__4].r;
/* L260: */
	    }
/* L270: */
	}
	sgemm_("T", "N", &nrp1, nrhs, &nrp1, &c_b9, &vt_ref(nrf, 1), ldu, &
		rwork[(nrp1 * *nrhs << 1) + 1], &nrp1, &c_b10, &rwork[1], &
		nrp1);
	j = nrp1 * *nrhs << 1;
	i__2 = *nrhs;
	for (jcol = 1; jcol <= i__2; ++jcol) {
	    i__3 = nrf + nrp1 - 1;
	    for (jrow = nrf; jrow <= i__3; ++jrow) {
		++j;
		rwork[j] = r_imag(&b_ref(jrow, jcol));
/* L280: */
	    }
/* L290: */
	}
	sgemm_("T", "N", &nrp1, nrhs, &nrp1, &c_b9, &vt_ref(nrf, 1), ldu, &
		rwork[(nrp1 * *nrhs << 1) + 1], &nrp1, &c_b10, &rwork[nrp1 * *
		nrhs + 1], &nrp1);
	jreal = 0;
	jimag = nrp1 * *nrhs;
	i__2 = *nrhs;
	for (jcol = 1; jcol <= i__2; ++jcol) {
	    i__3 = nrf + nrp1 - 1;
	    for (jrow = nrf; jrow <= i__3; ++jrow) {
		++jreal;
		++jimag;
		i__4 = bx_subscr(jrow, jcol);
		i__5 = jreal;
		i__6 = jimag;
		q__1.r = rwork[i__5], q__1.i = rwork[i__6];
		bx[i__4].r = q__1.r, bx[i__4].i = q__1.i;
/* L300: */
	    }
/* L310: */
	}

/* L320: */
    }

L330:

    return 0;

/*     End of CLALSA */

} /* clalsa_ */
Ejemplo n.º 3
0
/* Subroutine */ int dlalsa_(integer *icompq, integer *smlsiz, integer *n, 
	integer *nrhs, doublereal *b, integer *ldb, doublereal *bx, integer *
	ldbx, doublereal *u, integer *ldu, doublereal *vt, integer *k, 
	doublereal *difl, doublereal *difr, doublereal *z__, doublereal *
	poles, integer *givptr, integer *givcol, integer *ldgcol, integer *
	perm, doublereal *givnum, doublereal *c__, doublereal *s, doublereal *
	work, integer *iwork, integer *info)
{
    /* System generated locals */
    integer givcol_dim1, givcol_offset, perm_dim1, perm_offset, b_dim1, 
	    b_offset, bx_dim1, bx_offset, difl_dim1, difl_offset, difr_dim1, 
	    difr_offset, givnum_dim1, givnum_offset, poles_dim1, poles_offset,
	     u_dim1, u_offset, vt_dim1, vt_offset, z_dim1, z_offset, i__1, 
	    i__2;

    /* Builtin functions */
    integer pow_ii(integer *, integer *);

    /* Local variables */
    static integer nlvl, sqre, i__, j;
    extern /* Subroutine */ int dgemm_(char *, char *, integer *, integer *, 
	    integer *, doublereal *, doublereal *, integer *, doublereal *, 
	    integer *, doublereal *, doublereal *, integer *);
    static integer inode, ndiml, ndimr;
    extern /* Subroutine */ int dcopy_(integer *, doublereal *, integer *, 
	    doublereal *, integer *);
    static integer i1;
    extern /* Subroutine */ int dlals0_(integer *, integer *, integer *, 
	    integer *, integer *, doublereal *, integer *, doublereal *, 
	    integer *, integer *, integer *, integer *, integer *, doublereal 
	    *, integer *, doublereal *, doublereal *, doublereal *, 
	    doublereal *, integer *, doublereal *, doublereal *, doublereal *,
	     integer *);
    extern doublereal dopbl3_(char *, integer *, integer *, integer *)
	    ;
    static integer ic, lf, nd, ll, nl, nr;
    extern /* Subroutine */ int dlasdt_(integer *, integer *, integer *, 
	    integer *, integer *, integer *, integer *), xerbla_(char *, 
	    integer *);
    static integer im1, nlf, nrf, lvl, ndb1, nlp1, lvl2, nrp1;


#define difl_ref(a_1,a_2) difl[(a_2)*difl_dim1 + a_1]
#define difr_ref(a_1,a_2) difr[(a_2)*difr_dim1 + a_1]
#define perm_ref(a_1,a_2) perm[(a_2)*perm_dim1 + a_1]
#define b_ref(a_1,a_2) b[(a_2)*b_dim1 + a_1]
#define u_ref(a_1,a_2) u[(a_2)*u_dim1 + a_1]
#define z___ref(a_1,a_2) z__[(a_2)*z_dim1 + a_1]
#define poles_ref(a_1,a_2) poles[(a_2)*poles_dim1 + a_1]
#define bx_ref(a_1,a_2) bx[(a_2)*bx_dim1 + a_1]
#define vt_ref(a_1,a_2) vt[(a_2)*vt_dim1 + a_1]
#define givcol_ref(a_1,a_2) givcol[(a_2)*givcol_dim1 + a_1]
#define givnum_ref(a_1,a_2) givnum[(a_2)*givnum_dim1 + a_1]


/*  -- LAPACK routine (instrumented to count ops, version 3.0) --   
       Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,   
       Courant Institute, Argonne National Lab, and Rice University   
       June 30, 1999   


    Purpose   
    =======   

    DLALSA is an itermediate step in solving the least squares problem   
    by computing the SVD of the coefficient matrix in compact form (The   
    singular vectors are computed as products of simple orthorgonal   
    matrices.).   

    If ICOMPQ = 0, DLALSA applies the inverse of the left singular vector   
    matrix of an upper bidiagonal matrix to the right hand side; and if   
    ICOMPQ = 1, DLALSA applies the right singular vector matrix to the   
    right hand side. The singular vector matrices were generated in   
    compact form by DLALSA.   

    Arguments   
    =========   


    ICOMPQ (input) INTEGER   
           Specifies whether the left or the right singular vector   
           matrix is involved.   
           = 0: Left singular vector matrix   
           = 1: Right singular vector matrix   

    SMLSIZ (input) INTEGER   
           The maximum size of the subproblems at the bottom of the   
           computation tree.   

    N      (input) INTEGER   
           The row and column dimensions of the upper bidiagonal matrix.   

    NRHS   (input) INTEGER   
           The number of columns of B and BX. NRHS must be at least 1.   

    B      (input) DOUBLE PRECISION array, dimension ( LDB, NRHS )   
           On input, B contains the right hand sides of the least   
           squares problem in rows 1 through M. On output, B contains   
           the solution X in rows 1 through N.   

    LDB    (input) INTEGER   
           The leading dimension of B in the calling subprogram.   
           LDB must be at least max(1,MAX( M, N ) ).   

    BX     (output) DOUBLE PRECISION array, dimension ( LDBX, NRHS )   
           On exit, the result of applying the left or right singular   
           vector matrix to B.   

    LDBX   (input) INTEGER   
           The leading dimension of BX.   

    U      (input) DOUBLE PRECISION array, dimension ( LDU, SMLSIZ ).   
           On entry, U contains the left singular vector matrices of all   
           subproblems at the bottom level.   

    LDU    (input) INTEGER, LDU = > N.   
           The leading dimension of arrays U, VT, DIFL, DIFR,   
           POLES, GIVNUM, and Z.   

    VT     (input) DOUBLE PRECISION array, dimension ( LDU, SMLSIZ+1 ).   
           On entry, VT' contains the right singular vector matrices of   
           all subproblems at the bottom level.   

    K      (input) INTEGER array, dimension ( N ).   

    DIFL   (input) DOUBLE PRECISION array, dimension ( LDU, NLVL ).   
           where NLVL = INT(log_2 (N/(SMLSIZ+1))) + 1.   

    DIFR   (input) DOUBLE PRECISION array, dimension ( LDU, 2 * NLVL ).   
           On entry, DIFL(*, I) and DIFR(*, 2 * I -1) record   
           distances between singular values on the I-th level and   
           singular values on the (I -1)-th level, and DIFR(*, 2 * I)   
           record the normalizing factors of the right singular vectors   
           matrices of subproblems on I-th level.   

    Z      (input) DOUBLE PRECISION array, dimension ( LDU, NLVL ).   
           On entry, Z(1, I) contains the components of the deflation-   
           adjusted updating row vector for subproblems on the I-th   
           level.   

    POLES  (input) DOUBLE PRECISION array, dimension ( LDU, 2 * NLVL ).   
           On entry, POLES(*, 2 * I -1: 2 * I) contains the new and old   
           singular values involved in the secular equations on the I-th   
           level.   

    GIVPTR (input) INTEGER array, dimension ( N ).   
           On entry, GIVPTR( I ) records the number of Givens   
           rotations performed on the I-th problem on the computation   
           tree.   

    GIVCOL (input) INTEGER array, dimension ( LDGCOL, 2 * NLVL ).   
           On entry, for each I, GIVCOL(*, 2 * I - 1: 2 * I) records the   
           locations of Givens rotations performed on the I-th level on   
           the computation tree.   

    LDGCOL (input) INTEGER, LDGCOL = > N.   
           The leading dimension of arrays GIVCOL and PERM.   

    PERM   (input) INTEGER array, dimension ( LDGCOL, NLVL ).   
           On entry, PERM(*, I) records permutations done on the I-th   
           level of the computation tree.   

    GIVNUM (input) DOUBLE PRECISION array, dimension ( LDU, 2 * NLVL ).   
           On entry, GIVNUM(*, 2 *I -1 : 2 * I) records the C- and S-   
           values of Givens rotations performed on the I-th level on the   
           computation tree.   

    C      (input) DOUBLE PRECISION array, dimension ( N ).   
           On entry, if the I-th subproblem is not square,   
           C( I ) contains the C-value of a Givens rotation related to   
           the right null space of the I-th subproblem.   

    S      (input) DOUBLE PRECISION array, dimension ( N ).   
           On entry, if the I-th subproblem is not square,   
           S( I ) contains the S-value of a Givens rotation related to   
           the right null space of the I-th subproblem.   

    WORK   (workspace) DOUBLE PRECISION array.   
           The dimension must be at least N.   

    IWORK  (workspace) INTEGER array.   
           The dimension must be at least 3 * N   

    INFO   (output) INTEGER   
            = 0:  successful exit.   
            < 0:  if INFO = -i, the i-th argument had an illegal value.   

    =====================================================================   


       Test the input parameters.   

       Parameter adjustments */
    b_dim1 = *ldb;
    b_offset = 1 + b_dim1 * 1;
    b -= b_offset;
    bx_dim1 = *ldbx;
    bx_offset = 1 + bx_dim1 * 1;
    bx -= bx_offset;
    givnum_dim1 = *ldu;
    givnum_offset = 1 + givnum_dim1 * 1;
    givnum -= givnum_offset;
    poles_dim1 = *ldu;
    poles_offset = 1 + poles_dim1 * 1;
    poles -= poles_offset;
    z_dim1 = *ldu;
    z_offset = 1 + z_dim1 * 1;
    z__ -= z_offset;
    difr_dim1 = *ldu;
    difr_offset = 1 + difr_dim1 * 1;
    difr -= difr_offset;
    difl_dim1 = *ldu;
    difl_offset = 1 + difl_dim1 * 1;
    difl -= difl_offset;
    vt_dim1 = *ldu;
    vt_offset = 1 + vt_dim1 * 1;
    vt -= vt_offset;
    u_dim1 = *ldu;
    u_offset = 1 + u_dim1 * 1;
    u -= u_offset;
    --k;
    --givptr;
    perm_dim1 = *ldgcol;
    perm_offset = 1 + perm_dim1 * 1;
    perm -= perm_offset;
    givcol_dim1 = *ldgcol;
    givcol_offset = 1 + givcol_dim1 * 1;
    givcol -= givcol_offset;
    --c__;
    --s;
    --work;
    --iwork;

    /* Function Body */
    *info = 0;

    if (*icompq < 0 || *icompq > 1) {
	*info = -1;
    } else if (*smlsiz < 3) {
	*info = -2;
    } else if (*n < *smlsiz) {
	*info = -3;
    } else if (*nrhs < 1) {
	*info = -4;
    } else if (*ldb < *n) {
	*info = -6;
    } else if (*ldbx < *n) {
	*info = -8;
    } else if (*ldu < *n) {
	*info = -10;
    } else if (*ldgcol < *n) {
	*info = -19;
    }
    if (*info != 0) {
	i__1 = -(*info);
	xerbla_("DLALSA", &i__1);
	return 0;
    }

/*     Book-keeping and  setting up the computation tree. */

    inode = 1;
    ndiml = inode + *n;
    ndimr = ndiml + *n;

    dlasdt_(n, &nlvl, &nd, &iwork[inode], &iwork[ndiml], &iwork[ndimr], 
	    smlsiz);

/*     The following code applies back the left singular vector factors.   
       For applying back the right singular vector factors, go to 50. */

    if (*icompq == 1) {
	goto L50;
    }

/*     The nodes on the bottom level of the tree were solved by DLASDQ.   
       The corresponding left and right singular vector matrices are in   
       explicit form. First apply back the left singular vector matrices. */

    ndb1 = (nd + 1) / 2;
    i__1 = nd;
    for (i__ = ndb1; i__ <= i__1; ++i__) {

/*        IC : center row of each node   
          NL : number of rows of left  subproblem   
          NR : number of rows of right subproblem   
          NLF: starting row of the left   subproblem   
          NRF: starting row of the right  subproblem */

	i1 = i__ - 1;
	ic = iwork[inode + i1];
	nl = iwork[ndiml + i1];
	nr = iwork[ndimr + i1];
	nlf = ic - nl;
	nrf = ic + 1;
	latime_1.ops += dopbl3_("DGEMM ", &nl, nrhs, &nl);
	latime_1.ops += dopbl3_("DGEMM ", &nr, nrhs, &nr);
	dgemm_("T", "N", &nl, nrhs, &nl, &c_b9, &u_ref(nlf, 1), ldu, &b_ref(
		nlf, 1), ldb, &c_b10, &bx_ref(nlf, 1), ldbx);
	dgemm_("T", "N", &nr, nrhs, &nr, &c_b9, &u_ref(nrf, 1), ldu, &b_ref(
		nrf, 1), ldb, &c_b10, &bx_ref(nrf, 1), ldbx);
/* L10: */
    }

/*     Next copy the rows of B that correspond to unchanged rows   
       in the bidiagonal matrix to BX. */

    i__1 = nd;
    for (i__ = 1; i__ <= i__1; ++i__) {
	ic = iwork[inode + i__ - 1];
	dcopy_(nrhs, &b_ref(ic, 1), ldb, &bx_ref(ic, 1), ldbx);
/* L20: */
    }

/*     Finally go through the left singular vector matrices of all   
       the other subproblems bottom-up on the tree. */

    j = pow_ii(&c__2, &nlvl);
    sqre = 0;

    for (lvl = nlvl; lvl >= 1; --lvl) {
	lvl2 = (lvl << 1) - 1;

/*        find the first node LF and last node LL on   
          the current level LVL */

	if (lvl == 1) {
	    lf = 1;
	    ll = 1;
	} else {
	    i__1 = lvl - 1;
	    lf = pow_ii(&c__2, &i__1);
	    ll = (lf << 1) - 1;
	}
	i__1 = ll;
	for (i__ = lf; i__ <= i__1; ++i__) {
	    im1 = i__ - 1;
	    ic = iwork[inode + im1];
	    nl = iwork[ndiml + im1];
	    nr = iwork[ndimr + im1];
	    nlf = ic - nl;
	    nrf = ic + 1;
	    --j;
	    dlals0_(icompq, &nl, &nr, &sqre, nrhs, &bx_ref(nlf, 1), ldbx, &
		    b_ref(nlf, 1), ldb, &perm_ref(nlf, lvl), &givptr[j], &
		    givcol_ref(nlf, lvl2), ldgcol, &givnum_ref(nlf, lvl2), 
		    ldu, &poles_ref(nlf, lvl2), &difl_ref(nlf, lvl), &
		    difr_ref(nlf, lvl2), &z___ref(nlf, lvl), &k[j], &c__[j], &
		    s[j], &work[1], info);
/* L30: */
	}
/* L40: */
    }
    goto L90;

/*     ICOMPQ = 1: applying back the right singular vector factors. */

L50:

/*     First now go through the right singular vector matrices of all   
       the tree nodes top-down. */

    j = 0;
    i__1 = nlvl;
    for (lvl = 1; lvl <= i__1; ++lvl) {
	lvl2 = (lvl << 1) - 1;

/*        Find the first node LF and last node LL on   
          the current level LVL. */

	if (lvl == 1) {
	    lf = 1;
	    ll = 1;
	} else {
	    i__2 = lvl - 1;
	    lf = pow_ii(&c__2, &i__2);
	    ll = (lf << 1) - 1;
	}
	i__2 = lf;
	for (i__ = ll; i__ >= i__2; --i__) {
	    im1 = i__ - 1;
	    ic = iwork[inode + im1];
	    nl = iwork[ndiml + im1];
	    nr = iwork[ndimr + im1];
	    nlf = ic - nl;
	    nrf = ic + 1;
	    if (i__ == ll) {
		sqre = 0;
	    } else {
		sqre = 1;
	    }
	    ++j;
	    dlals0_(icompq, &nl, &nr, &sqre, nrhs, &b_ref(nlf, 1), ldb, &
		    bx_ref(nlf, 1), ldbx, &perm_ref(nlf, lvl), &givptr[j], &
		    givcol_ref(nlf, lvl2), ldgcol, &givnum_ref(nlf, lvl2), 
		    ldu, &poles_ref(nlf, lvl2), &difl_ref(nlf, lvl), &
		    difr_ref(nlf, lvl2), &z___ref(nlf, lvl), &k[j], &c__[j], &
		    s[j], &work[1], info);
/* L60: */
	}
/* L70: */
    }

/*     The nodes on the bottom level of the tree were solved by DLASDQ.   
       The corresponding right singular vector matrices are in explicit   
       form. Apply them back. */

    ndb1 = (nd + 1) / 2;
    i__1 = nd;
    for (i__ = ndb1; i__ <= i__1; ++i__) {
	i1 = i__ - 1;
	ic = iwork[inode + i1];
	nl = iwork[ndiml + i1];
	nr = iwork[ndimr + i1];
	nlp1 = nl + 1;
	if (i__ == nd) {
	    nrp1 = nr;
	} else {
	    nrp1 = nr + 1;
	}
	nlf = ic - nl;
	nrf = ic + 1;
	latime_1.ops += dopbl3_("DGEMM ", &nlp1, nrhs, &nlp1);
	latime_1.ops += dopbl3_("DGEMM ", &nrp1, nrhs, &nrp1);
	dgemm_("T", "N", &nlp1, nrhs, &nlp1, &c_b9, &vt_ref(nlf, 1), ldu, &
		b_ref(nlf, 1), ldb, &c_b10, &bx_ref(nlf, 1), ldbx);
	dgemm_("T", "N", &nrp1, nrhs, &nrp1, &c_b9, &vt_ref(nrf, 1), ldu, &
		b_ref(nrf, 1), ldb, &c_b10, &bx_ref(nrf, 1), ldbx);
/* L80: */
    }

L90:

    return 0;

/*     End of DLALSA */

} /* dlalsa_ */