dlalsa.c

提供矩阵类的函数库

    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_ */

#undef givnum_ref
#undef givcol_ref
#undef vt_ref
#undef bx_ref
#undef poles_ref
#undef z___ref
#undef u_ref
#undef b_ref
#undef perm_ref
#undef difr_ref
#undef difl_ref