#include "blaswrap.h"
/* zlaed0.f -- translated by f2c (version 20061008).
   You must link the resulting object file with libf2c:
	on Microsoft Windows system, link with libf2c.lib;
	on Linux or Unix systems, link with .../path/to/libf2c.a -lm
	or, if you install libf2c.a in a standard place, with -lf2c -lm
	-- in that order, at the end of the command line, as in
		cc *.o -lf2c -lm
	Source for libf2c is in /netlib/f2c/libf2c.zip, e.g.,

		http://www.netlib.org/f2c/libf2c.zip
*/

#include "f2c.h"

/* Table of constant values */

static integer c__9 = 9;
static integer c__0 = 0;
static integer c__2 = 2;
static integer c__1 = 1;

/* Subroutine */ int zlaed0_(integer *qsiz, integer *n, doublereal *d__, 
	doublereal *e, doublecomplex *q, integer *ldq, doublecomplex *qstore, 
	integer *ldqs, doublereal *rwork, integer *iwork, integer *info)
{
    /* System generated locals */
    integer q_dim1, q_offset, qstore_dim1, qstore_offset, i__1, i__2;
    doublereal d__1;

    /* Builtin functions */
    double log(doublereal);
    integer pow_ii(integer *, integer *);

    /* Local variables */
    static integer i__, j, k, ll, iq, lgn, msd2, smm1, spm1, spm2;
    static doublereal temp;
    static integer curr, iperm;
    extern /* Subroutine */ int dcopy_(integer *, doublereal *, integer *, 
	    doublereal *, integer *);
    static integer indxq, iwrem, iqptr, tlvls;
    extern /* Subroutine */ int zcopy_(integer *, doublecomplex *, integer *, 
	    doublecomplex *, integer *), zlaed7_(integer *, integer *, 
	    integer *, integer *, integer *, integer *, doublereal *, 
	    doublecomplex *, integer *, doublereal *, integer *, doublereal *,
	     integer *, integer *, integer *, integer *, integer *, 
	    doublereal *, doublecomplex *, doublereal *, integer *, integer *)
	    ;
    static integer igivcl;
    extern /* Subroutine */ int xerbla_(char *, integer *);
    extern integer ilaenv_(integer *, char *, char *, integer *, integer *, 
	    integer *, integer *, ftnlen, ftnlen);
    extern /* Subroutine */ int zlacrm_(integer *, integer *, doublecomplex *,
	     integer *, doublereal *, integer *, doublecomplex *, integer *, 
	    doublereal *);
    static integer igivnm, submat, curprb, subpbs, igivpt;
    extern /* Subroutine */ int dsteqr_(char *, integer *, doublereal *, 
	    doublereal *, doublereal *, integer *, doublereal *, integer *);
    static integer curlvl, matsiz, iprmpt, smlsiz;


/*  -- LAPACK routine (version 3.1) --   
       Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..   
       November 2006   


    Purpose   
    =======   

    Using the divide and conquer method, ZLAED0 computes all eigenvalues   
    of a symmetric tridiagonal matrix which is one diagonal block of   
    those from reducing a dense or band Hermitian matrix and   
    corresponding eigenvectors of the dense or band matrix.   

    Arguments   
    =========   

    QSIZ   (input) INTEGER   
           The dimension of the unitary matrix used to reduce   
           the full matrix to tridiagonal form.  QSIZ >= N if ICOMPQ = 1.   

    N      (input) INTEGER   
           The dimension of the symmetric tridiagonal matrix.  N >= 0.   

    D      (input/output) DOUBLE PRECISION array, dimension (N)   
           On entry, the diagonal elements of the tridiagonal matrix.   
           On exit, the eigenvalues in ascending order.   

    E      (input/output) DOUBLE PRECISION array, dimension (N-1)   
           On entry, the off-diagonal elements of the tridiagonal matrix.   
           On exit, E has been destroyed.   

    Q      (input/output) COMPLEX*16 array, dimension (LDQ,N)   
           On entry, Q must contain an QSIZ x N matrix whose columns   
           unitarily orthonormal. It is a part of the unitary matrix   
           that reduces the full dense Hermitian matrix to a   
           (reducible) symmetric tridiagonal matrix.   

    LDQ    (input) INTEGER   
           The leading dimension of the array Q.  LDQ >= max(1,N).   

    IWORK  (workspace) INTEGER array,   
           the dimension of IWORK must be at least   
                        6 + 6*N + 5*N*lg N   
                        ( lg( N ) = smallest integer k   
                                    such that 2^k >= N )   

    RWORK  (workspace) DOUBLE PRECISION array,   
                                 dimension (1 + 3*N + 2*N*lg N + 3*N**2)   
                          ( lg( N ) = smallest integer k   
                                      such that 2^k >= N )   

    QSTORE (workspace) COMPLEX*16 array, dimension (LDQS, N)   
           Used to store parts of   
           the eigenvector matrix when the updating matrix multiplies   
           take place.   

    LDQS   (input) INTEGER   
           The leading dimension of the array QSTORE.   
           LDQS >= max(1,N).   

    INFO   (output) INTEGER   
            = 0:  successful exit.   
            < 0:  if INFO = -i, the i-th argument had an illegal value.   
            > 0:  The algorithm failed to compute an eigenvalue while   
                  working on the submatrix lying in rows and columns   
                  INFO/(N+1) through mod(INFO,N+1).   

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

    Warning:      N could be as big as QSIZ!   


       Test the input parameters.   

       Parameter adjustments */
    --d__;
    --e;
    q_dim1 = *ldq;
    q_offset = 1 + q_dim1;
    q -= q_offset;
    qstore_dim1 = *ldqs;
    qstore_offset = 1 + qstore_dim1;
    qstore -= qstore_offset;
    --rwork;
    --iwork;

    /* Function Body */
    *info = 0;

/*     IF( ICOMPQ .LT. 0 .OR. ICOMPQ .GT. 2 ) THEN   
          INFO = -1   
       ELSE IF( ( ICOMPQ .EQ. 1 ) .AND. ( QSIZ .LT. MAX( 0, N ) ) )   
      $        THEN */
    if (*qsiz < max(0,*n)) {
	*info = -1;
    } else if (*n < 0) {
	*info = -2;
    } else if (*ldq < max(1,*n)) {
	*info = -6;
    } else if (*ldqs < max(1,*n)) {
	*info = -8;
    }
    if (*info != 0) {
	i__1 = -(*info);
	xerbla_("ZLAED0", &i__1);
	return 0;
    }

/*     Quick return if possible */

    if (*n == 0) {
	return 0;
    }

    smlsiz = ilaenv_(&c__9, "ZLAED0", " ", &c__0, &c__0, &c__0, &c__0, (
            ftnlen)6, (ftnlen)1);

/*     Determine the size and placement of the submatrices, and save in   
       the leading elements of IWORK. */

    iwork[1] = *n;
    subpbs = 1;
    tlvls = 0;
L10:
    if (iwork[subpbs] > smlsiz) {
	for (j = subpbs; j >= 1; --j) {
	    iwork[j * 2] = (iwork[j] + 1) / 2;
	    iwork[(j << 1) - 1] = iwork[j] / 2;
/* L20: */
	}
	++tlvls;
	subpbs <<= 1;
	goto L10;
    }
    i__1 = subpbs;
    for (j = 2; j <= i__1; ++j) {
	iwork[j] += iwork[j - 1];
/* L30: */
    }

/*     Divide the matrix into SUBPBS submatrices of size at most SMLSIZ+1   
       using rank-1 modifications (cuts). */

    spm1 = subpbs - 1;
    i__1 = spm1;
    for (i__ = 1; i__ <= i__1; ++i__) {
	submat = iwork[i__] + 1;
	smm1 = submat - 1;
	d__[smm1] -= (d__1 = e[smm1], abs(d__1));
	d__[submat] -= (d__1 = e[smm1], abs(d__1));
/* L40: */
    }

    indxq = (*n << 2) + 3;

/*     Set up workspaces for eigenvalues only/accumulate new vectors   
       routine */

    temp = log((doublereal) (*n)) / log(2.);
    lgn = (integer) temp;
    if (pow_ii(&c__2, &lgn) < *n) {
	++lgn;
    }
    if (pow_ii(&c__2, &lgn) < *n) {
	++lgn;
    }
    iprmpt = indxq + *n + 1;
    iperm = iprmpt + *n * lgn;
    iqptr = iperm + *n * lgn;
    igivpt = iqptr + *n + 2;
    igivcl = igivpt + *n * lgn;

    igivnm = 1;
    iq = igivnm + (*n << 1) * lgn;
/* Computing 2nd power */
    i__1 = *n;
    iwrem = iq + i__1 * i__1 + 1;
/*     Initialize pointers */
    i__1 = subpbs;
    for (i__ = 0; i__ <= i__1; ++i__) {
	iwork[iprmpt + i__] = 1;
	iwork[igivpt + i__] = 1;
/* L50: */
    }
    iwork[iqptr] = 1;

/*     Solve each submatrix eigenproblem at the bottom of the divide and   
       conquer tree. */

    curr = 0;
    i__1 = spm1;
    for (i__ = 0; i__ <= i__1; ++i__) {
	if (i__ == 0) {
	    submat = 1;
	    matsiz = iwork[1];
	} else {
	    submat = iwork[i__] + 1;
	    matsiz = iwork[i__ + 1] - iwork[i__];
	}
	ll = iq - 1 + iwork[iqptr + curr];
	dsteqr_("I", &matsiz, &d__[submat], &e[submat], &rwork[ll], &matsiz, &
		rwork[1], info);
	zlacrm_(qsiz, &matsiz, &q[submat * q_dim1 + 1], ldq, &rwork[ll], &
		matsiz, &qstore[submat * qstore_dim1 + 1], ldqs, &rwork[iwrem] );
/* Computing 2nd power */
	i__2 = matsiz;
	iwork[iqptr + curr + 1] = iwork[iqptr + curr] + i__2 * i__2;
	++curr;
	if (*info > 0) {
	    *info = submat * (*n + 1) + submat + matsiz - 1;
	    return 0;
	}
	k = 1;
	i__2 = iwork[i__ + 1];
	for (j = submat; j <= i__2; ++j) {
	    iwork[indxq + j] = k;
	    ++k;
/* L60: */
	}
/* L70: */
    }

/*     Successively merge eigensystems of adjacent submatrices   
       into eigensystem for the corresponding larger matrix.   

       while ( SUBPBS > 1 ) */

    curlvl = 1;
L80:
    if (subpbs > 1) {
	spm2 = subpbs - 2;
	i__1 = spm2;
	for (i__ = 0; i__ <= i__1; i__ += 2) {
	    if (i__ == 0) {
		submat = 1;
		matsiz = iwork[2];
		msd2 = iwork[1];
		curprb = 0;
	    } else {
		submat = iwork[i__] + 1;
		matsiz = iwork[i__ + 2] - iwork[i__];
		msd2 = matsiz / 2;
		++curprb;
	    }

/*     Merge lower order eigensystems (of size MSD2 and MATSIZ - MSD2)   
       into an eigensystem of size MATSIZ.  ZLAED7 handles the case   
       when the eigenvectors of a full or band Hermitian matrix (which   
       was reduced to tridiagonal form) are desired.   

       I am free to use Q as a valuable working space until Loop 150. */

	    zlaed7_(&matsiz, &msd2, qsiz, &tlvls, &curlvl, &curprb, &d__[
		    submat], &qstore[submat * qstore_dim1 + 1], ldqs, &e[
		    submat + msd2 - 1], &iwork[indxq + submat], &rwork[iq], &
		    iwork[iqptr], &iwork[iprmpt], &iwork[iperm], &iwork[
		    igivpt], &iwork[igivcl], &rwork[igivnm], &q[submat * 
		    q_dim1 + 1], &rwork[iwrem], &iwork[subpbs + 1], info);
	    if (*info > 0) {
		*info = submat * (*n + 1) + submat + matsiz - 1;
		return 0;
	    }
	    iwork[i__ / 2 + 1] = iwork[i__ + 2];
/* L90: */
	}
	subpbs /= 2;
	++curlvl;
	goto L80;
    }

/*     end while   

       Re-merge the eigenvalues/vectors which were deflated at the final   
       merge step. */

    i__1 = *n;
    for (i__ = 1; i__ <= i__1; ++i__) {
	j = iwork[indxq + i__];
	rwork[i__] = d__[j];
	zcopy_(qsiz, &qstore[j * qstore_dim1 + 1], &c__1, &q[i__ * q_dim1 + 1]
, &c__1);
/* L100: */
    }
    dcopy_(n, &rwork[1], &c__1, &d__[1], &c__1);

    return 0;

/*     End of ZLAED0 */

} /* zlaed0_ */