#include "blaswrap.h"
#include "f2c.h"

/* Subroutine */ int zungbr_(char *vect, integer *m, integer *n, integer *k, 
	doublecomplex *a, integer *lda, doublecomplex *tau, doublecomplex *
	work, integer *lwork, integer *info)
{
/*  -- LAPACK routine (version 3.1) --   
       Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..   
       November 2006   


    Purpose   
    =======   

    ZUNGBR generates one of the complex unitary matrices Q or P**H   
    determined by ZGEBRD when reducing a complex matrix A to bidiagonal   
    form: A = Q * B * P**H.  Q and P**H are defined as products of   
    elementary reflectors H(i) or G(i) respectively.   

    If VECT = 'Q', A is assumed to have been an M-by-K matrix, and Q   
    is of order M:   
    if m >= k, Q = H(1) H(2) . . . H(k) and ZUNGBR returns the first n   
    columns of Q, where m >= n >= k;   
    if m < k, Q = H(1) H(2) . . . H(m-1) and ZUNGBR returns Q as an   
    M-by-M matrix.   

    If VECT = 'P', A is assumed to have been a K-by-N matrix, and P**H   
    is of order N:   
    if k < n, P**H = G(k) . . . G(2) G(1) and ZUNGBR returns the first m   
    rows of P**H, where n >= m >= k;   
    if k >= n, P**H = G(n-1) . . . G(2) G(1) and ZUNGBR returns P**H as   
    an N-by-N matrix.   

    Arguments   
    =========   

    VECT    (input) CHARACTER*1   
            Specifies whether the matrix Q or the matrix P**H is   
            required, as defined in the transformation applied by ZGEBRD:   
            = 'Q':  generate Q;   
            = 'P':  generate P**H.   

    M       (input) INTEGER   
            The number of rows of the matrix Q or P**H to be returned.   
            M >= 0.   

    N       (input) INTEGER   
            The number of columns of the matrix Q or P**H to be returned.   
            N >= 0.   
            If VECT = 'Q', M >= N >= min(M,K);   
            if VECT = 'P', N >= M >= min(N,K).   

    K       (input) INTEGER   
            If VECT = 'Q', the number of columns in the original M-by-K   
            matrix reduced by ZGEBRD.   
            If VECT = 'P', the number of rows in the original K-by-N   
            matrix reduced by ZGEBRD.   
            K >= 0.   

    A       (input/output) COMPLEX*16 array, dimension (LDA,N)   
            On entry, the vectors which define the elementary reflectors,   
            as returned by ZGEBRD.   
            On exit, the M-by-N matrix Q or P**H.   

    LDA     (input) INTEGER   
            The leading dimension of the array A. LDA >= M.   

    TAU     (input) COMPLEX*16 array, dimension   
                                  (min(M,K)) if VECT = 'Q'   
                                  (min(N,K)) if VECT = 'P'   
            TAU(i) must contain the scalar factor of the elementary   
            reflector H(i) or G(i), which determines Q or P**H, as   
            returned by ZGEBRD in its array argument TAUQ or TAUP.   

    WORK    (workspace/output) COMPLEX*16 array, dimension (MAX(1,LWORK))   
            On exit, if INFO = 0, WORK(1) returns the optimal LWORK.   

    LWORK   (input) INTEGER   
            The dimension of the array WORK. LWORK >= max(1,min(M,N)).   
            For optimum performance LWORK >= min(M,N)*NB, where NB   
            is the optimal blocksize.   

            If LWORK = -1, then a workspace query is assumed; the routine   
            only calculates the optimal size of the WORK array, returns   
            this value as the first entry of the WORK array, and no error   
            message related to LWORK is issued by XERBLA.   

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

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


       Test the input arguments   

       Parameter adjustments */
    /* Table of constant values */
    static integer c__1 = 1;
    static integer c_n1 = -1;
    
    /* System generated locals */
    integer a_dim1, a_offset, i__1, i__2, i__3;
    /* Local variables */
    static integer i__, j, nb, mn;
    extern logical lsame_(char *, char *);
    static integer iinfo;
    static logical wantq;
    extern /* Subroutine */ int xerbla_(char *, integer *);
    extern integer ilaenv_(integer *, char *, char *, integer *, integer *, 
	    integer *, integer *, ftnlen, ftnlen);
    static integer lwkopt;
    static logical lquery;
    extern /* Subroutine */ int zunglq_(integer *, integer *, integer *, 
	    doublecomplex *, integer *, doublecomplex *, doublecomplex *, 
	    integer *, integer *), zungqr_(integer *, integer *, integer *, 
	    doublecomplex *, integer *, doublecomplex *, doublecomplex *, 
	    integer *, integer *);


    a_dim1 = *lda;
    a_offset = 1 + a_dim1;
    a -= a_offset;
    --tau;
    --work;

    /* Function Body */
    *info = 0;
    wantq = lsame_(vect, "Q");
    mn = min(*m,*n);
    lquery = *lwork == -1;
    if (! wantq && ! lsame_(vect, "P")) {
	*info = -1;
    } else if (*m < 0) {
	*info = -2;
    } else if (*n < 0 || wantq && (*n > *m || *n < min(*m,*k)) || ! wantq && (
	    *m > *n || *m < min(*n,*k))) {
	*info = -3;
    } else if (*k < 0) {
	*info = -4;
    } else if (*lda < max(1,*m)) {
	*info = -6;
    } else if (*lwork < max(1,mn) && ! lquery) {
	*info = -9;
    }

    if (*info == 0) {
	if (wantq) {
	    nb = ilaenv_(&c__1, "ZUNGQR", " ", m, n, k, &c_n1, (ftnlen)6, (
		    ftnlen)1);
	} else {
	    nb = ilaenv_(&c__1, "ZUNGLQ", " ", m, n, k, &c_n1, (ftnlen)6, (
		    ftnlen)1);
	}
	lwkopt = max(1,mn) * nb;
	work[1].r = (doublereal) lwkopt, work[1].i = 0.;
    }

    if (*info != 0) {
	i__1 = -(*info);
	xerbla_("ZUNGBR", &i__1);
	return 0;
    } else if (lquery) {
	return 0;
    }

/*     Quick return if possible */

    if (*m == 0 || *n == 0) {
	work[1].r = 1., work[1].i = 0.;
	return 0;
    }

    if (wantq) {

/*        Form Q, determined by a call to ZGEBRD to reduce an m-by-k   
          matrix */

	if (*m >= *k) {

/*           If m >= k, assume m >= n >= k */

	    zungqr_(m, n, k, &a[a_offset], lda, &tau[1], &work[1], lwork, &
		    iinfo);

	} else {

/*           If m < k, assume m = n   

             Shift the vectors which define the elementary reflectors one   
             column to the right, and set the first row and column of Q   
             to those of the unit matrix */

	    for (j = *m; j >= 2; --j) {
		i__1 = j * a_dim1 + 1;
		a[i__1].r = 0., a[i__1].i = 0.;
		i__1 = *m;
		for (i__ = j + 1; i__ <= i__1; ++i__) {
		    i__2 = i__ + j * a_dim1;
		    i__3 = i__ + (j - 1) * a_dim1;
		    a[i__2].r = a[i__3].r, a[i__2].i = a[i__3].i;
/* L10: */
		}
/* L20: */
	    }
	    i__1 = a_dim1 + 1;
	    a[i__1].r = 1., a[i__1].i = 0.;
	    i__1 = *m;
	    for (i__ = 2; i__ <= i__1; ++i__) {
		i__2 = i__ + a_dim1;
		a[i__2].r = 0., a[i__2].i = 0.;
/* L30: */
	    }
	    if (*m > 1) {

/*              Form Q(2:m,2:m) */

		i__1 = *m - 1;
		i__2 = *m - 1;
		i__3 = *m - 1;
		zungqr_(&i__1, &i__2, &i__3, &a[(a_dim1 << 1) + 2], lda, &tau[
			1], &work[1], lwork, &iinfo);
	    }
	}
    } else {

/*        Form P', determined by a call to ZGEBRD to reduce a k-by-n   
          matrix */

	if (*k < *n) {

/*           If k < n, assume k <= m <= n */

	    zunglq_(m, n, k, &a[a_offset], lda, &tau[1], &work[1], lwork, &
		    iinfo);

	} else {

/*           If k >= n, assume m = n   

             Shift the vectors which define the elementary reflectors one   
             row downward, and set the first row and column of P' to   
             those of the unit matrix */

	    i__1 = a_dim1 + 1;
	    a[i__1].r = 1., a[i__1].i = 0.;
	    i__1 = *n;
	    for (i__ = 2; i__ <= i__1; ++i__) {
		i__2 = i__ + a_dim1;
		a[i__2].r = 0., a[i__2].i = 0.;
/* L40: */
	    }
	    i__1 = *n;
	    for (j = 2; j <= i__1; ++j) {
		for (i__ = j - 1; i__ >= 2; --i__) {
		    i__2 = i__ + j * a_dim1;
		    i__3 = i__ - 1 + j * a_dim1;
		    a[i__2].r = a[i__3].r, a[i__2].i = a[i__3].i;
/* L50: */
		}
		i__2 = j * a_dim1 + 1;
		a[i__2].r = 0., a[i__2].i = 0.;
/* L60: */
	    }
	    if (*n > 1) {

/*              Form P'(2:n,2:n) */

		i__1 = *n - 1;
		i__2 = *n - 1;
		i__3 = *n - 1;
		zunglq_(&i__1, &i__2, &i__3, &a[(a_dim1 << 1) + 2], lda, &tau[
			1], &work[1], lwork, &iinfo);
	    }
	}
    }
    work[1].r = (doublereal) lwkopt, work[1].i = 0.;
    return 0;

/*     End of ZUNGBR */

} /* zungbr_ */