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

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


    Purpose   
    =======   

    SORGBR generates one of the real orthogonal matrices Q or P**T   
    determined by SGEBRD when reducing a real matrix A to bidiagonal   
    form: A = Q * B * P**T.  Q and P**T 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 SORGBR returns the first n   
    columns of Q, where m >= n >= k;   
    if m < k, Q = H(1) H(2) . . . H(m-1) and SORGBR returns Q as an   
    M-by-M matrix.   

    If VECT = 'P', A is assumed to have been a K-by-N matrix, and P**T   
    is of order N:   
    if k < n, P**T = G(k) . . . G(2) G(1) and SORGBR returns the first m   
    rows of P**T, where n >= m >= k;   
    if k >= n, P**T = G(n-1) . . . G(2) G(1) and SORGBR returns P**T as   
    an N-by-N matrix.   

    Arguments   
    =========   

    VECT    (input) CHARACTER*1   
            Specifies whether the matrix Q or the matrix P**T is   
            required, as defined in the transformation applied by SGEBRD:   
            = 'Q':  generate Q;   
            = 'P':  generate P**T.   

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

    N       (input) INTEGER   
            The number of columns of the matrix Q or P**T 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 SGEBRD.   
            If VECT = 'P', the number of rows in the original K-by-N   
            matrix reduced by SGEBRD.   
            K >= 0.   

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

    LDA     (input) INTEGER   
            The leading dimension of the array A. LDA >= max(1,M).   

    TAU     (input) REAL 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**T, as   
            returned by SGEBRD in its array argument TAUQ or TAUP.   

    WORK    (workspace/output) REAL 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);
    extern /* Subroutine */ int sorglq_(integer *, integer *, integer *, real 
	    *, integer *, real *, real *, integer *, integer *), sorgqr_(
	    integer *, integer *, integer *, real *, integer *, real *, real *
	    , integer *, integer *);
    static integer lwkopt;
    static logical lquery;


    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, "SORGQR", " ", m, n, k, &c_n1, (ftnlen)6, (
		    ftnlen)1);
	} else {
	    nb = ilaenv_(&c__1, "SORGLQ", " ", m, n, k, &c_n1, (ftnlen)6, (
		    ftnlen)1);
	}
	lwkopt = max(1,mn) * nb;
	work[1] = (real) lwkopt;
    }

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

/*     Quick return if possible */

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

    if (wantq) {

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

	if (*m >= *k) {

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

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

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

		i__1 = *m - 1;
		i__2 = *m - 1;
		i__3 = *m - 1;
		sorgqr_(&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 SGEBRD to reduce a k-by-n   
          matrix */

	if (*k < *n) {

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

	    sorglq_(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 */

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

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

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

/*     End of SORGBR */

} /* sorgbr_ */