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

/* Subroutine */ int dormtr_(char *side, char *uplo, char *trans, integer *m, 
	integer *n, doublereal *a, integer *lda, doublereal *tau, doublereal *
	c__, integer *ldc, doublereal *work, integer *lwork, 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   
    =======   

    DORMTR overwrites the general real M-by-N matrix C with   

                    SIDE = 'L'     SIDE = 'R'   
    TRANS = 'N':      Q * C          C * Q   
    TRANS = 'T':      Q**T * C       C * Q**T   

    where Q is a real orthogonal matrix of order nq, with nq = m if   
    SIDE = 'L' and nq = n if SIDE = 'R'. Q is defined as the product of   
    nq-1 elementary reflectors, as returned by DSYTRD:   

    if UPLO = 'U', Q = H(nq-1) . . . H(2) H(1);   

    if UPLO = 'L', Q = H(1) H(2) . . . H(nq-1).   

    Arguments   
    =========   

    SIDE    (input) CHARACTER*1   
            = 'L': apply Q or Q**T from the Left;   
            = 'R': apply Q or Q**T from the Right.   

    UPLO    (input) CHARACTER*1   
            = 'U': Upper triangle of A contains elementary reflectors   
                   from DSYTRD;   
            = 'L': Lower triangle of A contains elementary reflectors   
                   from DSYTRD.   

    TRANS   (input) CHARACTER*1   
            = 'N':  No transpose, apply Q;   
            = 'T':  Transpose, apply Q**T.   

    M       (input) INTEGER   
            The number of rows of the matrix C. M >= 0.   

    N       (input) INTEGER   
            The number of columns of the matrix C. N >= 0.   

    A       (input) DOUBLE PRECISION array, dimension   
                                 (LDA,M) if SIDE = 'L'   
                                 (LDA,N) if SIDE = 'R'   
            The vectors which define the elementary reflectors, as   
            returned by DSYTRD.   

    LDA     (input) INTEGER   
            The leading dimension of the array A.   
            LDA >= max(1,M) if SIDE = 'L'; LDA >= max(1,N) if SIDE = 'R'.   

    TAU     (input) DOUBLE PRECISION array, dimension   
                                 (M-1) if SIDE = 'L'   
                                 (N-1) if SIDE = 'R'   
            TAU(i) must contain the scalar factor of the elementary   
            reflector H(i), as returned by DSYTRD.   

    C       (input/output) DOUBLE PRECISION array, dimension (LDC,N)   
            On entry, the M-by-N matrix C.   
            On exit, C is overwritten by Q*C or Q**T*C or C*Q**T or C*Q.   

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

    WORK    (workspace/output) DOUBLE PRECISION array, dimension (LWORK)   
            On exit, if INFO = 0, WORK(1) returns the optimal LWORK.   

    LWORK   (input) INTEGER   
            The dimension of the array WORK.   
            If SIDE = 'L', LWORK >= max(1,N);   
            if SIDE = 'R', LWORK >= max(1,M).   
            For optimum performance LWORK >= N*NB if SIDE = 'L', and   
            LWORK >= M*NB if SIDE = 'R', 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;
    static integer c__2 = 2;
    
    /* System generated locals */
    address a__1[2];
    integer a_dim1, a_offset, c_dim1, c_offset, i__1[2], i__2, i__3;
    char ch__1[2];
    /* Builtin functions   
       Subroutine */ int s_cat(char *, char **, integer *, integer *, ftnlen);
    /* Local variables */
    static logical left;
    extern logical lsame_(char *, char *);
    static integer iinfo, i1;
    static logical upper;
    static integer i2, nb, mi, ni, nq, nw;
    extern /* Subroutine */ int xerbla_(char *, integer *);
    extern integer ilaenv_(integer *, char *, char *, integer *, integer *, 
	    integer *, integer *, ftnlen, ftnlen);
    extern /* Subroutine */ int dormql_(char *, char *, integer *, integer *, 
	    integer *, doublereal *, integer *, doublereal *, doublereal *, 
	    integer *, doublereal *, integer *, integer *), 
	    dormqr_(char *, char *, integer *, integer *, integer *, 
	    doublereal *, integer *, doublereal *, doublereal *, integer *, 
	    doublereal *, integer *, integer *);
    static integer lwkopt;
    static logical lquery;
#define a_ref(a_1,a_2) a[(a_2)*a_dim1 + a_1]
#define c___ref(a_1,a_2) c__[(a_2)*c_dim1 + a_1]


    a_dim1 = *lda;
    a_offset = 1 + a_dim1 * 1;
    a -= a_offset;
    --tau;
    c_dim1 = *ldc;
    c_offset = 1 + c_dim1 * 1;
    c__ -= c_offset;
    --work;

    /* Function Body */
    *info = 0;
    left = lsame_(side, "L");
    upper = lsame_(uplo, "U");
    lquery = *lwork == -1;

/*     NQ is the order of Q and NW is the minimum dimension of WORK */

    if (left) {
	nq = *m;
	nw = *n;
    } else {
	nq = *n;
	nw = *m;
    }
    if (! left && ! lsame_(side, "R")) {
	*info = -1;
    } else if (! upper && ! lsame_(uplo, "L")) {
	*info = -2;
    } else if (! lsame_(trans, "N") && ! lsame_(trans, 
	    "T")) {
	*info = -3;
    } else if (*m < 0) {
	*info = -4;
    } else if (*n < 0) {
	*info = -5;
    } else if (*lda < max(1,nq)) {
	*info = -7;
    } else if (*ldc < max(1,*m)) {
	*info = -10;
    } else if (*lwork < max(1,nw) && ! lquery) {
	*info = -12;
    }

    if (*info == 0) {
	if (upper) {
	    if (left) {
/* Writing concatenation */
		i__1[0] = 1, a__1[0] = side;
		i__1[1] = 1, a__1[1] = trans;
		s_cat(ch__1, a__1, i__1, &c__2, (ftnlen)2);
		i__2 = *m - 1;
		i__3 = *m - 1;
		nb = ilaenv_(&c__1, "DORMQL", ch__1, &i__2, n, &i__3, &c_n1, (
			ftnlen)6, (ftnlen)2);
	    } else {
/* Writing concatenation */
		i__1[0] = 1, a__1[0] = side;
		i__1[1] = 1, a__1[1] = trans;
		s_cat(ch__1, a__1, i__1, &c__2, (ftnlen)2);
		i__2 = *n - 1;
		i__3 = *n - 1;
		nb = ilaenv_(&c__1, "DORMQL", ch__1, m, &i__2, &i__3, &c_n1, (
			ftnlen)6, (ftnlen)2);
	    }
	} else {
	    if (left) {
/* Writing concatenation */
		i__1[0] = 1, a__1[0] = side;
		i__1[1] = 1, a__1[1] = trans;
		s_cat(ch__1, a__1, i__1, &c__2, (ftnlen)2);
		i__2 = *m - 1;
		i__3 = *m - 1;
		nb = ilaenv_(&c__1, "DORMQR", ch__1, &i__2, n, &i__3, &c_n1, (
			ftnlen)6, (ftnlen)2);
	    } else {
/* Writing concatenation */
		i__1[0] = 1, a__1[0] = side;
		i__1[1] = 1, a__1[1] = trans;
		s_cat(ch__1, a__1, i__1, &c__2, (ftnlen)2);
		i__2 = *n - 1;
		i__3 = *n - 1;
		nb = ilaenv_(&c__1, "DORMQR", ch__1, m, &i__2, &i__3, &c_n1, (
			ftnlen)6, (ftnlen)2);
	    }
	}
	lwkopt = max(1,nw) * nb;
	work[1] = (doublereal) lwkopt;
    }

    if (*info != 0) {
	i__2 = -(*info);
	xerbla_("DORMTR", &i__2);
	return 0;
    } else if (lquery) {
	return 0;
    }

/*     Quick return if possible */

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

    if (left) {
	mi = *m - 1;
	ni = *n;
    } else {
	mi = *m;
	ni = *n - 1;
    }

    if (upper) {

/*        Q was determined by a call to DSYTRD with UPLO = 'U' */

	i__2 = nq - 1;
	dormql_(side, trans, &mi, &ni, &i__2, &a_ref(1, 2), lda, &tau[1], &
		c__[c_offset], ldc, &work[1], lwork, &iinfo);
    } else {

/*        Q was determined by a call to DSYTRD with UPLO = 'L' */

	if (left) {
	    i1 = 2;
	    i2 = 1;
	} else {
	    i1 = 1;
	    i2 = 2;
	}
	i__2 = nq - 1;
	dormqr_(side, trans, &mi, &ni, &i__2, &a_ref(2, 1), lda, &tau[1], &
		c___ref(i1, i2), ldc, &work[1], lwork, &iinfo);
    }
    work[1] = (doublereal) lwkopt;
    return 0;

/*     End of DORMTR */

} /* dormtr_ */

#undef c___ref
#undef a_ref