dormtr.c File Reference

(r)

Functions
int	dormtr_fla (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)

Function Documentation

dormtr_fla()

int dormtr_fla	(	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
	)

{
    /* System generated locals */
    integer a_dim1, a_offset, c_dim1, c_offset, i__2, i__3;
    char ch__1[2];
    /* Builtin functions */
    /* Subroutine */
 
    /* Local variables */
    integer i1, i2, nb, mi, ni, nq, nw;
    logical left;
    extern logical lsame_(char *, char *);
    integer iinfo;
    logical upper;
    extern /* Subroutine */
    int xerbla_(char *, integer *);
    extern integer ilaenv_(integer *, char *, char *, integer *, integer *, integer *, integer *);
    extern /* Subroutine */
    int dormql_(char *, char *, integer *, integer *, integer *, doublereal *, integer *, doublereal *, doublereal *, integer *, doublereal *, integer *, integer *), dormqr_fla(char *, char *, integer *, integer *, integer *, doublereal *, integer *, doublereal *, doublereal *, integer *, doublereal *, integer *, integer *);
    integer lwkopt;
    logical lquery;
    /* -- LAPACK computational routine (version 3.4.0) -- */
    /* -- LAPACK is a software package provided by Univ. of Tennessee, -- */
    /* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- */
    /* November 2011 */
    /* .. Scalar Arguments .. */
    /* .. */
    /* .. Array Arguments .. */
    /* .. */
    /* ===================================================================== */
    /* .. Local Scalars .. */
    /* .. */
    /* .. External Functions .. */
    /* .. */
    /* .. External Subroutines .. */
    /* .. */
    /* .. Intrinsic Functions .. */
    /* .. */
    /* .. Executable Statements .. */
    /* Test the input arguments */
    /* Parameter adjustments */
    a_dim1 = *lda;
    a_offset = 1 + a_dim1;
    a -= a_offset;
    --tau;
    c_dim1 = *ldc;
    c_offset = 1 + c_dim1;
    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)
            {
                i__2 = *m - 1;
                i__3 = *m - 1;
                nb = ilaenv_(&c__1, "DORMQL", ch__1, &i__2, n, &i__3, &c_n1);
            }
            else
            {
                i__2 = *n - 1;
                i__3 = *n - 1;
                nb = ilaenv_(&c__1, "DORMQL", ch__1, m, &i__2, &i__3, &c_n1);
            }
        }
        else
        {
            if (left)
            {
                i__2 = *m - 1;
                i__3 = *m - 1;
                nb = ilaenv_(&c__1, "DORMQR", ch__1, &i__2, n, &i__3, &c_n1);
            }
            else
            {
                i__2 = *n - 1;
                i__3 = *n - 1;
                nb = ilaenv_(&c__1, "DORMQR", ch__1, m, &i__2, &i__3, &c_n1);
            }
        }
        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[(a_dim1 << 1) + 1], 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_fla(side, trans, &mi, &ni, &i__2, &a[a_dim1 + 2], lda, &tau[1], & c__[i1 + i2 * c_dim1], ldc, &work[1], lwork, &iinfo);
    }
    work[1] = (doublereal) lwkopt;
    return 0;
    /* End of DORMTR */
}

References dormqr_fla(), and i.