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

/* Subroutine */ int dlauu2_(char *uplo, integer *n, doublereal *a, integer *
	lda, integer *info)
{
/*  -- LAPACK auxiliary routine (version 3.1) --   
       Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..   
       November 2006   


    Purpose   
    =======   

    DLAUU2 computes the product U * U' or L' * L, where the triangular   
    factor U or L is stored in the upper or lower triangular part of   
    the array A.   

    If UPLO = 'U' or 'u' then the upper triangle of the result is stored,   
    overwriting the factor U in A.   
    If UPLO = 'L' or 'l' then the lower triangle of the result is stored,   
    overwriting the factor L in A.   

    This is the unblocked form of the algorithm, calling Level 2 BLAS.   

    Arguments   
    =========   

    UPLO    (input) CHARACTER*1   
            Specifies whether the triangular factor stored in the array A   
            is upper or lower triangular:   
            = 'U':  Upper triangular   
            = 'L':  Lower triangular   

    N       (input) INTEGER   
            The order of the triangular factor U or L.  N >= 0.   

    A       (input/output) DOUBLE PRECISION array, dimension (LDA,N)   
            On entry, the triangular factor U or L.   
            On exit, if UPLO = 'U', the upper triangle of A is   
            overwritten with the upper triangle of the product U * U';   
            if UPLO = 'L', the lower triangle of A is overwritten with   
            the lower triangle of the product L' * L.   

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

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

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


       Test the input parameters.   

       Parameter adjustments */
    /* Table of constant values */
    static doublereal c_b7 = 1.;
    static integer c__1 = 1;
    
    /* System generated locals */
    integer a_dim1, a_offset, i__1, i__2, i__3;
    /* Local variables */
    static integer i__;
    static doublereal aii;
    extern doublereal ddot_(integer *, doublereal *, integer *, doublereal *, 
	    integer *);
    extern /* Subroutine */ int dscal_(integer *, doublereal *, doublereal *, 
	    integer *);
    extern logical lsame_(char *, char *);
    extern /* Subroutine */ int dgemv_(char *, integer *, integer *, 
	    doublereal *, doublereal *, integer *, doublereal *, integer *, 
	    doublereal *, doublereal *, integer *);
    static logical upper;
    extern /* Subroutine */ int xerbla_(char *, integer *);


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

    /* Function Body */
    *info = 0;
    upper = lsame_(uplo, "U");
    if (! upper && ! lsame_(uplo, "L")) {
	*info = -1;
    } else if (*n < 0) {
	*info = -2;
    } else if (*lda < max(1,*n)) {
	*info = -4;
    }
    if (*info != 0) {
	i__1 = -(*info);
	xerbla_("DLAUU2", &i__1);
	return 0;
    }

/*     Quick return if possible */

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

    if (upper) {

/*        Compute the product U * U'. */

	i__1 = *n;
	for (i__ = 1; i__ <= i__1; ++i__) {
	    aii = a[i__ + i__ * a_dim1];
	    if (i__ < *n) {
		i__2 = *n - i__ + 1;
		a[i__ + i__ * a_dim1] = ddot_(&i__2, &a[i__ + i__ * a_dim1], 
			lda, &a[i__ + i__ * a_dim1], lda);
		i__2 = i__ - 1;
		i__3 = *n - i__;
		dgemv_("No transpose", &i__2, &i__3, &c_b7, &a[(i__ + 1) * 
			a_dim1 + 1], lda, &a[i__ + (i__ + 1) * a_dim1], lda, &
			aii, &a[i__ * a_dim1 + 1], &c__1);
	    } else {
		dscal_(&i__, &aii, &a[i__ * a_dim1 + 1], &c__1);
	    }
/* L10: */
	}

    } else {

/*        Compute the product L' * L. */

	i__1 = *n;
	for (i__ = 1; i__ <= i__1; ++i__) {
	    aii = a[i__ + i__ * a_dim1];
	    if (i__ < *n) {
		i__2 = *n - i__ + 1;
		a[i__ + i__ * a_dim1] = ddot_(&i__2, &a[i__ + i__ * a_dim1], &
			c__1, &a[i__ + i__ * a_dim1], &c__1);
		i__2 = *n - i__;
		i__3 = i__ - 1;
		dgemv_("Transpose", &i__2, &i__3, &c_b7, &a[i__ + 1 + a_dim1], 
			 lda, &a[i__ + 1 + i__ * a_dim1], &c__1, &aii, &a[i__ 
			+ a_dim1], lda);
	    } else {
		dscal_(&i__, &aii, &a[i__ + a_dim1], lda);
	    }
/* L20: */
	}
    }

    return 0;

/*     End of DLAUU2 */

} /* dlauu2_ */