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

/* Subroutine */ int dgesv_(integer *n, integer *nrhs, doublereal *a, integer 
	*lda, integer *ipiv, doublereal *b, integer *ldb, integer *info)
{
/*  -- LAPACK driver routine (version 3.0) --   
       Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,   
       Courant Institute, Argonne National Lab, and Rice University   
       March 31, 1993   


    Purpose   
    =======   

    DGESV computes the solution to a real system of linear equations   
       A * X = B,   
    where A is an N-by-N matrix and X and B are N-by-NRHS matrices.   

    The LU decomposition with partial pivoting and row interchanges is   
    used to factor A as   
       A = P * L * U,   
    where P is a permutation matrix, L is unit lower triangular, and U is   
    upper triangular.  The factored form of A is then used to solve the   
    system of equations A * X = B.   

    Arguments   
    =========   

    N       (input) INTEGER   
            The number of linear equations, i.e., the order of the   
            matrix A.  N >= 0.   

    NRHS    (input) INTEGER   
            The number of right hand sides, i.e., the number of columns   
            of the matrix B.  NRHS >= 0.   

    A       (input/output) DOUBLE PRECISION array, dimension (LDA,N)   
            On entry, the N-by-N coefficient matrix A.   
            On exit, the factors L and U from the factorization   
            A = P*L*U; the unit diagonal elements of L are not stored.   

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

    IPIV    (output) INTEGER array, dimension (N)   
            The pivot indices that define the permutation matrix P;   
            row i of the matrix was interchanged with row IPIV(i).   

    B       (input/output) DOUBLE PRECISION array, dimension (LDB,NRHS)   
            On entry, the N-by-NRHS matrix of right hand side matrix B.   
            On exit, if INFO = 0, the N-by-NRHS solution matrix X.   

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

    INFO    (output) INTEGER   
            = 0:  successful exit   
            < 0:  if INFO = -i, the i-th argument had an illegal value   
            > 0:  if INFO = i, U(i,i) is exactly zero.  The factorization   
                  has been completed, but the factor U is exactly   
                  singular, so the solution could not be computed.   

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


       Test the input parameters.   

       Parameter adjustments */
    /* System generated locals */
    integer a_dim1, a_offset, b_dim1, b_offset, i__1;
    /* Local variables */
    extern /* Subroutine */ int dgetrf_(integer *, integer *, doublereal *, 
	    integer *, integer *, integer *), xerbla_(char *, integer *), dgetrs_(char *, integer *, integer *, doublereal *, 
	    integer *, integer *, doublereal *, integer *, integer *);

    a_dim1 = *lda;
    a_offset = 1 + a_dim1 * 1;
    a -= a_offset;
    --ipiv;
    b_dim1 = *ldb;
    b_offset = 1 + b_dim1 * 1;
    b -= b_offset;

    /* Function Body */
    *info = 0;
    if (*n < 0) {
	*info = -1;
    } else if (*nrhs < 0) {
	*info = -2;
    } else if (*lda < max(1,*n)) {
	*info = -4;
    } else if (*ldb < max(1,*n)) {
	*info = -7;
    }
    if (*info != 0) {
	i__1 = -(*info);
	xerbla_("DGESV ", &i__1);
	return 0;
    }

/*     Compute the LU factorization of A. */

    dgetrf_(n, n, &a[a_offset], lda, &ipiv[1], info);
    if (*info == 0) {

/*        Solve the system A*X = B, overwriting B with X. */

	dgetrs_("No transpose", n, nrhs, &a[a_offset], lda, &ipiv[1], &b[
		b_offset], ldb, info);
    }
    return 0;

/*     End of DGESV */

} /* dgesv_ */

