CXML
        	    
LAPACK version 3.0
dgesv(3)

PURPOSE
  DGESV - compute the solution to a real system of linear equations A * X =
  B,

SYNTAX
  SUBROUTINE DGESV( N, NRHS, A, LDA, IPIV, B, LDB, INFO )

      INTEGER	    INFO, LDA, LDB, N, NRHS

      INTEGER	    IPIV( * )

      DOUBLE	    PRECISION A( LDA, * ), B( LDB, * )

DESCRIPTION
  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.