NAME

       dgesv.f -

SYNOPSIS

   Functions/Subroutines
       subroutine dgesv (N, NRHS, A, LDA, IPIV, B, LDB, INFO)
            DGESV computes the solution to system of linear equations A * X = B for GE matrices

Function/Subroutine Documentation

   subroutine dgesv (integerN, integerNRHS, double precision, dimension( lda, * )A, integerLDA,
       integer, dimension( * )IPIV, double precision, dimension( ldb, * )B, integerLDB,
       integerINFO)
        DGESV computes the solution to system of linear equations A * X = B for GE matrices

       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.

       Parameters:
           N

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

           NRHS

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

           A

                     A is 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

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

           IPIV

                     IPIV is 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

                     B is 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

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

           INFO

                     INFO is 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.

       Author:
           Univ. of Tennessee

           Univ. of California Berkeley

           Univ. of Colorado Denver

           NAG Ltd.

       Date:
           November 2011

       Definition at line 123 of file dgesv.f.

Author

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