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NAME
     dgetrs - solve a system of linear equations  A * X = B or A'
     * X = B with a general N-by-N matrix A using the LU factori-
     zation computed by DGETRF

SYNOPSIS
     SUBROUTINE DGETRS( TRANS, N, NRHS, A,  LDA,  IPIV,  B,  LDB,
               INFO )

     CHARACTER TRANS

     INTEGER INFO, LDA, LDB, N, NRHS

     INTEGER IPIV( * )

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



     #include <sunperf.h>

     void dgetrs(char trans, int n, int  nrhs,  double  *da,  int
               lda,  int *ipivot, double *db, int ldb, int *info)
               ;

PURPOSE
     DGETRS solves a system of linear equations
        A * X = B  or  A' * X = B with a general N-by-N matrix  A
     using the LU factorization computed by DGETRF.


ARGUMENTS
     TRANS     (input) CHARACTER*1
               Specifies the form of the system of equations:
               = 'N':  A * X = B  (No transpose)
               = 'T':  A'* X = B  (Transpose)
               = 'C':  A'* X = B  (Conjugate  transpose  =  Tran-
               spose)

     N         (input) INTEGER
               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) DOUBLE PRECISION array, dimension (LDA,N)
               The factors L and U from  the  factorization  A  =
               P*L*U as computed by DGETRF.

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

     IPIV      (input) INTEGER array, dimension (N)
               The pivot indices from DGETRF; for 1<=i<=N, row  i
               of the matrix was interchanged with row IPIV(i).

     B         (input/output) DOUBLE PRECISION  array,  dimension
               (LDB,NRHS)
               On entry, the right hand side matrix B.  On  exit,
               the 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 ille-
               gal value

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