SGETRS(3)      LAPACK routine of NEC Numeric Library Collection      SGETRS(3)



NAME
       SGETRS

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



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




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

           N         (input)
                     N is INTEGER
                     The order of the matrix A.  N >= 0.

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

           A         (input)
                     A is REAL array, dimension (LDA,N)
                     The factors L and U from the factorization A = P*L*U
                     as computed by SGETRF.

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

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

           B         (input/output)
                     B is REAL array, dimension (LDB,NRHS)
                     On entry, the right hand side matrix B.
                     On exit, the solution matrix X.

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

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



LAPACK routine                  31 October 2017                      SGETRS(3)