```      SUBROUTINE SGETRS( TRANS, N, NRHS, A, LDA, IPIV, B, LDB, INFO )
*
*  -- LAPACK routine (version 3.1) --
*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
*     November 2006
*
*     .. Scalar Arguments ..
CHARACTER          TRANS
INTEGER            INFO, LDA, LDB, N, NRHS
*     ..
*     .. Array Arguments ..
INTEGER            IPIV( * )
REAL               A( LDA, * ), B( LDB, * )
*     ..
*
*  Purpose
*  =======
*
*  SGETRS 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 SGETRF.
*
*  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 = Transpose)
*
*  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) REAL array, dimension (LDA,N)
*          The factors L and U from the factorization A = P*L*U
*          as computed by SGETRF.
*
*  LDA     (input) INTEGER
*          The leading dimension of the array A.  LDA >= max(1,N).
*
*  IPIV    (input) 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) REAL 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 illegal value
*
*  =====================================================================
*
*     .. Parameters ..
REAL               ONE
PARAMETER          ( ONE = 1.0E+0 )
*     ..
*     .. Local Scalars ..
LOGICAL            NOTRAN
*     ..
*     .. External Functions ..
LOGICAL            LSAME
EXTERNAL           LSAME
*     ..
*     .. External Subroutines ..
EXTERNAL           SLASWP, STRSM, XERBLA
*     ..
*     .. Intrinsic Functions ..
INTRINSIC          MAX
*     ..
*     .. Executable Statements ..
*
*     Test the input parameters.
*
INFO = 0
NOTRAN = LSAME( TRANS, 'N' )
IF( .NOT.NOTRAN .AND. .NOT.LSAME( TRANS, 'T' ) .AND. .NOT.
\$    LSAME( TRANS, 'C' ) ) THEN
INFO = -1
ELSE IF( N.LT.0 ) THEN
INFO = -2
ELSE IF( NRHS.LT.0 ) THEN
INFO = -3
ELSE IF( LDA.LT.MAX( 1, N ) ) THEN
INFO = -5
ELSE IF( LDB.LT.MAX( 1, N ) ) THEN
INFO = -8
END IF
IF( INFO.NE.0 ) THEN
CALL XERBLA( 'SGETRS', -INFO )
RETURN
END IF
*
*     Quick return if possible
*
IF( N.EQ.0 .OR. NRHS.EQ.0 )
\$   RETURN
*
IF( NOTRAN ) THEN
*
*        Solve A * X = B.
*
*        Apply row interchanges to the right hand sides.
*
CALL SLASWP( NRHS, B, LDB, 1, N, IPIV, 1 )
*
*        Solve L*X = B, overwriting B with X.
*
CALL STRSM( 'Left', 'Lower', 'No transpose', 'Unit', N, NRHS,
\$               ONE, A, LDA, B, LDB )
*
*        Solve U*X = B, overwriting B with X.
*
CALL STRSM( 'Left', 'Upper', 'No transpose', 'Non-unit', N,
\$               NRHS, ONE, A, LDA, B, LDB )
ELSE
*
*        Solve A' * X = B.
*
*        Solve U'*X = B, overwriting B with X.
*
CALL STRSM( 'Left', 'Upper', 'Transpose', 'Non-unit', N, NRHS,
\$               ONE, A, LDA, B, LDB )
*
*        Solve L'*X = B, overwriting B with X.
*
CALL STRSM( 'Left', 'Lower', 'Transpose', 'Unit', N, NRHS, ONE,
\$               A, LDA, B, LDB )
*
*        Apply row interchanges to the solution vectors.
*
CALL SLASWP( NRHS, B, LDB, 1, N, IPIV, -1 )
END IF
*
RETURN
*
*     End of SGETRS
*
END

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