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sgerfs.f(3)				      LAPACK				      sgerfs.f(3)

NAME
       sgerfs.f -

SYNOPSIS
   Functions/Subroutines
       subroutine sgerfs (TRANS, N, NRHS, A, LDA, AF, LDAF, IPIV, B, LDB, X, LDX, FERR, BERR,
	   WORK, IWORK, INFO)
	   SGERFS

Function/Subroutine Documentation
   subroutine sgerfs (characterTRANS, integerN, integerNRHS, real, dimension( lda, * )A,
       integerLDA, real, dimension( ldaf, * )AF, integerLDAF, integer, dimension( * )IPIV, real,
       dimension( ldb, * )B, integerLDB, real, dimension( ldx, * )X, integerLDX, real, dimension(
       * )FERR, real, dimension( * )BERR, real, dimension( * )WORK, integer, dimension( * )IWORK,
       integerINFO)
       SGERFS

       Purpose:

	    SGERFS improves the computed solution to a system of linear
	    equations and provides error bounds and backward error estimates for
	    the solution.

       Parameters:
	   TRANS

		     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**H * X = B  (Conjugate transpose = Transpose)

	   N

		     N is INTEGER
		     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 matrices B and X.  NRHS >= 0.

	   A

		     A is REAL array, dimension (LDA,N)
		     The original N-by-N matrix A.

	   LDA

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

	   AF

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

	   LDAF

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

	   IPIV

		     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

		     B is REAL array, dimension (LDB,NRHS)
		     The right hand side matrix B.

	   LDB

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

	   X

		     X is REAL array, dimension (LDX,NRHS)
		     On entry, the solution matrix X, as computed by SGETRS.
		     On exit, the improved solution matrix X.

	   LDX

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

	   FERR

		     FERR is REAL array, dimension (NRHS)
		     The estimated forward error bound for each solution vector
		     X(j) (the j-th column of the solution matrix X).
		     If XTRUE is the true solution corresponding to X(j), FERR(j)
		     is an estimated upper bound for the magnitude of the largest
		     element in (X(j) - XTRUE) divided by the magnitude of the
		     largest element in X(j).  The estimate is as reliable as
		     the estimate for RCOND, and is almost always a slight
		     overestimate of the true error.

	   BERR

		     BERR is REAL array, dimension (NRHS)
		     The componentwise relative backward error of each solution
		     vector X(j) (i.e., the smallest relative change in
		     any element of A or B that makes X(j) an exact solution).

	   WORK

		     WORK is REAL array, dimension (3*N)

	   IWORK

		     IWORK is INTEGER array, dimension (N)

	   INFO

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

       Internal Parameters:

	     ITMAX is the maximum number of steps of iterative refinement.

       Author:
	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

       Date:
	   November 2011

       Definition at line 185 of file sgerfs.f.

Author
       Generated automatically by Doxygen for LAPACK from the source code.

Version 3.4.2				 Tue Sep 25 2012			      sgerfs.f(3)
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