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chprfs.f(3)				      LAPACK				      chprfs.f(3)

       chprfs.f -

       subroutine chprfs (UPLO, N, NRHS, AP, AFP, IPIV, B, LDB, X, LDX, FERR, BERR, WORK, RWORK,

Function/Subroutine Documentation
   subroutine chprfs (characterUPLO, integerN, integerNRHS, complex, dimension( * )AP, complex,
       dimension( * )AFP, integer, dimension( * )IPIV, complex, dimension( ldb, * )B, integerLDB,
       complex, dimension( ldx, * )X, integerLDX, real, dimension( * )FERR, real, dimension( *
       )BERR, complex, dimension( * )WORK, real, dimension( * )RWORK, integerINFO)


	    CHPRFS improves the computed solution to a system of linear
	    equations when the coefficient matrix is Hermitian indefinite
	    and packed, and provides error bounds and backward error estimates
	    for the solution.


		     UPLO is CHARACTER*1
		     = 'U':  Upper triangle of A is stored;
		     = 'L':  Lower triangle of A is stored.


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


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


		     AP is COMPLEX array, dimension (N*(N+1)/2)
		     The upper or lower triangle of the Hermitian matrix A, packed
		     columnwise in a linear array.  The j-th column of A is stored
		     in the array AP as follows:
		     if UPLO = 'U', AP(i + (j-1)*j/2) = A(i,j) for 1<=i<=j;
		     if UPLO = 'L', AP(i + (j-1)*(2*n-j)/2) = A(i,j) for j<=i<=n.


		     AFP is COMPLEX array, dimension (N*(N+1)/2)
		     The factored form of the matrix A.  AFP contains the block
		     diagonal matrix D and the multipliers used to obtain the
		     factor U or L from the factorization A = U*D*U**H or
		     A = L*D*L**H as computed by CHPTRF, stored as a packed
		     triangular matrix.


		     IPIV is INTEGER array, dimension (N)
		     Details of the interchanges and the block structure of D
		     as determined by CHPTRF.


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


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


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


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


		     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 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 is COMPLEX array, dimension (2*N)


		     RWORK is REAL array, dimension (N)


		     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.

	   Univ. of Tennessee

	   Univ. of California Berkeley

	   Univ. of Colorado Denver

	   NAG Ltd.

	   November 2011

       Definition at line 180 of file chprfs.f.

       Generated automatically by Doxygen for LAPACK from the source code.

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