All Packages  Class Hierarchy  This Package  Previous  Next  Index

Class org.netlib.lapack.DGERFS

java.lang.Object
   |
   +----org.netlib.lapack.DGERFS

public class DGERFS

extends Object

DGERFS is a simplified interface to the JLAPACK routine dgerfs.
This interface converts Java-style 2D row-major arrays into
the 1D column-major linearized arrays expected by the lower
level JLAPACK routines.  Using this interface also allows you
to omit offset and leading dimension arguments.  However, because
of these conversions, these routines will be slower than the low
level ones.  Following is the description from the original Fortran
source.  Contact seymour@cs.utk.edu with any questions.

 *     ..
 *
 *  Purpose
 *  =======
 *
 *  DGERFS improves the computed solution to a system of linear
 *  equations and provides error bounds and backward error estimates for
 *  the solution.
 *
 *  Arguments
 *  =========
 *
 *  TRANS   (input) 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       (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 matrices B and X.  NRHS >= 0.
 *
 *  A       (input) DOUBLE PRECISION array, dimension (LDA,N)
 *          The original N-by-N matrix A.
 *
 *  LDA     (input) INTEGER
 *          The leading dimension of the array A.  LDA >= max(1,N).
 *
 *  AF      (input) DOUBLE PRECISION array, dimension (LDAF,N)
 *          The factors L and U from the factorization A = P*L*U
 *          as computed by DGETRF.
 *
 *  LDAF    (input) INTEGER
 *          The leading dimension of the array AF.  LDAF >= 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) DOUBLE PRECISION array, dimension (LDB,NRHS)
 *          The right hand side matrix B.
 *
 *  LDB     (input) INTEGER
 *          The leading dimension of the array B.  LDB >= max(1,N).
 *
 *  X       (input/output) DOUBLE PRECISION array, dimension (LDX,NRHS)
 *          On entry, the solution matrix X, as computed by DGETRS.
 *          On exit, the improved solution matrix X.
 *
 *  LDX     (input) INTEGER
 *          The leading dimension of the array X.  LDX >= max(1,N).
 *
 *  FERR    (output) DOUBLE PRECISION 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    (output) DOUBLE PRECISION 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    (workspace) DOUBLE PRECISION array, dimension (3*N)
 *
 *  IWORK   (workspace) INTEGER array, dimension (N)
 *
 *  INFO    (output) 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.
 *
 *  =====================================================================
 *
 *     .. Parameters ..

DGERFS()

DGERFS(String, int, int, double[][], double[][], int[], double[][], double[][], double[], double[], double[], int[], intW)

 public DGERFS()

 public static void DGERFS(String trans,
                           int n,
                           int nrhs,
                           double a[][],
                           double af[][],
                           int ipiv[],
                           double b[][],
                           double x[][],
                           double ferr[],
                           double berr[],
                           double work[],
                           int iwork[],
                           intW info)

All Packages  Class Hierarchy  This Package  Previous  Next  Index