org.netlib.lapack
Class DTRRFS

java.lang.Object
  org.netlib.lapack.DTRRFS

public class DTRRFS
extends java.lang.Object

DTRRFS is a simplified interface to the JLAPACK routine dtrrfs.
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
 *  =======
 *
 *  DTRRFS provides error bounds and backward error estimates for the
 *  solution to a system of linear equations with a triangular
 *  coefficient matrix.
 *
 *  The solution matrix X must be computed by DTRTRS or some other
 *  means before entering this routine.  DTRRFS does not do iterative
 *  refinement because doing so cannot improve the backward error.
 *
 *  Arguments
 *  =========
 *
 *  UPLO    (input) CHARACTER*1
 *          = 'U':  A is upper triangular;
 *          = 'L':  A is lower triangular.
 *
 *  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)
 *
 *  DIAG    (input) CHARACTER*1
 *          = 'N':  A is non-unit triangular;
 *          = 'U':  A is unit triangular.
 *
 *  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 triangular matrix A.  If UPLO = 'U', the leading N-by-N
 *          upper triangular part of the array A contains the upper
 *          triangular matrix, and the strictly lower triangular part of

 *          A is not referenced.  If UPLO = 'L', the leading N-by-N lower
 *          triangular part of the array A contains the lower triangular

 *          matrix, and the strictly upper triangular part of A is not
 *          referenced.  If DIAG = 'U', the diagonal elements of A are
 *          also not referenced and are assumed to be 1.
 *
 *  LDA     (input) INTEGER
 *          The leading dimension of the array A.  LDA >= max(1,N).
 *
 *  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) DOUBLE PRECISION array, dimension (LDX,NRHS)
 *          The 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
 *
 *  =====================================================================
 *
 *     .. Parameters ..

Constructor Summary

DTRRFS()

Method Summary

static void

DTRRFS(java.lang.String uplo, java.lang.String trans, java.lang.String diag, int n, int nrhs, double[][] a, double[][] b, double[][] x, double[] ferr, double[] berr, double[] work, int[] iwork, intW info)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DTRRFS

public DTRRFS()

Method Detail

DTRRFS

public static void DTRRFS(java.lang.String uplo,
                          java.lang.String trans,
                          java.lang.String diag,
                          int n,
                          int nrhs,
                          double[][] a,
                          double[][] b,
                          double[][] x,
                          double[] ferr,
                          double[] berr,
                          double[] work,
                          int[] iwork,
                          intW info)