org.netlib.lapack
Class SLARRJ
java.lang.Object
org.netlib.lapack.SLARRJ
public class SLARRJ
- extends java.lang.Object
SLARRJ is a simplified interface to the JLAPACK routine slarrj.
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
* =======
*
* Given the initial eigenvalue approximations of T, SLARRJ
* does bisection to refine the eigenvalues of T,
* W( IFIRST-OFFSET ) through W( ILAST-OFFSET ), to more accuracy. Initi
* guesses for these eigenvalues are input in W, the corresponding estim
* of the error in these guesses in WERR. During bisection, intervals
* [left, right] are maintained by storing their mid-points and
* semi-widths in the arrays W and WERR respectively.
*
* Arguments
* =========
*
* N (input) INTEGER
* The order of the matrix.
*
* D (input) REAL array, dimension (N)
* The N diagonal elements of T.
*
* E2 (input) REAL array, dimension (N-1)
* The Squares of the (N-1) subdiagonal elements of T.
*
* IFIRST (input) INTEGER
* The index of the first eigenvalue to be computed.
*
* ILAST (input) INTEGER
* The index of the last eigenvalue to be computed.
*
* RTOL (input) REAL
* Tolerance for the convergence of the bisection intervals.
* An interval [LEFT,RIGHT] has converged if
* RIGHT-LEFT.LT.RTOL*MAX(|LEFT|,|RIGHT|).
*
* OFFSET (input) INTEGER
* Offset for the arrays W and WERR, i.e., the IFIRST-OFFSET
* through ILAST-OFFSET elements of these arrays are to be used.
*
* W (input/output) REAL array, dimension (N)
* On input, W( IFIRST-OFFSET ) through W( ILAST-OFFSET ) are
* estimates of the eigenvalues of L D L^T indexed IFIRST throug
* ILAST.
* On output, these estimates are refined.
*
* WERR (input/output) REAL array, dimension (N)
* On input, WERR( IFIRST-OFFSET ) through WERR( ILAST-OFFSET )
* the errors in the estimates of the corresponding elements in
* On output, these errors are refined.
*
* WORK (workspace) REAL array, dimension (2*N)
* Workspace.
*
* IWORK (workspace) INTEGER array, dimension (2*N)
* Workspace.
*
* PIVMIN (input) DOUBLE PRECISION
* The minimum pivot in the Sturm sequence for T.
*
* SPDIAM (input) DOUBLE PRECISION
* The spectral diameter of T.
*
* INFO (output) INTEGER
* Error flag.
*
* Further Details
* ===============
*
* Based on contributions by
* Beresford Parlett, University of California, Berkeley, USA
* Jim Demmel, University of California, Berkeley, USA
* Inderjit Dhillon, University of Texas, Austin, USA
* Osni Marques, LBNL/NERSC, USA
* Christof Voemel, University of California, Berkeley, USA
*
* =====================================================================
*
* .. Parameters ..
Method Summary |
static void |
SLARRJ(int n,
float[] d,
float[] e2,
int ifirst,
int ilast,
float rtol,
int offset,
float[] w,
float[] werr,
float[] work,
int[] iwork,
float pivmin,
float spdiam,
intW info)
|
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
SLARRJ
public SLARRJ()
SLARRJ
public static void SLARRJ(int n,
float[] d,
float[] e2,
int ifirst,
int ilast,
float rtol,
int offset,
float[] w,
float[] werr,
float[] work,
int[] iwork,
float pivmin,
float spdiam,
intW info)