org.netlib.lapack
Class SLARRF
java.lang.Object
org.netlib.lapack.SLARRF
public class SLARRF
- extends java.lang.Object
SLARRF is a simplified interface to the JLAPACK routine slarrf.
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 representation L D L^T and its cluster of close
* eigenvalues (in a relative measure), W( CLSTRT ), W( CLSTRT+1 ), ...
* W( CLEND ), SLARRF finds a new relatively robust representation
* L D L^T - SIGMA I = L(+) D(+) L(+)^T such that at least one of the
* eigenvalues of L(+) D(+) L(+)^T is relatively isolated.
*
* Arguments
* =========
*
* N (input) INTEGER
* The order of the matrix (subblock, if the matrix splitted).
*
* D (input) REAL array, dimension (N)
* The N diagonal elements of the diagonal matrix D.
*
* L (input) REAL array, dimension (N-1)
* The (N-1) subdiagonal elements of the unit bidiagonal
* matrix L.
*
* LD (input) REAL array, dimension (N-1)
* The (N-1) elements L(i)*D(i).
*
* CLSTRT (input) INTEGER
* The index of the first eigenvalue in the cluster.
*
* CLEND (input) INTEGER
* The index of the last eigenvalue in the cluster.
*
* W (input) REAL array, dimension >= (CLEND-CLSTRT+1
* The eigenvalue APPROXIMATIONS of L D L^T in ascending order.
* W( CLSTRT ) through W( CLEND ) form the cluster of relatively
* close eigenalues.
*
* WGAP (input/output) REAL array, dimension >= (CLEND-C
* The separation from the right neighbor eigenvalue in W.
*
* WERR (input) REAL array, dimension >= (CLEND-CLSTRT+1
* WERR contain the semiwidth of the uncertainty
* interval of the corresponding eigenvalue APPROXIMATION in W
*
* SPDIAM (input) estimate of the spectral diameter obtained from the
* Gerschgorin intervals
*
* CLGAPL, CLGAPR (input) absolute gap on each end of the cluster.
* Set by the calling routine to protect against shifts too clos
* to eigenvalues outside the cluster.
*
* PIVMIN (input) DOUBLE PRECISION
* The minimum pivot allowed in the Sturm sequence.
*
* SIGMA (output) REAL
* The shift used to form L(+) D(+) L(+)^T.
*
* DPLUS (output) REAL array, dimension (N)
* The N diagonal elements of the diagonal matrix D(+).
*
* LPLUS (output) REAL array, dimension (N-1)
* The first (N-1) elements of LPLUS contain the subdiagonal
* elements of the unit bidiagonal matrix L(+).
*
* WORK (workspace) REAL array, dimension (2*N)
* Workspace.
*
* 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 |
SLARRF(int n,
float[] d,
float[] l,
float[] ld,
int clstrt,
int clend,
float[] w,
float[] wgap,
float[] werr,
float spdiam,
float clgapl,
float clgapr,
float pivmin,
floatW sigma,
float[] dplus,
float[] lplus,
float[] work,
intW info)
|
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
SLARRF
public SLARRF()
SLARRF
public static void SLARRF(int n,
float[] d,
float[] l,
float[] ld,
int clstrt,
int clend,
float[] w,
float[] wgap,
float[] werr,
float spdiam,
float clgapl,
float clgapr,
float pivmin,
floatW sigma,
float[] dplus,
float[] lplus,
float[] work,
intW info)