org.netlib.lapack
Class SLARRK
java.lang.Object
org.netlib.lapack.SLARRK
public class SLARRK
- extends java.lang.Object
SLARRK is a simplified interface to the JLAPACK routine slarrk.
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
* =======
*
* SLARRK computes one eigenvalue of a symmetric tridiagonal
* matrix T to suitable accuracy. This is an auxiliary code to be
* called from SSTEMR.
*
* To avoid overflow, the matrix must be scaled so that its
* largest element is no greater than overflow**(1/2) *
* underflow**(1/4) in absolute value, and for greatest
* accuracy, it should not be much smaller than that.
*
* See W. Kahan "Accurate Eigenvalues of a Symmetric Tridiagonal
* Matrix", Report CS41, Computer Science Dept., Stanford
* University, July 21, 1966.
*
* Arguments
* =========
*
* N (input) INTEGER
* The order of the tridiagonal matrix T. N >= 0.
*
* IW (input) INTEGER
* The index of the eigenvalues to be returned.
*
* GL (input) REAL
* GU (input) REAL
* An upper and a lower bound on the eigenvalue.
*
* D (input) REAL array, dimension (N)
* The n diagonal elements of the tridiagonal matrix T.
*
* E2 (input) REAL array, dimension (N-1)
* The (n-1) squared off-diagonal elements of the tridiagonal ma
*
* PIVMIN (input) REAL
* The minimum pivot allowed in the Sturm sequence for T.
*
* RELTOL (input) REAL
* The minimum relative width of an interval. When an interval
* is narrower than RELTOL times the larger (in
* magnitude) endpoint, then it is considered to be
* sufficiently small, i.e., converged. Note: this should
* always be at least radix*machine epsilon.
*
* W (output) REAL
*
* WERR (output) REAL
* The error bound on the corresponding eigenvalue approximation
* in W.
*
* INFO (output) INTEGER
* = 0: Eigenvalue converged
* = -1: Eigenvalue did NOT converge
*
* Internal Parameters
* ===================
*
* FUDGE REAL , default = 2
* A "fudge factor" to widen the Gershgorin intervals.
*
* =====================================================================
*
* .. Parameters ..
Method Summary |
static void |
SLARRK(int n,
int iw,
float gl,
float gu,
float[] d,
float[] e2,
float pivmin,
float reltol,
floatW w,
floatW werr,
intW info)
|
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
SLARRK
public SLARRK()
SLARRK
public static void SLARRK(int n,
int iw,
float gl,
float gu,
float[] d,
float[] e2,
float pivmin,
float reltol,
floatW w,
floatW werr,
intW info)