org.netlib.lapack
Class SLASD5
java.lang.Object
org.netlib.lapack.SLASD5
public class SLASD5
- extends java.lang.Object
SLASD5 is a simplified interface to the JLAPACK routine slasd5.
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
* =======
*
* This subroutine computes the square root of the I-th eigenvalue
* of a positive symmetric rank-one modification of a 2-by-2 diagonal
* matrix
*
* diag( D ) * diag( D ) + RHO * Z * transpose(Z) .
*
* The diagonal entries in the array D are assumed to satisfy
*
* 0 <= D(i) < D(j) for i < j .
*
* We also assume RHO > 0 and that the Euclidean norm of the vector
* Z is one.
*
* Arguments
* =========
*
* I (input) INTEGER
* The index of the eigenvalue to be computed. I = 1 or I = 2.
*
* D (input) REAL array, dimension (2)
* The original eigenvalues. We assume 0 <= D(1) < D(2).
*
* Z (input) REAL array, dimension (2)
* The components of the updating vector.
*
* DELTA (output) REAL array, dimension (2)
* Contains (D(j) - sigma_I) in its j-th component.
* The vector DELTA contains the information necessary
* to construct the eigenvectors.
*
* RHO (input) REAL
* The scalar in the symmetric updating formula.
*
* DSIGMA (output) REAL
* The computed sigma_I, the I-th updated eigenvalue.
*
* WORK (workspace) REAL array, dimension (2)
* WORK contains (D(j) + sigma_I) in its j-th component.
*
* Further Details
* ===============
*
* Based on contributions by
* Ren-Cang Li, Computer Science Division, University of California
* at Berkeley, USA
*
* =====================================================================
*
* .. Parameters ..
Method Summary |
static void |
SLASD5(int i,
float[] d,
float[] z,
float[] delta,
float rho,
floatW dsigma,
float[] work)
|
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
SLASD5
public SLASD5()
SLASD5
public static void SLASD5(int i,
float[] d,
float[] z,
float[] delta,
float rho,
floatW dsigma,
float[] work)