org.netlib.lapack
Class DLAQR1
java.lang.Object
org.netlib.lapack.DLAQR1
public class DLAQR1
- extends java.lang.Object
DLAQR1 is a simplified interface to the JLAPACK routine dlaqr1.
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.
* ..
*
* Given a 2-by-2 or 3-by-3 matrix H, DLAQR1 sets v to a
* scalar multiple of the first column of the product
*
* (*) K = (H - (sr1 + i*si1)*I)*(H - (sr2 + i*si2)*I)
*
* scaling to avoid overflows and most underflows. It
* is assumed that either
*
* 1) sr1 = sr2 and si1 = -si2
* or
* 2) si1 = si2 = 0.
*
* This is useful for starting double implicit shift bulges
* in the QR algorithm.
*
*
* N (input) integer
* Order of the matrix H. N must be either 2 or 3.
*
* H (input) DOUBLE PRECISION array of dimension (LDH,N)
* The 2-by-2 or 3-by-3 matrix H in (*).
*
* LDH (input) integer
* The leading dimension of H as declared in
* the calling procedure. LDH.GE.N
*
* SR1 (input) DOUBLE PRECISION
* SI1 The shifts in (*).
* SR2
* SI2
*
* V (output) DOUBLE PRECISION array of dimension N
* A scalar multiple of the first column of the
* matrix K in (*).
*
* ================================================================
* Based on contributions by
* Karen Braman and Ralph Byers, Department of Mathematics,
* University of Kansas, USA
*
* ================================================================
*
* .. Parameters ..
Method Summary |
static void |
DLAQR1(int n,
double[][] h,
double sr1,
double si1,
double sr2,
double si2,
double[] v)
|
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
DLAQR1
public DLAQR1()
DLAQR1
public static void DLAQR1(int n,
double[][] h,
double sr1,
double si1,
double sr2,
double si2,
double[] v)