org.netlib.arpack
Class Dngets

java.lang.Object
  extended by org.netlib.arpack.Dngets

public class Dngets
extends java.lang.Object

Following is the description from the original
Fortran source.  For each array argument, the Java
version will include an integer offset parameter, so
the arguments may not match the description exactly.
Contact seymour@cs.utk.edu with any questions.

*----------------------------------------------------------------------- \BeginDoc \Name: dngets \Description: Given the eigenvalues of the upper Hessenberg matrix H, computes the NP shifts AMU that are zeros of the polynomial of degree NP which filters out components of the unwanted eigenvectors corresponding to the AMU's based on some given criteria. NOTE: call this even in the case of user specified shifts in order to sort the eigenvalues, and error bounds of H for later use. \Usage: call dngets ( ISHIFT, WHICH, KEV, NP, RITZR, RITZI, BOUNDS, SHIFTR, SHIFTI ) \Arguments ISHIFT Integer. (INPUT) Method for selecting the implicit shifts at each iteration. ISHIFT = 0: user specified shifts ISHIFT = 1: exact shift with respect to the matrix H. WHICH Character*2. (INPUT) Shift selection criteria. 'LM' -> want the KEV eigenvalues of largest magnitude. 'SM' -> want the KEV eigenvalues of smallest magnitude. 'LR' -> want the KEV eigenvalues of largest real part. 'SR' -> want the KEV eigenvalues of smallest real part. 'LI' -> want the KEV eigenvalues of largest imaginary part. 'SI' -> want the KEV eigenvalues of smallest imaginary part. KEV Integer. (INPUT/OUTPUT) INPUT: KEV+NP is the size of the matrix H. OUTPUT: Possibly increases KEV by one to keep complex conjugate pairs together. NP Integer. (INPUT/OUTPUT) Number of implicit shifts to be computed. OUTPUT: Possibly decreases NP by one to keep complex conjugate pairs together. RITZR, Double precision array of length KEV+NP. (INPUT/OUTPUT) RITZI On INPUT, RITZR and RITZI contain the real and imaginary parts of the eigenvalues of H. On OUTPUT, RITZR and RITZI are sorted so that the unwanted eigenvalues are in the first NP locations and the wanted portion is in the last KEV locations. When exact shifts are selected, the unwanted part corresponds to the shifts to be applied. Also, if ISHIFT .eq. 1, the unwanted eigenvalues are further sorted so that the ones with largest Ritz values are first. BOUNDS Double precision array of length KEV+NP. (INPUT/OUTPUT) Error bounds corresponding to the ordering in RITZ. SHIFTR, SHIFTI *** USE deprecated as of version 2.1. *** \EndDoc ----------------------------------------------------------------------- \BeginLib \Local variables: xxxxxx real \Routines called: dsortc ARPACK sorting routine. dcopy Level 1 BLAS that copies one vector to another . \Author Danny Sorensen Phuong Vu Richard Lehoucq CRPC / Rice University Dept. of Computational & Houston, Texas Applied Mathematics Rice University Houston, Texas \Revision history: xx/xx/92: Version ' 2.1' \SCCS Information: @(#) FILE: ngets.F SID: 2.3 DATE OF SID: 4/20/96 RELEASE: 2 \Remarks 1. xxxx \EndLib -----------------------------------------------------------------------


Field Summary
static org.netlib.util.floatW t0
           
static org.netlib.util.floatW t1
           
static float t2
           
static float t3
           
static float t4
           
static float t5
           
 
Constructor Summary
Dngets()
           
 
Method Summary
static void dngets(int ishift, java.lang.String which, org.netlib.util.intW kev, org.netlib.util.intW np, double[] ritzr, int _ritzr_offset, double[] ritzi, int _ritzi_offset, double[] bounds, int _bounds_offset, double[] shiftr, int _shiftr_offset, double[] shifti, int _shifti_offset)
           
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

t0

public static org.netlib.util.floatW t0

t1

public static org.netlib.util.floatW t1

t2

public static float t2

t3

public static float t3

t4

public static float t4

t5

public static float t5
Constructor Detail

Dngets

public Dngets()
Method Detail

dngets

public static void dngets(int ishift,
                          java.lang.String which,
                          org.netlib.util.intW kev,
                          org.netlib.util.intW np,
                          double[] ritzr,
                          int _ritzr_offset,
                          double[] ritzi,
                          int _ritzi_offset,
                          double[] bounds,
                          int _bounds_offset,
                          double[] shiftr,
                          int _shiftr_offset,
                          double[] shifti,
                          int _shifti_offset)