org.netlib.arpack
Class Ssgets

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

public class Ssgets
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: ssgets \Description: Given the eigenvalues of the symmetric tridiagonal 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: This is called even in the case of user specified shifts in order to sort the eigenvalues, and error bounds of H for later use. \Usage: call ssgets ( ISHIFT, WHICH, KEV, NP, RITZ, BOUNDS, SHIFTS ) \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' -> KEV eigenvalues of largest magnitude are retained. 'SM' -> KEV eigenvalues of smallest magnitude are retained. 'LA' -> KEV eigenvalues of largest value are retained. 'SA' -> KEV eigenvalues of smallest value are retained. 'BE' -> KEV eigenvalues, half from each end of the spectrum. If KEV is odd, compute one more from the high end. KEV Integer. (INPUT) KEV+NP is the size of the matrix H. NP Integer. (INPUT) Number of implicit shifts to be computed. RITZ Real array of length KEV+NP. (INPUT/OUTPUT) On INPUT, RITZ contains the eigenvalues of H. On OUTPUT, RITZ are sorted so that the unwanted eigenvalues are in the first NP locations and the wanted part is in the last KEV locations. When exact shifts are selected, the unwanted part corresponds to the shifts to be applied. BOUNDS Real array of length KEV+NP. (INPUT/OUTPUT) Error bounds corresponding to the ordering in RITZ. SHIFTS Real array of length NP. (INPUT/OUTPUT) On INPUT: contains the user specified shifts if ISHIFT = 0. On OUTPUT: contains the shifts sorted into decreasing order of magnitude with respect to the Ritz estimates contained in BOUNDS. If ISHIFT = 0, SHIFTS is not modified on exit. \EndDoc ----------------------------------------------------------------------- \BeginLib \Local variables: xxxxxx real \Routines called: ssortr ARPACK utility sorting routine. ivout ARPACK utility routine that prints integers. second ARPACK utility routine for timing. svout ARPACK utility routine that prints vectors. scopy Level 1 BLAS that copies one vector to another. sswap Level 1 BLAS that swaps the contents of two vectors. \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/93: Version ' 2.1' \SCCS Information: @(#) FILE: sgets.F SID: 2.4 DATE OF SID: 4/19/96 RELEASE: 2 \Remarks \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
Ssgets()
           
 
Method Summary
static void ssgets(int ishift, java.lang.String which, org.netlib.util.intW kev, org.netlib.util.intW np, float[] ritz, int _ritz_offset, float[] bounds, int _bounds_offset, float[] shifts, int _shifts_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

Ssgets

public Ssgets()
Method Detail

ssgets

public static void ssgets(int ishift,
                          java.lang.String which,
                          org.netlib.util.intW kev,
                          org.netlib.util.intW np,
                          float[] ritz,
                          int _ritz_offset,
                          float[] bounds,
                          int _bounds_offset,
                          float[] shifts,
                          int _shifts_offset)