org.netlib.arpack
Class Sgetv0

java.lang.Object
  extended by org.netlib.arpack.Sgetv0

public class Sgetv0
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: sgetv0 \Description: Generate a random initial residual vector for the Arnoldi process. Force the residual vector to be in the range of the operator OP. \Usage: call sgetv0 ( IDO, BMAT, ITRY, INITV, N, J, V, LDV, RESID, RNORM, IPNTR, WORKD, IERR ) \Arguments IDO Integer. (INPUT/OUTPUT) Reverse communication flag. IDO must be zero on the first call to sgetv0. ------------------------------------------------------------- IDO = 0: first call to the reverse communication interface IDO = -1: compute Y = OP * X where IPNTR(1) is the pointer into WORKD for X, IPNTR(2) is the pointer into WORKD for Y. This is for the initialization phase to force the starting vector into the range of OP. IDO = 2: compute Y = B * X where IPNTR(1) is the pointer into WORKD for X, IPNTR(2) is the pointer into WORKD for Y. IDO = 99: done ------------------------------------------------------------- BMAT Character*1. (INPUT) BMAT specifies the type of the matrix B in the (generalized) eigenvalue problem A*x = lambda*B*x. B = 'I' -> standard eigenvalue problem A*x = lambda*x B = 'G' -> generalized eigenvalue problem A*x = lambda*B*x ITRY Integer. (INPUT) ITRY counts the number of times that sgetv0 is called. It should be set to 1 on the initial call to sgetv0. INITV Logical variable. (INPUT) .TRUE. => the initial residual vector is given in RESID. .FALSE. => generate a random initial residual vector. N Integer. (INPUT) Dimension of the problem. J Integer. (INPUT) Index of the residual vector to be generated, with respect to the Arnoldi process. J > 1 in case of a "restart". V Real N by J array. (INPUT) The first J-1 columns of V contain the current Arnoldi basis if this is a "restart". LDV Integer. (INPUT) Leading dimension of V exactly as declared in the calling program. RESID Real array of length N. (INPUT/OUTPUT) Initial residual vector to be generated. If RESID is provided, force RESID into the range of the operator OP. RNORM Real scalar. (OUTPUT) B-norm of the generated residual. IPNTR Integer array of length 3. (OUTPUT) WORKD Real work array of length 2*N. (REVERSE COMMUNICATION). On exit, WORK(1:N) = B*RESID to be used in SSAITR. IERR Integer. (OUTPUT) = 0: Normal exit. = -1: Cannot generate a nontrivial restarted residual vector in the range of the operator OP. \EndDoc ----------------------------------------------------------------------- \BeginLib \Local variables: xxxxxx real \References: 1. D.C. Sorensen, "Implicit Application of Polynomial Filters in a k-Step Arnoldi Method", SIAM J. Matr. Anal. Apps., 13 (1992), pp 357-385. 2. R.B. Lehoucq, "Analysis and Implementation of an Implicitly Restarted Arnoldi Iteration", Rice University Technical Report TR95-13, Department of Computational and Applied Mathematics. \Routines called: second ARPACK utility routine for timing. svout ARPACK utility routine for vector output. slarnv LAPACK routine for generating a random vector. sgemv Level 2 BLAS routine for matrix vector multiplication. scopy Level 1 BLAS that copies one vector to another. sdot Level 1 BLAS that computes the scalar product of two vectors. snrm2 Level 1 BLAS that computes the norm of a vector. \Author Danny Sorensen Phuong Vu Richard Lehoucq CRPC / Rice University Dept. of Computational & Houston, Texas Applied Mathematics Rice University Houston, Texas \SCCS Information: @(#) FILE: getv0.F SID: 2.7 DATE OF SID: 04/07/99 RELEASE: 2 \EndLib -----------------------------------------------------------------------


Field Summary
static boolean first
           
static boolean inits
           
static int[] iseed
           
static int iter
           
static int msglvl
           
static boolean orth
           
static org.netlib.util.floatW rnorm0
           
static org.netlib.util.floatW t0
           
static org.netlib.util.floatW t1
           
static org.netlib.util.floatW t2
           
static org.netlib.util.floatW t3
           
static float t4
           
static float t5
           
 
Constructor Summary
Sgetv0()
           
 
Method Summary
static void sgetv0(org.netlib.util.intW ido, java.lang.String bmat, int itry, boolean initv, int n, int j, float[] v, int _v_offset, int ldv, float[] resid, int _resid_offset, org.netlib.util.floatW rnorm, int[] ipntr, int _ipntr_offset, float[] workd, int _workd_offset, org.netlib.util.intW ierr)
           
 
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 org.netlib.util.floatW t2

t3

public static org.netlib.util.floatW t3

t4

public static float t4

t5

public static float t5

first

public static boolean first

orth

public static boolean orth

iseed

public static int[] iseed

iter

public static int iter

msglvl

public static int msglvl

rnorm0

public static org.netlib.util.floatW rnorm0

inits

public static boolean inits
Constructor Detail

Sgetv0

public Sgetv0()
Method Detail

sgetv0

public static void sgetv0(org.netlib.util.intW ido,
                          java.lang.String bmat,
                          int itry,
                          boolean initv,
                          int n,
                          int j,
                          float[] v,
                          int _v_offset,
                          int ldv,
                          float[] resid,
                          int _resid_offset,
                          org.netlib.util.floatW rnorm,
                          int[] ipntr,
                          int _ipntr_offset,
                          float[] workd,
                          int _workd_offset,
                          org.netlib.util.intW ierr)