org.netlib.arpack
Class Sneigh

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

public class Sneigh
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: sneigh \Description: Compute the eigenvalues of the current upper Hessenberg matrix and the corresponding Ritz estimates given the current residual norm. \Usage: call sneigh ( RNORM, N, H, LDH, RITZR, RITZI, BOUNDS, Q, LDQ, WORKL, IERR ) \Arguments RNORM Real scalar. (INPUT) Residual norm corresponding to the current upper Hessenberg matrix H. N Integer. (INPUT) Size of the matrix H. H Real N by N array. (INPUT) H contains the current upper Hessenberg matrix. LDH Integer. (INPUT) Leading dimension of H exactly as declared in the calling program. RITZR, Real arrays of length N. (OUTPUT) RITZI On output, RITZR(1:N) (resp. RITZI(1:N)) contains the real (respectively imaginary) parts of the eigenvalues of H. BOUNDS Real array of length N. (OUTPUT) On output, BOUNDS contains the Ritz estimates associated with the eigenvalues RITZR and RITZI. This is equal to RNORM times the last components of the eigenvectors corresponding to the eigenvalues in RITZR and RITZI. Q Real N by N array. (WORKSPACE) Workspace needed to store the eigenvectors of H. LDQ Integer. (INPUT) Leading dimension of Q exactly as declared in the calling program. WORKL Real work array of length N**2 + 3*N. (WORKSPACE) Private (replicated) array on each PE or array allocated on the front end. This is needed to keep the full Schur form of H and also in the calculation of the eigenvectors of H. IERR Integer. (OUTPUT) Error exit flag from slaqrb or strevc. \EndDoc ----------------------------------------------------------------------- \BeginLib \Local variables: xxxxxx real \Routines called: slaqrb ARPACK routine to compute the real Schur form of an upper Hessenberg matrix and last row of the Schur vectors. second ARPACK utility routine for timing. smout ARPACK utility routine that prints matrices svout ARPACK utility routine that prints vectors. slacpy LAPACK matrix copy routine. slapy2 LAPACK routine to compute sqrt(x**2+y**2) carefully. strevc LAPACK routine to compute the eigenvectors of a matrix in upper quasi-triangular form sgemv Level 2 BLAS routine for matrix vector multiplication. scopy Level 1 BLAS that copies one vector to another . snrm2 Level 1 BLAS that computes the norm of a vector. sscal Level 1 BLAS that scales a vector. \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: neigh.F SID: 2.3 DATE OF SID: 4/20/96 RELEASE: 2 \Remarks None \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
Sneigh()
           
 
Method Summary
static void sneigh(float rnorm, org.netlib.util.intW n, float[] h, int _h_offset, int ldh, float[] ritzr, int _ritzr_offset, float[] ritzi, int _ritzi_offset, float[] bounds, int _bounds_offset, float[] q, int _q_offset, int ldq, float[] workl, int _workl_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 float t2

t3

public static float t3

t4

public static float t4

t5

public static float t5
Constructor Detail

Sneigh

public Sneigh()
Method Detail

sneigh

public static void sneigh(float rnorm,
                          org.netlib.util.intW n,
                          float[] h,
                          int _h_offset,
                          int ldh,
                          float[] ritzr,
                          int _ritzr_offset,
                          float[] ritzi,
                          int _ritzi_offset,
                          float[] bounds,
                          int _bounds_offset,
                          float[] q,
                          int _q_offset,
                          int ldq,
                          float[] workl,
                          int _workl_offset,
                          org.netlib.util.intW ierr)