HP MLIB User's Guide Vol. 2 7th Ed.

Chapter 15 Sparse Eigenvalues and Eigenvectors 1061
Return eigenvalue results DSEVRL
Name DSEVRL
Return eigenvalue results
Purpose This subprogram retrieves all or selected eigenvalues after eigenextraction.
Usage VECLIB:
INTEGER*4 levalu, fstval, lstval, ier
REAL*8 evalue(levalu), global(150)
CALL DSEVRL(levalu, evalue, fstval, lstval, global, ier)
VECLIB8:
INTEGER*8 levalu, fstval, lstval, ier
REAL*8 evalue(levalu), global(150)
CALL DSEVRL(levalu, evalue, fstval, lstval, global, ier)
Input levalu Length of vector for storing eigenvalues.
fstval Ordinal position of first eigenvalue to be returned in
evalue.
lstval Ordinal position of last eigenvalue to be returned in
evalue.
The sign of fstval and lstval determine whether
eigenvalues returned are from the confirmed set or the
discarded set. Positive indices indicate eigenvalues in
the final confirmed trust region, while negative indices
the discardable set. The following pairs illustrate the
meaning of fstval and lstval:
fstval lstval
1 nfound All final trust-region eigenvalues.
−1 −ndiscd All other eigenvalues.
1 −ndiscd All computed eigenvalues.
iii-th final trust-region eigenvalue.
−i −ii-th discardable eigenvalue.
ij
i-th through j-th final trust-region
eigenvalues.
i −j
i-th through nfound-th final trust-region
eigenvalues and 1st through j-th
discardable eigenvalues.