_HTRIBK(3F)_HTRIBK(3F)NAME
HTRIBK, SHTRIBK - EISPACK routine. This subroutine forms the
eigenvectors of a COMPLEX HERMITIAN matrix by back transforming those of
the corresponding real symmetric tridiagonal matrix determined by
HTRIDI.
SYNOPSYS
subroutine htribk(nm, n, ar, ai, tau, m, zr, zi)
integer nm, n, m
double precision ar(nm,n),ai(nm,n),tau(2,n),zr(nm,m),zi(nm,m)
subroutine shtribk(nm, n, ar, ai, tau, m, zr, zi)
integer nm, n, m
real ar(nm,n),ai(nm,n),tau(2,n),zr(nm,m),zi(nm,m)
DESCRIPTION
On INPUT
NM must be set to the row dimension of two-dimensional array parameters
as declared in the calling program dimension statement.
N is the order of the matrix.
AR and AI contain information about the unitary trans- formations used in
the reduction by HTRIDI in their full lower triangles except for the
diagonal of AR.
TAU contains further information about the transformations.
M is the number of eigenvectors to be back transformed.
ZR contains the eigenvectors to be back transformed in its first M
columns. On OUTPUT
ZR and ZI contain the real and imaginary parts, respectively, of the
transformed eigenvectors in their first M columns. Note that the last
component of each returned vector is real and that vector Euclidean norms
are preserved. Questions and comments should be directed to B. S.
Garbow, APPLIED MATHEMATICS DIVISION, ARGONNE NATIONAL LABORATORY
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