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The subroutine `Xgetv0` is responsible for generating starting
vectors. It is called upon to construct the initial Arnoldi/Lanczos vector
when this option is requested. `Xgetv0` is also called upon to generate
a new basis vector when the re-orthogonalization scheme of `XYaitr`
calls for this, i.e. when an invariant subspace is encountered early during
the construction of the Arnoldi factorization. In the latter case,
the vector that is returned by `Xgetv0`
is already orthogonalized against the existing set of basis vectors. In either
case, if the (shift-invert) computational mode calls for it, the vector
is also forced to be in the range of `OP`.
The LAPACK subroutine `Xlarnv` is used to generate the random vectors.
Subroutine `Xgetv0` is called by `XYaup2` and `XYaitr`.

*Chao Yang*

*11/7/1997*