  We present a hybrid model of the unitary-evolution-based quantum computation
model and the measurement-based quantum computation model. In the hybrid model
part of a quantum circuit is simulated by unitary evolution and the rest by
measurements on star graph states, thereby combining the advantages of the two
standard quantum computation models. In the hybrid model, a complicated unitary
gate under simulation is decomposed in terms of a sequence of single-qubit
operations, the controlled-Z gates, and multi-qubit rotations around the
z-axis. Every single-qubit- and the controlled-Z gate are realized by a
respective unitary evolution, and every multi-qubit rotation is executed by a
single measurement on a required star graph state. The classical information
processing in our model only needs an information flow vector and propagation
matrices. We provide the implementation of multi-control gates in the hybrid
model. They are very useful for implementing Grover's search algorithm, which
is studied as an illustrating example.
