  Evolution of entanglement with the processing of quantum algorithms affects
the outcome of the algorithm. Particularly, the performance of Grover's search
algorithm gets worsened if the initial state of the algorithm is an entangled
one. Biham et al [14] have shown that the success probability of search
algorithm can be seen as an operational measure of entanglement. Following the
same line of thought, analytical expressions for entanglement measure for three
and five qubit system have been derived, which reveals that entanglement
measure based on Grover's search algorithm is valid for any state with real
coefficients for even number of qubits.
