  In this work we study five Grovers algorithm modifications, where each
iteration is constructed by two generalized Householder reflections, against
inaccuracies in the phases. By using semi-empirical methods, we investigate
various characteristics of the dependence between the probability to find
solution and the phase errors. The first of them is the robustness of the
probability to errors in the phase. The second one is how quickly the
probability falls beyond the stability interval. And finally, the average
success rate of the algorithm when the parameters are in the range of the
highly robust interval. Two of the modifications require usage of the same
Grover operator each iteration and in the other three it differs. Those
semi-empirical methods give us the, tool to make prediction of the quantum
algorithm modifications overall behavior and compare them for even larger
register size
