The present invention provides a method and apparatus to significantly accelerate the searching process based on the Monte Carlo principle and the lattice model. The containment apparatus can include a fluid container that can be positioned on an exterior surface of the pipe. The constant amplitude control according to the output amplitude control, for instance, gives a feedback of the amplitude value of the pulse output outputted by the power control, obtains a difference value between the feedback value and the set amplitude value, and controls the amplitude value of the pulse output so that the difference value becomes zero.