1. A machine-implemented method for circuit analysis, the method comprising: unrolling a sequential circuit having a feedback loop into a plurality of unrolled circuits; and introducing a spatial correlation via an encoding circuit coupled to the plurality of unrolled circuits for an activity analysis of the sequential circuit, the spatial correlation representing a dependency relationship between logic states of an input to the unrolled sequential circuit and logic states of other signals of the unrolled sequential circuit, wherein joint probability information of multiple signals is propagated by the encoding circuit to introduce the spatial correlation to the input of the unrolled sequential circuit, wherein at least one of the unrolling and introducing is performed by a processor.