1. A method for adaptively performing state-to-symbolic transformation in a canonical representation during constrained-random simulation, wherein the canonical representation is used for generating random stimulus that satisfies a set of constraints which are defined over a set of state variables and a set of random variables, the method comprising: using a first canonical representation to generate random stimulus for the constrained-random simulation, wherein the first canonical representation is constructed using the set of random variables and a first subset of the set of state variables; monitoring parameters associated with the constrained-random simulation to obtain monitoring data; determining, based at least on the monitoring data, a second subset of the set of state variables which is different from the first subset of the set of state variables; constructing a second canonical representation using the set of random variables and the second subset of the set of state variables; and using the second canonical representation to generate random stimulus for the constrained-random simulation.