A computer-implemented method for modeling a target system includes defining a cloned constraint satisfaction problem (CSP) that characterizes the target system in terms of a set of variables and constraints applicable to the variables. The cloned CSP includes a non-predetermined number of duplicate sub-problems corresponding to instances of a repeating feature of the target system. The variables are partitioned so as to define an abstract CSP containing a subset of the variables relating to the duplicate sub-problems. The abstract CSP is solved to generate an abstract solution indicating the number of duplicate sub-problems to use in the cloned CSP. A concrete solution to the cloned CSP is found using the abstract solution.