1. A computer-implemented method for associating multiple domains with a block diagram model, the computer-implemented method comprising: providing a first domain and a second domain within the block diagram model, the first domain comprising one or more nodes having a first function specifying parameters associated with the one or more nodes of the first domain, and the second domain comprising one or more nodes having a second function specifying parameters associated with the one or more nodes of the second domain, the parameters associated with the one or more nodes of the first domain or the parameters associated with the one or more nodes of the second domain specifying solver strategies or solver tolerances to be used in simulating the block diagram model; providing a plurality of partitioning blocks for defining a first region and a second region of the block diagram model; associating the first domain with the first region of the block diagram model; associating the second domain with the second region of the block diagram model; and passing parameters specific to the first domain to the associated first region of the block diagram model using the first function, not passing the parameters specific to the first domain to the second region of the block diagram model.