1. A computer implemented method of converting a data set of a first type to a data set type of a second type, the computer having a processor and a computer readable media storing code that, when executed, performs the method, the method comprising: casting up a first data set of a first type to a prescribed data set type that is large enough to encompass a data set of a second type, wherein the first data set is stored on the computer readable media; and casting down the casted up first data set from the prescribed data set type to the second data set of the second data set type, wherein the second data set is stored on the computer readable media.