An apparatus, system, and method are disclosed for interpolating data. A cluster module locates a plurality of variable granularity data clusters within a source data set using a center selection/clustering algorithm. A conversion selection module selects a conversion function for converting each data cluster. A norm selection module selects a norm function for each data cluster. An interpolation module converts each data cluster. In one embodiment, a cross validation module iteratively cross validates and optimizes the data conversions.