@hackage vector-space-map0.2.1.1

Data.Map.Vector provides MapVector, a wrapper around Map from containers which supports constant maps, i.e. maps containing only one value. This allows an identity under intersection and an Applicative instance. It also has instances of AdditiveGroup, VectorSpace, InnerSpace, and HasBasis with appropriate value types. Provides operations for addition, subtraction, element-wise operations (through Applicative), scalar multiplication (through VectorSpace), and dot product. Also consider Conal Elliott's total-map package.