1. An adaptive computing integrated circuit configurable to perform a plurality of functions, comprising: a plurality of heterogeneous computational elements; and an interconnection network coupled to the plurality of heterogeneous computational elements, the interconnection network operative to configure the plurality of heterogeneous computational elements by changing interconnections between the plurality of heterogeneous computational elements; wherein a first group of heterogeneous computational elements is configurable by changing the interconnections of the interconnection network to form a first functional unit to implement a first function; wherein a second group of heterogeneous computational elements is configurable by changing interconnections of the interconnection network to form a second functional unit to implement a second function; and wherein if the second function is not currently used, one or more of the second group of heterogeneous computational elements are reconfigurable by changing the interconnections of the interconnection network to implement the first function.