Defining length

In genetic algorithms and genetic programming defining length L(H) is the maximum distance between two defining (i.e. non-#) symbols in schema H. In tree GP schemata, L(H) is the number of links in the minimum tree fragment including all the non-= symbols within a schema H.

Example: Schemata "00##0", "1###1", "01###", and "##0##" have defining lengths of 4, 4, 1, and 0, respectively. Lengths are computed by determining the last fixed position and subtracting it from the first fixed position.