How would you measure the size of the difference between the source code in the patent an the source code in an alleged patent-violating piece of code? If you

How would you measure the size of the difference between the source code in the patent an the source code in an alleged patent-violating piece of code? If you were to require that the patent code and the alleged patent-violating source code were defined functionally and represented the exact same function (prove f(x) = g(x)), that would cut down the space of potential patent violations, but patent holders would scream that such a limitation is unfair. There would still be plenty of silly patents that would be patentable, and the same problems would exist as with the existing system: if you read patents to see whether your code violates one of them, you're on the hook for more damages. In any case where exact behavior is not critical, someone might be able to get around patents simply by changing the mechanism/computation slightly. I'm thinking of things like mpeg patents, where encoding and decoding techniques are constantly being tweaked, improved, and getting new settings. Would allowing an additional input to a function f(a, b, c, ..., m), i.e. f(a, b, c, ..., m, n) render it immune to a patent that hardcodes n as "5" in the function?