Thijs van den Berg wrote:
Hahaha the compiler pointed that out! The non-member function get a "const distribution" passed so it needs to const indeed! I think a good place for a validation caching mechanism could be in the constructor. The constructor can then set a private bool, and that can be accessed ala "RealType is_valid() const {..};"
This would imply a small change of error reporting. E.g. pdf(dist, x) will have two checks 1) is dist valid? 2) is x valid?
The first check can throw a domain_error telling that the distribution has (some combination) of invalid parameters. The throwing can be done in the pdf function or in the is_valid() member function.. If we put it in the is_valid() member function, then it should maybe be called check_validity(), to make it clearer that it's doing some action. That's probably the best interface. check_validity() can either do a check on all parameters,or lookup a the cached checking result that was stored during the initial checking done in the constructor.
Don't forget that the policy may be for domain errors to return a custom error value - or take some other action - so you would have to store the RealType result of the error checks on the parameters as well as the true/false result.
John, I need to validate the code before you can waste your time on it. I'm currently collecting benchmark values & writing a test file. That should get rid of all the bugs. Paul gave me some good help with going that way (with the test)
Nod. John.