Support distribution constructor args and enable DirichletCategorical.

[emilyfertig]

This also addresses @ThomasColthurst 's remaining comments from #33 and #40 .

[ThomasColthurst]

Overall, looks very nice!

[ThomasColthurst]

Feel free to delete DistributionAdapter if we aren't using it in your design.

[emilyfertig]

Done.

[ThomasColthurst]

This would be a lot cleaner if it used regular expressions (using Boost.Regex say). For example, that way you could parse out the distribution name and then look it up in a map from names to DistributionEnum values and not have to do it through a chain of if's.

[emilyfertig]

Thanks -- I parsed out the distribution name just using substr and find without regex (if you have ideas as to how to clean it up further using regex let me know, my regex-fu is not very good).

[ThomasColthurst]

I have not tested the following code, but it should be something like

#include <boost/regex.hpp>

boost::regex re{"^(\w+)(?:(((\w+)\s*=\s*(\w+),?)*))?$"};
boost:smatch match;

if (boost::regex_search(dist_str, match, re)) {
string dist_name = match[1];

// First keyword will be in match[2][0] and its value in match[2][1] etc.
}

[ThomasColthurst]

Here and below, printing an error message before aborting would be nice.

[emilyfertig]

Done.

[ThomasColthurst]

Rather than storing this as a DistributionType*, you could store the DistributionSpec and just use cluster_prior_from_spec to generate the new distributions when needed. That way you wouldn't need to add the prior() method to all the distributions.

[emilyfertig]

Thanks for catching that! In an earlier iteration I was storing the whole distribution_args string in DistributionSpec, and I wanted to avoid re-parsing the string every time a new prior instance was needed, but now that DistributionSpec contains an argname/argval map I agree this is better.

[ThomasColthurst]

Could you add a
// TODO(thomaswc): Change BetaBernoulli to use bool's instead of double's.
?

[emilyfertig]

Done, in the BetaBernoulli class. This was on my list of things to get to also.

[ThomasColthurst]

I have not tested the following code, but it should be something like

#include <boost/regex.hpp>

boost::regex re{"^(\w+)(?:(((\w+)\s*=\s*(\w+),?)*))?$"};
boost:smatch match;

if (boost::regex_search(dist_str, match, re)) {
string dist_name = match[1];

// First keyword will be in match[2][0] and its value in match[2][1] etc.
}

[emilyfertig]

I haven't managed to get this working, so I'm going to leave it as-is for now and maybe come back to it (feel free to send a PR if you get around to it too).