Bugs in MHSampler

[datang1992]

@lileicc @cberzan

The current MHSampler implementation fails on the following small example (just a baby version of the hurricane-new):

/**
 * Hurricane 
 * Figure 4.2 in Milch's thesis
 * this one doesnot have deterministic relationship
 */

type City;
type PrepLevel;
type DamageLevel;

random City First ~ UniformChoice({c for City c});

random PrepLevel Prep(City c) ~
  if (First == c) then Categorical({High -> 0.5, Low -> 0.5})
  else case Damage(First) in {
    Severe -> Categorical({High -> 0.9, Low -> 0.1}),
    Mild -> Categorical({High -> 0.1, Low -> 0.9})
  };

random DamageLevel Damage(City c) ~
  case Prep(c) in {
    High -> Categorical({Severe -> 0.2, Mild -> 0.8}),
  Low -> Categorical({Severe -> 0.8, Mild -> 0.2})
  };

distinct City A, B;
distinct PrepLevel Low, High;
distinct DamageLevel Severe, Mild;

obs Damage(First) = Severe;

query First;

In BLOG-0.9, it will have exceptions on this example. Though in BLOG-0.7 no exceptions exist, the output is always incorrect.

[cberzan]

@datang1992 That's because the syntax changed in 0.9. See the updated example/hurricane.blog and let me know if there's any problem.

[datang1992]

@cberzan It's not because the syntax problem. I have updated the latest version and this BLOG problem won't have syntax error in BLOG-0.9 but it will fail on MHSampler saying that some variables are not instantiated.

[lileicc]

It is not because the syntax problem. Da, would you please double check (git diff) the changes to GenericProposal btw 0.7 and 0.9?

On Wed, Aug 20, 2014 at 4:29 PM, Da Tang notifications@github.com wrote:

@cberzan https://github.com/cberzan It's not because the syntax problem. This BLOG problem won't have syntax error in BLOG-0.9 but it will fail on MHSampler saying that some variables are not instantiated.

— Reply to this email directly or view it on GitHub https://github.com/BayesianLogic/blog/issues/301#issuecomment-52859684.