Branching in HINT_SEARCH with incomplete hint.

[Samrat Kadge]

Provided an incomplete hint,

1) Will the search tree be started with variables listed in the hint,

similar to PARTIAL_FIXED_SEARCH ?

2) Apart from using larger hint_conflict_limit,

are there are any tips to complete the hint (and quickly)

Context:

I solve a rostering problem using many minizinc globals

e.g global_cardinality, cost_regular, sliding_sum

roster  is my independent variable, all other variables being dependent.

Log details

%% The solution hint is incomplete: 29070 out of 439570 non fixed variables hinted.
%% The solution hint is incomplete: 4152 out of 1908198 non fixed variables hinted.

Thanks,

Samrat

[Laurent Perron]

If there is an incomplete hint, the search starts with hint_search, then after the hint conflict limit switches to the normal search.

You can use the parameter: fix_variables_to_their_hinted_value:true 

Laurent Perron | Operations Research | lpe...@google.com | (33) 1 42 68 53 00

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[Samrat Kadge]

1. I am performing lexicographic optimization, and the solution hint is from the previous stage

(whatever variables are available at the minizinc level)

2. Using fix_variables_to_their_hinted_value:true

%% Fixing 46029 variables to their value in the solution hints.
%% The solution hint is incomplete: 26076 out of 166972 non fixed variables hinted.
%% The solution hint is complete and is feasible. Its objective value is 12973.

(under a minute)

3. I want to start with this solution and find better solutions

4. Is there a similar parameter for a subsolver?

The situation gets worse with every stage of optimization. (upto an hour before a first solution)

Thanks