PartialMCTSNode.h

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#pragma once 

#include "MCTSBase.h"

template<typename this_t, typename HYP>
class PartialMCTSNode : public MCTSBase<this_t,HYP> {
    using Super = MCTSBase<this_t,HYP>;
    using Super::Super; // get constructors

    using data_t = typename HYP::data_t;
    
    virtual generator<HYP&> search_one(HYP& current) override {
        if(DEBUG_MCTS) DEBUG("PartialMCTSNode SEARCH ONE ", this, "\t["+current.string()+"] ", (unsigned long)this->nvisits);
    
        auto c = this->descend_to_childless(current); //sets current and returns the node. 
        
//      DEBUG("descend_to_childless ", this, "\t["+current.string()+"] ");
        
        // if we are a terminal 
        if(current.is_evaluable()) {
            c->process_evaluable(current);
            co_yield current;           
        }
        else {
            // else add the next row of children and choose one to playout
            c->add_children(current); 
            auto idx = c->sample_child_index(current);
            current.expand_to_neighbor(idx); 
            for(auto& h : c->child(idx).playout(current)) { // the difference is that here, we call playout instead of search_one
                co_yield h;
            }
        }
    }

    virtual generator<HYP&> playout(HYP& current) {
        if(current.is_evaluable()) {
            this->process_evaluable(current);
            co_yield current;
        }
        else {
            PriorInference samp(current.get_grammar(), this->data, &current);
            for(auto& h : samp.run(Control(FleetArgs::inner_steps, FleetArgs::inner_runtime, 1, FleetArgs::inner_restart))){
                co_yield h;
                this->add_sample(h.posterior);
            }
        }
    }   
};