Support parallel computing for treeshap function？ #49

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1. mayer79 commented on Apr 24, 2026

   

   mayer79

   on Apr 24, 2026

   Last edited by mayer79

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   The easiest way would be to parallelize the outer for-loop (the one that loops over observations) in the treeshap_cpp() function in https://github.com/ModelOriented/treeshap/blob/master/src/treeshap.cpp:

     for (int obs = 0; obs < x.ncol(); obs++) {
       NumericVector observation = x[obs];
       LogicalVector observation_is_na = is_na[obs];
   
       NumericVector shaps_row(x.nrow());
   
       for (int i = 0; i < roots.size(); ++i) {
         Path m;
         recurse(yes, no, missing, feature, is_leaf, value, cover, split, decision_type, observation, observation_is_na, shaps_row,
                 m, roots[i], 1, 1, -1,
                 0, 0, 1);
       }
   
       shaps(obs, _) = shaps_row;
   
   #if !defined(WIN32) && !defined(__WIN32) && !defined(__WIN32__)
       if (verbose) {
         updateProgressBar(obs + 1, x.ncol());
       }
   #endif
     }

   Maybe one could do that with rcppParallel?
2. mayer79 commented on Apr 24, 2026

   

   mayer79

   on Apr 24, 2026

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   Or we could even move the outer loop outside cpp