implemented Dist.marginal with list of variables

python/bindings.cpp

@@ -39,6 +39,7 @@ PYBIND11_MODULE(pygin, m) {
             .def("mass", [](const Dist& dist) { return toString(dist.mass()); })
             .def("normalize", &Dist::normalize)
             .def("marginal", [](const Dist& dist, const string& x) {return dist.marginal(x);})
+            .def("marginal", [](const Dist& dist, const std::vector<string>& vars) {return dist.marginal(vars);})
             .def("is_zero", &Dist::isZero)
             .def("is_trivial", &Dist::isTrivial)
             .def("update", &Dist::update)

src/Dist.cpp

@@ -158,12 +158,14 @@ namespace prodigy {
         return Dist{res};
     }
 
-    Dist Dist::marginal(std::initializer_list<std::string> vars) const {
+    Dist Dist::marginal(const std::vector<std::string>& vars) const {
         for (const auto &v : vars) {
             EXPECTS(!isKnownAsParam(v), "given symbol is considered a parameter");
         }
         ex res{_gf};
+        // go over all variables v we currently know
         for (const auto &v : _vars) {
+            // if v is not in the given list vars then project it away
             if (std::find(vars.begin(), vars.end(), v.first) == vars.end()) {
                 res = res.subs(v.second == 1);
             }

src/Dist.h

@@ -144,7 +144,8 @@ namespace prodigy {
          * returns marginal distribution in given variable(s)
          */
         Dist marginal(const std::string& x) const;
-        Dist marginal(std::initializer_list<std::string> vars) const;
+        Dist marginal(const std::vector<std::string>& vars) const;
+        Dist marginal(std::initializer_list<std::string> vars) const { return this->marginal(std::vector<std::string>{vars}); }
 
         /*
          * attempts to prove that *this is the zero distribution (mass 0)