Function optimize_transpose

fem/tensorcoefficient.cpp:756–782

        }

        shared_ptr<CoefficientFunction>
        optimize_transpose(const string& signature,
                           const Array<shared_ptr<CoefficientFunction>>& cfs,
                           [[maybe_unused]] const map<string, bool> &aoptions)
        {
          const auto parts = split_signature(signature);
          if (set<char>{parts[0].begin(), parts[0].end()}.size() != parts[0].size() ||
              set<char>{parts[1].begin(), parts[1].end()}.size() != parts[1].size())
            return {};
          else if (parts[0] == parts[1])
            return cfs[0];
          else if (parts[0].size() == 2)
          {
            cout << IM(5) << "EinsumCF: detected transpose" << endl;
            return TransposeCF(cfs[0]);
          }
          else
          {
            cout << IM(5) << "EinsumCF: detected tensor transpose" << endl;
            Array<int> ordering;
            ordering.SetSize(cfs[0]->Dimensions().Size());
            for (auto i : Range(ordering))
              ordering[i] = parts[1].find(parts[0][i]);
            return MakeTensorTransposeCoefficientFunction(cfs[0],
                                                          std::move(ordering));
          }
        }

        shared_ptr<CoefficientFunction>
        optimize_path(const string &signature,