Allow error output when calibration is attempted on blocks without update_gradient (SimVascular#193)

Author: federicaninno

src/optimize/calibrate.cpp

@@ -44,7 +44,9 @@ nlohmann::json calibrate(const nlohmann::json& config) {
     std::vector<int> param_ids;
     for (size_t k = 0; k < num_params; k++)
       param_ids.push_back(param_counter++);
-    model.add_block("BloodVessel", param_ids, vessel_name);
+    std::string block_type =
+        vessel_config["zero_d_element_type"].get<std::string>();
+    model.add_block(block_type, param_ids, vessel_name);
     vessel_id_map.insert({vessel_config["vessel_id"], vessel_name});
     DEBUG_MSG("Created vessel " << vessel_name);