Added initialize start values function

include/cosim/algorithm/simulator.hpp

@@ -119,6 +119,11 @@ class simulator : public manipulable
      */
     virtual void start_simulation() = 0;
 
+    /**
+     * Runs fmiXSetINI (4.2.4) functions to initialize variables' start values.
+     */
+    virtual void initialize_start_values() = 0;
+
     /**
      *  Performs a single time step.
      *

src/cosim/algorithm/fixed_step_algorithm.cpp

@@ -151,6 +151,23 @@ class fixed_step_algorithm::impl
 
     void initialize()
     {
+        // FMU's start values are set in "instantiated" state (4.2.4)
+        // Some of the FMUs do not see start values if this is not 
+        // done before fmiXEnterInitializationMode
+        for (auto& s : simulators_) {
+            pool_.submit([&] {
+                s.second.sim->initialize_start_values();
+            });
+        }
+        pool_.wait_for_tasks_to_finish();
+
+        for (auto& s : simulators_) {
+            pool_.submit([&] {
+                s.second.sim->setup(startTime_, stopTime_, std::nullopt);
+            });
+        }
+        pool_.wait_for_tasks_to_finish();
+
         // Run N iterations of the simulators' and functions' step/calculation
         // procedures, where N is the number of simulators in the system,
         // to propagate initial values.
@@ -164,13 +181,6 @@ class fixed_step_algorithm::impl
             calculate_and_transfer();
         }
 
-        for (auto& s : simulators_) {
-            pool_.submit([&] {
-                s.second.sim->setup(startTime_, stopTime_, std::nullopt);
-            });
-        }
-        pool_.wait_for_tasks_to_finish();
-
 
         for (auto& s : simulators_) {
             pool_.submit([&] {

src/cosim/slave_simulator.cpp

@@ -12,6 +12,7 @@
 #include <sstream>
 #include <stdexcept>
 #include <unordered_map>
+#include <iostream>
 
 
 namespace cosim
@@ -216,19 +217,23 @@ class set_variable_cache
         }
     }
 
-    std::pair<gsl::span<value_reference>, gsl::span<const T>> modify_and_get(duration deltaT)
+    std::pair<gsl::span<value_reference>, gsl::span<const T>> modify_and_get(
+        duration deltaT,
+        std::optional<std::function<bool(const value_reference&)>> filter = std::nullopt)
     {
         if (!hasRunModifiers_) {
             for (const auto& entry : modifiers_) {
                 const auto ref = entry.first;
-                auto& arrayIndex = exposedVariables_.at(ref).arrayIndex;
-                if (arrayIndex < 0) {
-                    arrayIndex = references_.size();
-                    assert(references_.size() == values_.size());
-                    references_.emplace_back(ref);
-                    values_.emplace_back(exposedVariables_.at(ref).lastValue);
+                if (!filter || filter && (*filter)(ref)) {
+                    auto& arrayIndex = exposedVariables_.at(ref).arrayIndex;
+                    if (arrayIndex < 0) {
+                        arrayIndex = references_.size();
+                        assert(references_.size() == values_.size());
+                        references_.emplace_back(ref);
+                        values_.emplace_back(exposedVariables_.at(ref).lastValue);
+                    }
+                    values_[arrayIndex] = entry.second(values_[arrayIndex], deltaT);
                 }
-                values_[arrayIndex] = entry.second(values_[arrayIndex], deltaT);
             }
             assert(references_.size() == values_.size());
             hasRunModifiers_ = true;
@@ -518,6 +523,34 @@ class slave_simulator::impl
         return result;
     }
 
+    void initialize_start_values()
+    {
+        auto deltaT = duration::zero();
+        auto filter = [&](variable_type vt) {
+            return [&vt, this](const value_reference &vr) {
+                const auto &vd = this->find_variable_description(vr, vt);
+                /// FMI Specification 2.0.4 - Section 4.2.4
+                return vd.variability != variable_variability::constant &&
+                       vd.causality != variable_causality::input;
+            };
+        };
+
+        const auto [realRefs, realValues] = realSetCache_.modify_and_get(deltaT, filter(variable_type::real));
+        const auto [integerRefs, integerValues] = integerSetCache_.modify_and_get(deltaT, filter(variable_type::integer));
+        const auto [booleanRefs, booleanValues] = booleanSetCache_.modify_and_get(deltaT, filter(variable_type::boolean));
+        const auto [stringRefs, stringValues] = stringSetCache_.modify_and_get(deltaT, filter(variable_type::string));
+
+        slave_->set_variables(
+            gsl::make_span(realRefs),
+            gsl::make_span(realValues),
+            gsl::make_span(integerRefs),
+            gsl::make_span(integerValues),
+            gsl::make_span(booleanRefs),
+            gsl::make_span(booleanValues),
+            gsl::make_span(stringRefs),
+            gsl::make_span(stringValues));
+    }
+
 private:
     void set_variables(duration deltaT)
     {
@@ -803,4 +836,9 @@ step_result slave_simulator::do_step(
 }
 
 
+void slave_simulator::initialize_start_values()
+{
+    return pimpl_->initialize_start_values();
+}
+
 } // namespace cosim

src/cosim/slave_simulator.hpp

@@ -133,6 +133,8 @@ class slave_simulator : public simulator
 
     void do_iteration() override;
 
+    void initialize_start_values() override;
+
     void start_simulation() override;
 
     step_result do_step(

tests/data/msmi/OspSystemStructure_StateInitExample.xml

@@ -7,7 +7,7 @@
         <Simulator name="example" source="../fmi2/StateInitExample.fmu">
             <InitialValues>
                 <InitialValue variable="Parameters.Integrator1_x0">
-                    <Real value="10" />
+                    <Real value="10.0" />
                 </InitialValue>
             </InitialValues>
         </Simulator>

tests/last_value_observer_test.cpp

@@ -93,6 +93,7 @@ int main()
 
         observer->get_real(sim, gsl::make_span(&realInRef, 1), gsl::make_span(&realInValue, 1));
         observer->get_real(sim, gsl::make_span(&realOutRef, 1), gsl::make_span(&realOutValue, 1));
+        std::cout << realInValue << std::endl;
         REQUIRE(std::fabs(realInValue - 2.0) < 1.0e-9);
         REQUIRE(std::fabs(realOutValue - 3.234) < 1.0e-9);
 

tests/state_init_test.cpp

@@ -35,15 +35,15 @@ int main()
         execution.simulate_until(cosim::to_time_point(0.1));
 
         auto sim = entityMaps.simulators.at("example"); 
-        const cosim::value_reference inRef = 2;
-        const cosim::value_reference outRef = 3;
+        const auto inRef = config.system_structure.get_variable_description({"example", "Parameters.Integrator1_x0"}).reference;
+        const auto outRef = config.system_structure.get_variable_description({"example", "Integrator_out1"}).reference;
 
         double initialValue = 0.0;
         double outputValue = 0.0;
         lvObserver->get_real(sim, gsl::make_span(&inRef, 1), gsl::make_span(&initialValue, 1));
         lvObserver->get_real(sim, gsl::make_span(&outRef, 1), gsl::make_span(&outputValue, 1));
 
-        REQUIRE(initialValue == 1.0);
+        REQUIRE(std::fabs(initialValue - 10.0) < 1.0e-9);
         REQUIRE(std::fabs(outputValue - 10.1) < 1.0e-9);
 
     } catch (const std::exception& e) {