Send slave start dates to master

opm/simulators/flow/ReservoirCouplingMaster.cpp

@@ -50,6 +50,37 @@ ReservoirCouplingMaster::ReservoirCouplingMaster(
 // Public methods
 // ------------------
 
+void ReservoirCouplingMaster::receiveSimulationStartDateFromSlaves() {
+    this->slave_start_dates_.resize(this->num_slaves_);
+    if (this->comm_.rank() == 0) {
+        // Ensure that std::time_t is of type long since we are sending it over MPI with MPI_LONG
+        static_assert(std::is_same<std::time_t, long>::value, "std::time_t is not of type long");
+        for (unsigned int i = 0; i < this->master_slave_comm_.size(); i++) {
+            std::time_t start_date;
+            int result = MPI_Recv(
+                &start_date,
+                /*count=*/1,
+                /*datatype=*/MPI_LONG,
+                /*source_rank=*/0,
+                /*tag=*/static_cast<int>(MessageTag::SimulationStartDate),
+                *this->master_slave_comm_[i].get(),
+                MPI_STATUS_IGNORE
+            );
+            if (result != MPI_SUCCESS) {
+                OPM_THROW(std::runtime_error, "Failed to receive simulation start date from slave process");
+            }
+            this->slave_start_dates_[i] = start_date;
+            OpmLog::info(
+                fmt::format(
+                    "Received simulation start date from slave process with name: {}. "
+                    "Start date: {}", this->slave_names_[i], start_date
+                )
+            );
+        }
+    }
+    this->comm_.broadcast(this->slave_start_dates_.data(), this->num_slaves_, /*emitter_rank=*/0);
+}
+
 // NOTE: This functions is executed for all ranks, but only rank 0 will spawn
 //   the slave processes
 void ReservoirCouplingMaster::spawnSlaveProcesses(int argc, char **argv) {
@@ -101,6 +132,7 @@ void ReservoirCouplingMaster::spawnSlaveProcesses(int argc, char **argv) {
         );
         this->master_slave_comm_.push_back(std::move(master_slave_comm));
         this->slave_names_.push_back(slave_name);
+        this->num_slaves_++;
     }
 }
 

opm/simulators/flow/ReservoirCouplingMaster.hpp

@@ -34,12 +34,13 @@ namespace Opm {
 
 class ReservoirCouplingMaster {
 public:
+    using MPI_Comm_Ptr = ReservoirCoupling::MPI_Comm_Ptr;
+    using MessageTag = ReservoirCoupling::MessageTag;
 
     ReservoirCouplingMaster(const Parallel::Communication &comm, const Schedule &schedule);
 
     void spawnSlaveProcesses(int argc, char **argv);
-
+    void receiveSimulationStartDateFromSlaves();
-    using MPI_Comm_Ptr = ReservoirCoupling::MPI_Comm_Ptr;
 
 private:
     std::vector<char *> getSlaveArgv(
@@ -52,9 +53,10 @@ private:
 
     const Parallel::Communication &comm_;
     const Schedule& schedule_;
-    // MPI communicators for the slave processes
+    std::size_t num_slaves_ = 0;  // Initially zero, will be updated in spawnSlaveProcesses()
-    std::vector<MPI_Comm_Ptr> master_slave_comm_;
+    std::vector<MPI_Comm_Ptr> master_slave_comm_; // MPI communicators for the slave processes
     std::vector<std::string> slave_names_;
+    std::vector<std::time_t> slave_start_dates_;
 };
 
 } // namespace Opm

opm/simulators/flow/ReservoirCouplingSlave.cpp

@@ -38,17 +38,30 @@ ReservoirCouplingSlave::ReservoirCouplingSlave(
 ) :
     comm_{comm},
     schedule_{schedule}
-{ }
+{
-void ReservoirCouplingSlave::sendSimulationStartDateToMasterProcess() {
+    this->slave_master_comm_ = MPI_Comm_Ptr(new MPI_Comm(MPI_COMM_NULL));
-    // TODO: Implement this function next
+    MPI_Comm_get_parent(this->slave_master_comm_.get());
+    if (*(this->slave_master_comm_) == MPI_COMM_NULL) {
+        OPM_THROW(std::runtime_error, "Slave process is not spawned by a master process");
+    }
+}
 
-    //this->slave_master_comm_ = MPI_Comm_Ptr(new MPI_Comm(MPI_COMM_NULL));
+void ReservoirCouplingSlave::sendSimulationStartDateToMasterProcess() {
-    //MPI_Comm_get_parent(this->slave_master_comm_.get());
+
-    //if (*(this->slave_master_comm_) == MPI_COMM_NULL) {
+    if (this->comm_.rank() == 0) {
-    //    OPM_THROW(std::runtime_error, "Slave process is not spawned by a master process");
+        // Ensure that std::time_t is of type long since we are sending it over MPI with MPI_LONG
-    //}
+        static_assert(std::is_same<std::time_t, long>::value, "std::time_t is not of type long");
-    //MPI_Send(&start_date, 1, MPI_INT, 0, 0, parentcomm);
+        std::time_t start_date = this->schedule_.getStartTime();
-    OpmLog::info("Sent simulation start date to master process");
+        MPI_Send(
+            &start_date,
+            /*count=*/1,
+            /*datatype=*/MPI_LONG,
+            /*dest_rank=*/0,
+            /*tag=*/static_cast<int>(MessageTag::SimulationStartDate),
+            *this->slave_master_comm_
+        );
+        OpmLog::info("Sent simulation start date to master process from rank 0");
+   }
 }
 
 } // namespace Opm

opm/simulators/flow/ReservoirCouplingSlave.hpp

@@ -20,7 +20,7 @@
 #ifndef OPM_RESERVOIR_COUPLING_SLAVE_HPP
 #define OPM_RESERVOIR_COUPLING_SLAVE_HPP
 
-#include <opm/simulators/flow/ReservoirCouplingMaster.hpp>
+#include <opm/simulators/flow/ReservoirCoupling.hpp>
 #include <opm/input/eclipse/Schedule/Schedule.hpp>
 #include <opm/simulators/utils/ParallelCommunication.hpp>
 #include <opm/common/OpmLog/OpmLog.hpp>
@@ -33,7 +33,8 @@ namespace Opm {
 
 class ReservoirCouplingSlave {
 public:
-    using MPI_Comm_Ptr = ReservoirCouplingMaster::MPI_Comm_Ptr;
+    using MPI_Comm_Ptr = ReservoirCoupling::MPI_Comm_Ptr;
+    using MessageTag = ReservoirCoupling::MessageTag;
 
     ReservoirCouplingSlave(const Parallel::Communication &comm, const Schedule &schedule);
     void sendSimulationStartDateToMasterProcess();

opm/simulators/flow/SimulatorFullyImplicitBlackoil.hpp

@@ -218,7 +218,6 @@ public:
             // For now, we require that SLAVES and GRUPMAST are defined at the first
             //  schedule step, so it is enough to check the first step. See the
             //  keyword handlers in opm-common for more information.
-            if (!this->schedule()[0].rescoup.empty()) {
             auto master_mode = this->schedule()[0].rescoup().masterMode();
             if (master_mode) {
                 this->reservoirCouplingMaster_ =
@@ -227,7 +226,7 @@ public:
                         this->schedule()
                     );
                 this->reservoirCouplingMaster_->spawnSlaveProcesses(argc, argv);
-                }
+                this->reservoirCouplingMaster_->receiveSimulationStartDateFromSlaves();
             }
         }
 #endif