comments on mpi communicator

src/simulation/messaging/communication/communicators.rs

@@ -13,12 +13,12 @@ use tracing::{debug, info, instrument, span, Level};
 
 use crate::simulation::wire_types::messages::{SimMessage, SyncMessage, TravelTimesMessage};
 
-pub trait Message {
-    fn serialize(&self) -> Vec<u8>;
-    fn deserialize(data: &[u8]) -> Self;
-    fn to(&self) -> u32;
-    fn from(&self) -> u32;
-}
+// pub trait Message {
+//     fn serialize(&self) -> Vec<u8>;
+//     fn deserialize(data: &[u8]) -> Self;
+//     fn to(&self) -> u32;
+//     fn from(&self) -> u32;
+// }
 
 pub trait SimCommunicator {
     fn send_receive_vehicles<F>(
@@ -36,13 +36,13 @@ pub trait SimCommunicator {
         travel_times: HashMap<u64, u32>,
     ) -> Vec<TravelTimesMessage>;
 
-    fn isend_request<M>(&mut self, message: M)
-    where
-        M: Message;
-
-    fn irecv_request<M>(&mut self) -> Vec<M>
-    where
-        M: Message;
+    // fn isend_request<M>(&mut self, message: M)
+    // where
+    //     M: Message;
+    //
+    // fn irecv_request<M>(&mut self) -> Vec<M>
+    // where
+    //     M: Message;
 
     fn barrier(&self);
 
@@ -72,19 +72,19 @@ impl SimCommunicator for DummySimCommunicator {
         vec![TravelTimesMessage::from(travel_times)]
     }
 
-    fn isend_request<M>(&mut self, message: M)
-    where
-        M: Message,
-    {
-        todo!()
-    }
-
-    fn irecv_request<M>(&mut self) -> Vec<M>
-    where
-        M: Message,
-    {
-        todo!()
-    }
+    // fn isend_request<M>(&mut self, message: M)
+    // where
+    //     M: Message,
+    // {
+    //     todo!()
+    // }
+    //
+    // fn irecv_request<M>(&mut self) -> Vec<M>
+    // where
+    //     M: Message,
+    // {
+    //     todo!()
+    // }
 
     fn barrier(&self) {
         info!("Barrier was called on DummySimCommunicator, which doesn't do anything.")
@@ -214,19 +214,19 @@ impl SimCommunicator for ChannelSimCommunicator {
         result
     }
 
-    fn isend_request<M>(&mut self, message: M)
-    where
-        M: Message,
-    {
-        todo!()
-    }
-
-    fn irecv_request<M>(&mut self) -> Vec<M>
-    where
-        M: Message,
-    {
-        todo!()
-    }
+    // fn isend_request<M>(&mut self, message: M)
+    // where
+    //     M: Message,
+    // {
+    //     todo!()
+    // }
+    //
+    // fn irecv_request<M>(&mut self) -> Vec<M>
+    // where
+    //     M: Message,
+    // {
+    //     todo!()
+    // }
 
     fn barrier(&self) {
         self.barrier.wait();
@@ -237,13 +237,19 @@ impl SimCommunicator for ChannelSimCommunicator {
     }
 }
 
-pub struct MpiSimCommunicator<'data, 'scope, 'send_buffer>
+/// We need the send buffer to allow asynchronous communication. More on that can be found here:
+/// https://github.com/rsmpi/rsmpi/discussions/190
+///
+/// To put it in a nutshell: Since we don't know when the message is actually sent, we need to store the requests in this struct.
+/// Since the requests depend on the buffer, the buffer lifetime (`'send_buffer`) must outlive the request lifetime (`'request`).
+/// Thus, the buffer is created before starting the simulation in the controller.
+pub struct MpiSimCommunicator<'data, 'request, 'send_buffer>
 where
-    'send_buffer: 'scope,
+    'send_buffer: 'request,
 {
     pub mpi_communicator: SystemCommunicator,
-    pub scope: &'data LocalScope<'scope>,
-    pub requests: &'data mut RequestCollection<'scope, Vec<u8>>,
+    pub scope: &'data LocalScope<'request>,
+    pub requests: &'data mut RequestCollection<'request, Vec<u8>>,
     pub send_buffer: &'send_buffer Vec<OnceCell<Vec<u8>>>,
     pub send_count: u64,
 }
@@ -349,26 +355,26 @@ where
         messages
     }
 
-    fn isend_request<M>(&mut self, message: M)
-    where
-        M: Message,
-    {
-        let vec = self.send_buffer[self.send_count as usize].get_or_init(|| message.serialize());
-        let req = self
-            .mpi_communicator
-            .process_at_rank(message.to() as Rank)
-            .immediate_send(self.scope, vec);
-        self.requests.add(req);
-        self.send_count += 1;
-    }
-
-    fn irecv_request<M>(&mut self) -> Vec<M>
-    where
-        M: Message,
-    {
-        let (encoded_msg, _status) = self.mpi_communicator.any_process().receive_vec();
-        vec![M::deserialize(&encoded_msg)]
-    }
+    // fn isend_request<M>(&mut self, message: M)
+    // where
+    //     M: Message,
+    // {
+    //     let vec = self.send_buffer[self.send_count as usize].get_or_init(|| message.serialize());
+    //     let req = self
+    //         .mpi_communicator
+    //         .process_at_rank(message.to() as Rank)
+    //         .immediate_send(self.scope, vec);
+    //     self.requests.add(req);
+    //     self.send_count += 1;
+    // }
+    //
+    // fn irecv_request<M>(&mut self) -> Vec<M>
+    // where
+    //     M: Message,
+    // {
+    //     let (encoded_msg, _status) = self.mpi_communicator.any_process().receive_vec();
+    //     vec![M::deserialize(&encoded_msg)]
+    // }
 
     fn barrier(&self) {
         self.mpi_communicator.barrier();