BugFix: Agent ID's were not static during host functions.

If agents were created via host agent creation, then accessed via DeviceAgentVector, their HostAgentCreation assigned IDs would be replaced.
FLAMEGPU · Dec 10, 2024 · c3f3574 · c3f3574
1 parent 12811d4
commit c3f3574
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Showing 2 changed files with 36 additions and 3 deletions.
diff --git a/src/flamegpu/runtime/agent/DeviceAgentVector_impl.cu b/src/flamegpu/runtime/agent/DeviceAgentVector_impl.cu
@@ -185,10 +185,10 @@ void DeviceAgentVector_impl::_insert(size_type pos, size_type count) {
             _require(ID_VARIABLE_NAME);
             id_t *h_ptr = static_cast<id_t*>(d->second->getDataPtr());
             for (unsigned int i = pos; i < pos + count; ++i) {
-                // Always assign ID, as AgentVector should reset these to unset, but this saves us checking
-                // if (h_ptr[i] == ID_NOT_SET) {
+                // Do not reassign ID if it has been set during HostAgentCreation
+                if (h_ptr[i] == ID_NOT_SET) {
                     h_ptr[i] = cuda_agent.nextID();
-                // }
+                }
             }
             _changedAfter(ID_VARIABLE_NAME, pos);
         } else {

diff --git a/tests/test_cases/runtime/agent/test_host_agent_creation.cu b/tests/test_cases/runtime/agent/test_host_agent_creation.cu
@@ -787,6 +787,39 @@ TEST(HostAgentCreationTest, AgentID_MultipleAgents) {
     }
     ASSERT_EQ(ids_b.size(), 2 * POP_SIZE);  // No collisions
 }
+FLAMEGPU_INIT_FUNCTION(AgentID_Consistent1) {
+    for (unsigned int i = 0; i < 10; ++i) {
+        auto a = FLAMEGPU->agent("agent").newAgent();
+        a.setVariable<id_t>("id_copy", a.getID());
+    }
+}
+FLAMEGPU_INIT_FUNCTION(AgentID_Consistent2) {
+    DeviceAgentVector v = FLAMEGPU->agent("agent").getPopulationData();
+    for (const auto &a : v) {
+        id_t t1 = a.getID();
+        id_t t2 = a.getVariable<id_t>("id_copy");
+        EXPECT_EQ(t1, t2);
+    }
+}
+TEST(HostAgentCreationTest, AgentID_Consistent) {
+    // PTHeywood found that when agents were created in a host function they would be given an ID
+    // This would then be reassigned, if they were accessed via a DeviceAgentVector in the same host function
+    // This was also present with multiple init functions, as shown in this test.
+    // Pull request #1270
+
+    ModelDescription model("test_agentid");
+    AgentDescription agent = model.newAgent("agent");
+    agent.newVariable<id_t>("id_copy", ID_NOT_SET);
+
+    model.addInitFunction(AgentID_Consistent1);
+    model.addInitFunction(AgentID_Consistent2);
+
+    CUDASimulation sim(model);
+
+    sim.SimulationConfig().steps = 10;
+
+    sim.simulate();
+}
 #ifdef FLAMEGPU_USE_GLM
 FLAMEGPU_STEP_FUNCTION(ArrayVarHostBirthSetGet_glm) {
     auto t = FLAMEGPU->agent("agent_name");