优化雅可比矩阵计算；端口转发情况下仿真结果传输方式优化

app/simulation/native_codegen/runner.py

@@ -41,6 +41,11 @@ def execute_native(build: NativeBuild, config: SolveIVPConfig, sample_step: floa
         command.append("--solve-only")
     creationflags = subprocess.CREATE_NO_WINDOW if os.name == "nt" else 0
     started = time.perf_counter()
+    # A fast worker may finish before the monitor's first iteration. Honor a
+    # cancellation already requested during preparation before spawning it.
+    cancelled_at = started if cancel_check is not None and cancel_check() else None
+    if cancelled_at is not None:
+        cancel_path.write_text("cancel\n", encoding="ascii")
     process = subprocess.Popen(command, cwd=build.executable.parent, stdin=subprocess.DEVNULL,
                                stdout=subprocess.DEVNULL, stderr=subprocess.PIPE,
                                text=True, encoding="utf-8", errors="replace", creationflags=creationflags)
@@ -53,7 +58,6 @@ def execute_native(build: NativeBuild, config: SolveIVPConfig, sample_step: floa
     reader.start()
     if activity_tracker is not None:
         activity_tracker.start_integration(config.t_start)
-    cancelled_at = None
     last_time = config.t_start
     try:
         with (run_dir / "worker.log").open("w", encoding="utf-8") as log: