fix(heatconduction): keep the FEniCS JIT cache on the host

engibench/problems/heatconduction2d/shared.py

@@ -27,6 +27,10 @@ def run_container_script(
     shutil.copy(cli_module_path, "templates/engibench/utils")
     shutil.copy(script, "templates/")
 
+    # Keep the FEniCS JIT cache on the host, otherwise every container run recompiles all forms.
+    jit_cache = Path(os.environ.get("SCRATCH") or Path.home(), ".cache", "engibench", "dijitso")
+    jit_cache.mkdir(parents=True, exist_ok=True)
+
     container.run(
         command=[
             "python3",
@@ -39,7 +43,9 @@ def run_container_script(
         mounts=[
             (os.getcwd(), "/home/fenics/shared"),
             (cli_module_path, "/home/fenics/shared/templates/engibench/utils/cli.py"),
+            (str(jit_cache), "/home/fenics/.cache/dijitso"),
         ],
+        env={"DIJITSO_CACHE_DIR": "/home/fenics/.cache/dijitso"},
         stdin=stdin,
     )
     return output_path

tests/test_heatconduction.py

@@ -0,0 +1,21 @@
+from pathlib import Path
+from typing import Any
+
+import pytest
+
+from engibench.problems.heatconduction2d import shared
+from engibench.utils import container
+
+
+def test_run_container_script_mounts_jit_cache(monkeypatch: pytest.MonkeyPatch, tmp_path: Path) -> None:
+    calls: list[dict[str, Any]] = []
+    monkeypatch.setattr(container, "run", lambda **kwargs: calls.append(kwargs))
+    monkeypatch.setenv("SCRATCH", str(tmp_path))
+    monkeypatch.chdir(tmp_path)
+
+    shared.run_container_script("image", Path(shared.__file__), (), "out.txt")
+
+    jit_cache = tmp_path / ".cache" / "engibench" / "dijitso"
+    assert jit_cache.is_dir()
+    assert (str(jit_cache), "/home/fenics/.cache/dijitso") in calls[0]["mounts"]
+    assert calls[0]["env"] == {"DIJITSO_CACHE_DIR": "/home/fenics/.cache/dijitso"}