New command: Load trajectory

paths_cli/commands/load_trajectory.py

@@ -0,0 +1,51 @@
+import click
+
+import paths_cli.utils
+from paths_cli.parameters import APPEND_FILE, ENGINE, MULTI_TAG
+from paths_cli import OPSCommandPlugin
+
+
+@click.command(
+    "load-trajectory",
+    short_help="Load an external trajectory file",
+)
+@click.argument('traj_file')
+@click.option(
+    '--top',
+    help=(
+        "Topology file (typically PDB). Only for required "
+        "formats."
+    ),
+    default=None,
+)
+@APPEND_FILE.clicked(required=True)
+@MULTI_TAG.clicked()
+def load_trajectory(traj_file, top, append_file, tag):
+    """Load a trajectory from a file.
+
+    This uses MDTraj under the hood, and can load any file format that
+    MDTraj can. NB: This stores in a format based on OpenMM snapshots.
+    Trajectories loaded this way will work with engines compatible with
+    that input (e.g., GROMACS).
+    """
+    from openpathsampling.engines.openmm.tools import ops_load_trajectory
+    if top:
+        traj = ops_load_trajectory(traj_file, top=top)
+    else:
+        traj = ops_load_trajectory(traj_file)
+
+    storage = APPEND_FILE.get(append_file)
+    storage.save(traj)
+    for tag_name in tag:
+        storage.tags[tag_name] = traj
+
+
+PLUGIN = OPSCommandPlugin(
+    command=load_trajectory,
+    section="Miscellaneous",
+    requires_ops=(1, 6),
+    requires_cli=(0, 4),
+)
+
+if __name__ == "__main__":  # -no-cov-
+    load_trajectory()

paths_cli/tests/commands/test_load_trajectory.py

@@ -0,0 +1,89 @@
+from click.testing import CliRunner
+from contextlib import contextmanager
+import pytest
+from importlib import resources
+from openpathsampling.tests.test_helpers import data_filename
+import openpathsampling as paths
+
+from paths_cli.commands.load_trajectory import *
+
+
+@contextmanager
+def run_load_trajectory(args):
+    runner = CliRunner()
+    with runner.isolated_filesystem():
+        storage = paths.Storage("setup.nc", 'w')
+        storage.close()
+        results = runner.invoke(
+            load_trajectory,
+            args
+        )
+        assert results.exit_code == 0
+        st = paths.Storage("setup.nc", mode='r')
+        assert len(st.trajectories) == 1
+        yield st
+
+
+@pytest.mark.parametrize("with_top", [True, False])
+@pytest.mark.parametrize("with_tag", [True, False])
+def test_load_trajectory_pdb(with_top, with_tag):
+    # test that we can load a PDB file with or without topology; also tests
+    # that the taging works correctly
+    pytest.importorskip("openmm")
+    pytest.importorskip("mdtraj")
+    pdb_path = data_filename("ala_small_traj.pdb")
+    out_file = "setup.nc"
+    args = [
+        pdb_path,
+        '--append-file', out_file,
+    ]
+    if with_top:
+        args.extend(['--top', pdb_path])
+
+    if with_tag:
+        args.extend(['--tag', 'init_snap'])
+
+    with run_load_trajectory(args) as st:
+        traj = st.trajectories[0]
+        assert len(traj) == 10
+        if with_tag:
+            tagged = st.tags['init_snap']
+            assert tagged == traj
+
+def test_load_trajectory_trr():
+    pytest.importorskip("openmm")
+    pytest.importorskip("mdtraj")
+    trr = data_filename("gromacs_engine/project_trr/0000000.trr")
+    gro = data_filename("gromacs_engine/conf.gro")
+    out_file = "setup.nc"
+    args = [
+        trr,
+        '--append-file', out_file,
+        '--top', gro,
+    ]
+    with run_load_trajectory(args) as st:
+        traj = st.trajectories[0]
+        assert len(traj) == 4
+
+def test_load_trajectory_bad_topology():
+    pytest.importorskip("openmm")
+    pytest.importorskip("mdtraj")
+    trr = data_filename("gromacs_engine/project_trr/0000000.trr")
+    pdb = data_filename("tip4p_water.pdb")
+    out_file = "setup.nc"
+    args = [
+        trr,
+        '--append-file', out_file,
+        '--top', pdb,
+    ]
+    runner = CliRunner()
+    with runner.isolated_filesystem():
+        storage = paths.Storage("setup.nc", 'w')
+        storage.close()
+        result = runner.invoke(
+            load_trajectory,
+            args
+        )
+        assert result.exit_code == 1
+        assert "topology" in str(result.exception)
+        assert "same atoms" in str(result.exception)