feat(tf): support tensor fitting with hybrid descriptor (#4542)

Fix #4527.

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

- **New Features**
	- Added rotation matrix handling methods to descriptor classes.
	- Introduced validation for model initialization.

- **Bug Fixes**
	- Improved error handling for fitting network configuration.

- **Tests**
	- Added new test suite for dipole hybrid descriptor model validation.

- **Refactor**
- Enhanced descriptor class functionality with default rotation matrix
methods.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Signed-off-by: Jinzhe Zeng <[email protected]>

deepmd/tf/descriptor/descriptor.py

@@ -105,7 +105,8 @@ def get_dim_rot_mat_1(self) -> int:
         int
             the first dimension of the rotation matrix
         """
-        raise NotImplementedError
+        # by default, no rotation matrix
+        return 0
 
     def get_nlist(self) -> tuple[tf.Tensor, tf.Tensor, list[int], list[int]]:
         """Returns neighbor information.
@@ -534,3 +535,9 @@ def serialize(self, suffix: str = "") -> dict:
     def input_requirement(self) -> list[DataRequirementItem]:
         """Return data requirements needed for the model input."""
         return []
+
+    def get_rot_mat(self) -> tf.Tensor:
+        """Get rotational matrix."""
+        nframes = tf.shape(self.dout)[0]
+        natoms = tf.shape(self.dout)[1]
+        return tf.zeros([nframes, natoms, 0], dtype=GLOBAL_TF_FLOAT_PRECISION)

deepmd/tf/descriptor/hybrid.py

@@ -492,3 +492,21 @@ def deserialize(cls, data: dict, suffix: str = "") -> "DescrptHybrid":
             if hasattr(ii, "type_embedding"):
                 raise NotImplementedError("hybrid + type embedding is not supported")
         return obj
+
+    def get_dim_rot_mat_1(self) -> int:
+        """Returns the first dimension of the rotation matrix. The rotation is of shape
+        dim_1 x 3.
+
+        Returns
+        -------
+        int
+            the first dimension of the rotation matrix
+        """
+        return sum([ii.get_dim_rot_mat_1() for ii in self.descrpt_list])
+
+    def get_rot_mat(self) -> tf.Tensor:
+        """Get rotational matrix."""
+        all_rot_mat = []
+        for ii in self.descrpt_list:
+            all_rot_mat.append(ii.get_rot_mat())
+        return tf.concat(all_rot_mat, axis=2)

deepmd/tf/model/model.py

@@ -668,6 +668,11 @@ def __init__(
         else:
             if fitting_net["type"] in ["dipole", "polar"]:
                 fitting_net["embedding_width"] = self.descrpt.get_dim_rot_mat_1()
+                if fitting_net["embedding_width"] == 0:
+                    raise ValueError(
+                        "This descriptor cannot provide a rotation matrix "
+                        "for a tensorial fitting."
+                    )
             self.fitting = Fitting(
                 **fitting_net,
                 descrpt=self.descrpt,

source/tests/tf/test_dipole_hybrid_descrpt.py

@@ -0,0 +1,143 @@
+# SPDX-License-Identifier: LGPL-3.0-or-later
+import numpy as np
+
+from deepmd.tf.descriptor.hybrid import (
+    DescrptHybrid,
+)
+from deepmd.tf.env import (
+    tf,
+)
+from deepmd.tf.fit import (
+    DipoleFittingSeA,
+)
+from deepmd.tf.model import (
+    DipoleModel,
+)
+
+from .common import (
+    DataSystem,
+    gen_data,
+    j_loader,
+)
+
+GLOBAL_ENER_FLOAT_PRECISION = tf.float64
+GLOBAL_TF_FLOAT_PRECISION = tf.float64
+GLOBAL_NP_FLOAT_PRECISION = np.float64
+
+
+class TestModel(tf.test.TestCase):
+    def setUp(self) -> None:
+        gen_data()
+
+    def test_model(self) -> None:
+        jfile = "polar_se_a.json"
+        jdata = j_loader(jfile)
+
+        systems = jdata["systems"]
+        set_pfx = "set"
+        batch_size = 1
+        test_size = 1
+        rcut = jdata["model"]["descriptor"]["rcut"]
+
+        data = DataSystem(systems, set_pfx, batch_size, test_size, rcut, run_opt=None)
+
+        test_data = data.get_test()
+        numb_test = 1
+
+        descrpt = DescrptHybrid(
+            list=[
+                {
+                    "type": "se_e2_a",
+                    "sel": [20, 20],
+                    "rcut_smth": 1.8,
+                    "rcut": 6.0,
+                    "neuron": [2, 4, 8],
+                    "resnet_dt": False,
+                    "axis_neuron": 8,
+                    "precision": "float64",
+                    "type_one_side": True,
+                    "seed": 1,
+                },
+                {
+                    "type": "se_e2_a",
+                    "sel": [20, 20],
+                    "rcut_smth": 1.8,
+                    "rcut": 6.0,
+                    "neuron": [2, 4, 8],
+                    "resnet_dt": False,
+                    "axis_neuron": 8,
+                    "precision": "float64",
+                    "type_one_side": True,
+                    "seed": 1,
+                },
+                {
+                    "type": "se_e3",
+                    "sel": [5, 5],
+                    "rcut_smth": 1.8,
+                    "rcut": 2.0,
+                    "neuron": [2],
+                    "resnet_dt": False,
+                    "precision": "float64",
+                    "seed": 1,
+                },
+            ]
+        )
+        jdata["model"]["fitting_net"].pop("type", None)
+        jdata["model"]["fitting_net"].pop("fit_diag", None)
+        jdata["model"]["fitting_net"]["ntypes"] = descrpt.get_ntypes()
+        jdata["model"]["fitting_net"]["dim_descrpt"] = descrpt.get_dim_out()
+        jdata["model"]["fitting_net"]["embedding_width"] = descrpt.get_dim_rot_mat_1()
+        fitting = DipoleFittingSeA(**jdata["model"]["fitting_net"], uniform_seed=True)
+        model = DipoleModel(descrpt, fitting)
+
+        # model._compute_dstats([test_data['coord']], [test_data['box']], [test_data['type']], [test_data['natoms_vec']], [test_data['default_mesh']])
+        input_data = {
+            "coord": [test_data["coord"]],
+            "box": [test_data["box"]],
+            "type": [test_data["type"]],
+            "natoms_vec": [test_data["natoms_vec"]],
+            "default_mesh": [test_data["default_mesh"]],
+            "fparam": [test_data["fparam"]],
+        }
+        model._compute_input_stat(input_data)
+
+        t_prop_c = tf.placeholder(tf.float32, [5], name="t_prop_c")
+        t_coord = tf.placeholder(GLOBAL_TF_FLOAT_PRECISION, [None], name="i_coord")
+        t_type = tf.placeholder(tf.int32, [None], name="i_type")
+        t_natoms = tf.placeholder(tf.int32, [model.ntypes + 2], name="i_natoms")
+        t_box = tf.placeholder(GLOBAL_TF_FLOAT_PRECISION, [None, 9], name="i_box")
+        t_mesh = tf.placeholder(tf.int32, [None], name="i_mesh")
+        is_training = tf.placeholder(tf.bool)
+        t_fparam = None
+
+        model_pred = model.build(
+            t_coord,
+            t_type,
+            t_natoms,
+            t_box,
+            t_mesh,
+            t_fparam,
+            suffix="dipole_hybrid",
+            reuse=False,
+        )
+        dipole = model_pred["dipole"]
+        gdipole = model_pred["global_dipole"]
+        force = model_pred["force"]
+        virial = model_pred["virial"]
+        atom_virial = model_pred["atom_virial"]
+
+        feed_dict_test = {
+            t_prop_c: test_data["prop_c"],
+            t_coord: np.reshape(test_data["coord"][:numb_test, :], [-1]),
+            t_box: test_data["box"][:numb_test, :],
+            t_type: np.reshape(test_data["type"][:numb_test, :], [-1]),
+            t_natoms: test_data["natoms_vec"],
+            t_mesh: test_data["default_mesh"],
+            is_training: False,
+        }
+
+        sess = self.cached_session().__enter__()
+        sess.run(tf.global_variables_initializer())
+        [p, gp, f, v, av] = sess.run(
+            [dipole, gdipole, force, virial, atom_virial], feed_dict=feed_dict_test
+        )