Sync Paddle DPA3 with dpmodel: add default_chg_spin, rename fparam to charge_spin

Co-authored-by: HydrogenSulfate <23737287+HydrogenSulfate@users.noreply.github.com>

Author: Copilot

deepmd/pd/model/descriptor/dpa3.py

@@ -122,6 +122,7 @@ def __init__(
         use_loc_mapping: bool = True,
         type_map: list[str] | None = None,
         add_chg_spin_ebd: bool = False,
+        default_chg_spin: list[float] | None = None,
     ) -> None:
         super().__init__()
 
@@ -177,6 +178,11 @@ def init_subclass_params(sub_data: dict | Any, sub_class: type) -> Any:
 
         self.use_econf_tebd = use_econf_tebd
         self.add_chg_spin_ebd = add_chg_spin_ebd
+        if default_chg_spin is not None and len(default_chg_spin) != 2:
+            raise ValueError(
+                "default_chg_spin must have exactly 2 values [charge, spin]"
+            )
+        self.default_chg_spin = default_chg_spin
         self.use_loc_mapping = use_loc_mapping
         self.use_tebd_bias = use_tebd_bias
         self.type_map = type_map
@@ -447,6 +453,18 @@ def get_stat_mean_and_stddev(
         stddev_list = [self.repflows.stddev]
         return mean_list, stddev_list
 
+    def get_dim_chg_spin(self) -> int:
+        """Returns the dimension of charge_spin input."""
+        return 2 if self.add_chg_spin_ebd else 0
+
+    def has_default_chg_spin(self) -> bool:
+        """Returns whether default charge_spin values are set."""
+        return self.default_chg_spin is not None
+
+    def get_default_chg_spin(self) -> list[float] | None:
+        """Returns the default charge_spin values."""
+        return self.default_chg_spin
+
     def serialize(self) -> dict:
         repflows = self.repflows
         data = {
@@ -465,6 +483,7 @@ def serialize(self) -> dict:
             "use_tebd_bias": self.use_tebd_bias,
             "use_loc_mapping": self.use_loc_mapping,
             "add_chg_spin_ebd": self.add_chg_spin_ebd,
+            "default_chg_spin": self.default_chg_spin,
             "type_map": self.type_map,
             "type_embedding": self.type_embedding.embedding.serialize(),
         }
@@ -541,7 +560,7 @@ def forward(
         nlist: paddle.Tensor,
         mapping: paddle.Tensor | None = None,
         comm_dict: list[paddle.Tensor] | None = None,
-        fparam: paddle.Tensor | None = None,
+        charge_spin: paddle.Tensor | None = None,
     ) -> tuple[
         paddle.Tensor,
         paddle.Tensor | None,
@@ -593,11 +612,11 @@ def forward(
             node_ebd_ext = self.type_embedding(extended_atype)
 
         if self.add_chg_spin_ebd:
-            assert fparam is not None
+            assert charge_spin is not None
             assert self.chg_embedding is not None
             assert self.spin_embedding is not None
-            charge = fparam[:, 0].to(dtype=paddle.int64) + 100
-            spin = fparam[:, 1].to(dtype=paddle.int64)
+            charge = charge_spin[:, 0].to(dtype=paddle.int64) + 100
+            spin = charge_spin[:, 1].to(dtype=paddle.int64)
             chg_ebd = self.chg_embedding(charge)
             spin_ebd = self.spin_embedding(spin)
             sys_cs_embd = self.act(