update success reprod code

Author: HydrogenSulfate

examples/bracket/bracket.py

@@ -17,7 +17,6 @@
 """
 
 import numpy as np
-from paddle import fluid
 
 import ppsci
 from ppsci.utils import config

ppsci/geometry/mesh.py

@@ -348,7 +348,9 @@ def random_boundary_points(self, n, random="pseudo", criteria=None):
             face_points = sample_in_triangle(
                 self.v0[i], self.v1[i], self.v2[i], npoint, random, criteria
             )
-            face_normal = np.tile(self.face_normal[i], [npoint, 1])
+            face_normal = np.tile(self.face_normal[i], [npoint, 1]).astype(
+                paddle.get_default_dtype()
+            )
             valid_area = np.full(
                 [npoint, 1],
                 valid_areas[i] / npoint,

ppsci/utils/expression.py

@@ -65,6 +65,10 @@ def train_forward(
                 else:
                     raise TypeError(f"expr type({type(expr)}) is invalid")
 
+            # put field 'area' into output_dict
+            if "area" in input_dicts[i]:
+                output_dict["area"] = input_dicts[i]["area"]
+
             output_dicts.append(output_dict)
 
             # clear differentiation cache
@@ -104,6 +108,10 @@ def eval_forward(
             else:
                 raise TypeError(f"expr type({type(expr)}) is invalid")
 
+        # put field 'area' into output_dict
+        if "area" in input_dict:
+            output_dict["area"] = input_dict["area"]
+
         # clear differentiation cache
         clear()