[Fix] Correct desciprtion of epsilon of AllenCahn equation (#911)

* Correct desciprtion of epsilon of AllenCahn equation

* fix seed for test_detach

Author: HydrogenSulfate

docs/zh/api/equation.md

@@ -5,8 +5,9 @@
     options:
       members:
         - PDE
-        - FractionalPoisson
+        - AllenCahn
         - Biharmonic
+        - FractionalPoisson
         - HeatExchanger
         - Laplace
         - LinearElasticity

examples/allen_cahn/allen_cahn_causal.py

@@ -63,7 +63,7 @@ def train(cfg: DictConfig):
     model = ppsci.arch.MLP(**cfg.MODEL)
 
     # set equation
-    equation = {"AllenCahn": ppsci.equation.AllenCahn(0.01**2)}
+    equation = {"AllenCahn": ppsci.equation.AllenCahn(eps=0.01)}
 
     data = sio.loadmat(cfg.DATA_PATH)
     u_ref = data["usol"].astype(dtype)  # (nt, nx)

examples/allen_cahn/allen_cahn_default.py

@@ -64,7 +64,7 @@ def train(cfg: DictConfig):
     model = ppsci.arch.MLP(**cfg.MODEL)
 
     # set equation
-    equation = {"AllenCahn": ppsci.equation.AllenCahn(0.01**2)}
+    equation = {"AllenCahn": ppsci.equation.AllenCahn(eps=0.01)}
 
     # set constraint
     data = sio.loadmat(cfg.DATA_PATH)

examples/allen_cahn/allen_cahn_piratenet.py

@@ -64,7 +64,7 @@ def train(cfg: DictConfig):
     model = ppsci.arch.PirateNet(**cfg.MODEL)
 
     # set equation
-    equation = {"AllenCahn": ppsci.equation.AllenCahn(0.01**2)}
+    equation = {"AllenCahn": ppsci.equation.AllenCahn(eps=0.01)}
 
     # set constraint
     data = sio.loadmat(cfg.DATA_PATH)

examples/allen_cahn/allen_cahn_plain.py

@@ -63,7 +63,7 @@ def train(cfg: DictConfig):
     model = ppsci.arch.MLP(**cfg.MODEL)
 
     # set equation
-    equation = {"AllenCahn": ppsci.equation.AllenCahn(0.01**2)}
+    equation = {"AllenCahn": ppsci.equation.AllenCahn(eps=0.01)}
 
     data = sio.loadmat(cfg.DATA_PATH)
     u_ref = data["usol"].astype(dtype)  # (nt, nx)

ppsci/equation/pde/allen_cahn.py

@@ -60,6 +60,6 @@ def allen_cahn(out):
             u__t, u__x = jacobian(u, [t, x])
             u__x__x = jacobian(u__x, x)
 
-            return u__t - self.eps * u__x__x + 5 * u * u * u - 5 * u
+            return u__t - (self.eps**2) * u__x__x + 5 * u * u * u - 5 * u
 
         self.add_equation("allen_cahn", allen_cahn)

test/equation/test_detach.py

@@ -4,6 +4,9 @@
 
 import ppsci
 
+paddle.seed(42)
+np.random.seed(42)
+
 
 def test_equation_detach():
     # use N-S equation for test