fix img_pool maxout doc

python/paddle/trainer_config_helpers/layers.py

@@ -2729,15 +2729,17 @@ def img_pool_layer(input,
 
     ..  math::
 
-        w = 1 + \frac{ceil(input\_width + 2 * padding - pool\_size)}{stride} \\\\
-        h = 1 + \frac{ceil(input\_height + 2 * padding\_y - pool\_size\_y)}{stride\_y}
+        w & = 1 + \\frac{ceil(input\_width + 2 * padding - pool\_size)}{stride}
+
+        h & = 1 + \\frac{ceil(input\_height + 2 * padding\_y - pool\_size\_y)}{stride\_y}
 
     - ceil_mode=False:
 
     ..  math::
 
-        w = 1 + \frac{floor(input\_width + 2 * padding - pool\_size)}{stride} \\\\
-        h = 1 + \frac{floor(input\_height + 2 * padding\_y - pool\_size\_y)}{stride\_y}
+        w & = 1 + \\frac{floor(input\_width + 2 * padding - pool\_size)}{stride}
+
+        h & = 1 + \\frac{floor(input\_height + 2 * padding\_y - pool\_size\_y)}{stride\_y}
 
     The example usage is:
 
@@ -2870,17 +2872,21 @@ def img_pool3d_layer(input,
 
     ..  math::
 
-        w = 1 + \frac{ceil(input\_width + 2 * padding - pool\_size)}{stride} \\\\
-        h = 1 + \frac{ceil(input\_height + 2 * padding\_y - pool\_size\_y)}{stride\_y} \\\\
-        d = 1 + \frac{ceil(input\_depth + 2 * padding\_z - pool\_size\_z)}{stride\_z}
+        w & = 1 + \\frac{ceil(input\_width + 2 * padding - pool\_size)}{stride}
+
+        h & = 1 + \\frac{ceil(input\_height + 2 * padding\_y - pool\_size\_y)}{stride\_y}
+
+        d & = 1 + \\frac{ceil(input\_depth + 2 * padding\_z - pool\_size\_z)}{stride\_z}
 
     - ceil_mode=False:
 
     ..  math::
 
-        w = 1 + \frac{floor(input\_width + 2 * padding - pool\_size)}{stride} \\\\
-        h = 1 + \frac{floor(input\_height + 2 * padding\_y - pool\_size\_y)}{stride\_y} \\\\
-        d = 1 + \frac{floor(input\_depth + 2 * padding\_z - pool\_size\_z)}{stride\_z} \\\\
+        w & = 1 + \\frac{floor(input\_width + 2 * padding - pool\_size)}{stride}
+
+        h & = 1 + \\frac{floor(input\_height + 2 * padding\_y - pool\_size\_y)}{stride\_y}
+
+        d & = 1 + \\frac{floor(input\_depth + 2 * padding\_z - pool\_size\_z)}{stride\_z}
 
     The example usage is:
 
@@ -5437,13 +5443,21 @@ def maxout_layer(input, groups, num_channels=None, name=None, layer_attr=None):
 
 
     .. math::
-       out = \max_k (in[n, k, o_c , s])   \\\\
-       out_{i * s + j} = \max_k in_{  k * o_{c} * s + i * s + j}  \\\\
-       s = \frac{input.size}{ num\_channels}       \\\\
-       o_{c} =\frac{num\_channels}{groups}         \\\\
-       0 \le i < o_{c}                             \\\\
-       0 \le j < s                                 \\\\
-       0 \le k < groups                            \\\\
+
+       out & = \max_k (in[n, k, o_c , s])
+
+       out_{i * s + j} & = \max_k in_{  k * o_{c} * s + i * s + j}
+
+       s & = \\frac{input.size}{ num\_channels}
+
+       o_{c} & = \\frac{num\_channels}{groups}
+
+       0 \le i & < o_{c}
+
+       0 \le j & < s
+
+       0 \le k & < groups
+
 
     The simple usage is: