fix bug in tests of vm conv2d

tests/vm_impl/vm_me.py

@@ -161,7 +161,7 @@ def col2im(col, input_shape, filter_h, filter_w, stride=1, pad=0):
     elif isinstance(stride, tuple) and len(stride) == 2:
         stride_h = stride[0]
         stride_w = stride[1]
-    elif isinstance(stride, tuple) and len(stride) == 3:
+    elif isinstance(stride, tuple) and len(stride) == 4:
         stride_h = stride[2]
         stride_w = stride[3]
     else:
@@ -328,7 +328,7 @@ def im2col(img, filter_h, filter_w, stride=1, pad=0, dilation=1):
     elif isinstance(stride, tuple) and len(stride) == 2:
         stride_h = stride[0]
         stride_w = stride[1]
-    elif isinstance(stride, tuple) and len(stride) == 3:
+    elif isinstance(stride, tuple) and len(stride) == 4:
         stride_h = stride[2]
         stride_w = stride[3]
     else:
@@ -340,7 +340,7 @@ def im2col(img, filter_h, filter_w, stride=1, pad=0, dilation=1):
     elif isinstance(dilation, tuple) and len(dilation) == 2:
         dilation_h = dilation[0]
         dilation_w = dilation[1]
-    elif isinstance(dilation, tuple) and len(dilation) == 3:
+    elif isinstance(dilation, tuple) and len(dilation) == 4:
         dilation_h = dilation[2]
         dilation_w = dilation[3]
     else: