diff --git a/imperative/python/tools/gen_ops.py b/imperative/python/tools/gen_ops.py
index 7fcdb422a8aed5931ef9b28484dae1de7f9d550d..dde93e983423ec477276d6bdeddba853637c6778 100755
--- a/imperative/python/tools/gen_ops.py
+++ b/imperative/python/tools/gen_ops.py
@@ -14,7 +14,6 @@ import os
 import textwrap
 import inspect
 
-
 def camel2underscore(
         name, *,
         first_cap_re=re.compile('([A-Z])([A-Z][a-z]+)'),
@@ -50,9 +49,9 @@ class Context:
     def __init__(self):
         self.fout = StringIO()
         self.indent = 0
-        self.generated = []
         self.skipped = []
         self.generated_signature = set()
+        self.generated_opr = dict()
 
     def write(self, text, *fmt, indent=0):
         text = textwrap.dedent(text)
@@ -181,6 +180,15 @@ class Context:
         :param outputs: the indices of output vars to be selected from raw opr
             result
         """
+
+        class OprItem:
+            def __init__(self, inputs, desc, params, version, has_out_dtype):
+                self.inputs = inputs
+                self.desc = desc
+                self.params = params
+                self.version = version
+                self.has_out_dtype = has_out_dtype
+
         if body:
             self.skipped.append(name)
             return
@@ -197,29 +205,56 @@ class Context:
             params = [('param', params)]
         assert params
 
-        self.write('# %s', caller_lineno())
-        self.write('class %s(PodOpVisitor):', name)
-        self.indent += 1
+        if name in self.generated_opr:
+            org_opr = self.generated_opr[name]
+            if version > org_opr.version:
+                def compare_doc(a, b):
+                    if isinstance(a, str):
+                        return a == b
+                    else:
+                        assert isinstance(a, Doc)
+                        return a.doc == b.doc
+
+                assert compare_doc(desc, org_opr.desc)
+                assert len(inputs) == len(org_opr.inputs)
+                for i, j in zip(inputs, org_opr.inputs):
+                    assert compare_doc(i, j)
+
+                self.generated_opr[name] = OprItem(inputs, desc, params, version, has_out_dtype)
+        else:
+            self.generated_opr[name] = OprItem(inputs, desc, params, version, has_out_dtype)
+
+    def write_generated_oprs(self):
+
+        for opr, opr_item in self.generated_opr.items():
+
+            name = opr
+            params = opr_item.params
+            version = opr_item.version
+            has_out_dtype = opr_item.has_out_dtype
+
+            self.write('# %s', caller_lineno())
+            self.write('class %s(PodOpVisitor):', name)
+            self.indent += 1
 
-        param_names, _ = zip(*params)
-        self.write('param_names = (%s,)', ', '.join(map('"{}"'.format, param_names)))
-        self.write('name = "%s"', '{}V{}'.format(name, version) if version else name)
-        self.write('\n')
+            param_names, _ = zip(*params)
+            self.write('param_names = (%s,)', ', '.join(map('"{}"'.format, param_names)))
+            self.write('name = "%s"', '{}V{}'.format(name, version) if version else name)
+            self.write('\n')
 
-        self.write('def __init__(%s):',
-                    self._gen_signature(params,
-                                        has_out_dtype=has_out_dtype))
-        self.indent += 1
+            self.write('def __init__(%s):',
+                        self._gen_signature(params,
+                                            has_out_dtype=has_out_dtype))
+            self.indent += 1
 
-        self._write_gen_config(has_out_dtype=has_out_dtype)
-        self.write('\n')
+            self._write_gen_config(has_out_dtype=has_out_dtype)
+            self.write('\n')
 
-        self._write_make_params(params)
+            self._write_make_params(params)
 
-        self.write('\n')
-        self.indent -= 2
+            self.write('\n')
+            self.indent -= 2
 
-        self.generated.append(name)
 
     def decl_raw_opr(self, name, *, inputs, inputs_cvt=[], body=None,
                      desc=None, local_defs=[], have_config=True):
@@ -232,7 +267,7 @@ class Context:
         buf = StringIO()
         print(
             '[',
-            *('    "%s",' % i for i in self.generated),
+            *('    "%s",' % i for i in self.generated_opr),
             ']',
             sep='\n',
             file=buf
@@ -259,6 +294,7 @@ def main():
         with open(i) as fin:
             exec(compile(fin.read(), i, 'exec'), exec_globals)
 
+    gen.write_generated_oprs()
     try:
         git_commit = subprocess.check_output(
             ['git', 'rev-parse', 'HEAD'], universal_newlines=True,
diff --git a/src/opr/impl/dnn/dnn.oprdecl b/src/opr/impl/dnn/dnn.oprdecl
index cadc8da0098112f83df5bd88717c36115c6f8c41..af790c39e646b9247882911ed1f371f200674099 100644
--- a/src/opr/impl/dnn/dnn.oprdecl
+++ b/src/opr/impl/dnn/dnn.oprdecl
@@ -95,6 +95,7 @@ r"""
 """))
 
 decl_opr('Local',
+         pyname='local',
          inputs=[Doc('src',
                      'input image in (batch, channel, row, col) format'),
                  Doc('filter',
@@ -105,6 +106,19 @@ decl_opr('Local',
          desc='batched convolution on channeled 2D images, but kernels are '
          'not shared across different output positions')
 
+decl_opr('Local',
+         pyname='local_v1',
+         inputs=[Doc('src',
+                     'input image in (batch, channel, row, col) format'),
+                 Doc('filter',
+                     'convolution kernel in '
+                     '(out row, out col, in channel, '
+                     'kern row, kern col, out channel) format')],
+         params='Convolution',
+         desc='batched convolution on channeled 2D images, but kernels are '
+         'not shared across different output positions',
+         version=1)
+
 decl_opr('GroupLocal',
          inputs=[Doc('src',
                      'input image in (batch, channel, row, col) format'),
@@ -113,7 +127,7 @@ decl_opr('GroupLocal',
                      '(group, out row, out col, in channel / group, '
                      'kern row, kern col, out channel / group) format')],
          params=[('param', 'Convolution')],
-		 desc='batched convolution on groupped channeled 2D images, but '
+         desc='batched convolution on groupped channeled 2D images, but '
          'kernels are not shared across different output positions',
          version=1)