[Relay][VTA] Add ChangeBatch pass (#3656)

* init

* lint

* lint

python/tvm/relay/expr_functor.py

@@ -195,9 +195,10 @@ class ExprMutator(ExprFunctor):
     and reconstructs the AST.
     """
     def visit_function(self, fn):
+        new_params = [self.visit(x) for x in fn.params]
         new_body = self.visit(fn.body)
         return Function(
-            list(fn.params),
+            list(new_params),
             new_body,
             fn.ret_type,
             fn.type_params,
@@ -214,8 +215,8 @@ class ExprMutator(ExprFunctor):
         new_args = [self.visit(arg) for arg in call.args]
         return Call(new_fn, new_args, call.attrs)
 
-    def visit_var(self, rvar):
-        return rvar
+    def visit_var(self, var):
+        return var
 
     def visit_global_id(self, global_var):
         return global_var

python/tvm/relay/transform.py

@@ -14,7 +14,7 @@
 # KIND, either express or implied.  See the License for the
 # specific language governing permissions and limitations
 # under the License.
-# pylint: disable=invalid-name
+# pylint: disable=invalid-name,arguments-differ,no-else-return,unused-argument,missing-docstring
 """
 Relay pass transformation infrastructure.
 """
@@ -22,7 +22,9 @@ import types
 import inspect
 import functools
 
+import tvm
 from tvm._ffi.runtime_ctypes import TVMContext
+from tvm import relay
 from . import _transform
 from .base import RelayNode, register_relay_node
 from .. import nd as _nd
@@ -908,3 +910,40 @@ def function_pass(pass_func=None, opt_level=None, name=None, required=None):
     if pass_func:
         return create_function_pass(pass_func)
     return create_function_pass
+
+@function_pass(opt_level=1)
+class ChangeBatch:
+    """
+    Change the batch size.
+
+    Parameters
+    ----------
+    data: Dict[relay.Var, int]
+      A dictionary of all the params to change.
+      The keys are all params, and the values is which dimension hold the batch.
+
+    batch_size: int
+      The batch size to change to.
+
+    Returns
+    -------
+    pass: FunctionPass
+      The pass.
+    """
+    def __init__(self, data, batch_size=16):
+        self.data = data
+        self.batch_size = batch_size
+
+    def transform_function(self, func, mod, ctx):
+        func = relay.Function(func.params, func.body, None, func.type_params, func.attrs)
+        change_batch = self
+        class ChangeBatchMutator(tvm.relay.ExprMutator):
+            def visit_var(self, var):
+                if var in change_batch.data:
+                    ty = var.type_annotation
+                    new_shape = list(ty.shape)
+                    new_shape[change_batch.data[var]] = change_batch.batch_size
+                    return relay.Var(var.name_hint, relay.TensorType(new_shape, ty.dtype))
+                else:
+                    return var
+        return ChangeBatchMutator().visit(func)

tests/python/relay/test_change_batch.py

+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+import tvm
+from tvm import relay
+from tvm.relay.testing import resnet
+from tvm.relay import transform
+
+def test_change_batch_resnet():
+    net, params = resnet.get_workload()
+    new_net = transform.ChangeBatch({net["main"].params[0]: 0}, batch_size=123)(net)
+    assert new_net["main"].checked_type.ret_type == relay.TensorType((123, 1000))
+
+if __name__ == "__main__":
+    test_change_batch_resnet()