Add Python API: Measure & Task (apache#7)

* Update the return value of state operation

* Add task

* Copy measure.py & utils.py

* Fix LocalBuilder

* Fix LocalRunner

python/tvm/ansor/__init__.py

@@ -18,3 +18,5 @@
 """Namespace for Ansor autoSchedule"""
 
 from .compute_dag import ComputeDAG
+from .task import SearchTask
+from .measure import MeasureInput, LocalBuilder, LocalRunner

python/tvm/ansor/compute_dag.py

@@ -25,10 +25,56 @@
 from . import _ffi_api
 
 
+class LayoutRewriteLevel(object):
+    NO_REWRITE = 0           # No layout rewrite
+    PLACEHOLDER_REWRITE = 1  # Only rewrite layout of placeholder in the compute dag
+    COMPUTE_REWRITE = 2      # Only rewrite compute body for new layout in the compute dag
+    BOTH_REWRITE = 3         # Rewrite both placeholder and compute body in the compute dag
+
+
 @tvm._ffi.register_object("ansor.ComputeDAG")
 class ComputeDAG(Object):
+    """
+    Parameters
+    ----------
+    tensors : List[Tensor]
+    """
+
     def __init__(self, tensors):
         self.__init_handle_by_constructor__(_ffi_api.ComputeDAG, tensors)
 
-    def get_init_state(self) -> State:
-        return self.init_state
+    def get_init_state(self):
+        """ Get init state of this ComputeDAG
+
+        Returns
+        -------
+        state : State
+        """
+        return _ffi_api.ComputeDAGGetInitState(self)
+
+    def apply_steps_from_state(self, state, layout_rewrite_level):
+        """
+        Parameters
+        ----------
+        state : State
+        layout_rewrite_level : LayoutRewriteLevel(***)
+
+        Returns
+        -------
+        sch : Schedule
+        args : List[Tensor]
+        """
+        sch, args = _ffi_api.ComputeDAGApplyStepsFromState(self, state)
+        return sch, args
+
+    def print_python_code_from_state(self, state):
+        """
+        Parameters
+        ----------
+        state : State
+
+        Returns
+        -------
+        str : Str
+        """
+        return _ffi_api.ComputeDAGPrintPythonCodeFromState(self, state)