[Frame] supporting partial row on first column and individual column initializers (#160)

addresses issue #156

python/dgl/frame.py

@@ -160,7 +160,7 @@ class Column(object):
             return Column(data)
 
 
-def _default_zero_initializer(shape, dtype, ctx):
+def zero_initializer(shape, dtype, ctx):
     return F.zeros(shape, dtype, ctx)
 
 
@@ -198,16 +198,33 @@ class Frame(MutableMapping):
         # Initializer for empty values. Initializer is a callable.
         # If is none, then a warning will be raised
         # in the first call and zero initializer will be used later.
-        self._initializer = None
+        self._initializers = {}
+        self._default_initializer = None
 
     def _warn_and_set_initializer(self):
         dgl_warning('Initializer is not set. Use zero initializer instead.'
                     ' To suppress this warning, use `set_initializer` to'
                     ' explicitly specify which initializer to use.')
-        self._initializer = _default_zero_initializer
+        self._default_initializer = zero_initializer
 
-    def set_initializer(self, initializer):
-        """Set the initializer for empty values.
+    def get_initializer(self, column=None):
+        """Get the initializer for empty values for the given column.
+
+        Parameters
+        ----------
+        column : str
+            The column
+
+        Returns
+        -------
+        callable
+            The initializer
+        """
+        return self._initializers.get(column, self._default_initializer)
+
+    def set_initializer(self, initializer, column=None):
+        """Set the initializer for empty values, for a given column or all future
+        columns.
 
         Initializer is a callable that returns a tensor given the shape and data type.
 
@@ -215,13 +232,13 @@ class Frame(MutableMapping):
         ----------
         initializer : callable
             The initializer.
+        column : str, optional
+            The column name
         """
-        self._initializer = initializer
-
-    @property
-    def initializer(self):
-        """Return the initializer of this frame."""
-        return self._initializer
+        if column is None:
+            self._default_initializer = initializer
+        else:
+            self._initializers[column] = initializer
 
     @property
     def schemes(self):
@@ -302,11 +319,37 @@ class Frame(MutableMapping):
             raise DGLError('Cannot add column "%s" using column schemes because'
                            ' number of rows is unknown. Make sure there is at least'
                            ' one column in the frame so number of rows can be inferred.' % name)
-        if self.initializer is None:
+        if self.get_initializer(name) is None:
             self._warn_and_set_initializer()
-        init_data = self.initializer((self.num_rows,) + scheme.shape, scheme.dtype, ctx)
+        init_data = self.get_initializer(name)(
+                (self.num_rows,) + scheme.shape, scheme.dtype, ctx)
         self._columns[name] = Column(init_data, scheme)
 
+    def add_rows(self, num_rows):
+        """Add blank rows to this frame.
+
+        For existing fields, the rows will be extended according to their
+        initializers.
+
+        Parameters
+        ----------
+        num_rows : int
+            The number of new rows
+        """
+        self._num_rows += num_rows
+
+        feat_placeholders = {}
+        for key, col in self._columns.items():
+            scheme = col.scheme
+            ctx = F.context(col.data)
+            if self.get_initializer(key) is None:
+                self._warn_and_set_initializer()
+            new_data = self.get_initializer(key)(
+                    (num_rows,) + scheme.shape, scheme.dtype, ctx)
+            feat_placeholders[key] = new_data
+
+        self._append(Frame(feat_placeholders))
+
     def update_column(self, name, data):
         """Add or replace the column with the given name and data.
 
@@ -325,6 +368,14 @@ class Frame(MutableMapping):
                            (self._num_rows, len(col)))
         self._columns[name] = col
 
+    def _append(self, other):
+        # NOTE: `other` can be empty.
+        if len(self._columns) == 0:
+            self._columns = {key: col for key, col in other.items()}
+        else:
+            for key, col in other.items():
+                self._columns[key].extend(col.data, col.scheme)
+
     def append(self, other):
         """Append another frame's data into this frame.
 
@@ -339,13 +390,8 @@ class Frame(MutableMapping):
         """
         if not isinstance(other, Frame):
             other = Frame(other)
-        if len(self._columns) == 0:
-            for key, col in other.items():
-                self._columns[key] = col
-            self._num_rows = other.num_rows
-        else:
-            for key, col in other.items():
-                self._columns[key].extend(col.data, col.scheme)
+
+        self._append(other)
         self._num_rows += other.num_rows
 
     def clear(self):
@@ -416,7 +462,7 @@ class FrameRef(MutableMapping):
         else:
             return len(self._index_data)
 
-    def set_initializer(self, initializer):
+    def set_initializer(self, initializer, column=None):
         """Set the initializer for empty values.
 
         Initializer is a callable that returns a tensor given the shape and data type.
@@ -425,8 +471,10 @@ class FrameRef(MutableMapping):
         ----------
         initializer : callable
             The initializer.
+        column : str, optional
+            The column name
         """
-        self._frame.set_initializer(initializer)
+        self._frame.set_initializer(initializer, column=column)
 
     def index(self):
         """Return the index object.
@@ -605,28 +653,27 @@ class FrameRef(MutableMapping):
             fcol.update(self.index_or_slice(), data, inplace)
 
     def add_rows(self, num_rows):
-        """Add blank rows.
+        """Add blank rows to the underlying frame.
 
         For existing fields, the rows will be extended according to their
         initializers.
 
+        Note: only available for FrameRef that spans the whole column.  The row
+        span will extend to new rows.  Other FrameRefs referencing the same
+        frame will not be affected.
+
         Parameters
         ----------
         num_rows : int
             Number of rows to add
         """
-
-        feat_placeholders = {}
-
-        for key in self._frame:
-            scheme = self._frame[key].scheme
-            ctx = F.context(self._frame[key].data)
-            if self._frame.initializer is None:
-                self._frame._warn_and_set_initializer()
-            new_data = self._frame.initializer((num_rows,) + scheme.shape, scheme.dtype, ctx)
-            feat_placeholders[key] = new_data
-
-        self.append(feat_placeholders)
+        if not self.is_span_whole_column():
+            raise RuntimeError('FrameRef not spanning whole column.')
+        self._frame.add_rows(num_rows)
+        if self.is_contiguous():
+            self._index_data = slice(0, self._index_data.stop + num_rows)
+        else:
+            self._index_data.extend(range(self.num_rows, self.num_rows + num_rows))
 
     def update_rows(self, query, data, inplace):
         """Update the rows.

python/dgl/graph.py

@@ -170,7 +170,6 @@ class DGLGraph(object):
         assert reprs is None
 
         # Initialize feature placeholders if there are features existing
-        if self._node_frame.num_columns > 0 and self._node_frame.num_rows > 0:
         self._node_frame.add_rows(num)
 
     def add_edge(self, u, v, reprs=None):
@@ -194,7 +193,6 @@ class DGLGraph(object):
         assert reprs is None
 
         # Initialize feature placeholders if there are features existing
-        if self._edge_frame.num_columns > 0 and self._edge_frame.num_rows > 0:
         self._edge_frame.add_rows(1)
 
     def add_edges(self, u, v, reprs=None):
@@ -220,7 +218,6 @@ class DGLGraph(object):
         assert reprs is None
 
         # Initialize feature placeholders if there are features existing
-        if self._edge_frame.num_columns > 0 and self._edge_frame.num_rows > 0:
         self._edge_frame.add_rows(len(u))
 
     def clear(self):

tests/pytorch/test_frame.py

@@ -269,6 +269,21 @@ def test_slicing():
     f2_a1[0:2] = 0
     assert U.allclose(f2['a1'], f2_a1)
 
+def test_add_rows():
+    data = Frame()
+    f1 = FrameRef(data)
+    f1.add_rows(4)
+    x = th.randn(1, 4)
+    f1[Index(th.tensor([0]))] = {'x': x}
+    ans = th.cat([x, th.zeros(3, 4)])
+    assert U.allclose(f1['x'], ans)
+    f1.add_rows(4)
+    f1[4:8] = {'x': th.ones(4, 4), 'y': th.ones(4, 5)}
+    ans = th.cat([ans, th.ones(4, 4)])
+    assert U.allclose(f1['x'], ans)
+    ans = th.cat([th.zeros(4, 5), th.ones(4, 5)])
+    assert U.allclose(f1['y'], ans)
+
 if __name__ == '__main__':
     test_create()
     test_column1()
@@ -280,3 +295,4 @@ if __name__ == '__main__':
     test_row3()
     test_sharing()
     test_slicing()
+    test_add_rows()