def map_many_values(
root: expression.Expression, parent_path: path.Path,
source_fields: Sequence[path.Step],
operation: Callable[..., tf.Tensor], dtype: tf.DType,
new_field_name: path.Step) -> Tuple[expression.Expression, path.Path]:
"""Map multiple sibling fields into a new sibling.
All source fields must have the same shape, and the shape of the output
must be the same as well.
Args:
root: original root.
parent_path: parent path of all sources and the new field.
source_fields: source fields of the operation. Must have the same shape.
operation: operation from source_fields to new field.
dtype: type of new field.
new_field_name: name of the new field.
Returns:
The new expression and the new path as a pair.
"""
new_path = parent_path.get_child(new_field_name)
return expression_add.add_paths(
root, {
new_path:
_MapValuesExpression([
root.get_descendant_or_error(parent_path.get_child(f))
for f in source_fields
], operation, dtype)
}), new_path
def _broadcast_impl(
root: expression.Expression, origin: path.Path, sibling: path.Step,
new_field_name: path.Step) -> Tuple[expression.Expression, path.Path]:
sibling_path = origin.get_parent().get_child(sibling)
new_expr = _BroadcastExpression(
root.get_descendant_or_error(origin),
root.get_descendant_or_error(origin.get_parent().get_child(sibling)))
new_path = sibling_path.get_child(new_field_name)
return expression_add.add_paths(root, {new_path: new_expr}), new_path
def _promote_impl(
root: expression.Expression, p: path.Path,
new_field_name: path.Step) -> Tuple[expression.Expression, path.Path]:
"""Promotes a path to be a child of its grandparent, and gives it a name.
Args:
root: The root expression.
p: The path to promote. This can be the path to a leaf or child node.
new_field_name: The name of the promoted field.
Returns:
An _AddPathsExpression that wraps a PromoteExpression.
"""
if len(p) < 2:
raise ValueError("Cannot do a promotion beyond the root: {}".format(
str(p)))
parent_path = p.get_parent()
grandparent_path = parent_path.get_parent()
p_expression = root.get_descendant_or_error(p)
new_path = grandparent_path.get_child(new_field_name)
if p_expression.is_leaf:
promote_expression_factory = PromoteExpression
else:
promote_expression_factory = PromoteChildExpression
return expression_add.add_paths(
root, {
new_path:
promote_expression_factory(
p_expression, root.get_descendant_or_error(parent_path))
}), new_path
def slice_expression(expr: expression.Expression, p: path.Path,
new_field_name: path.Step, begin: Optional[IndexValue],
end: Optional[IndexValue]) -> expression.Expression:
"""Creates a new subtree with a sliced expression.
This follows the pattern of python slice() method.
See module-level comments for examples.
Args:
expr: the original root expression
p: the path to the source to be sliced.
new_field_name: the name of the new subtree.
begin: beginning index
end: end index.
Returns:
A new root expression.
"""
work_expr, mask_anonymous_path = _get_slice_mask(expr, p, begin, end)
work_expr = filter_expression.filter_by_sibling(
work_expr, p, mask_anonymous_path.field_list[-1], new_field_name)
new_path = p.get_parent().get_child(new_field_name)
# We created a lot of anonymous fields and intermediate expressions. Just grab
# the final result (and its children).
return expression_add.add_to(expr, {new_path: work_expr})
def filter_by_sibling(expr: expression.Expression, p: path.Path,
sibling_field_name: path.Step,
new_field_name: path.Step) -> expression.Expression:
"""Filter an expression by its sibling.
This is similar to boolean_mask. The shape of the path being filtered and
the sibling must be identical (e.g., each parent object must have an
equal number of source and sibling children).
Args:
expr: the root expression.
p: a path to the source to be filtered.
sibling_field_name: the sibling to use as a mask.
new_field_name: a new sibling to create.
Returns:
a new root.
"""
origin = expr.get_descendant_or_error(p)
parent_path = p.get_parent()
sibling = expr.get_descendant_or_error(
parent_path.get_child(sibling_field_name))
new_expr = _FilterBySiblingExpression(origin, sibling)
new_path = parent_path.get_child(new_field_name)
return expression_add.add_paths(expr, {new_path: new_expr})
def promote_and_broadcast(
root: expression.Expression, path_dictionary: Mapping[path.Step,
path.Path],
dest_path_parent: path.Path) -> expression.Expression:
"""Promote and broadcast a set of paths to a particular location.
Args:
root: the original expression.
path_dictionary: a map from destination fields to origin paths.
dest_path_parent: a map from destination strings.
Returns:
A new expression, where all the origin paths are promoted and broadcast
until they are children of dest_path_parent.
"""
result_paths = {}
# Here, we branch out and create a different tree for each field that is
# promoted and broadcast.
for field_name, origin_path in path_dictionary.items():
result_path = dest_path_parent.get_child(field_name)
new_root = _promote_and_broadcast_name(root, origin_path,
dest_path_parent, field_name)
result_paths[result_path] = new_root
# We create a new tree that has all of the generated fields from the older
# trees.
return expression_add.add_to(root, result_paths)
def _get_leaf_node_path(p: path.Path, t: prensor.Prensor) -> _LeafNodePath:
"""Creates a _LeafNodePath to p."""
leaf_node = t.get_descendant_or_error(p).node
if not isinstance(leaf_node, prensor.LeafNodeTensor):
raise ValueError("Expected Leaf Node at {} in {}".format(
str(p), str(t)))
if not p:
raise ValueError("Leaf should not be at the root")
# If there is a leaf at the root, this will return a ValueError.
root_node = _as_root_node_tensor(t.node)
# Not the root, not p.
strict_ancestor_paths = [p.prefix(i) for i in range(1, len(p))]
child_node_pairs = [(t.get_descendant_or_error(ancestor).node, ancestor)
for ancestor in strict_ancestor_paths]
bad_struct_paths = [
ancestor for node, ancestor in child_node_pairs
if not isinstance(node, prensor.ChildNodeTensor)
]
if bad_struct_paths:
raise ValueError("Expected ChildNodeTensor at {} in {}".format(
" ".join([str(x) for x in bad_struct_paths]), str(t)))
# This should select all elements: the isinstance is for type-checking.
child_nodes = [
node for node, ancestor in child_node_pairs
if isinstance(node, prensor.ChildNodeTensor)
]
assert len(child_nodes) == len(child_node_pairs)
return _LeafNodePath(root_node, child_nodes, leaf_node)
def get_index_from_end(
t: expression.Expression, source_path: path.Path,
new_field_name: path.Step) -> Tuple[expression.Expression, path.Path]:
"""Gets the number of steps from the end of the array.
Given an array ["a", "b", "c"], with indices [0, 1, 2], the result of this
is [-3,-2,-1].
Args:
t: original expression
source_path: path in expression to get index of.
new_field_name: the name of the new field.
Returns:
The new expression and the new path as a pair.
"""
new_path = source_path.get_parent().get_child(new_field_name)
work_expr, positional_index_path = get_positional_index(
t, source_path, path.get_anonymous_field())
work_expr, size_path = size.size_anonymous(work_expr, source_path)
work_expr = expression_add.add_paths(
work_expr, {
new_path:
_PositionalIndexFromEndExpression(
work_expr.get_descendant_or_error(positional_index_path),
work_expr.get_descendant_or_error(size_path))
})
# Removing the intermediate anonymous nodes.
result = expression_add.add_to(t, {new_path: work_expr})
return result, new_path
def _promote_and_broadcast_name(
root: expression.Expression, origin: path.Path,
dest_path_parent: path.Path,
field_name: path.Step) -> expression.Expression:
new_root, anonymous_path = promote_and_broadcast_anonymous(
root, origin, dest_path_parent)
path_result = dest_path_parent.get_child(field_name)
return expression_add.add_paths(
new_root,
{path_result: new_root.get_descendant_or_error(anonymous_path)})
def _broadcast_impl(
root: expression.Expression, origin: path.Path, sibling: path.Step,
new_field_name: path.Step) -> Tuple[expression.Expression, path.Path]:
"""Broadcasts origin to sibling for an expression."""
sibling_path = origin.get_parent().get_child(sibling)
origin_expression = root.get_descendant_or_error(origin)
broadcast_expression_factory = (_BroadcastExpression
if origin_expression.is_leaf else
_BroadcastChildExpression)
new_expr = broadcast_expression_factory(
origin_expression,
root.get_descendant_or_error(origin.get_parent().get_child(sibling)))
new_path = sibling_path.get_child(new_field_name)
result = expression_add.add_paths(root, {new_path: new_expr})
return result, new_path
def _get_slice_mask(
expr: expression.Expression, p: path.Path, begin: Optional[IndexValue],
end: Optional[IndexValue]) -> Tuple[expression.Expression, path.Path]:
"""Gets a mask for slicing a path.
One way to consider the elements of a path "foo.bar" is as a list of list of
list of elements. Slicing a path slices this doubly nested list of elements,
based upon positions in its parent list. Each parent list has a size, and
there is a beginning and end relative to the elements in that list.
At each path p, there is conceptually a list of...list of elements.
For example, given:
an index with respect to its parent
The range is specified with beginning and an end.
1. If begin is not present, begin_index is implied to be zero.
2. If begin is negative, begin_index is the size of a particular
list + begin
3. If end is not present, end_index is the length of the list + 1.
4. If end is negative, end_index is the length of the list + end
5. If end is non-negative, end_index is end.
The mask is positive for all elements in range(begin_index, end_index), and
negative elsewhere.
The mask returned is a sibling of path p, where for every element in p, there
is a corresponding element in the mask.
Args:
expr: the root expression
p: the path to be sliced
begin: the beginning index
end: the ending index
Returns:
An expression,path pair, where the expression contains all the children in
`expr` and an anonymous field of the mask and the path points to
the mask field.
"""
if begin is None:
if end is None:
raise ValueError("Must specify begin or end.")
return _get_end_mask(expr, p, end)
else:
if end is None:
return _get_begin_mask(expr, p, begin)
work_expr, begin_mask = _get_begin_mask(expr, p, begin)
work_expr, end_mask = _get_end_mask(work_expr, p, end)
return map_values.map_many_values(
work_expr, p.get_parent(),
[x.field_list[-1]
for x in [begin_mask, end_mask]], tf.logical_and, tf.bool,
path.get_anonymous_field())
def _get_mask(
t: expression.Expression, p: path.Path, threshold: IndexValue,
relation: Callable[[tf.Tensor, IndexValue], tf.Tensor]
) -> Tuple[expression.Expression, path.Path]:
"""Gets a mask based on a relation of the index to a threshold.
If the threshold is non-negative, then we create a mask that is true if
the relation(index, threshold) is true.
If the threshold is negative, then we create a mask that is true if
the relation(size - index, threshold) is true.
Args:
t: expression to add the field to.
p: path to create the mask for.
threshold: the cutoff threshold.
relation: tf.less or tf.greater_equal.
Returns:
A boolean mask on the fields to keep on the model.
Raises:
ValueError: if p is not in t.
"""
if t.get_descendant(p) is None:
raise ValueError("Path not found: {}".format(str(p)))
work_expr, index_from_end = index.get_index_from_end(
t, p, path.get_anonymous_field())
work_expr, mask_for_negative_threshold = map_values.map_values_anonymous(
work_expr, index_from_end,
lambda x: relation(x, tf.cast(threshold, tf.int64)), tf.bool)
work_expr, positional_index = index.get_positional_index(
work_expr, p, path.get_anonymous_field())
work_expr, mask_for_non_negative_threshold = map_values.map_values_anonymous(
work_expr, positional_index,
lambda x: relation(x, tf.cast(threshold, tf.int64)), tf.bool)
if isinstance(threshold, int):
if threshold >= 0:
return work_expr, mask_for_non_negative_threshold
return work_expr, mask_for_negative_threshold
else:
def tf_cond_on_threshold(a, b):
return tf.cond(tf.greater_equal(threshold, 0), a, b)
return map_values.map_many_values(work_expr, p.get_parent(), [
x.field_list[-1] for x in
[mask_for_non_negative_threshold, mask_for_negative_threshold]
], tf_cond_on_threshold, tf.bool, path.get_anonymous_field())
def _map_prensor_impl(
root: expression.Expression, root_path: path.Path,
paths_needed: Sequence[path.Path],
operation: Callable[[prensor.Prensor, calculate_options.Options],
prensor.LeafNodeTensor], is_repeated: bool,
dtype: tf.DType,
new_field_name: path.Step) -> Tuple[expression.Expression, path.Path]:
"""Map prensor implementation."""
child_expr = root.get_descendant_or_error(root_path)
sibling_child_expr = project.project(child_expr, paths_needed)
new_field_expr = _MapPrensorExpression(sibling_child_expr, operation,
is_repeated, dtype)
new_path = root_path.get_child(new_field_name)
return expression_add.add_paths(root, {new_path: new_field_expr}), new_path
def test_cmp(self):
self.assertGreater(Path([1]), Path("foo"))
self.assertLess(Path("foo"), Path([1]))
self.assertGreater(Path([1]), Path([0]))
self.assertGreater(create_path("foo.baz"), create_path("foo"))
self.assertGreater(create_path("foo.baz"), create_path("foo.bar"))
self.assertLess(create_path("foo"), create_path("foo.bar"))
self.assertLess(create_path("foo.bar"), create_path("foo.baz"))
self.assertEqual(create_path("foo.baz"), create_path("foo.baz"))
def _size_impl(
root: expression.Expression, source_path: path.Path,
new_field_name: path.Step) -> Tuple[expression.Expression, path.Path]:
if not source_path:
raise ValueError("Cannot get the size of the root.")
if root.get_descendant(source_path) is None:
raise ValueError("Path not found: {}".format(str(source_path)))
parent_path = source_path.get_parent()
new_path = parent_path.get_child(new_field_name)
return expression_add.add_paths(
root, {
new_path:
SizeExpression(root.get_descendant_or_error(source_path),
root.get_descendant_or_error(parent_path))
}), new_path
def _promote_impl(root: expression.Expression, p: path.Path,
new_field_name: path.Step
) -> Tuple[expression.Expression, path.Path]:
if len(p) < 2:
raise ValueError("Cannot do a promotion beyond the root: {}".format(str(p)))
parent_path = p.get_parent()
grandparent_path = parent_path.get_parent()
new_path = grandparent_path.get_child(new_field_name)
return expression_add.add_paths(
root, {
new_path:
PromoteExpression(
root.get_descendant_or_error(p),
root.get_descendant_or_error(parent_path))
}), new_path
def promote_and_broadcast_anonymous(
root: expression.Expression, origin: path.Path,
new_parent: path.Path) -> Tuple[expression.Expression, path.Path]:
"""Promotes then broadcasts the origin until its parent is new_parent."""
least_common_ancestor = origin.get_least_common_ancestor(new_parent)
new_expr, new_path = root, origin
while new_path.get_parent() != least_common_ancestor:
new_expr, new_path = promote.promote_anonymous(new_expr, new_path)
while new_path.get_parent() != new_parent:
new_parent_step = new_parent.field_list[len(new_path) - 1]
new_expr, new_path = broadcast.broadcast_anonymous(
new_expr, new_path, new_parent_step)
return new_expr, new_path
def map_values(root: expression.Expression, source_path: path.Path,
operation: Callable[[tf.Tensor], tf.Tensor], dtype: tf.DType,
new_field_name: path.Step) -> expression.Expression:
"""Map field into a new sibling.
The shape of the output must be the same as the input.
Args:
root: original root.
source_path: source of the operation.
operation: operation from source_fields to new field.
dtype: type of new field.
new_field_name: name of the new field.
Returns:
The new expression.
"""
if not source_path:
raise ValueError('Cannot map the root.')
return map_many_values(root, source_path.get_parent(),
[source_path.field_list[-1]], operation, dtype,
new_field_name)[0]
def get_positional_index(
expr: expression.Expression, source_path: path.Path,
new_field_name: path.Step) -> Tuple[expression.Expression, path.Path]:
"""Gets the positional index.
Given a field with parent_index [0,1,1,2,3,4,4], this returns:
parent_index [0,1,1,2,3,4,4] and value [0,0,1,0,0,0,1]
Args:
expr: original expression
source_path: path in expression to get index of.
new_field_name: the name of the new field.
Returns:
The new expression and the new path as a pair.
"""
new_path = source_path.get_parent().get_child(new_field_name)
return expression_add.add_paths(
expr, {
new_path:
_PositionalIndexExpression(
expr.get_descendant_or_error(source_path))
}), new_path
def filter_by_child(expr: expression.Expression, p: path.Path,
child_field_name: path.Step,
new_field_name: path.Step) -> expression.Expression:
"""Filter an expression by an optional boolean child field.
If the child field is present and True, then keep that parent.
Otherwise, drop the parent.
Args:
expr: the original expression
p: the path to filter.
child_field_name: the boolean child field to use to filter.
new_field_name: the new, filtered version of path.
Returns:
The new root expression.
"""
origin = expr.get_descendant_or_error(p)
child = origin.get_child_or_error(child_field_name)
new_expr = _FilterByChildExpression(origin, child)
new_path = p.get_parent().get_child(new_field_name)
return expression_add.add_paths(expr, {new_path: new_expr})
def map_prensor_to_prensor(root_expr: expression.Expression, source: path.Path,
paths_needed: Sequence[path.Path],
prensor_op: Callable[[prensor.Prensor],
prensor.Prensor],
output_schema: Schema) -> expression.Expression:
r"""Maps an expression to a prensor, and merges that prensor.
For example, suppose you have an op my_op, that takes a prensor of the form:
event
/ \
foo bar
and produces a prensor of the form my_result_schema:
event
/ \
foo2 bar2
If you give it an expression original with the schema:
session
|
event
/ \
foo bar
result = map_prensor_to_prensor(
original,
path.Path(["session","event"]),
my_op,
my_output_schema)
Result will have the schema:
session
|
event--------
/ \ \ \
foo bar foo2 bar2
Args:
root_expr: the root expression
source: the path where the prensor op is applied.
paths_needed: the paths needed for the op.
prensor_op: the prensor op
output_schema: the output schema of the op.
Returns:
A new expression where the prensor is merged.
"""
original_child = root_expr.get_descendant_or_error(source).project(
paths_needed)
prensor_child = _PrensorOpExpression(original_child, prensor_op,
output_schema)
paths_map = {
source.get_child(k): prensor_child.get_child_or_error(k)
for k in prensor_child.known_field_names()
}
result = expression_add.add_paths(root_expr, paths_map)
return result
