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Applies a function or op to a number of partially flattened inputs.
tf.contrib.framework.nest.map_structure_up_to(
shallow_tree,
func,
*inputs,
**kwargs
)
The inputs
are flattened up to shallow_tree
before being mapped.
Use Case:
Sometimes we wish to apply a function to a partially flattened
sequence (for example when the function itself takes sequence inputs). We
achieve this by specifying a shallow structure, shallow_tree
we wish to
flatten up to.
The inputs
, can be thought of as having the same structure layout as
shallow_tree
, but with leaf nodes that are themselves tree structures.
This function therefore will return something with the same base structure as
shallow_tree
.
Examples:
shallow_tree = [None, None]
inp_val = [1, 2, 3]
out = map_structure_up_to(shallow_tree, lambda x: 2 * x, inp_val)
# Output is: [2, 4]
ab_tuple = collections.namedtuple("ab_tuple", "a, b")
op_tuple = collections.namedtuple("op_tuple", "add, mul")
inp_val = ab_tuple(a=2, b=3)
inp_ops = ab_tuple(a=op_tuple(add=1, mul=2), b=op_tuple(add=2, mul=3))
out = map_structure_up_to(inp_val, lambda val, ops: (val + ops.add) * ops.mul,
inp_val, inp_ops)
# Output is: ab_tuple(a=6, b=15)
data_list = [[2, 4, 6, 8], [[1, 3, 5, 7, 9], [3, 5, 7]]]
name_list = ['evens', ['odds', 'primes']]
out = map_structure_up_to(
name_list,
lambda name, sec: "first_{}_{}".format(len(sec), name),
name_list, data_list)
# Output is: ['first_4_evens', ['first_5_odds', 'first_3_primes']]
Args:
shallow_tree
: a shallow tree, common to all the inputs.func
: callable which will be applied to each input individually.*inputs
: arbitrarily nested combination of objects that are compatible with shallow_tree. The functionfunc
is applied to corresponding partially flattened elements of each input, so the function must support arity oflen(inputs)
.**kwargs
: kwargs to feed to func(). Special kwargcheck_types
is not passed to func, but instead determines whether the types of iterables within the structures have to be same (e.g.map_structure(func, [1], (1,))
raises aTypeError
exception). To allow this set this argument toFalse
.
Raises:
TypeError
: Ifshallow_tree
is a sequence butinput_tree
is not.TypeError
: If the sequence types ofshallow_tree
are different frominput_tree
.ValueError
: If the sequence lengths ofshallow_tree
are different frominput_tree
.
Returns:
result of repeatedly applying func
, with the same structure layout as
shallow_tree
.