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Simplify dense_to_sparse_tensor and indicators_to_sparse_ids, and…
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… fix them to work with inputs of undefined rank.

Add test for `indicators_to_sparse_ids` `dtype` arg.
Small update to `unstack` pydoc.

PiperOrigin-RevId: 157160634
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@tensorflower-gardener
tensorflower-gardener committed May 25, 2017
1 parent 4659e56 commit 8f0d0bd
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Showing 3 changed files with 107 additions and 68 deletions.
125 changes: 68 additions & 57 deletions tensorflow/contrib/layers/python/ops/sparse_ops.py
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Original file line number Diff line number Diff line change
Expand Up @@ -38,21 +38,25 @@ def _multiplier_helper(shape):
return multipliers


def _ignore_value(dtype):
if dtype == dtypes.string:
# Exception due to TF strings are converted to numpy objects by default.
return ""
# NOTE: `as_numpy_dtype` is a property, so with the parentheses this is
# constructing a new numpy object of the given type, which yields the
# default value for that type.
return dtype.as_numpy_dtype()
def _ignore_value_tensor(dtype, ignore_value=None):
"""Create `Tensor` from provided `ignore_value` and `dtype`."""
if ignore_value is None:
if dtype == dtypes.string:
# Exception due to TF strings are converted to numpy objects by default.
ignore_value = ""
else:
# NOTE: `as_numpy_dtype` is a property, so with the parentheses this is
# constructing a new numpy object of the given type, which yields the
# default value for that type.
ignore_value = dtype.as_numpy_dtype()
return math_ops.cast(ignore_value, dtype, name="ignore_value")


def dense_to_sparse_tensor(dense_tensor, ignore_value=None):
"""Converts dense `Tensor` to `SparseTensor`, dropping `ignore_value` cells.
Args:
dense_tensor: A `Tensor`. This must have a statically defined rank.
dense_tensor: A `Tensor`.
ignore_value: Entries in `dense_tensor` equal to this value will be
absent from the return `SparseTensor`. If `None`, default value of
`dense_tensor` dtype will be used (e.g. '' for `str`, 0 for `int`).
Expand All @@ -64,65 +68,72 @@ def dense_to_sparse_tensor(dense_tensor, ignore_value=None):
ValueError: when `dense_tensor`'s rank is `None`.
"""
with ops.name_scope("DenseToSparseTensor"):
dense_t = ops.convert_to_tensor(dense_tensor)
if dense_t.get_shape().ndims is None:
# TODO(b/32318825): Implement dense_to_sparse_tensor for undefined rank.
raise ValueError("dense_tensor.get_shape() should be defined, got None.")
if ignore_value is None:
ignore_value = _ignore_value(dense_t.dtype)
dense_shape = math_ops.cast(array_ops.shape(dense_t), dtypes.int64)
dense_tensor = ops.convert_to_tensor(dense_tensor)
ignore_value = _ignore_value_tensor(dense_tensor.dtype, ignore_value)
indices = array_ops.where(
math_ops.not_equal(dense_t, math_ops.cast(ignore_value, dense_t.dtype)))
index_dims = len(dense_t.get_shape())
# Flattens the tensor and indices for use with gather.
flat_tensor = array_ops.reshape(dense_t, [-1])
flat_indices = indices[:, index_dims - 1]
# Computes the correct flattened indices for 2d (or higher) tensors.
if index_dims > 1:
higher_dims = indices[:, :index_dims - 1]
shape_multipliers = array_ops.stack(
_multiplier_helper(array_ops.unstack(dense_shape)[1:]))
offsets = math_ops.reduce_sum(
math_ops.multiply(higher_dims, shape_multipliers),
reduction_indices=[1])
flat_indices = math_ops.add(flat_indices, offsets)
values = array_ops.gather(flat_tensor, flat_indices)
return sparse_tensor.SparseTensor(indices, values, dense_shape)


# TODO(ptucker): Support integer dtype arg, and cast values back to that.
math_ops.not_equal(dense_tensor, ignore_value), name="indices")
return sparse_tensor.SparseTensor(
indices=indices,
values=array_ops.gather_nd(dense_tensor, indices, name="values"),
dense_shape=array_ops.shape(
dense_tensor, out_type=dtypes.int64, name="dense_shape"))


def indicators_to_sparse_ids(indicators, ignore_value=None, dtype=dtypes.int64):
"""Convert a dense indicator tensor to sparse IDs.
This is commonly used for converting a dense classification label to sparse.
In the following example, we have an input of shape (2, 2, num_classes),
where num_classes=4.
```python
indicators = [
[[0, 0, 1, 0], [0, 0, 0, 0]],
[[1, 0, 1, 1], [0, 0, 1, 0]],
[
[0, 0, 1, 0],
[0, 0, 0, 0]
], [
[1, 0, 1, 1],
[0, 0, 1, 0]
]
]
indicator_to_sparse_ids(indicators) => [
[[2], []],
[[0, 2, 3], [2]],
sparse_ids = indicator_to_sparse_ids(indicators)
```
`sparse_ids` in "jagged" format:
[
[
[2],
[]
], [
[0, 2, 3],
[2]
]
]
`sparse_ids` in `SparseTensor` format:
```python
{
indices: [[0, 0, 1], [1, 0, 0], [1, 0, 1], [1, 0, 2], [1, 1, 0]],
values: [2, 0, 2, 3, 2],
dense_shape: [2, 2, 3]
}
```
Args:
indicators: Dense `Tensor` of shape `(d0, ..., dn, num_classes)`. This must
have a statically defined rank. `ignore_value` values are ignored. For
other values (typically, ones), the index along the last dimension is
returned.
indicators: Dense `Tensor` of shape `(d0, ..., dn, num_classes)`.
`ignore_value` values are ignored. For other values (typically, ones), the
index along the last dimension is returned.
ignore_value: Entries in `indicators` equal to this value will be
absent from the returned `SparseTensor`. If `None`, default value of
`indicators` dtype will be used (e.g. '' for `str`, 0 for `int`).
dtype: Type of result, must be integer type.
Returns:
`tf.int64` `SparseTensor` of shape `(d0, ..., dn, max_num_labels)`,
`SparseTensor` of type `dtype` and shape `(d0, ..., dn, max_num_labels)`,
where `max_num_labels` is the maximum number of non-zero values in any
row (in the example above, row (1, 1) has 3 non-zero values, so the result
shape is (2, 2, 3)). The values of this `SparseTensor` are in the range
`[0, num_classes)` and correspond to the index of non-empty values along
`[0, num_classes)` and correspond to the index of non-ignore values along
the last dimension of `indicators`.
Raises:
Expand All @@ -135,10 +146,9 @@ def indicators_to_sparse_ids(indicators, ignore_value=None, dtype=dtypes.int64):
# Convert indicators to binary ones and zeros. We use int64 since
# SparseTensor requires int64 indices.
indicators = ops.convert_to_tensor(indicators, name="indicators")
if ignore_value is None:
ignore_value = _ignore_value(indicators.dtype)
missing_indicators = math_ops.equal(
indicators, ignore_value, name="missing")
indicators, _ignore_value_tensor(indicators.dtype, ignore_value),
name="missing")
zeros_like_indicators = array_ops.zeros_like(
indicators, dtype=dtypes.int64, name="zeros")
binary_indicators = array_ops.where(
Expand All @@ -149,7 +159,7 @@ def indicators_to_sparse_ids(indicators, ignore_value=None, dtype=dtypes.int64):
# Use cumsum along the last dimension to generate per-row indexes.
# Note that these are 1-based (since 0 indicates missing values), so they're
# off-by-1 from the actual indices. We'll subtract 1 below. Since they're
# off-by-one, the max value is the size of last dimension (i.e.,
# off-by-one, the max value is the size of the last dimension (i.e.,
# last_index + 1).
row_index_indicators = array_ops.where(
missing_indicators, zeros_like_indicators,
Expand All @@ -161,16 +171,17 @@ def indicators_to_sparse_ids(indicators, ignore_value=None, dtype=dtypes.int64):
# Convert to a SparseTensor. The values of this SparseTensor are the last
# indices of our result, and the last indices of this SparseTensor (i.e.,
# the class IDs indicated by `indicators`) are the values of our result, so
# we use unstack/stack to swap them.
# we use tensor slicing and concat to swap them.
sparse_row_index_indicators = dense_to_sparse_tensor(
row_index_indicators, ignore_value=0)
index_columns = array_ops.unstack(
sparse_row_index_indicators.indices, axis=1)
return sparse_tensor.SparseTensor(
indices=array_ops.stack(
index_columns[0:-1] + [sparse_row_index_indicators.values - 1],
axis=1, name="indices"),
values=math_ops.cast(index_columns[-1], dtype=dtype, name="values"),
indices=array_ops.concat((
sparse_row_index_indicators.indices[:, :-1],
array_ops.reshape(sparse_row_index_indicators.values - 1, (-1, 1))
), axis=1, name="indices"),
values=math_ops.cast(
sparse_row_index_indicators.indices[:, -1], dtype=dtype,
name="values"),
dense_shape=array_ops.concat(
(sparse_row_index_indicators.dense_shape[0:-1], result_last_dim),
axis=0, name="dense_shape"))
Expand Down
47 changes: 37 additions & 10 deletions tensorflow/contrib/layers/python/ops/sparse_ops_test.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -116,7 +116,7 @@ def test_dense_to_sparse_tensor_3d(self):
self.assertAllEqual([1, 2, 3, 4, 5, 7, 8, 9], result.values)
self.assertAllEqual([2, 2, 4], result.dense_shape)

def test_dense_to_sparse_tensor_1d_no_shape(self):
def test_dense_to_sparse_tensor_unknown_1d_shape(self):
with self.test_session() as sess:
tensor = array_ops.placeholder(shape=[None], dtype=dtypes.int32)
st = sparse_ops.dense_to_sparse_tensor(tensor)
Expand All @@ -125,7 +125,7 @@ def test_dense_to_sparse_tensor_1d_no_shape(self):
self.assertAllEqual([100, 3], result.values)
self.assertAllEqual([4], result.dense_shape)

def test_dense_to_sparse_tensor_3d_no_shape(self):
def test_dense_to_sparse_tensor_unknown_3d_shape(self):
with self.test_session() as sess:
tensor = array_ops.placeholder(
shape=[None, None, None], dtype=dtypes.int32)
Expand All @@ -140,11 +140,15 @@ def test_dense_to_sparse_tensor_3d_no_shape(self):
self.assertAllEqual([1, 2, 3, 4, 5, 7, 8, 9], result.values)
self.assertAllEqual([2, 2, 4], result.dense_shape)

def test_convert_to_sparse_undef_shape(self):
with self.test_session():
with self.assertRaises(ValueError):
tensor = array_ops.placeholder(dtype=dtypes.int32)
sparse_ops.dense_to_sparse_tensor(tensor)
def test_dense_to_sparse_unknown_rank(self):
ph = array_ops.placeholder(dtype=dtypes.int32)
with self.test_session() as sess:
st = sparse_ops.dense_to_sparse_tensor(ph)
result = sess.run(st, feed_dict={ph: [[1, 2, 0, 0], [3, 4, 5, 0]]})
self.assertAllEqual([[0, 0], [0, 1], [1, 0], [1, 1], [1, 2]],
result.indices)
self.assertAllEqual([1, 2, 3, 4, 5], result.values)
self.assertAllEqual([2, 4], result.dense_shape)


class SparseRowEnvelopeTest(test.TestCase):
Expand Down Expand Up @@ -244,6 +248,20 @@ def test_indicators_to_sparse_ids_3d(self):
), dense_shape=(4, 2, 3),
), sparse_ids.eval())

def test_int16_to_sparse_ids_2d(self):
indicators = (
(0, 0, 1, 0),
(1, 0, 0, 1),
)
sparse_ids = sparse_ops.indicators_to_sparse_ids(
indicators, dtype=dtypes.int16)
with self.test_session():
_assert_sparse_tensor_value(self, sparse_tensor.SparseTensorValue(
indices=((0, 0), (1, 0), (1, 1)),
values=np.array((2, 0, 3), dtype=np.int16),
dense_shape=(2, 2),
), sparse_ids.eval())

def test_indicators_to_sparse_ids_ignore_value(self):
indicators = (
((-1, -1, 10, -1), (-1, -1, -1, -1)),
Expand Down Expand Up @@ -285,7 +303,7 @@ def test_string_indicators_to_sparse_ids_ignore_value(self):
dense_shape=(2, 2, 2),
), sparse_ids.eval())

def test_indicators_to_sparse_ids_unknown_dims(self):
def test_indicators_to_sparse_ids_unknown_3d_shape(self):
indicators_values = (
((0, 0, 1, 0), (0, 0, 0, 0)),
((1, 0, 0, 1), (0, 0, 1, 0)),
Expand All @@ -301,9 +319,18 @@ def test_indicators_to_sparse_ids_unknown_dims(self):
), sparse_ids.eval(feed_dict={indicators: indicators_values}))

def test_indicators_to_sparse_ids_unknown_rank(self):
indicators_values = (
((0, 0, 1, 0), (0, 0, 0, 0)),
((1, 0, 0, 1), (0, 0, 1, 0)),
)
indicators = array_ops.placeholder(dtype=dtypes.int32)
with self.assertRaisesRegexp(ValueError, r'shape.*should be defined'):
sparse_ops.indicators_to_sparse_ids(indicators)
sparse_ids = sparse_ops.indicators_to_sparse_ids(indicators)
with self.test_session():
_assert_sparse_tensor_value(self, sparse_tensor.SparseTensorValue(
indices=((0, 0, 0), (1, 0, 0), (1, 0, 1), (1, 1, 0)),
values=(2, 0, 3, 2),
dense_shape=(2, 2, 2),
), sparse_ids.eval(feed_dict={indicators: indicators_values}))


if __name__ == '__main__':
Expand Down
3 changes: 2 additions & 1 deletion tensorflow/python/ops/array_ops.py
View file
Original file line number Diff line number Diff line change
Expand Up @@ -783,6 +783,7 @@ def parallel_stack(values, name="parallel_stack"):
return gen_array_ops._parallel_concat(
[expand_dims(value, 0) for value in values], shape=output_shape)


def stack(values, axis=0, name="stack"):
"""Stacks a list of rank-`R` tensors into one rank-`(R+1)` tensor.
Expand Down Expand Up @@ -944,7 +945,7 @@ def unstack(value, num=None, axis=0, name="unstack"):
`value[:, i, :, :]` and each tensor in `output` will have shape `(A, C, D)`.
Etc.
This is the opposite of pack. The numpy equivalent is
This is the opposite of stack. The numpy equivalent is
tf.unstack(x, n) = list(x)
Expand Down

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