提交 68f9e435 authored 作者: serdyuk's avatar serdyuk

Merged documentation with docstrings

上级 17146f0c
...@@ -12,99 +12,8 @@ ...@@ -12,99 +12,8 @@
- Functions - Functions
- Function :func:`images2neibs <theano.sandbox.neighbours.images2neibs>` .. autofunction:: theano.tensor.nnet.neighbours.images2neibs
allows to apply a sliding window operation to a tensor containing images
or other two-dimensional objects. The sliding window operation loops
over points in input data and stores a rectangular neighbourhood of each
point. The input `ten4` is a 4-dimensional array which represents a list
of lists of images. The first two dimensions can be
useful to store different channels and batches.
The second input of the function `neib_shape` is a tuple containing two .. autofunction:: theano.tensor.nnet.neighbours.neibs2images
values: height and width of the neighbourhood.
It is possible to assign a step of selecting patches (parameter
`neib_step`). The parameter should be a tuple of two elements: number of
rows and number of columns to skip each iteration. Basically, when the
step is 1, the neighbourhood of every first element is taken and every
possible rectangular subset is returned. By default it is equal to
`neib_shape` in other words, the
patches are disjoint. When the step is greater than `neib_shape`, some
elements are omitted.
.. note:: Currently the step size should be chosen in the way that the
corresponding dimension :math:`i` (width or height) is equal to
:math:`n * step\_size_i + neib\_shape_i` for some :math:`n`
The output can be defined using the following pseudo-code
.. code-block:: python
idx = 0
for i in xrange(list 1 dim):
for j in xrange(list 2 dim):
for k in <image column coordinates>:
for l in <image row coordinates>:
output[idx,:]
= flattened version of ten4[i,j,l:l+r,k:k+c]
idx += 1
.. note:: The operation isn't necessarily implemented internally with
these for loops, they're just the easiest way to describe the output
pattern.
Example:
.. code-block:: python
# Defining variables
images = T.tensor4('images')
neibs = images2neibs(images, neib_shape=(5, 5))
# Constructing theano function
window_function = theano.function([images], neibs)
# Input tensor (one image 10x10)
im_val = np.arange(100.).reshape((1, 1, 10, 10))
# Function application
neibs_val = window_function(im_val)
.. note:: The underlying code will construct a 2D tensor of disjoint
patches 5x5. The output has shape 4x25.
- Function :func:`neibs2images <theano.sandbox.neighbours.neibs2images>`
performs the inverse operation of
:func:`images2neibs <theano.sandbox.neigbours.neibs2images>`. It inputs
the output of :func:`images2neibs <theano.sandbox.neigbours.neibs2images>`,
`neib_shape` -- `neib_shape` that was used in
:func:`images2neibs <theano.sandbox.neigbours.neibs2images>`,
`original_shape` -- original shape of 4d tensor given to
:func:`images2neibs <theano.sandbox.neigbours.neibs2images>`
and reconstructs its input.
.. note:: Currently, the function doesn't support tensors created with
`neib_step` different from default value. This means that it may be
impossible to compute the gradient of a variable gained by
:func:`images2neibs <theano.sandbox.neigbours.neibs2images>` w.r.t.
its inputs in this case because it uses
:func:`images2neibs <theano.sandbox.neigbours.neibs2images>` for
gradient computation.
Example:
.. code-block:: python
im_new = neibs2images(neibs, (5, 5), im_val.shape)
# Theano function definition
inv_window = theano.function([neibs], im_new)
# Function application
im_new_val = inv_window(neibs_val)
.. note:: The code will output the initial image array.
- See also: :ref:`indexing`, :ref:`lib_scan` - See also: :ref:`indexing`, :ref:`lib_scan`
...@@ -448,12 +448,55 @@ def images2neibs(ten4, neib_shape, neib_step=None, mode='valid'): ...@@ -448,12 +448,55 @@ def images2neibs(ten4, neib_shape, neib_step=None, mode='valid'):
idx += 1 idx += 1
.. note:: The operation isn't necessarily implemented internally with .. note:: The operation isn't necessarily implemented internally with
these for loops, they're just the easiest way to describe the output these for loops, they're just the easiest way to describe the
pattern. output pattern.
Function :func:`images2neibs <theano.sandbox.neighbours.images2neibs>`
allows to apply a sliding window operation to a tensor containing
images
or other two-dimensional objects.
The sliding window operation loops
over points in input data and stores a rectangular neighbourhood of
each point. The input `ten4` is a 4-dimensional array which represents
a list of lists of images. The first two dimensions can be
useful to store different channels and batches.
The second input of the function `neib_shape` is a tuple containing two
values: height and width of the neighbourhood.
It is possible to assign a step of selecting patches (parameter
`neib_step`). The parameter should be a tuple of two elements: number of
rows and number of columns to skip each iteration. Basically, when the
step is 1, the neighbourhood of every first element is taken and every
possible rectangular subset is returned. By default it is equal to
`neib_shape` in other words, the
patches are disjoint. When the step is greater than `neib_shape`, some
elements are omitted.
.. note:: Currently the step size should be chosen in the way that the .. note:: Currently the step size should be chosen in the way that the
corresponding dimension :math:`i` (width or height) is equal to corresponding dimension :math:`i` (width or height) is equal to
:math:`n * step\_size_i + neib\_shape_i` for some :math:`n` :math:`n * step\_size_i + neib\_shape_i` for some :math:`n`
Example:
.. code-block:: python
# Defining variables
images = T.tensor4('images')
neibs = images2neibs(images, neib_shape=(5, 5))
# Constructing theano function
window_function = theano.function([images], neibs)
# Input tensor (one image 10x10)
im_val = np.arange(100.).reshape((1, 1, 10, 10))
# Function application
neibs_val = window_function(im_val)
.. note:: The underlying code will construct a 2D tensor of disjoint
patches 5x5. The output has shape 4x25.
""" """
return Images2Neibs(mode)(ten4, neib_shape, neib_step) return Images2Neibs(mode)(ten4, neib_shape, neib_step)
...@@ -475,6 +518,28 @@ def neibs2images(neibs, neib_shape, original_shape, mode='valid'): ...@@ -475,6 +518,28 @@ def neibs2images(neibs, neib_shape, original_shape, mode='valid'):
its inputs in this case because it uses its inputs in this case because it uses
:func:`images2neibs <theano.sandbox.neigbours.neibs2images>` for :func:`images2neibs <theano.sandbox.neigbours.neibs2images>` for
gradient computation. gradient computation.
Function :func:`neibs2images <theano.sandbox.neighbours.neibs2images>`
performs the inverse operation of
:func:`images2neibs <theano.sandbox.neigbours.neibs2images>`. It inputs
the output of :func:`images2neibs <theano.sandbox.neigbours.neibs2images>`,
`neib_shape` -- `neib_shape` that was used in
:func:`images2neibs <theano.sandbox.neigbours.neibs2images>`,
`original_shape` -- original shape of 4d tensor given to
:func:`images2neibs <theano.sandbox.neigbours.neibs2images>`
and reconstructs its input.
Example:
.. code-block:: python
im_new = neibs2images(neibs, (5, 5), im_val.shape)
# Theano function definition
inv_window = theano.function([neibs], im_new)
# Function application
im_new_val = inv_window(neibs_val)
.. note:: The code will output the initial image array.
""" """
neibs = T.as_tensor_variable(neibs) neibs = T.as_tensor_variable(neibs)
neib_shape = T.as_tensor_variable(neib_shape) neib_shape = T.as_tensor_variable(neib_shape)
......
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