Module Expr Str ImportFrom alias alias alias Assign NameStore Str Assign NameStore Str Assign NameStore Str Assign NameStore Str ImportFrom alias ImportFrom alias ImportFrom alias alias alias alias ImportFrom alias alias
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This module provides the Scan Op.

Scanning is a general form of recurrence, which can be used for looping.
The idea is that you *scan* a function along some input sequence, producing
an output at each time-step that can be seen (but not modified) by the
function at the next time-step. (Technically, the function can see the
previous K  time-steps of your outputs and L time steps (from the past and
future) of your inputs.

So for example, ``sum()`` could be computed by scanning the ``z+x_i``
function over a list, given an initial state of ``z=0``.

Special cases:

* A *reduce* operation can be performed by returning only the last
  output of a ``scan``.
* A *map* operation can be performed by applying a function that
  ignores previous steps of the outputs.

Often a for-loop can be expressed as a ``scan()`` operation, and ``scan`` is
the closest that theano comes to looping. The advantage of using ``scan``
over for loops is that it allows the number of iterations to be a part of
the symbolic graph.

The Scan Op should typically be used by calling any of the following
functions: ``scan()``, ``map()``, ``reduce()``, ``foldl()``,
``foldr()``.

 __future__ absolute_import print_function division N/A __docformat__ restructedtext en N/A __authors__ Razvan Pascanu Frederic Bastien James Bergstra Pascal Lamblin Arnaud Bergeron  N/A __copyright__ (c) 2010, Universite de Montreal N/A __contact__ Razvan Pascanu <r.pascanu@gmail> theano.scan_module scan_opt theano.scan_module.scan scan theano.scan_module.scan_views map reduce foldl foldr theano.scan_module.scan_utils clone until