提交 de95e004 authored 作者: Olivier Breuleux's avatar Olivier Breuleux

advanced -> topics

上级 999910f3
......@@ -11,10 +11,9 @@ Contents
LICENSE
introduction
install
numpy
basic_tutorial/index
advanced_tutorial/index
advanced/index
topics/index
indexes/index
glossary
links
......
......@@ -6,30 +6,32 @@ Introduction
============
Theano is a Python library that allows you to define, optimize, and
efficiently evaluate mathematical expressions involving multi-dimensional
arrays. Using Theano, it is not uncommon to see speed improvements of
ten-fold over using pure NumPy.
efficiently evaluate mathematical expressions involving
multi-dimensional arrays. Using Theano, for problems involving large
amounts of data, it is possible to attain speeds that are only a few
percentage points slower than hand-crafted C implementations.
Theano melds some aspects of a computer algebra system (CAS) with
aspects of an optimizing compiler. It can even transform some or
all of the mathematical expression into C code and compile it into
native machine instructions. This combination of CAS with optimizing
compilation is particularly useful for computational fields in which
complicated mathematical expressions are evaluated repeatedly and evaluation
speed is critical.
aspects of an optimizing compiler. It can even transform some or all
of the mathematical expression into C code and compile it into native
machine instructions. This combination of CAS with optimizing
compilation is particularly useful for tasks in which complicated
mathematical expressions are evaluated repeatedly and evaluation speed
is critical.
Theano supports a range of numerical types in multiple dimensions and
a number of well-tested operations. It also allows you to compute the
gradient of an expression with respect to another. Symbolic expressions
may be compiled into functions, which work on the same data structures
as numpy_, allowing for easy interoperability.
gradient of an expression with respect to another. Symbolic
expressions may be compiled into functions, which work on the same
data structures as numpy_, allowing for easy interoperability.
Theano's compiler applies many optimizations of varying complexity
to these symbolic expressions. These optimizations include, but are
not limited to:
Theano's compiler applies many optimizations of varying complexity to
these symbolic expressions. These optimizations include, but are not
limited to:
* constant folding
* merging of similar subgraphs, to avoid calculating the same values more than once
* merging of similar subgraphs, to avoid calculating the same values
more than once
* arithmetic simplification (``x*y/x -> y``)
* inserting efficient BLAS_ operations
* using inplace operations wherever it is safe to do so.
......@@ -37,20 +39,18 @@ not limited to:
Theano defines several optimizations which improve the numerical
stability of computations.
Theano was written at the LISA_ lab to support the development
of efficient machine learning algorithms while minimizing human time. We
use it especially in gradient-based learning techniques.
Theano is named after the `Greek mathematician`_, who may have
been Pythagoras' wife.
Theano is released under a BSD license (:ref:`link <license>`)
Theano was written at the LISA_ lab to support the development of
efficient machine learning algorithms while minimizing human time. We
use it especially in gradient-based learning techniques. Theano is
named after the `Greek mathematician`_, who may have been Pythagoras'
wife. Theano is released under a BSD license (:ref:`link <license>`)
Sneak peek
==========
Here is an example of how to use Theano. It doesn't show
off many of Theano's features, but it illustrates concretely what
Theano is.
Here is an example of how to use Theano. It doesn't show off many of
Theano's features, but it illustrates concretely what Theano is.
.. code-block:: python
......@@ -73,8 +73,8 @@ Theano is.
Theano is not a programming language in the normal sense because you
write a program in Python that builds expressions for Theano. Still
it is like a programming language in the sense that you have to
write a program in Python that builds expressions for Theano. Still it
is like a programming language in the sense that you have to
- declare variables (``a,b``) and give their types
......@@ -119,7 +119,6 @@ Theano is a sort of hybrid of the two which tries to make the best of
both worlds.
Getting started
===============
......@@ -152,8 +151,8 @@ Questions, comments, praise, criticism as well as bug reports should
be submitted to these mailing lists.
We welcome all kinds of contributions. If you have any questions
regarding how to extend Theano, please feel free to ask on the theano-dev_
mailing list.
regarding how to extend Theano, please feel free to ask on the
theano-dev_ mailing list.
......
......@@ -41,6 +41,7 @@ In the example above, there is no way to guarantee that a future call to say,
There following are DebugMode exceptions you might encounter:
BadCLinkerOutput
----------------
......@@ -116,6 +117,7 @@ performed, but the plan is that it will be. (see ticket #320)
For detailed documentation see :api:`FloatError`.
InvalidValueError
-----------------
......@@ -126,6 +128,7 @@ Type.
For detailed documentation see :api:`InvalidValueError`.
DebugModeError
--------------
......
......@@ -9,9 +9,7 @@ Advanced Topics
:maxdepth: 2
pipeline
unittest
profilemode
debug_faq
debugmode
module_vs_op
randomstreams
......
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