Py keras extension (#3468)

* Added support for building Theano with GPU support.  Added a package
for the libgpuarry libary needed for Theano.

* Added dependency on py-pexpect package which ipython requires.

var/spack/repos/builtin/packages/libgpuarray/package.py

+##############################################################################
+# Copyright (c) 2013-2016, Lawrence Livermore National Security, LLC.
+# Produced at the Lawrence Livermore National Laboratory.
+#
+# This file is part of Spack.
+# Created by Todd Gamblin, tgamblin@llnl.gov, All rights reserved.
+# LLNL-CODE-647188
+#
+# For details, see https://github.com/llnl/spack
+# Please also see the LICENSE file for our notice and the LGPL.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License (as
+# published by the Free Software Foundation) version 2.1, February 1999.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the IMPLIED WARRANTY OF
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the terms and
+# conditions of the GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+##############################################################################
+from spack import *
+
+
+class Libgpuarray(CMakePackage):
+    """Make a common GPU ndarray(n dimensions array) that can be reused by all
+    projects that is as future proof as possible, while keeping it easy to use
+    for simple need/quick test."""
+
+    homepage = "http://deeplearning.net/software/libgpuarray/"
+    url      = "https://github.com/Theano/libgpuarray/archive/v0.6.1.tar.gz"
+
+    version('0.6.2', '7f163bd5f48f399cd6e608ee3d528ee4')
+    version('0.6.1', 'cfcd1b54447f9d55b05514df62c70ae2')
+    version('0.6.0', '98a4ec1b4c8f225f0b89c18b899a000b')
+
+    depends_on('cuda')
+
+    extends('python')

var/spack/repos/builtin/packages/py-ipython/package.py

@@ -53,6 +53,7 @@ class PyIpython(PythonPackage):
     depends_on('py-prompt-toolkit@1.0.4:1.999', type=('build', 'run'))
     depends_on('py-traitlets@4.2:',             type=('build', 'run'))
     depends_on('py-decorator',                  type=('build', 'run'))
+    depends_on('py-pexpect',                    type=('build', 'run'))
 
     depends_on('py-appnope', type=('build', 'run'),
                     when=sys.platform == 'darwin' and

var/spack/repos/builtin/packages/py-theano/package.py

@@ -34,12 +34,20 @@ class PyTheano(PythonPackage):
 
     version('0.8.2', 'f2d0dfe7df141115201077cd933b2c52')
 
+    variant('gpu', default=False, 
+            description='Builds with support for GPUs via CUDA and cuDNN')
+
     depends_on('python@2.6:2.8,3.3:')
 
     depends_on('py-setuptools', type='build')
     depends_on('py-scipy@0.11:', type=('build', 'run'))
     depends_on('py-numpy@1.7.1:', type=('build', 'run'))
     depends_on('py-six@1.9.0:', type=('build', 'run'))
+
+    depends_on('blas')
+
+    depends_on('cuda', when='+gpu')
+    depends_on('libgpuarray', when='+gpu')
     # test requirements
     # depends_on('py-nose@1.3.0:', type=('build', 'run'))
     # depends_on('py-nose-parameterized@0.5.0:', type=('build', 'run'))