prompt: You will be provided with a partial code base and an issue statement explaining a problem to resolve.
  <issue>
  Support basic indexing in Variable class
  Currently `Variable` partially supports `__getitem__`. I need full support of basic indexing.
  - [x] int index #1343 
  - [x] slices #1154
  - [x] new axis #1257 
  - [x] elipsis #1343 
  
  see also: http://docs.scipy.org/doc/numpy/reference/arrays.indexing.html#basic-slicing-and-indexing
  
  
  </issue>
  <code>
  [start of chainer/functions/array/get_item.py]
  1 import collections
  2 
  3 from chainer import cuda
  4 from chainer import function
  5 from chainer.utils import type_check
  6 from chainer import variable
  7 
  8 
  9 class GetItem(function.Function):
  10 
  11     """Function that slices array and extract elements."""
  12 
  13     def __init__(self, slices):
  14         if not isinstance(slices, collections.Iterable):
  15             slices = tuple([slices])
  16         self.slices = slices
  17 
  18     def check_type_forward(self, in_types):
  19         type_check.expect(in_types.size() == 1)
  20         valid_slice = len(self.slices) - self.slices.count(None)
  21         type_check.expect(in_types[0].ndim == valid_slice)
  22 
  23     def forward(self, xs):
  24         ary = xs[0]
  25         return ary[tuple(self.slices)],
  26 
  27     def backward(self, xs, gys):
  28         xp = cuda.get_array_module(*xs)
  29         gy = gys[0]
  30         gx = xp.zeros_like(xs[0])
  31         gx[tuple(self.slices)] = gy
  32         return gx,
  33 
  34 
  35 def get_item(x, slices):
  36     """Extract elements from array with specified shape, axes and offsets.
  37 
  38     Args:
  39         x (tuple of Variables): Variable to be sliced.
  40         slices (slice or tuple of slices): Slice objects to slice variable.
  41 
  42     Returns:
  43         Variable: :class:`~chainer.Variable` object
  44             which contains sliced array of ``x``.
  45 
  46     """
  47     return GetItem(slices)(x)
  48 
  49 
  50 def install_variable_get_item():
  51     variable.Variable.__getitem__ = get_item
  52
  [end of chainer/functions/array/get_item.py]
  </code>
  
  I need you to solve this issue by generating a single patch file that I can apply directly to this repository using git apply. Please respond with a single patch file in the following format.
  <patch>
  diff --git a/file.py b/file.py
  --- a/file.py
  +++ b/file.py
  @@ -1,27 +1,35 @@
   def euclidean(a, b):
  -    while b:
  -        a, b = b, a % b
  -    return a
  +    if b == 0:
  +        return a
  +    return euclidean(b, a % b)
   
   
   def bresenham(x0, y0, x1, y1):
       points = []
       dx = abs(x1 - x0)
       dy = abs(y1 - y0)
  -    sx = 1 if x0 < x1 else -1
  -    sy = 1 if y0 < y1 else -1
  -    err = dx - dy
  +    x, y = x0, y0
  +    sx = -1 if x0 > x1 else 1
  +    sy = -1 if y0 > y1 else 1
   
  -    while True:
  -        points.append((x0, y0))
  -        if x0 == x1 and y0 == y1:
  -            break
  -        e2 = 2 * err
  -        if e2 > -dy:
  -            err -= dy
  -            x0 += sx
  -        if e2 < dx:
  -            err += dx
  -            y0 += sy
  +    if dx > dy:
  +        err = dx / 2.0
  +        while x != x1:
  +            points.append((x, y))
  +            err -= dy
  +            if err < 0:
  +                y += sy
  +                err += dx
  +            x += sx
  +    else:
  +        err = dy / 2.0
  +        while y != y1:
  +            points.append((x, y))
  +            err -= dx
  +            if err < 0:
  +                x += sx
  +                err += dy
  +            y += sy
  +
  +    points.append((x, y))
       return points
  
  </patch>
golden_diff: diff --git a/chainer/functions/array/get_item.py b/chainer/functions/array/get_item.py
  --- a/chainer/functions/array/get_item.py
  +++ b/chainer/functions/array/get_item.py
  @@ -1,7 +1,11 @@
   import collections
   
  +import numpy
  +
  +import chainer
   from chainer import cuda
   from chainer import function
  +from chainer import utils
   from chainer.utils import type_check
   from chainer import variable
   
  @@ -13,16 +17,29 @@
       def __init__(self, slices):
           if not isinstance(slices, collections.Iterable):
               slices = tuple([slices])
  +
  +        if chainer.is_debug():
  +            n_ellipses = 0
  +            for s in slices:
  +                if numpy.isscalar(s) or s is None or isinstance(s, slice):
  +                    pass
  +                elif s is Ellipsis:
  +                    n_ellipses += 1
  +                else:
  +                    raise ValueError('Only basic indexing is supported')
  +            if n_ellipses > 1:
  +                raise ValueError('Only one Ellipsis is allowed')
  +
           self.slices = slices
   
       def check_type_forward(self, in_types):
           type_check.expect(in_types.size() == 1)
           valid_slice = len(self.slices) - self.slices.count(None)
  -        type_check.expect(in_types[0].ndim == valid_slice)
  +        type_check.expect(in_types[0].ndim >= valid_slice)
   
       def forward(self, xs):
           ary = xs[0]
  -        return ary[tuple(self.slices)],
  +        return utils.force_array(ary[tuple(self.slices)]),
   
       def backward(self, xs, gys):
           xp = cuda.get_array_module(*xs)
  @@ -37,12 +54,19 @@
   
       Args:
           x (tuple of Variables): Variable to be sliced.
  -        slices (slice or tuple of slices): Slice objects to slice variable.
  +        slices (int, slice, None or Ellipsis or tuple of them): Basic slicing
  +            to slice a variable. It supports ``int``, ``slice``, ``newaxis``
  +            (equivalent to ``None``) and ``Ellipsis``.
   
       Returns:
           Variable: :class:`~chainer.Variable` object
               which contains sliced array of ``x``.
   
  +    .. note::
  +
  +       See NumPy document for details of `indexing
  +       <http://docs.scipy.org/doc/numpy/reference/arrays.indexing.html>`_.
  +
       """
       return GetItem(slices)(x)
  
verification_info: {"golden_diff": "diff --git a/chainer/functions/array/get_item.py b/chainer/functions/array/get_item.py\n--- a/chainer/functions/array/get_item.py\n+++ b/chainer/functions/array/get_item.py\n@@ -1,7 +1,11 @@\n import collections\n \n+import numpy\n+\n+import chainer\n from chainer import cuda\n from chainer import function\n+from chainer import utils\n from chainer.utils import type_check\n from chainer import variable\n \n@@ -13,16 +17,29 @@\n     def __init__(self, slices):\n         if not isinstance(slices, collections.Iterable):\n             slices = tuple([slices])\n+\n+        if chainer.is_debug():\n+            n_ellipses = 0\n+            for s in slices:\n+                if numpy.isscalar(s) or s is None or isinstance(s, slice):\n+                    pass\n+                elif s is Ellipsis:\n+                    n_ellipses += 1\n+                else:\n+                    raise ValueError('Only basic indexing is supported')\n+            if n_ellipses > 1:\n+                raise ValueError('Only one Ellipsis is allowed')\n+\n         self.slices = slices\n \n     def check_type_forward(self, in_types):\n         type_check.expect(in_types.size() == 1)\n         valid_slice = len(self.slices) - self.slices.count(None)\n-        type_check.expect(in_types[0].ndim == valid_slice)\n+        type_check.expect(in_types[0].ndim >= valid_slice)\n \n     def forward(self, xs):\n         ary = xs[0]\n-        return ary[tuple(self.slices)],\n+        return utils.force_array(ary[tuple(self.slices)]),\n \n     def backward(self, xs, gys):\n         xp = cuda.get_array_module(*xs)\n@@ -37,12 +54,19 @@\n \n     Args:\n         x (tuple of Variables): Variable to be sliced.\n-        slices (slice or tuple of slices): Slice objects to slice variable.\n+        slices (int, slice, None or Ellipsis or tuple of them): Basic slicing\n+            to slice a variable. It supports ``int``, ``slice``, ``newaxis``\n+            (equivalent to ``None``) and ``Ellipsis``.\n \n     Returns:\n         Variable: :class:`~chainer.Variable` object\n             which contains sliced array of ``x``.\n \n+    .. note::\n+\n+       See NumPy document for details of `indexing\n+       <http://docs.scipy.org/doc/numpy/reference/arrays.indexing.html>`_.\n+\n     \"\"\"\n     return GetItem(slices)(x)\n", "issue": "Support basic indexing in Variable class\nCurrently `Variable` partially supports `__getitem__`. I need full support of basic indexing.\n- [x] int index #1343 \n- [x] slices #1154\n- [x] new axis #1257 \n- [x] elipsis #1343 \n\nsee also: http://docs.scipy.org/doc/numpy/reference/arrays.indexing.html#basic-slicing-and-indexing\n\n", "before_files": [{"content": "import collections\n\nfrom chainer import cuda\nfrom chainer import function\nfrom chainer.utils import type_check\nfrom chainer import variable\n\n\nclass GetItem(function.Function):\n\n    \"\"\"Function that slices array and extract elements.\"\"\"\n\n    def __init__(self, slices):\n        if not isinstance(slices, collections.Iterable):\n            slices = tuple([slices])\n        self.slices = slices\n\n    def check_type_forward(self, in_types):\n        type_check.expect(in_types.size() == 1)\n        valid_slice = len(self.slices) - self.slices.count(None)\n        type_check.expect(in_types[0].ndim == valid_slice)\n\n    def forward(self, xs):\n        ary = xs[0]\n        return ary[tuple(self.slices)],\n\n    def backward(self, xs, gys):\n        xp = cuda.get_array_module(*xs)\n        gy = gys[0]\n        gx = xp.zeros_like(xs[0])\n        gx[tuple(self.slices)] = gy\n        return gx,\n\n\ndef get_item(x, slices):\n    \"\"\"Extract elements from array with specified shape, axes and offsets.\n\n    Args:\n        x (tuple of Variables): Variable to be sliced.\n        slices (slice or tuple of slices): Slice objects to slice variable.\n\n    Returns:\n        Variable: :class:`~chainer.Variable` object\n            which contains sliced array of ``x``.\n\n    \"\"\"\n    return GetItem(slices)(x)\n\n\ndef install_variable_get_item():\n    variable.Variable.__getitem__ = get_item\n", "path": "chainer/functions/array/get_item.py"}]}