| | import numpy |
| |
|
| | import cupy |
| | from cupy import _core |
| | from cupy._core import internal |
| |
|
| |
|
| | class flatiter: |
| | """Flat iterator object to iterate over arrays. |
| | |
| | A flatiter iterator is returned by ``x.flat`` for any array ``x``. It |
| | allows iterating over the array as if it were a 1-D array, either in a |
| | for-loop or by calling its ``next`` method. |
| | |
| | Iteration is done in row-major, C-style order (the last index varying the |
| | fastest). |
| | |
| | Attributes: |
| | base (cupy.ndarray): A reference to the array that is iterated over. |
| | |
| | .. note:: |
| | Restricted support of basic slicing is currently supplied. Advanced |
| | indexing is not supported yet. |
| | |
| | .. seealso:: :func:`numpy.flatiter` |
| | |
| | """ |
| |
|
| | def __init__(self, a): |
| | self._base = a |
| | self._index = 0 |
| |
|
| | def __setitem__(self, ind, value): |
| | if ind is Ellipsis: |
| | self[:] = value |
| | return |
| |
|
| | if isinstance(ind, tuple): |
| | raise IndexError('unsupported iterator index') |
| |
|
| | if isinstance(ind, bool): |
| | raise IndexError('unsupported iterator index') |
| |
|
| | if numpy.isscalar(ind): |
| | ind = int(ind) |
| | base = self._base |
| | size = base.size |
| | indices = [] |
| | for s in base.shape: |
| | size = size // s |
| | indices.append(ind // size) |
| | ind %= size |
| | base[tuple(indices)] = value |
| | return |
| |
|
| | if isinstance(ind, slice): |
| | base = self._base |
| | s = internal.complete_slice(ind, base.size) |
| | s_start = s.start |
| | s_step = s.step |
| | size = s.stop - s.start |
| | if s_step > 0: |
| | size = (size - 1) // s_step + 1 |
| | else: |
| | size = (size + 1) // s_step + 1 |
| | value = cupy.asarray(value, dtype=base.dtype) |
| | _flatiter_setitem_slice(value, s_start, s_step, base, size=size) |
| | return |
| |
|
| | raise IndexError('unsupported iterator index') |
| |
|
| | def __getitem__(self, ind): |
| | if ind is Ellipsis: |
| | return self[:] |
| |
|
| | if isinstance(ind, tuple): |
| | raise IndexError('unsupported iterator index') |
| |
|
| | if isinstance(ind, bool): |
| | raise IndexError('unsupported iterator index') |
| |
|
| | if numpy.isscalar(ind): |
| | ind = int(ind) |
| | base = self._base |
| | size = base.size |
| | indices = [] |
| | for s in base.shape: |
| | size = size // s |
| | indices.append(ind // size) |
| | ind %= size |
| | return base[tuple(indices)].copy() |
| |
|
| | if isinstance(ind, slice): |
| | base = self._base |
| | s = internal.complete_slice(ind, base.size) |
| | s_start = s.start |
| | s_step = s.step |
| | size = s.stop - s.start |
| | if s_step > 0: |
| | size = (size - 1) // s_step + 1 |
| | else: |
| | size = (size + 1) // s_step + 1 |
| | return _flatiter_getitem_slice(base, s_start, s_step, size=size) |
| |
|
| | raise IndexError('unsupported iterator index') |
| |
|
| | def __iter__(self): |
| | return self |
| |
|
| | def __next__(self): |
| | index = self._index |
| | if index == len(self): |
| | raise StopIteration() |
| | self._index += 1 |
| | return self[index] |
| |
|
| | def copy(self): |
| | """Get a copy of the iterator as a 1-D array.""" |
| | return self.base.flatten() |
| |
|
| | @property |
| | def base(self): |
| | """A reference to the array that is iterated over.""" |
| | return self._base |
| |
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|
| | def __len__(self): |
| | return self.base.size |
| |
|
| |
|
| | _flatiter_setitem_slice = _core.ElementwiseKernel( |
| | 'raw T val, int64 start, int64 step', 'raw T a', |
| | 'a[start + i * step] = val[i % val.size()]', |
| | 'cupy_flatiter_setitem_slice') |
| |
|
| |
|
| | _flatiter_getitem_slice = _core.ElementwiseKernel( |
| | 'raw T a, int64 start, int64 step', 'T o', |
| | 'o = a[start + i * step]', |
| | 'cupy_flatiter_getitem_slice') |
| |
|
