reminisce commented on a change in pull request #16621: [Numpy] Basic indexing
in symbolic interface of DeepNumpy
URL: https://github.com/apache/incubator-mxnet/pull/16621#discussion_r350463623
##########
File path: python/mxnet/symbol/numpy/_symbol.py
##########
@@ -43,31 +50,131 @@
'less_equal', 'hsplit', 'rot90', 'einsum', 'true_divide',
'shares_memory', 'may_share_memory', 'diff',
'resize', 'nan_to_num', 'where']
-def _num_outputs(sym):
- return len(sym.as_nd_ndarray())
-
@set_module('mxnet.symbol.numpy')
class _Symbol(Symbol):
- def __getitem__(self, key):
- num_outputs = _num_outputs(self)
- if num_outputs == 1:
- raise NotImplementedError
- if not isinstance(key, int):
- raise NotImplementedError
- if key >= num_outputs:
- # Important, python determines the end by this exception
- raise IndexError
- handle = SymbolHandle()
- check_call(_LIB.MXSymbolGetOutput(
- self.handle, mx_uint(key), ctypes.byref(handle)))
- return _Symbol(handle=handle)
+ def __init__(self, handle):
+ super(_Symbol, self).__init__(handle)
+
+ def __getitem__(self, key): # pylint: disable =
too-many-return-statements, inconsistent-return-statements
+ """Return self[key].
+
+ If the symbol is a symbol list, it returns the i-th symbol or a list
of symbols
+ selected by key.
+
+ Otherwise, it outputs a symbol that slice the input by the given key.
Currently, this
+ function supports the following types of key:
+
+ - integer types, e.g., int, long, np.int32, np.int64
+ - slice containing integer constants, e.g., slice(0, None, None)
+ - tuple contaning the above elements, which is used for
multidimensional indexing
+
+ Parameters
+ ----------
+ key : int, slice, or tuple of all previous types
+ Indexing key.
+
+ """
+ num_outputs = self.num_outputs
+ if num_outputs > 1:
+ num_outputs = self.num_outputs
+ if isinstance(key, integer_types):
+ key = int(key)
+ if key < -num_outputs or key >= num_outputs:
+ raise IndexError('list index out of range')
+ if key < 0:
+ key += num_outputs
+ ret_handle = SymbolHandle()
+ check_call(_LIB.MXSymbolGetOutput(self.handle, mx_uint(key),
+ ctypes.byref(ret_handle)))
+ return _Symbol(handle=ret_handle)
+ elif isinstance(key, py_slice):
+ start, stop, step = key.indices(num_outputs)
+ return Group([self[i] for i in range(start, stop, step)],
_Symbol)
+ else:
+ raise TypeError('indices of symbol group must be integers or
slices, not {}'
+ .format(type(key)))
+ else:
+ if isinstance(key, integer_types):
+ sliced = _npi.slice(self, [key], [key+1])
+ return _npi.reshape(sliced, (-3, -4))
+ elif isinstance(key, py_slice):
+ if key.step is None or key.step != 0:
+ start = [None] if key.start is None else key.start
+ stop = [None] if key.stop is None else key.stop
+ return _npi.slice(self, start, stop, key.step)
+ else:
+ raise ValueError("slice step cannot be zero")
+ elif isinstance(key, tuple):
+ begin = []
+ end = []
+ step = []
+ new_shape = ()
+ if len(key) == 0:
+ return self
+ for index in key:
+ if isinstance(index, py_slice):
+ if index.step is not None and index.step == 0:
+ raise ValueError("slice step cannot be zero")
+ begin.append(index.start)
+ end.append(index.stop)
+ step.append(index.step)
+ new_shape += (-2,)
+ elif isinstance(index, integer_types):
+ if index >= 0:
+ begin.append(index)
+ end.append(index+1)
+ step.append(1)
+ else:
+ begin.append(index)
+ end.append(index - 1)
+ step.append(-1)
+ new_shape += (-3,)
+ else:
+ raise IndexError('Only integer, slice, or tuple of
these types'
+ ' are supported! Received
key={}'.format(key))
+ new_shape += (-4,)
+ sliced = _npi.slice(self, begin, end, step)
+ return _npi.reshape(sliced, new_shape)
+ else:
+ raise IndexError('Only integer, slice, or tuple of these types
are supported! '
+ 'Received key={}'.format(key))
def __setitem__(self, key, value):
raise NotImplementedError
+ def __repr__(self):
+ """Gets a string representation of the symbol."""
+ if self.num_outputs > 1:
+ name = ', '.join([str(ele_sym) for ele_sym in self])
+ return '<%s group [%s]>' % (self.__class__.__name__, name)
+ else:
+ return '<%s %s>' % (self.__class__.__name__, self.name)
+
+ @property
+ def name(self):
+ """Gets name string from the symbol, this function only works for
symbols
+ that are not a list (grouped symbols).
+
+ Returns
+ -------
+ value : str
+ The name of this symbol, returns ``None`` for list symbol.
+ """
+ if self.num_outputs > 1:
+ return None
Review comment:
`raise` instead of `return`?
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