def Placeholder(_inf, name='placeholder'):
p = placeholder_variable(shape=_as_tuple(_inf.shape),
dynamic_axes=_inf.axis,
name=name)
_name_node(p, name)
if _trace_layers:
print("new " + _node_description(p))
return p
def Placeholder(shape=None, name='placeholder'):
if shape is not None:
p = placeholder_variable(shape=shape, name=name) # TODO: use (*args, **kwargs)?
else:
p = placeholder_variable(name=name) # TODO: use (*args, **kwargs)?
_name_node(p, name)
if _trace_layers:
print("new " + _node_description(p))
return p
def _apply(f, args):
import operator # add()
import functools # reduce()
from cntk.ops.functions import CloneMethod
# flatten args to a list. Note it may be a a tuple or even a nested tree of tuples, e.g. LSTM (x, (h, c))
def flatten_tuple(args):
if not isinstance(
args,
tuple): # not a tuple: singleton; create a singleton tuple
return (args, )
return functools.reduce(operator.add,
[(flatten_tuple(item)) for item in args])
args = list(flatten_tuple(args))
# TODO: This should go into Function.replace_placeholders()
def _output_of(
arg
): # helper to get the output of an arg; use arg itself if no output() method (that'd be a Variable)
try:
return arg.output
except AttributeError:
return arg # Variables have no output()
args = [_output_of(arg) for arg in args]
placeholders = f.placeholders # f parameters to fill in
if len(args) != len(placeholders):
raise TypeError(
"_apply ({}): number of arguments {} must match number of placeholders {}"
.format(_node_description(f), len(args), len(placeholders)))
_function_name = _node_name(f) # these are for logging/debugging only
_function_description = _node_description(f)
_arg_description = ", ".join([_node_name(f) for f in list(args)])
f = f.clone(CloneMethod.share, dict(zip(f.placeholders, args)))
_name_and_extend_Function(f, _function_name)
if _trace_layers:
print("{} = {} ({})".format(_node_description(f),
_function_description, _arg_description))
return f
def _extend_Function(f):
class FunctionEx(f.__class__):
def __call__(self, *args):
return _apply(self, _as_tuple(args))
def __rshift__(self, other):
return other(self)
def _name(self): # retrieve the debug name
return _node_name(self)
if hasattr(f, '__call__'): # already extended: don't do it again
return f
f.__class__ = FunctionEx
if _trace_layers:
print("def {}".format(_node_description(f)))
return f