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@layer_register(log_shape=False) def PReLU(x, init=tf.constant_initializer(0.001), name=None): '\n Parameterized relu as in `Delving Deep into Rectifiers: Surpassing\n Human-Level Performance on ImageNet Classification\n <http://arxiv.org/abs/1502.01852>`_.\n\n :param input: any tensor.\n :param in...
@layer_register(use_scope=False, log_shape=False) def LeakyReLU(x, alpha, name=None): '\n Leaky relu as in `Rectifier Nonlinearities Improve Neural Network Acoustic\n Models\n <http://ai.stanford.edu/~amaas/papers/relu_hybrid_icml2013_final.pdf>`_.\n\n :param input: any tensor.\n :param alpha: the ...
@layer_register(log_shape=False, use_scope=False) def BNReLU(x, name=None): x = BatchNorm('bn', x) x = tf.nn.relu(x, name=name) return x
@memoized def _log_regularizer(name): logger.info('Apply regularizer for {}'.format(name))
def regularize_cost(regex, func, name=None): '\n Apply a regularizer on every trainable variable matching the regex.\n\n :param func: a function that takes a tensor and return a scalar.\n ' G = tf.get_default_graph() params = G.get_collection(tf.GraphKeys.TRAINABLE_VARIABLES) costs = [] f...
@layer_register(log_shape=False, use_scope=False) def Dropout(x, keep_prob=0.5, is_training=None): '\n :param is_training: if None, will use the current context by default.\n ' if (is_training is None): is_training = get_current_tower_context().is_training keep_prob = tf.constant((keep_prob ...
@layer_register(use_scope=False, log_shape=False) def ConcatWith(x, dim, tensor): '\n A wrapper around `tf.concat` to support `LinearWrap`\n :param x: the input tensor\n :param dim: the dimension along which to concatenate\n :param tensor: a tensor or list of tensor to concatenate with x. x will be\n ...
@layer_register() def SoftMax(x, use_temperature=False, temperature_init=1.0): '\n A SoftMax layer (no linear projection) with optional temperature\n :param x: a 2D tensor\n ' if use_temperature: t = tf.get_variable('invtemp', [], initializer=tf.constant_initializer((1.0 / float(temperature_i...
def global_import(name): p = __import__(name, globals(), locals(), level=1) lst = (p.__all__ if ('__all__' in dir(p)) else dir(p)) del globals()[name] for k in lst: globals()[k] = p.__dict__[k] __all__.append(k)
@six.add_metaclass(ABCMeta) class PredictorBase(object): '\n Available attributes:\n session\n return_input\n ' def __call__(self, *args): '\n if len(args) == 1, assume args[0] is a datapoint (a list)\n else, assume args is a datapoinnt\n ' if (len(args) != 1)...
class AsyncPredictorBase(PredictorBase): @abstractmethod def put_task(self, dp, callback=None): '\n :param dp: A data point (list of component) as inputs.\n (It should be either batched or not batched depending on the predictor implementation)\n :param callback: a thread-safe...
class OnlinePredictor(PredictorBase): def __init__(self, sess, input_tensors, output_tensors, return_input=False): self.session = sess self.return_input = return_input self.input_tensors = input_tensors self.output_tensors = output_tensors def _do_call(self, dp): asse...
class OfflinePredictor(OnlinePredictor): ' Build a predictor from a given config, in an independent graph' def __init__(self, config): self.graph = tf.Graph() with self.graph.as_default(): input_placehdrs = config.model.get_input_vars() with TowerContext('', False): ...
def build_multi_tower_prediction_graph(build_tower_fn, towers): '\n :param build_tower_fn: the function to be called inside each tower, taking tower as the argument\n :param towers: a list of gpu relative id.\n ' for k in towers: logger.info('Building graph for predictor tower {}...'.format(k...
class MultiTowerOfflinePredictor(OnlinePredictor): def __init__(self, config, towers): self.graph = tf.Graph() self.predictors = [] with self.graph.as_default(): fn = (lambda _: config.model.build_graph(config.model.get_input_vars())) build_multi_tower_prediction_g...
class DataParallelOfflinePredictor(OnlinePredictor): def __init__(self, config, towers): self.graph = tf.Graph() with self.graph.as_default(): sess = tf.Session(config=config.session_config) input_var_names = [] output_vars = [] for k in towers: ...
class PredictConfig(object): def __init__(self, **kwargs): '\n The config used by `get_predict_func`.\n\n :param session_init: a `utils.sessinit.SessionInit` instance to\n initialize variables of a session.\n :param model: a `ModelDesc` instance\n :param input_names...
def get_predict_func(config): '\n Produce a offline predictor run inside a new session.\n\n :param config: a `PredictConfig` instance.\n :returns: A callable predictor that takes a list of input values, and return\n a list of output values defined in ``config.output_var_names``.\n ' return ...
class MultiProcessPredictWorker(multiprocessing.Process): ' Base class for predict worker that runs offline in multiprocess' def __init__(self, idx, config): '\n :param idx: index of the worker. the 0th worker will print log.\n :param config: a `PredictConfig`\n ' super(M...
class MultiProcessQueuePredictWorker(MultiProcessPredictWorker): ' An offline predictor worker that takes input and produces output by queue' def __init__(self, idx, inqueue, outqueue, config): '\n :param inqueue: input queue to get data point. elements are (task_id, dp)\n :param outque...
class PredictorWorkerThread(threading.Thread): def __init__(self, queue, pred_func, id, batch_size=5): super(PredictorWorkerThread, self).__init__() self.queue = queue self.func = pred_func self.daemon = True self.batch_size = batch_size self.id = id def run(s...
class MultiThreadAsyncPredictor(AsyncPredictorBase): '\n An multithread online async predictor which run a list of PredictorBase.\n It would do an extra batching internally.\n ' def __init__(self, predictors, batch_size=5): ' :param predictors: a list of OnlinePredictor' assert len(p...
@six.add_metaclass(ABCMeta) class DatasetPredictorBase(object): def __init__(self, config, dataset): '\n :param config: a `PredictConfig` instance.\n :param dataset: a `DataFlow` instance.\n ' assert isinstance(dataset, DataFlow) assert isinstance(config, PredictConfi...
class SimpleDatasetPredictor(DatasetPredictorBase): '\n Run the predict_config on a given `DataFlow`.\n ' def __init__(self, config, dataset): super(SimpleDatasetPredictor, self).__init__(config, dataset) self.predictor = OfflinePredictor(config) def get_result(self): ' A g...
class MultiProcessDatasetPredictor(DatasetPredictorBase): def __init__(self, config, dataset, nr_proc, use_gpu=True, ordered=True): "\n Run prediction in multiprocesses, on either CPU or GPU. Mix mode not supported.\n\n :param nr_proc: number of processes to use\n :param use_gpu: use...
def _global_import(name): p = __import__(name, globals(), None, level=1) lst = (p.__all__ if ('__all__' in dir(p)) else dir(p)) for k in lst: globals()[k] = p.__dict__[k] __all__.append(k)
@contextmanager def argscope(layers, **param): if (not isinstance(layers, list)): layers = [layers] def _check_args_exist(l): args = inspect.getargspec(l).args for (k, v) in six.iteritems(param): assert (k in args), 'No argument {} in {}'.format(k, l.__name__) for l in...
def get_arg_scope(): '\n :returns: the current argscope.\n An argscope is a dict of dict: dict[layername] = {arg: val}\n ' if (len(_ArgScopeStack) > 0): return _ArgScopeStack[(- 1)] else: return defaultdict(dict)
def get_default_sess_config(mem_fraction=0.99): '\n Return a better session config to use as default.\n Tensorflow default session config consume too much resources.\n\n :param mem_fraction: fraction of memory to use. default to 0.99\n :returns: a `tf.ConfigProto` object.\n ' conf = tf.ConfigPr...
def get_global_step_var(): ' :returns: the global_step variable in the current graph. create if not existed' try: return tf.get_default_graph().get_tensor_by_name(GLOBAL_STEP_VAR_NAME) except KeyError: scope = tf.get_variable_scope() assert (scope.name == ''), 'Creating global_step...
def get_global_step(): ' :returns: global_step value in current graph and session' return tf.train.global_step(tf.get_default_session(), get_global_step_var())
def get_op_tensor_name(name): "\n Tensor name is assumed to be ``op_name + ':0'``\n\n :param name: an op or a tensor name\n :returns: (op_name, tensor_name)\n " if name.endswith(':0'): return (name[:(- 2)], name) else: return (name, (name + ':0'))
def get_tensors_by_names(names): '\n Get a list of tensors in the default graph by a list of names\n ' ret = [] G = tf.get_default_graph() for n in names: (opn, varn) = get_op_var_name(n) ret.append(G.get_tensor_by_name(varn)) return ret
def backup_collection(keys): ret = {} for k in keys: ret[k] = copy(tf.get_collection(k)) return ret
def restore_collection(backup): for (k, v) in six.iteritems(backup): del tf.get_collection_ref(k)[:] tf.get_collection_ref(k).extend(v)
def clear_collection(keys): for k in keys: del tf.get_collection_ref(k)[:]
@contextmanager def freeze_collection(keys): backup = backup_collection(keys) (yield) restore_collection(backup)
def get_tf_version(): return int(tf.__version__.split('.')[1])
def apply_grad_processors(grads, gradprocs): '\n :param grads: list of (grad, var).\n :param gradprocs: list of `GradientProcessor` instances.\n :returns: list of (grad, var) went through the processors\n ' g = [] for (grad, var) in grads: if (grad is None): logger.warn('No...
@six.add_metaclass(ABCMeta) class GradientProcessor(object): def process(self, grads): '\n Process the symbolic gradients.\n\n :param grads: list of (grad, var)\n :returns: symbolic gradients with the same type as input\n ' with tf.name_scope(type(self).__name__): ...
class GlobalNormClip(GradientProcessor): def __init__(self, global_norm): ' Clip by global norm\n Note that the global norm is the sum of norm for **all** gradients\n ' self._norm = global_norm def _process(self, grads): g = [k[0] for k in grads] v = [k[1] f...
class MapGradient(GradientProcessor): '\n Apply a function on all gradient if the name matches regex.\n Keep the other gradients unchanged.\n ' def __init__(self, func, regex='.*'): '\n :param func: takes a grad or (grad, var) pair and returns a grad. If return None, the\n ...
class SummaryGradient(MapGradient): '\n Summary history and RMS for each graident variable\n ' def __init__(self): super(SummaryGradient, self).__init__(self._mapper) def _mapper(self, grad, var): name = var.op.name if (name not in _summaried_gradient): _summari...
class CheckGradient(MapGradient): '\n Check for numeric issue.\n ' def __init__(self): super(CheckGradient, self).__init__(self._mapper) def _mapper(self, grad, var): grad = tf.check_numerics(grad, ('CheckGradient-' + var.op.name)) return grad
class ScaleGradient(MapGradient): '\n Scale certain gradient by a multiplier\n ' def __init__(self, multipliers, log=True): '\n :param multipliers: list of (regex, float)\n :param log: whether to do logging or not\n ' if (not isinstance(multipliers, list)): ...
def describe_model(): ' print a description of the current model parameters ' train_vars = tf.get_collection(tf.GraphKeys.TRAINABLE_VARIABLES) msg = [''] total = 0 for v in train_vars: shape = v.get_shape() ele = shape.num_elements() total += ele msg.append('{}: sha...
def get_shape_str(tensors): '\n :param tensors: a tensor or a list of tensors\n :returns: a string to describe the shape\n ' if isinstance(tensors, (list, tuple)): for v in tensors: assert isinstance(v, (tf.Tensor, tf.Variable)), 'Not a tensor: {}'.format(type(v)) shape_st...
@six.add_metaclass(ABCMeta) class SessionInit(object): ' Base class for utilities to initialize a session' def init(self, sess): ' Initialize a session\n\n :param sess: a `tf.Session`\n ' self._init(sess) @abstractmethod def _init(self, sess): pass
class JustCurrentSession(SessionInit): ' Just use the current default session. This is a no-op placeholder' def _init(self, sess): pass
class NewSession(SessionInit): '\n Create a new session. All variables will be initialized by their\n initializer.\n ' def _init(self, sess): sess.run(tf.initialize_all_variables())
class SaverRestore(SessionInit): '\n Restore an old model saved by `ModelSaver`.\n ' def __init__(self, model_path, prefix=None): '\n :param model_path: a model name (model-xxxx) or a ``checkpoint`` file.\n :param prefix: add a `prefix/` for every variable in this checkpoint\n ...
class ParamRestore(SessionInit): '\n Restore variables from a dictionary.\n ' def __init__(self, param_dict): '\n :param param_dict: a dict of {name: value}\n ' self.prms = {get_op_var_name(n)[1]: v for (n, v) in six.iteritems(param_dict)} def _init(self, sess): ...
class ChainInit(SessionInit): ' Init a session by a list of SessionInit instance.' def __init__(self, sess_inits, new_session=True): '\n :params sess_inits: list of `SessionInit` instances.\n :params new_session: add a `NewSession()` and the beginning, if not there\n ' if...
def get_model_loader(filename): '\n Get a corresponding model loader by looking at the file name\n :return: either a ParamRestore or SaverRestore\n ' if filename.endswith('.npy'): assert os.path.isfile(filename), filename return ParamRestore(np.load(filename, encoding='latin1').item()...
def create_summary(name, v): '\n Return a tf.Summary object with name and simple scalar value v\n ' assert isinstance(name, six.string_types), type(name) v = float(v) s = tf.Summary() s.value.add(tag=name, simple_value=v) return s
def add_activation_summary(x, name=None): '\n Add summary to graph for an activation tensor x.\n If name is None, use x.name.\n ' ctx = get_current_tower_context() if ((ctx is not None) and (not ctx.is_main_training_tower)): return ndim = x.get_shape().ndims assert (ndim >= 2), 'S...
def add_param_summary(summary_lists): "\n Add summary for all trainable variables matching the regex\n\n :param summary_lists: list of (regex, [list of summary type to perform]).\n Type can be 'mean', 'scalar', 'histogram', 'sparsity', 'rms'\n " ctx = get_current_tower_context() if ((ctx i...
def add_moving_summary(v, *args): '\n :param v: tensor or list of tensor to summary\n :param args: tensors to summary\n ' ctx = get_current_tower_context() if ((ctx is not None) and (not ctx.is_main_training_tower)): return if (not isinstance(v, list)): v = [v] v.extend(ar...
@memoized def summary_moving_average(tensors=None): '\n Create a MovingAverage op and add summary for tensors\n :param tensors: list of tf.Tensor to summary. default to the collection MOVING_SUMMARY_VARS_KEY\n :returns: a op to maintain these average.\n ' if (tensors is None): tensors = tf...
def prediction_incorrect(logits, label, topk=1, name='incorrect_vector'): '\n :param logits: NxC\n :param label: N\n :returns: a float32 vector of length N with 0/1 values. 1 means incorrect prediction\n ' return tf.cast(tf.logical_not(tf.nn.in_top_k(logits, label, topk)), tf.float32, name=name)
def flatten(x): '\n Flatten the tensor.\n ' return tf.reshape(x, [(- 1)])
def batch_flatten(x): '\n Flatten the tensor except the first dimension.\n ' shape = x.get_shape().as_list()[1:] if (None not in shape): return tf.reshape(x, [(- 1), int(np.prod(shape))]) return tf.reshape(x, tf.pack([tf.shape(x)[0], (- 1)]))
def class_balanced_cross_entropy(pred, label, name='cross_entropy_loss'): '\n The class-balanced cross entropy loss,\n as in `Holistically-Nested Edge Detection\n <http://arxiv.org/abs/1504.06375>`_.\n\n :param pred: size: b x ANYTHING. the predictions in [0,1].\n :param label: size: b x ANYTHING. ...
def class_balanced_sigmoid_cross_entropy(logits, label, name='cross_entropy_loss'): '\n The class-balanced cross entropy loss,\n as in `Holistically-Nested Edge Detection\n <http://arxiv.org/abs/1504.06375>`_.\n This is more numerically stable than class_balanced_cross_entropy\n\n :param logits: si...
def print_stat(x, message=None): ' a simple print op.\n Use it like: x = print_stat(x)\n ' if (message is None): message = x.op.name return tf.Print(x, [tf.shape(x), tf.reduce_mean(x), x], summarize=20, message=message, name=('print_' + x.op.name))
def rms(x, name=None): if (name is None): name = (x.op.name + '/rms') with tf.name_scope(None): return tf.sqrt(tf.reduce_mean(tf.square(x)), name=name) return tf.sqrt(tf.reduce_mean(tf.square(x)), name=name)
def huber_loss(x, delta=1, name='huber_loss'): sqrcost = tf.square(x) abscost = tf.abs(x) return tf.reduce_sum(tf.select((abscost < delta), (sqrcost * 0.5), ((abscost * delta) - (0.5 * (delta ** 2)))), name=name)
def get_scalar_var(name, init_value, summary=False, trainable=False): '\n get a scalar variable with certain initial value\n :param summary: summary this variable\n ' ret = tf.get_variable(name, shape=[], initializer=tf.constant_initializer(init_value), trainable=trainable) if summary: tf...
class TowerContext(object): def __init__(self, tower_name, is_training=None): " tower_name: 'tower0', 'towerp0', or '' " self._name = tower_name if (is_training is None): is_training = (not self._name.startswith(PREDICT_TOWER)) self._is_training = is_training @pro...
def get_current_tower_context(): global _CurrentTowerContext return _CurrentTowerContext
def get_savename_from_varname(varname, varname_prefix=None, savename_prefix=None): '\n :param varname: a variable name in the graph\n :param varname_prefix: an optional prefix that may need to be removed in varname\n :param savename_prefix: an optional prefix to append to all savename\n :returns: the ...
class SessionUpdate(object): ' Update the variables in a session ' def __init__(self, sess, vars_to_update): '\n :param vars_to_update: a collection of variables to update\n ' self.sess = sess self.assign_ops = defaultdict(list) for v in vars_to_update: ...
def dump_session_params(path): ' Dump value of all trainable + to_save variables to a dict and save to `path` as\n npy format, loadable by ParamRestore\n ' var = tf.get_collection(tf.GraphKeys.TRAINABLE_VARIABLES) var.extend(tf.get_collection(tf.GraphKeys.MODEL_VARIABLES)) assert (len(set(var)) ...
def dump_chkpt_vars(model_path): ' Dump all variables from a checkpoint to a dict' if (os.path.basename(model_path) == model_path): model_path = os.path.join('.', model_path) reader = tf.train.NewCheckpointReader(model_path) var_names = reader.get_variable_to_shape_map().keys() result = {}...
def is_training_name(name): '\n This is only used to improve logging.\n :returns: guess whether this tensor is something only used in training.\n ' name = get_op_tensor_name(name)[0] if (name.endswith('/Adam') or name.endswith('/Adam_1')): return True if name.endswith('/Momentum'): ...
def global_import(name): p = __import__(name, globals(), locals(), level=1) lst = (p.__all__ if ('__all__' in dir(p)) else []) del globals()[name] for k in lst: globals()[k] = p.__dict__[k] __all__.append(k)
class StopTraining(BaseException): pass
@six.add_metaclass(ABCMeta) class Trainer(object): ' Base class for a trainer.' 'a `StatHolder` instance' stat_holder = None '`tf.SummaryWriter`' summary_writer = None 'a tf.Tensor which returns summary string' summary_op = None ' TrainConfig ' config = None ' a ModelDesc' ...
class TrainConfig(object): '\n Config for training a model with a single loss\n ' def __init__(self, **kwargs): '\n :param dataset: the dataset to train. a `DataFlow` instance.\n :param data: an `InputData` instance\n\n :param optimizer: a `tf.train.Optimizer` instance defi...
class FeedfreeTrainer(Trainer): ' A trainer which runs iteration without feed_dict (therefore faster) ' def _trigger_epoch(self): if (self.summary_op is not None): summary_str = self.summary_op.eval() self._process_summary(summary_str) def _get_input_tensors(self): ...
class SingleCostFeedfreeTrainer(FeedfreeTrainer): def _get_cost_and_grad(self): ' get the cost and gradient on a new tower' actual_inputs = self._get_input_tensors() self.model.build_graph(actual_inputs) cost_var = self.model.get_cost() grads = self.config.optimizer.comput...
class SimpleFeedfreeTrainer(MultiPredictorTowerTrainer, SingleCostFeedfreeTrainer): def __init__(self, config): '\n A trainer with single cost, single training tower and feed-free input\n config.data must exists\n ' self._input_method = config.data assert isinstance(s...
class QueueInputTrainer(SimpleFeedfreeTrainer): def __init__(self, config, input_queue=None, predict_tower=None): '\n Single tower Trainer, takes input from a queue\n\n :param config: a `TrainConfig` instance. config.dataset must exist\n :param input_queue: a `tf.QueueBase` instance\...
@six.add_metaclass(ABCMeta) class InputData(object): pass
class FeedInput(InputData): def __init__(self, ds): assert isinstance(ds, DataFlow), ds self.ds = ds def size(self): return self.ds.size() def _setup(self, trainer): self.input_vars = trainer.model.get_input_vars() rds = RepeatedData(self.ds, (- 1)) rds.r...
class FeedfreeInput(InputData): def get_input_tensors(self): return self._get_input_tensors() @abstractmethod def _get_input_tensors(self): '\n always create and return a list of new input tensors\n '
class EnqueueThread(threading.Thread): def __init__(self, trainer, queue, ds, input_placehdrs): super(EnqueueThread, self).__init__() self.name = 'EnqueueThread' self.daemon = True self.dataflow = ds self.queue = queue self.sess = trainer.sess self.coord = ...
class QueueInput(FeedfreeInput): def __init__(self, ds, queue=None): '\n :param ds: a `DataFlow` instance\n :param queue: a `tf.QueueBase` instance to be used to buffer datapoints.\n Defaults to a FIFO queue of size 50.\n ' assert isinstance(ds, DataFlow), ds ...
class DummyConstantInput(QueueInput): ' only for debugging performance issues ' def __init__(self, ds, shapes): super(DummyConstantInput, self).__init__(ds) self.shapes = shapes logger.warn('Using dummy input for debug!') def _get_input_tensors(self): placehdrs = self.inp...
class TensorInput(FeedfreeInput): def __init__(self, get_tensor_fn, size=None): self.get_tensor_fn = get_tensor_fn self._size = size def size(self): if (self._size is None): raise ValueError('size of TensorInput is undefined!') return self._size def _setup(se...
class MultiGPUTrainer(Trainer): ' Base class for multi-gpu training' @staticmethod def _multi_tower_grads(towers, get_tower_grad_func): ' ret[i] is a lists of (grad,var) tuple for tower i' logger.info('Training a model of {} tower'.format(len(towers))) grad_list = [] globa...
class SyncMultiGPUTrainer(MultiGPUTrainer, SingleCostFeedfreeTrainer, MultiPredictorTowerTrainer): def __init__(self, config, input_queue=None, predict_tower=None): if hasattr(config, 'dataset'): self._input_method = QueueInput(config.dataset, input_queue) else: self._inpu...
class AsyncMultiGPUTrainer(MultiGPUTrainer, SingleCostFeedfreeTrainer, MultiPredictorTowerTrainer): def __init__(self, config, input_queue=None, average_gradient=True, predict_tower=None): if hasattr(config, 'dataset'): self._input_method = QueueInput(config.dataset, input_queue) else...
class PredictorFactory(object): ' Make predictors for a trainer' def __init__(self, sess, model, towers): '\n :param towers: list of gpu relative id\n ' self.sess = sess self.model = model self.towers = towers self.tower_built = False def get_predict...
class SimpleTrainer(Trainer): ' A naive demo trainer ' def __init__(self, config): super(SimpleTrainer, self).__init__(config) self._predictor_factory = PredictorFactory(self.sess, self.model, [0]) if (not hasattr(config, 'dataset')): self._input_method = config.data ...
class MultiPredictorTowerTrainer(Trainer): ' A trainer with possibly multiple prediction tower ' def _setup_predictor_factory(self, predict_tower): predict_tower = (predict_tower or [0]) self._predictor_factory = PredictorFactory(self.sess, self.model, predict_tower) def get_predict_func...
def _global_import(name): p = __import__(name, globals(), None, level=1) lst = (p.__all__ if ('__all__' in dir(p)) else dir(p)) for k in lst: globals()[k] = p.__dict__[k] __all__.append(k)
def map_arg(**maps): '\n Apply a mapping on certains argument before calling original function.\n maps: {key: map_func}\n ' def deco(func): @functools.wraps(func) def wrapper(*args, **kwargs): argmap = inspect.getcallargs(func, *args, **kwargs) for (k, map_fu...
class memoized(object): "Decorator. Caches a function's return value each time it is called.\n If called later with the same arguments, the cached value is returned\n (not reevaluated).\n " def __init__(self, func): self.func = func self.cache = {} def __call__(self, *args, **kw...
def memoized_ignoreargs(func): h = hash(func) def wrapper(*args, **kwargs): if (func not in _MEMOIZED_NOARGS): res = func(*args, **kwargs) _MEMOIZED_NOARGS[func] = res return res return _MEMOIZED_NOARGS[func] return wrapper