""" A very basic example for how to use current Raw SWIG API to train mnist network. Current implementation uses Raw SWIG, which means the API call is directly \ passed to C++ side of Paddle. The user api could be simpler and carefully designed. """ import random import numpy as np import paddle.trainer.PyDataProvider2 as dp import paddle.v2 as paddle_v2 import py_paddle.swig_paddle as api from paddle.trainer_config_helpers import * from py_paddle import DataProviderConverter from mnist_util import read_from_mnist def init_parameter(network): assert isinstance(network, api.GradientMachine) for each_param in network.getParameters(): assert isinstance(each_param, api.Parameter) array_size = len(each_param) array = np.random.uniform(-1.0, 1.0, array_size).astype('float32') each_param.getBuf(api.PARAMETER_VALUE).copyFromNumpyArray(array) def generator_to_batch(generator, batch_size): ret_val = list() for each_item in generator: ret_val.append(each_item) if len(ret_val) == batch_size: yield ret_val ret_val = list() if len(ret_val) != 0: yield ret_val class BatchPool(object): def __init__(self, generator, batch_size): self.data = list(generator) self.batch_size = batch_size def __call__(self): random.shuffle(self.data) for offset in xrange(0, len(self.data), self.batch_size): limit = min(offset + self.batch_size, len(self.data)) yield self.data[offset:limit] def input_order_converter(generator): for each_item in generator: yield each_item['pixel'], each_item['label'] def main(): api.initPaddle("-use_gpu=false", "-trainer_count=4") # use 4 cpu cores optimizer = paddle_v2.optimizer.Adam( learning_rate=1e-4, batch_size=1000, model_average=ModelAverage(average_window=0.5), regularization=L2Regularization(rate=0.5)) # Create Local Updater. Local means not run in cluster. # For a cluster training, here we can change to createRemoteUpdater # in future. updater = optimizer.create_local_updater() assert isinstance(updater, api.ParameterUpdater) # define network images = paddle_v2.layer.data(name='pixel', size=784) label = paddle_v2.layer.data(name='label', size=10) hidden1 = paddle_v2.layer.fc(input=images, size=200) hidden2 = paddle_v2.layer.fc(input=hidden1, size=200) inference = paddle_v2.layer.fc(input=hidden2, size=10, act=paddle_v2.activation.Softmax()) cost = paddle_v2.layer.classification_cost(input=inference, label=label) # Create Simple Gradient Machine. model_config = paddle_v2.layer.parse_network(cost) m = api.GradientMachine.createFromConfigProto(model_config, api.CREATE_MODE_NORMAL, optimizer.enable_types()) # This type check is not useful. Only enable type hint in IDE. # Such as PyCharm assert isinstance(m, api.GradientMachine) # Initialize Parameter by numpy. init_parameter(network=m) # Initialize ParameterUpdater. updater.init(m) # DataProvider Converter is a utility convert Python Object to Paddle C++ # Input. The input format is as same as Paddle's DataProvider. converter = DataProviderConverter( input_types=[dp.dense_vector(784), dp.integer_value(10)]) train_file = './data/raw_data/train' test_file = './data/raw_data/t10k' # start gradient machine. # the gradient machine must be started before invoke forward/backward. # not just for training, but also for inference. m.start() # evaluator can print error rate, etc. It is a C++ class. batch_evaluator = m.makeEvaluator() test_evaluator = m.makeEvaluator() # Get Train Data. # TrainData will stored in a data pool. Currently implementation is not care # about memory, speed. Just a very naive implementation. train_data_generator = input_order_converter(read_from_mnist(train_file)) train_data = BatchPool(train_data_generator, 512) # outArgs is Neural Network forward result. Here is not useful, just passed # to gradient_machine.forward outArgs = api.Arguments.createArguments(0) for pass_id in xrange(2): # we train 2 passes. updater.startPass() for batch_id, data_batch in enumerate(train_data()): # data_batch is input images. # here, for online learning, we could get data_batch from network. # Start update one batch. pass_type = updater.startBatch(len(data_batch)) # Start BatchEvaluator. # batch_evaluator can be used between start/finish. batch_evaluator.start() # forwardBackward is a shortcut for forward and backward. # It is sometimes faster than invoke forward/backward separately, # because in GradientMachine, it may be async. m.forwardBackward(converter(data_batch), outArgs, pass_type) for each_param in m.getParameters(): updater.update(each_param) # Get cost. We use numpy to calculate total cost for this batch. cost_vec = outArgs.getSlotValue(0) cost_vec = cost_vec.copyToNumpyMat() cost = cost_vec.sum() / len(data_batch) # Make evaluator works. m.eval(batch_evaluator) # Print logs. print 'Pass id', pass_id, 'Batch id', batch_id, 'with cost=', \ cost, batch_evaluator batch_evaluator.finish() # Finish batch. # * will clear gradient. # * ensure all values should be updated. updater.finishBatch(cost) # testing stage. use test data set to test current network. updater.apply() test_evaluator.start() test_data_generator = input_order_converter(read_from_mnist(test_file)) for data_batch in generator_to_batch(test_data_generator, 512): # in testing stage, only forward is needed. m.forward(converter(data_batch), outArgs, api.PASS_TEST) m.eval(test_evaluator) # print error rate for test data set print 'Pass', pass_id, ' test evaluator: ', test_evaluator test_evaluator.finish() updater.restore() updater.catchUpWith() params = m.getParameters() for each_param in params: assert isinstance(each_param, api.Parameter) value = each_param.getBuf(api.PARAMETER_VALUE) value = value.copyToNumpyArray() # Here, we could save parameter to every where you want print each_param.getName(), value updater.finishPass() m.finish() if __name__ == '__main__': main()