diff --git a/example/image-classification/nets.py b/example/image-classification/nets.py new file mode 100644 index 0000000000000000000000000000000000000000..22e67286d621bfdbf3a1bddd019f006659f7dfd2 --- /dev/null +++ b/example/image-classification/nets.py @@ -0,0 +1,126 @@ +# coding: utf-8 +# this model is copy from paddle models repo as a demo for fine-tuning +# for more detail, see https://github.com/PaddlePaddle/models/blob/develop/fluid/PaddleCV/image_classification/ + +from __future__ import absolute_import +from __future__ import division +from __future__ import print_function +import paddle +import paddle.fluid as fluid +import math + +__all__ = ["ResNet", "ResNet50", "ResNet101", "ResNet152"] + +train_parameters = { + "input_size": [3, 224, 224], + "input_mean": [0.485, 0.456, 0.406], + "input_std": [0.229, 0.224, 0.225], + "learning_strategy": { + "name": "piecewise_decay", + "batch_size": 256, + "epochs": [30, 60, 90], + "steps": [0.1, 0.01, 0.001, 0.0001] + } +} + + +class ResNet(): + def __init__(self, layers=50): + self.params = train_parameters + self.layers = layers + + def net(self, input, class_dim=1000): + layers = self.layers + supported_layers = [50, 101, 152] + assert layers in supported_layers, \ + "supported layers are {} but input layer is {}".format(supported_layers, layers) + + if layers == 50: + depth = [3, 4, 6, 3] + elif layers == 101: + depth = [3, 4, 23, 3] + elif layers == 152: + depth = [3, 8, 36, 3] + num_filters = [64, 128, 256, 512] + + conv = self.conv_bn_layer( + input=input, num_filters=64, filter_size=7, stride=2, act='relu') + conv = fluid.layers.pool2d( + input=conv, + pool_size=3, + pool_stride=2, + pool_padding=1, + pool_type='max') + + for block in range(len(depth)): + for i in range(depth[block]): + conv = self.bottleneck_block( + input=conv, + num_filters=num_filters[block], + stride=2 if i == 0 and block != 0 else 1) + + pool = fluid.layers.pool2d( + input=conv, pool_size=7, pool_type='avg', global_pooling=True) + stdv = 1.0 / math.sqrt(pool.shape[1] * 1.0) + out = fluid.layers.fc( + input=pool, + size=class_dim, + param_attr=fluid.param_attr.ParamAttr( + initializer=fluid.initializer.Uniform(-stdv, stdv))) + return out, pool + + def conv_bn_layer(self, + input, + num_filters, + filter_size, + stride=1, + groups=1, + act=None): + conv = fluid.layers.conv2d( + input=input, + num_filters=num_filters, + filter_size=filter_size, + stride=stride, + padding=(filter_size - 1) // 2, + groups=groups, + act=None, + bias_attr=False) + return fluid.layers.batch_norm(input=conv, act=act) + + def shortcut(self, input, ch_out, stride): + ch_in = input.shape[1] + if ch_in != ch_out or stride != 1: + return self.conv_bn_layer(input, ch_out, 1, stride) + else: + return input + + def bottleneck_block(self, input, num_filters, stride): + conv0 = self.conv_bn_layer( + input=input, num_filters=num_filters, filter_size=1, act='relu') + conv1 = self.conv_bn_layer( + input=conv0, + num_filters=num_filters, + filter_size=3, + stride=stride, + act='relu') + conv2 = self.conv_bn_layer( + input=conv1, num_filters=num_filters * 4, filter_size=1, act=None) + + short = self.shortcut(input, num_filters * 4, stride) + + return fluid.layers.elementwise_add(x=short, y=conv2, act='relu') + + +def ResNet50(): + model = ResNet(layers=50) + return model + + +def ResNet101(): + model = ResNet(layers=101) + return model + + +def ResNet152(): + model = ResNet(layers=152) + return model