From 323a048348bca6aefc749a1dcfbf241531291430 Mon Sep 17 00:00:00 2001 From: qiaolongfei Date: Mon, 18 Jun 2018 09:07:18 +0800 Subject: [PATCH] add doc for BilinearInitializer MSRAInitializer --- python/paddle/fluid/initializer.py | 105 ++++++++++++++++------------- 1 file changed, 60 insertions(+), 45 deletions(-) diff --git a/python/paddle/fluid/initializer.py b/python/paddle/fluid/initializer.py index 6b8b0aab3ed..df42449dcda 100644 --- a/python/paddle/fluid/initializer.py +++ b/python/paddle/fluid/initializer.py @@ -19,10 +19,10 @@ from framework import convert_np_dtype_to_dtype_ from core import VarDesc __all__ = [ - 'Constant', 'Uniform', 'Normal', 'Xavier', 'Bilinear', 'force_init_on_cpu', - 'init_on_cpu', 'ConstantInitializer', 'UniformInitializer', - 'NormalInitializer', 'XavierInitializer', 'BilinearInitializer', - 'MSRAInitializer' + 'Constant', 'Uniform', 'Normal', 'Xavier', 'Bilinear', 'MSRA', + 'force_init_on_cpu', 'init_on_cpu', 'ConstantInitializer', + 'UniformInitializer', 'NormalInitializer', 'XavierInitializer', + 'BilinearInitializer', 'MSRAInitializer' ] _force_init_on_cpu_ = False @@ -353,30 +353,42 @@ class MSRAInitializer(Initializer): """Implements the MSRA initializer a.k.a. Kaiming Initializer This class implements the weight initialization from the paper - Delving Deep into Rectifiers: Surpassing Human-Level Performance on - ImageNet Classification[1] by Kaiming He, Xiangyu Zhang, Shaoqing Ren - and Jian Sun. This is a robust initialization method that particularly - considers the rectifier nonlinearities. In case of Uniform distribution, - the range is [-x, x], where x = sqrt(6 / fan_in). In case of Normal - distribution, the mean is 0 and the standard deviation - is sqrt(2/ fan_in). - - References: - [1] Delving Deep into Rectifiers: Surpassing Human-Level Performance - on ImageNet Classification - (https://arxiv.org/abs/1502.01852) + `Delving Deep into Rectifiers: Surpassing Human-Level Performance on + ImageNet Classification `_ + by Kaiming He, Xiangyu Zhang, Shaoqing Ren and Jian Sun. This is a + robust initialization method that particularly considers the rectifier + nonlinearities. In case of Uniform distribution, the range is [-x, x], where + + .. math:: + + x = \sqrt{\\frac{6.0}{fan\_in}} + + In case of Normal distribution, the mean is 0 and the standard deviation + is + + .. math:: + + \sqrt{\\frac{2.0}{fan\_in}} + + Args: + uniform (bool): whether to use uniform or normal distribution + fan_in (float): fan_in for MSRAInitializer. If None, it is\ + inferred from the variable. + seed (int): random seed + + Note: + It is recommended to set fan_in to None for most cases. + + Examples: + .. code-block:: python + + fc = fluid.layers.fc( + input=queries, size=10, + param_attr=fluid.initializer.MSRA(uniform=False)) """ def __init__(self, uniform=True, fan_in=None, seed=0): """Constructor for MSRAInitializer - - Args: - uniform: whether to use uniform or normal distribution - fan_in: fan_in for MSRAInitializer. If None, it is - inferred from the variable. - seed: random seed - - Note: It is recommended to set fan_in to None for most cases. """ assert uniform is not None assert seed is not None @@ -436,34 +448,37 @@ class MSRAInitializer(Initializer): class BilinearInitializer(Initializer): - """Implements the bilinear initializer. - + """ This initializer can be used in transposed convolution operator to act as upsampling. Users can upsample a feature map with shape of (B, C, H, W) by any integer factor. The usage is: - - >>> factor = 2 - >>> w_attr = ParamAttr(learning_rate=0., regularizer=L2Decay(0.), - >>> initializer=Bilinear()) - >>> conv_up = fluid.layers.conv2d_transpose( - >>> input, - >>> num_filters=C, - >>> output_size=None, - >>> filter_size=2 * factor - factor % 2, - >>> padding=ceil((factor - 1) / 2.), - >>> stride=factor, - >>> groups=C, - >>> param_attr=w_attr, - >>> bias_attr=False) - - - Where, `num_filters=C` and `groups=C` means this is channel-wise tranposed + + Examples: + + .. code-block:: python + + factor = 2 + w_attr = ParamAttr(learning_rate=0., regularizer=L2Decay(0.), + initializer=Bilinear()) + conv_up = fluid.layers.conv2d_transpose( + input, + num_filters=C, + output_size=None, + filter_size=2 * factor - factor % 2, + padding=ceil((factor - 1) / 2.), + stride=factor, + groups=C, + param_attr=w_attr, + bias_attr=False) + + Where, `num_filters=C` and `groups=C` means this is channel-wise transposed convolution. The filter shape will be (C, 1, K, K) where K is `filer_size`, This initializer will set a (K, K) interpolation kernel for every channel of the filter identically. The resulting shape of the output feature map will be (B, C, factor * H, factor * W). Note that the learning rate and the weight decay are set to 0 in order to keep coefficient values of bilinear - interpolation unchanged during training. + interpolation unchanged during training. + """ def __init__(self): @@ -480,7 +495,7 @@ class BilinearInitializer(Initializer): be added. Returns: - the initialization op + Operator: the initialization op Raises: ValueError: If type of `var` and `block` is not right. -- GitLab