视频里 Andrej Karpathy上课的时候说,这次的作业meaty but educational,确实很meaty,作业一般是由.ipynb文件和.py文件组成,这次因为每个.ipynb文件涉及到的.py文件较多,且互相之间有交叉,所以每篇博客只贴出一个.ipynb或者一个.py文件.(因为之前的作业由于是一个.ipynb文件对应一个.py文件,所以就整合到一篇博客里)
**还是那句话,有错误希望帮我指出来,多多指教,谢谢 **
layer_utils.py内容：
from cs231n.layers import *
from cs231n.fast_layers import *
def affine_relu_forward(x, w, b):
"""
Convenience layer that perorms an affine transform followed by a ReLU
Inputs:
- x: Input to the affine layer
- w, b: Weights for the affine layer
Returns a tuple of:
- out: Output from the ReLU
- cache: Object to give to the backward pass
"""
a, fc_cache = affine_forward(x, w, b)
out, relu_cache = relu_forward(a)
cache = (fc_cache, relu_cache)
return out, cache
def affine_relu_backward(dout, cache):
"""
Backward pass for the affine-relu convenience layer
"""
fc_cache, relu_cache = cache
da = relu_backward(dout, relu_cache)
dx, dw, db = affine_backward(da, fc_cache)
return dx, dw, db
pass
#############################################################################
## help layer affine_bn_relu start
#############################################################################
def affine_bn_relu_forward(x, w, b, gamma, beta, bn_param):
"""
affine - batchnorm - ReLU
Inputs:
- x: Input to the affine layer
- w, b: Weights for the affine layer
- gamma, beta, bn_param parameters for batchnorm layer
Returns a tuple of:
- out: Output from the ReLU
- cache: Object to give to the backward pass
"""
a_out, fc_cache = affine_forward(x, w, b)
b_out, bn_cache = batchnorm_forward(a_out, gamma, beta, bn_param)
out, relu_cache = relu_forward(b_out)
cache = (fc_cache, bn_cache, relu_cache)
return out, cache
def affine_bn_relu_backward(dout, cache):
"""
Backward pass for the affine-bn-relu convenience layer
"""
fc_cache, bn_cache, relu_cache = cache
db = relu_backward(dout, relu_cache)
da, dgamma, dbeta = batchnorm_backward_alt(db, bn_cache)
dx, dw, db = affine_backward(da, fc_cache)
return dx, dw, db, dgamma, dbeta
#############################################################################
## help layer affine_bn_relu end
#############################################################################
#############################################################################
## help layer affine_bn_relu_dp start
#############################################################################
def affine_bn_relu_dp_forward(x, w, b, gamma, beta, bn_param, dropout_param):
"""
affine - batchnorm - ReLU - dropout
Inputs:
- x: Input to the affine layer
- w, b: Weights for the affine layer
- gamma, beta, bn_param parameters for batchnorm layer
- dropout_param parameters for dropout layer
Returns a tuple of:
- out: Output from the dropout
- cache: Object to give to the backward pass
"""
a_out, fc_cache = affine_forward(x, w, b)
b_out, bn_cache = batchnorm_forward(a_out, gamma, beta, bn_param)
r_out, relu_cache = relu_forward(b_out)
out, dp_cache = dropout_forward(r_out, dropout_param)
cache = (fc_cache, bn_cache, relu_cache, dp_cache)
return out, cache
def affine_bn_relu_dp_backward(dout, cache):
"""
Backward pass for the affine-bn-relu-dp convenience layer
"""
fc_cache, bn_cache, relu_cache, dp_cache = cache
d_dp = dropout_backward(dout, dp_cache)
db = relu_backward(d_dp, relu_cache)
da, dgamma, dbeta = batchnorm_backward_alt(db, bn_cache)
dx, dw, db = affine_backward(da, fc_cache)
return dx, dw, db, dgamma, dbeta
#############################################################################
## help layer affine_bn_relu_dp end
#############################################################################
def conv_relu_forward(x, w, b, conv_param):
"""
A convenience layer that performs a convolution followed by a ReLU.
Inputs:
- x: Input to the convolutional layer
- w, b, conv_param: Weights and parameters for the convolutional layer
Returns a tuple of:
- out: Output from the ReLU
- cache: Object to give to the backward pass
"""
a, conv_cache = conv_forward_fast(x, w, b, conv_param)
out, relu_cache = relu_forward(a)
cache = (conv_cache, relu_cache)
return out, cache
def conv_relu_backward(dout, cache):
"""
Backward pass for the conv-relu convenience layer.
"""
conv_cache, relu_cache = cache
da = relu_backward(dout, relu_cache)
dx, dw, db = conv_backward_fast(da, conv_cache)
return dx, dw, db
def conv_relu_pool_forward(x, w, b, conv_param, pool_param):
"""
Convenience layer that performs a convolution, a ReLU, and a pool.
Inputs:
- x: Input to the convolutional layer
- w, b, conv_param: Weights and parameters for the convolutional layer
- pool_param: Parameters for the pooling layer
Returns a tuple of:
- out: Output from the pooling layer
- cache: Object to give to the backward pass
"""
a, conv_cache = conv_forward_fast(x, w, b, conv_param)
s, relu_cache = relu_forward(a)
out, pool_cache = max_pool_forward_fast(s, pool_param)
cache = (conv_cache, relu_cache, pool_cache)
return out, cache
def conv_relu_pool_backward(dout, cache):
"""
Backward pass for the conv-relu-pool convenience layer
"""
conv_cache, relu_cache, pool_cache = cache
ds = max_pool_backward_fast(dout, pool_cache)
da = relu_backward(ds, relu_cache)
dx, dw, db = conv_backward_fast(da, conv_cache)
return dx, dw, db
################### help layer ######################################
def conv_bn_relu_pool_forward(x, w, b, gamma, beta, \
conv_param, pool_param, bn_param):
"""
Convenience layer that performs a convolution, a ReLU, and a pool.
Inputs:
- x: Input to the convolutional layer
- w, b, conv_param: Weights and parameters for the convolutional layer
- pool_param: Parameters for the pooling layer
- bn_param: Parameters for the batch normalization layer
Returns a tuple of:
- out: Output from the pooling layer
- cache: Object to give to the backward pass
"""
a, conv_cache = conv_forward_fast(x, w, b, conv_param)
bn, bn_cache = spatial_batchnorm_forward(a, gamma, beta, bn_param)
s, relu_cache = relu_forward(bn)
out, pool_cache = max_pool_forward_fast(s, pool_param)
cache = (conv_cache, bn_cache, relu_cache, pool_cache)
return out, cache
def conv_bn_relu_pool_backward(dout, cache):
"""
Backward pass for the conv-relu-pool convenience layer
"""
conv_cache, bn_cache, relu_cache, pool_cache = cache
ds = max_pool_backward_fast(dout, pool_cache)
da = relu_backward(ds, relu_cache)
dbn, dgamma, dbeta = spatial_batchnorm_backward(da, bn_cache)
dx, dw, db = conv_backward_fast(dbn, conv_cache)
return dx, dw, db, dgamma, dbeta