## @package conv
# Module caffe2.python.layers.conv
from caffe2.python import schema
from caffe2.python.layers.layers import (
ModelLayer,
)
import numpy as np
class Conv(ModelLayer):
"""
Convolutional layer
Input:
- input_record: at least has the shape info of C (num_channels)
- output_dim: number of convolutional filters
- kernel_h, kernel_w: kernel size for h and w
- stride_h, stride_w: stride for h and w
- pad_b, pad_l, pad_r, pad_t: padding sizes, if stride == 1,
'None' value will do auto padding
- order: either 'NHWC' or 'NCHW'
"""
def __init__(self, model, input_record, output_dim, kernel_h, kernel_w,
stride_h, stride_w, pad_b=None, pad_l=None, pad_r=None,
pad_t=None, order='NHWC', kernel_init=None, bias_init=None,
kernel_optim=None, bias_optim=None,
name='conv', **kwargs):
super(Conv, self).__init__(model, name, input_record, **kwargs)
assert isinstance(input_record, schema.Scalar), "Incorrect input type"
# input num_channels (C) is needed
input_dims = input_record.field_type().shape
assert (kernel_h > 0 and isinstance(kernel_h, int)), (
"kernel_h should be positive integer")
assert (kernel_w > 0 and isinstance(kernel_w, int)), (
"kernel_w should be positive integer")
self.kernel_h = kernel_h
self.kernel_w = kernel_w
assert (stride_h > 0 and isinstance(stride_h, int)), (
"stride_h should be positive integer")
assert (stride_w > 0 and isinstance(stride_w, int)), (
"stride_w should be positive integer")
self.stride_h = stride_h
self.stride_w = stride_w
# output_dim calculation (http://cs231n.github.io/convolutional-networks/)
# output_dim_w = (input_dim_w - kernel_w + pad_r + pad_l) / stride_w + 1
# so, do auto_padding requires
# pad_r, pad_l = [(input_dim_w - 1) * stride_w - input_dim_w + kernel_w] / 2
# similair for pad_t and pad_b to auto pad kernel_h
# here we only do auto padding for stride = 1 case
if stride_h == 1:
pad_t = int((kernel_h - 1) / 2) if pad_t is None else pad_t
pad_b = int((kernel_h - 1) / 2) if pad_b is None else pad_b
else:
pad_t = 0 if pad_t is None else pad_t
pad_b = 0 if pad_b is None else pad_b
if stride_w == 1:
pad_r = int((kernel_w - 1) / 2) if pad_r is None else pad_r
pad_l = int((kernel_w - 1) / 2) if pad_l is None else pad_l
else:
pad_r = 0 if pad_r is None else pad_r
pad_l = 0 if pad_l is None else pad_l
assert (pad_t >= 0 and isinstance(pad_t, int)), "pad_t should be int >= 0"
assert (pad_b >= 0 and isinstance(pad_b, int)), "pad_b should be int >= 0"
assert (pad_r >= 0 and isinstance(pad_r, int)), "pad_r should be int >= 0"
assert (pad_l >= 0 and isinstance(pad_l, int)), "pad_l should be int >= 0"
self.pad_t = pad_t
self.pad_b = pad_b
self.pad_r = pad_r
self.pad_l = pad_l
assert order in ['NHWC', 'NCHW'], "order should either 'NHWC' or 'NCHW'"
self.order = order
if order == 'NHWC':
input_c = input_dims[-1]
kernel_shape = [output_dim, kernel_h, kernel_w, input_c]
elif order == 'NCHW':
input_c = input_dims[0]
kernel_shape = [output_dim, input_c, kernel_h, kernel_w]
assert input_c > 0, (
"Number of input channels in conv parameters should be positive")
kernel_init = kernel_init if kernel_init else (
'XavierFill', {}
)
bias_init = bias_init if bias_init else (
'ConstantFill', {'value': 0.0}
)
self.kernel = self.create_param(
param_name='conv_kernel',
shape=kernel_shape,
initializer=kernel_init,
optimizer=kernel_optim,
)
self.bias = self.create_param(
param_name='conv_bias',
shape=[output_dim],
initializer=bias_init,
optimizer=bias_optim,
)
# the output_schema only has the num of output channels
# output_h and output_w would be inferred internally
self.output_schema = schema.Scalar(
(np.float32, (output_dim,)),
self.get_next_blob_reference('output')
)
def add_ops(self, net):
net.Conv(
self.input_record.field_blobs() + [self.kernel, self.bias],
self.output_schema.field_blobs(),
kernel_h=self.kernel_h,
kernel_w=self.kernel_w,
stride_h=self.stride_h,
stride_w=self.stride_w,
pad_t=self.pad_t,
pad_l=self.pad_l,
pad_b=self.pad_b,
pad_r=self.pad_r,
order=self.order
)