Table Of Contents

Description

ThereorgPlugin is specifically used for the reorg layer in the YOLOv2 model in TensorRT. It reorganizes the elements in the input tensor and generates an output tensor of a different shape. In YOLOv2, the output tensor from the reorg layer matches the shape of the output tensor from a downstream layer Conv20_1024 in the neural network. The two output tensors are then concatenated together as one single tensor.

Structure

The reorgPlugin takes one input and generates one output. The tensor format must be in NCHW format.

The input is a tensor that has a shape of [N, C, H, W] where:

N is the batch size
C is the number of channels
H is the height of tensor
W is the width of the tensor

After a unique one-to-one mapping, the output tensor of shape [N, C x s x s, H / s, W / s], where s is the stride, is generated.

For example, if we have an input tensor of shape [2, 4, 6, 6].

[[[[ 0 1 2 3 4 5]
[ 6 7 8 9 10 11]
[ 12 13 14 15 16 17]
[ 18 19 20 21 22 23]
[ 24 25 26 27 28 29]
[ 30 31 32 33 34 35]]
 
[[ 36 37 38 39 40 41]
[ 42 43 44 45 46 47]
[ 48 49 50 51 52 53]
[ 54 55 56 57 58 59]
[ 60 61 62 63 64 65]
[ 66 67 68 69 70 71]]
 
[[ 72 73 74 75 76 77]
[ 78 79 80 81 82 83]
[ 84 85 86 87 88 89]
[ 90 91 92 93 94 95]
[ 96 97 98 99 100 101]
[102 103 104 105 106 107]]
 
[[108 109 110 111 112 113]
[114 115 116 117 118 119]
[120 121 122 123 124 125]
[126 127 128 129 130 131]
[132 133 134 135 136 137]
[138 139 140 141 142 143]]]
  
 
[[[144 145 146 147 148 149]
[150 151 152 153 154 155]
[156 157 158 159 160 161]
[162 163 164 165 166 167]
[168 169 170 171 172 173]
[174 175 176 177 178 179]]
 
[[180 181 182 183 184 185]
[186 187 188 189 190 191]
[192 193 194 195 196 197]
[198 199 200 201 202 203]
[204 205 206 207 208 209]
[210 211 212 213 214 215]]
 
[[216 217 218 219 220 221]
[222 223 224 225 226 227]
[228 229 230 231 232 233]
[234 235 236 237 238 239]
[240 241 242 243 244 245]
[246 247 248 249 250 251]]
 
[[252 253 254 255 256 257]
[258 259 260 261 262 263]
[264 265 266 267 268 269]
[270 271 272 273 274 275]
[276 277 278 279 280 281]
[282 283 284 285 286 287]]]]

We set stride = 2 and perform the reorganization, we will get the following output tensor of shape [2, 16, 3, 3].

[[[[ 0 2 4]
[ 6 8 10]
[ 24 26 28]]
 
[[ 30 32 34]
[ 48 50 52]
[ 54 56 58]]
 
[[ 72 74 76]
[ 78 80 82]
[ 96 98 100]]
 
[[102 104 106]
[120 122 124]
[126 128 130]]
 
[[ 1 3 5]
[ 7 9 11]
[ 25 27 29]]
 
[[ 31 33 35]
[ 49 51 53]
[ 55 57 59]]
 
[[ 73 75 77]
[ 79 81 83]
[ 97 99 101]]
 
[[103 105 107]
[121 123 125]
[127 129 131]]
 
[[ 12 14 16]
[ 18 20 22]
[ 36 38 40]]
 
[[ 42 44 46]
[ 60 62 64]
[ 66 68 70]]
 
[[ 84 86 88]
[ 90 92 94]
[108 110 112]]
 
[[114 116 118]
[132 134 136]
[138 140 142]]
 
[[ 13 15 17]
[ 19 21 23]
[ 37 39 41]]
 
[[ 43 45 47]
[ 61 63 65]
[ 67 69 71]]
 
[[ 85 87 89]
[ 91 93 95]
[109 111 113]]
 
[[115 117 119]
[133 135 137]
[139 141 143]]]
  
 
[[[144 146 148]
[150 152 154]
[168 170 172]]
 
[[174 176 178]
[192 194 196]
[198 200 202]]
 
[[216 218 220]
[222 224 226]
[240 242 244]]
 
[[246 248 250]
[264 266 268]
[270 272 274]]
 
[[145 147 149]
[151 153 155]
[169 171 173]]
 
[[175 177 179]
[193 195 197]
[199 201 203]]
 
[[217 219 221]
[223 225 227]
[241 243 245]]
 
[[247 249 251]
[265 267 269]
[271 273 275]]
 
[[156 158 160]
[162 164 166]
[180 182 184]]
 
[[186 188 190]
[204 206 208]
[210 212 214]]
 
[[228 230 232]
[234 236 238]
[252 254 256]]
 
[[258 260 262]
[276 278 280]
[282 284 286]]
 
[[157 159 161]
[163 165 167]
[181 183 185]]
 
[[187 189 191]
[205 207 209]
[211 213 215]]
 
[[229 231 233]
[235 237 239]
[253 255 257]]
 
[[259 261 263]
[277 279 281]
[283 285 287]]]]

Parameters

The reorgPlugin has plugin creator class ReorgPluginCreator and plugin class Reorg.

The following parameters were used to create the Reorg instance.

Type	Parameter	Description
`int`	`stride`	Dimension reduction factor for the input tensor. The stride has to be divisible by the height and the width of the input tensor.

Additional resources

The following resources provide a deeper understanding of the regionPlugin plugin:

License

For terms and conditions for use, reproduction, and distribution, see the TensorRT Software License Agreement documentation.

Changelog

May 2019 This is the first release of this README.md file.

Known issues

There are no known issues in this plugin.