CUDA out of memory.


While running the 
```
python ./src/m_utils/demo.py -d Shelf
```
I got:
```
RuntimeError: CUDA out of memory. Tried to allocate 81.00 MiB (GPU 0; 7.80 GiB total capacity; 241.56 MiB already allocated; 98.38 MiB free; 5.69 MiB cached)
```
Envs:
- Nvidia 2080 8GB.
- Ubuntu 16

It is ok for running 
```
python ./src/m_utils/demo.py -d Campus
```