CUDA out of memory.

[IamGroot19]

I ran everything with default settings just to test the code ( run train.py --img lincoln.png). I got the 2x enlarged image.

Then I used this 2x image as input to magnify it to 4x. During this run, all the 15000 epochs were completed and a new image file called 'low_res.png' was found in the folder. But after this, the program stopped without completion with the following message :

CUDA out of memory. Tried to allocate 788.00 MiB (GPU 0; 4.00 GiB total capacity; 2.38 GiB already allocated; 531.39 MiB free; 128.68 MiB cached)

Also, during the running of the program, I checked the task manager and it was always like CPU(near 100%), GPU(2%).

Can someone help me understand the issue and help me find a solution?