app.py

import gradio as gr
import spaces
import torch

print('cuda avaliable: ' + str(torch.cuda.is_available()))
torch.set_default_device('cuda')

zero = torch.Tensor([0]).cuda()
print('zero device: ' + str(zero.device))  # cpu

one = torch.ones(2, 2, device='cuda')
print('one device: ' + str(one.device))  # cpu

two = torch.matmul(one, one).cuda()
print('two device: ' + str(two.device))  # cpu


@spaces.GPU
def greet(n):
    print('zero device: ' + str(zero.device))  # cuda
    print('one device: ' + str(one.device))  # cuda
    print('two device: ' + str(two.device))  # cuda
    return f"Hello {zero + n} Tensor"


gr.Interface(fn=greet, inputs=gr.Number(), outputs=gr.Text()).launch()