Windiows 10 cuda gpu and pytorch

I installed CUDA on windows 10 to manage a RTX 2070 geforce.
On python program
print(torch.cuda.device_count())
i have the respons : 0
and i couldn’t map CUDA on the GPU for pytorch
print(torch.cuda.is_available()) the response is ‘false’

My problem, install Pytorch with Cuda enable to be able to use the gpu or how to install the nvidia drivers, it seems be linked.

Many thanks

Victor