From the docs of torch.manual_seed
:
seed (int) – The desired seed. Value must be within the inclusive range [-0x8000_0000_0000_0000, 0xffff_ffff_ffff_ffff]. Otherwise, a RuntimeError is raised. Negative inputs are remapped to positive values with the formula 0xffff_ffff_ffff_ffff + seed.
So the largest valid value would be 2**64-1
:
torch.manual_seed(18446744073709551615) # works
torch.manual_seed(2**64-1) # works
torch.manual_seed(18446744073709551615+1) # fails
# > RuntimeError: Overflow when unpacking long
torch.manual_seed(2**64) # fails
# > RuntimeError: Overflow when unpacking long