model $=$ nn$.$Linear$(5,1)$ # linear model with input dim $=5,$ and a single output

model.weight.grad $=$ torch.Tensor$([[1,2,3,4,5.]])$

model.bias.grad $=$ torch.Tensor$([1.])$

max$\_$grad$\_$norm $=0\mathrm{.}5$

torch.nn$.$utils.clip$\_$grad$\_$norm$\_($model$.$parameters$(),$ max$\_$grad$\_$norm$)$

print$($model$.$weight.grad, model.bias.grad$)$

tensor$([[0\mathrm{.}0668,0\mathrm{.}1336,0\mathrm{.}2004,0\mathrm{.}2673,0\mathrm{.}3341]])$ tensor$([0\mathrm{.}0668])$

Explain why if we set max$\_$grad$\_$norm $>=7\mathrm{.}49$ above, the gradient will be unchanged. Your explanation should demonstrate the calculation of where the number $7\mathrm{.}49$ comes from.