About parameters have no gradient

[LogSSim]

'''
Parameter A_log has no gradient.
Parameter D has no gradient.
Parameter in_proj.weight has no gradient.
Parameter conv1d.weight has no gradient.
Parameter conv1d.bias has no gradient.
Parameter x_proj.weight has no gradient.
Parameter dt_proj.weight has no gradient.
Parameter dt_proj.bias has no gradient.
Parameter out_proj.weight has no gradient.
'''

Is this normal?