def get_l2_act_cost(self, state, target, coeff):
        avg = state.mean(axis=0)
        diff = avg - target
        return coeff * T.sqr(diff).mean()
.. todo::
dataset/ETHPy150Open lisa-lab/pylearn2/pylearn2/models/dbm/ising.py/BoltzmannIsingHidden.get_l2_act_cost