Is an atomic explosion an over unity reaction?

Are you getting more energy out than you are putting in when an atomic weapon is detonated? If so or even if not, how does this compare to the principles of cold fusion? If it is the conversion of the matter into energy then there would be no difference between both a hot fusion and a cold fusion except for the temperature at which the experiment is conducted. One would require a little more energy that the other to get the reaction started but once started there is still a hell of a lot more energy coming out than going in.