A storage cluster including a first storage apparatus and a second storage apparatus is defined. The architecture and energy gap of the ligated chromophore are suitable for generation of high efficiency blue, green and even red emissions. The halves are designated even or odd by virtue of the register addresses which they contain. Thereby, even in the case where the radial positions of the test areas of the plurality of layers are substantially overlapped with each other, it is possible to precisely perform the learning of optical power. The method includes determining serving cells of users, respectively, based on a Frank-Wolfe algorithm. Through a learning module designed for a computer accessible recording medium, the method is implemented in a computer controllable device.