EOS get started and input examples

Equation of State (EOS) here calculates the energies of the most stable structures as a function of volume. Users can refer to Figure 4 of the dpgen CPC paper for more information of EOS.

An example of the input file for EOS by VASP:

{
	"structures":	["confs/mp-*","confs/std-*","confs/test-*"],
	"interaction": {
		"type":		"vasp",
		"incar":	"vasp_input/INCAR",
                "potcar_prefix":"vasp_input",
		"potcars":	{"Al": "POTCAR.al", "Mg": "POTCAR.mg"}
	},
	"properties": [
        {
         "type":         "eos",
         "vol_start":    0.9,
         "vol_end":      1.1,
         "vol_step":     0.01
        }
        ]
}

vol_start is the starting volume relative to the equilibrium structure, vol_step is the volume increment step relative to the equilibrium structure, and the biggest relative volume is smaller than vol_end.