PreFuncStruct

先验函数
{
    "type": 0,
    "param": {
        "a": 0,
        "b": 0,
        "n": 0
    },
    "mttf": 0,
    "samples": {
        "x0": 0,
        "y0": 0,
        "x1": 0,
        "y1": 0
    },
    "inflection": {
        "x": 0,
        "y": 0
    }
}