Radial neighbor list length of type 1 is not enough

[GitWhilebear]

hi~
when I try to train a Al2O3 model with my Al2O3_se_r.json and you Al2O3 data sets, I get this Warning. So I want to know how to set the parameter sel, why should this parameter be set and what does this parameter do in descriptor ?

Al2O3_se_r.json:
{
"_comment": " model parameters",
"model_type": "se_r",
"model": {
"type_map": ["Al", "O"],
"descriptor": {
"type": "se_r",
"sel": [68, 102],
"rcut_smth": 4.00,
"rcut": 8.00,
"neuron": [5, 10, 20],
"resnet_dt": false,
"seed": 1,
"_comment": " that's all"
},
"fitting_net" :{
"neuron": [120, 120, 120],
"resnet_dt": true,
"seed": 1,
"_comment": "that's all"
},
"_comment": " that's all"
},

"learning_rate" : {
"start_lr":	0.005,
"decay_steps":	5000,
"decay_rate":	0.95,
"_comment":	" that's all"
},

"loss" : {
"start_pref_e":	0.02,
"limit_pref_e":	1,
"start_pref_f":	1000,
"limit_pref_f":	1,
"start_pref_v":	0,
"limit_pref_v":	0,
"_comment":	" that's all"
},

"_comment": " traing controls",
"training" : {
"systems":	["/data/deepmd-se-dataset/Al2O3"],
"set_prefix":	"set",    
"stop_batch":	5000000,
"batch_size":	1,

"seed":		1,

"_comment": " display and restart",
"_comment": " frequencies counted in batch",
"disp_file":	"lcurve_Al2O3_ser_01.out",
"disp_freq":	100,
"numb_test":	10,
"save_freq":	1000,
"save_ckpt":	"Al2O3_ser_01.ckpt",
"load_ckpt":	"Al2O3_ser_01.ckpt",
"disp_training":true,
"time_training":true,
"profiling":	false,
"profiling_file":	"timeline.json",
"_comment":	"that's all"
},

[njzjz]

Same as #108.