When I used "find_pair 0.pdb | analyze" to analyze the Gromacs simulation output pdb file, I got the following tips, whether this affects the result and how I should solve the problem.
'''
handling file <0.pdb>
Time used: 00:00:00:00
missing ' P ' atom : residue name ' DG', chain , number [ 1 ]
missing ' OP1' atom : residue name ' DG', chain , number [ 1 ]
missing ' OP2' atom : residue name ' DG', chain , number [ 1 ]
missing ' P ' atom : residue name ' DG', chain , number [ 1 ]
missing ' OP1' atom : residue name ' DG', chain , number [ 1 ]
missing ' OP2' atom : residue name ' DG', chain , number [ 1 ]
missing ' P ' atom : residue name ' DG', chain , number [ 1 ]
missing ' P ' atom : residue name ' DG', chain , number [ 1 ]
Time used: 00:00:00:01
'''