[gmx-users] problem while calculating order parameter

[Devargya Chakraborty]

i want to calculate the order prameter between two carbon atom namrd C01
and C03 in my topology file but while calculating, i am getting the
following error.

 Taking z axis as normal to the membrane
Reading file nvt.tpr, VERSION 2019.1 (single precision)
Using following groups:
Groupname: System First atomname: C01 First atomnr 0
Groupname: Other First atomname: C01 First atomnr 0
Groupname: EMI First atomname: C01 First atomnr 0
Groupname: NSC First atomname: NBT First atomnr 760
Groupname: Water First atomname: OW First atomnr 1360
Groupname: SOL First atomname: OW First atomnr 1360
Groupname: non-Water First atomname: C01 First atomnr 0
Groupname: C01 First atomname: C01 First atomnr 0
Groupname: C04 First atomname: C04 First atomnr 1
Groupname: C03 First atomname: C03 First atomnr 2
Groupname: H07 First atomname: H07 First atomnr 3
Groupname: H09 First atomname: H09 First atomnr 4
Groupname: H08 First atomname: H08 First atomnr 5
Groupname: C05 First atomname: C05 First atomnr 6
Groupname: H0B First atomname: H0B First atomnr 7
Groupname: H0C First atomname: H0C First atomnr 8
Groupname: H0D First atomname: H0D First atomnr 9
Groupname: N00 First atomname: N00 First atomnr 10
Groupname: C06 First atomname: C06 First atomnr 11
Groupname: H0F First atomname: H0F First atomnr 12
Groupname: C0N First atomname: C0N First atomnr 13
Groupname: H0O First atomname: H0O First atomnr 14
Groupname: H0P First atomname: H0P First atomnr 15
Groupname: H0Q First atomname: H0Q First atomnr 16
Groupname: N02 First atomname: N02 First atomnr 17
Groupname: H0E First atomname: H0E First atomnr 18
Groupname: NBT First atomname: NBT First atomnr 760
Groupname: SBT First atomname: SBT First atomnr 761
Groupname: OBT First atomname: OBT First atomnr 763
Groupname: CBT First atomname: CBT First atomnr 764
Groupname: F1 First atomname: F1 First atomnr 768

Reading frame       0 time    0.000   Number of elements in first group:
10360

-------------------------------------------------------
Program:     gmx order, version 2019.1
Source file: src/gromacs/gmxana/gmx_order.cpp (line 546)

Fatal error:
grp 1 does not have same number of elements as grp 1

can anybody help.

Thanks