Hello Charmm users,

I'm simulating a monoclinic crystal with P21 space group.
I used the following command to build the crystal:
................................................
crystal define Monoclinic 10.839 13.349 4.954 90 91.31 90
crystal build noper 1 cutoff 16
(-X,Y+1/2,-Z)
Crystal Write card unit 20
image BYSEgments xcen 0.0 ycen 0.0 zcen 0.0 select segid CARB end
...............................................
Then update image atom lists

update inbfrq -1 imgfrq -1 ihbfrq 0 -
ewald pmewald kappa 0.34 fftx 32 ffty 32 fftz 32 order 6 lrc -
atom switch vatom vswitch cutnb 16 ctonnb 10 ctofnb 12 -
cutim 16
ener
..........................................

Error message occurs after energy command, showing:
***** LEVEL -5 WARNING FROM PME_column *****
***** no symmetry operations for column FFT yet*****

Could anybody tell me what is this error about. I have searched for it, but did not get any info about it.

Thank you.