k-point symmetry affects final energy in simple monoclinic lattice in both pw and LCAO base

[hongriTianqi]

Describe the Bug

k-point symmetry affects final energy in simple monoclinic lattice in both pw and LCAO base

To Reproduce

Steps to reproduce the behavior:
diff 812_PW_LT_sm_symmetry_0/result.ref 812_PW_LT_sm_symmetry_1/result.ref
diff 826_NO_LT_sm_symmetry_0/result.ref 826_NO_LT_sm_symmetry_1/result.ref
simple_monoclinic_bug.tar.gz

[dyzheng]

This error come from function "Symmetry_rho::psymm", if I ignore this function, Symmetry=1 result correspond with Symmetry=0 case. this case is special that k point didn't fold.

[dyzheng]

The symmetry average operation for electronic density take place in real space, but not in reciprocal space.
So sometimes k-point symmetry would affects final energy.
But it is not a bug, If k-points for the system is as many as enough, this error would disappear.
@hongriTianqi