Hi, I'm trying to calculate a large number of conduction band states for cubic Si (to be used in a subsequent GW calculation). However, when doing this I sometimes run into errors like "problems computing cholesky decomposition" or "too many bands are unconverged". An example file of the nscf calculation that generates an error for me is below:<br>
<br>The problems can sometimes be avoided by going to a larger wavefunction cutoff, but I'm not sure if this is for good reason or if changing the wavefunction cutoff just happens to avoid the error in the cases I've tried. Also, for a chosen grid (not the one listed below) I get errors when trying to calculate 400,500, and 700 total bands, but the calculation works fine for 600 bands. <br>
<br>Any insight to why this might happen or suggestions as to how to avoid it?<br><br>Thanks,<br>Brad Malone<br>UC Berkeley <br><br>-------------------------------------------------------------<br>&control<br> prefix = 'si'<br>
calculation = 'nscf'<br> restart_mode = 'from_scratch'<br> wf_collect = .true.<br> tstress = .false.<br> tprnfor = .false.<br> outdir = './'<br> wfcdir = './'<br> pseudo_dir = './'<br>
/<br>&system<br> ibrav = 0<br> celldm(1) = 10.2612<br> nat = 2<br> ntyp = 1<br> nbnd = 300<br> ecutwfc = 40.0<br>/<br>&electrons<br> conv_thr = 1.0d-10<br> diagonalization = 'cg'<br> diago_full_acc = .true.<br>
/<br>CELL_PARAMETERS cubic<br> +0.000000000 +0.500000000 +0.500000000<br> +0.500000000 +0.000000000 +0.500000000<br> +0.500000000 +0.500000000 +0.000000000<br>ATOMIC_SPECIES<br> Si 28.086 Si.UPF<br>
ATOMIC_POSITIONS crystal<br> Si -0.125000000 -0.125000000 -0.125000000<br> Si +0.125000000 +0.125000000 +0.125000000<br>K_POINTS crystal<br> 8<br> 0.000000000 0.000000000 0.000000000 1.0<br> 0.000000000 0.000000000 0.250000000 8.0<br>
0.000000000 0.000000000 0.500000000 4.0<br> 0.000000000 0.250000000 0.250000000 6.0<br> 0.000000000 0.250000000 0.500000000 24.0<br> 0.000000000 0.250000000 0.750000000 12.0<br> 0.000000000 0.500000000 0.500000000 3.0<br>
0.250000000 0.500000000 0.750000000 6.0<br>----------------------------------------------------------------------------<br>