appropriate nyquist value? 0, 1 or 2?

[mnergizci]

Dear All,

I’m running RELAX for a coseismic model:

and I set the grid sizes as below (in meter):

SX=512 SX2=$((SX/2)) DX=2000 OMP_NUM_THREADS=16 relax <<EOF #grid size $SX $SX $SX2 #sampling (dx1,dx2,dx3,beta,nyquist) $DX $DX $DX 0.4 2

The problem is: When I set nyquist=0, the run finishes normally (very quickly, within about 1–5 minutes). However, when I set nyquist=2, the computation never ends (likely due to memory usage or FFT grid size explosion). It runs for around 10 hours before I have to terminate it, as I believe the coseismic deformation and stress model should complete much sooner.

The coseismic fault patch size is 4 × 4 km, and the total number of patches is 1024.

Has anyone encountered a similar issue?

Is it important to keep nyquist=2, or is 0 sufficient?

Alternatively, should I keep nyquist=2 but reduce the grid size and increase SX to cover the same area?

Many thanks! MN