Skip to content

appropriate nyquist value? 0, 1 or 2? #16

Description

@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

Metadata

Metadata

Assignees

No one assigned

    Labels

    No labels
    No labels

    Type

    No type

    Fields

    No fields configured for issues without a type.

    Projects

    No projects

    Milestone

    No milestone

    Relationships

    None yet

    Development

    No branches or pull requests

    Issue actions