"""
Using an Unstructured Grid
--------------------------

For many applications, the random fields are needed on an unstructured grid.
Normally, such a grid would be read in, but we can simply generate one and
then create a random field at those coordinates.
"""

import numpy as np

import gstools as gs

###############################################################################
# Creating our own unstructured grid
seed = gs.random.MasterRNG(19970221)
rng = np.random.RandomState(seed())
x = rng.randint(0, 100, size=10000)
y = rng.randint(0, 100, size=10000)

model = gs.Exponential(dim=2, var=1, len_scale=[12, 3], angles=np.pi / 8)
srf = gs.SRF(model, seed=20170519)
field = srf((x, y))
srf.vtk_export("field")
# Or create a PyVista dataset
# mesh = srf.to_pyvista()

###############################################################################
ax = srf.plot()
ax.set_aspect("equal")

###############################################################################
# Comparing this image to the previous one, you can see that be using the same
# seed, the same field can be computed on different grids.