def test_setter(self):
krige1 = gs.krige.Krige(gs.Exponential(), self.cond_pos, self.cond_val)
krige2 = gs.krige.Krige(
gs.Gaussian(var=2),
self.cond_pos,
self.cond_val,
mean=-1,
trend=-2,
normalizer=gs.normalizer.YeoJohnson(),
)
crf1 = gs.CondSRF(krige1)
crf2 = gs.CondSRF(krige2, seed=19970221)
# update settings
crf1.model = gs.Gaussian(var=2)
crf1.mean = -1
crf1.trend = -2
# also checking correctly setting uninitialized normalizer
crf1.normalizer = gs.normalizer.YeoJohnson
# check if setting went right
self.assertTrue(crf1.model == crf2.model)
self.assertTrue(crf1.normalizer == crf2.normalizer)
self.assertAlmostEqual(crf1.mean, crf2.mean)
self.assertAlmostEqual(crf1.trend, crf2.trend)
# reset kriging
crf1.krige.set_condition()
# compare fields
field1 = crf1(self.pos, seed=19970221)
field2 = crf2(self.pos)
self.assertTrue(np.all(np.isclose(field1, field2)))
def test_krige_mean(self):
# check for constant mean (simple kriging)
krige = gs.krige.Simple(gs.Gaussian(), self.cond_pos, self.cond_val)
mean_f = krige.structured(self.pos, only_mean=True)
self.assertTrue(np.all(np.isclose(mean_f, 0)))
krige = gs.krige.Simple(
gs.Gaussian(),
self.cond_pos,
self.cond_val,
mean=mean_func,
normalizer=gs.normalizer.YeoJohnson,
trend=trend,
)
# check applying mean, norm, trend
mean_f1 = krige.structured(self.pos, only_mean=True)
mean_f2 = gs.normalizer.tools.apply_mean_norm_trend(
self.pos,
np.zeros(tuple(map(len, self.pos))),
mean=mean_func,
normalizer=gs.normalizer.YeoJohnson,
trend=trend,
mesh_type="structured",
)
self.assertTrue(np.all(np.isclose(mean_f1, mean_f2)))
krige = gs.krige.Simple(gs.Gaussian(), self.cond_pos, self.cond_val)
mean_f = krige.structured(self.pos, only_mean=True)
self.assertTrue(np.all(np.isclose(mean_f, 0)))
# check for constant mean (ordinary kriging)
krige = gs.krige.Ordinary(gs.Gaussian(), self.cond_pos, self.cond_val)
mean_f = krige.structured(self.pos, only_mean=True)
self.assertTrue(np.all(np.isclose(mean_f, krige.get_mean())))
def test_field_mean_std_convergence(seed):
np.random.seed(seed)
np.random.rand(1000)
# =========== A structured grid of points: =====================================
bounds = ([13, 3], [40, 32])
grid_size = [10, 15]
grid_points = PointSet(bounds, grid_size)
random_points = PointSet(bounds, grid_size[0] * grid_size[1])
exponential = 1.0
gauss = 2.0
corr_length = 2
n_terms = (np.inf, np.inf
) # Use full expansion to avoid error in approximation.
impl = SpatialCorrelatedField
#print("Test exponential, grid points.")
impl_test_mu_sigma(impl, exponential, grid_points, n_terms_range=n_terms)
#print("Test Gauss, grid points.")
impl_test_mu_sigma(impl, gauss, grid_points, n_terms_range=n_terms)
#print("Test exponential, random points.")
impl_test_mu_sigma(impl, exponential, random_points, n_terms_range=n_terms)
#print("Test Gauss, random points.")
impl_test_mu_sigma(impl, gauss, random_points, n_terms_range=n_terms)
len_scale = corr_length * 2 * np.pi
# Random points gauss model
gauss_model = gstools.Gaussian(dim=random_points.dim, len_scale=len_scale)
impl = GSToolsSpatialCorrelatedField(gauss_model)
impl_test_mu_sigma(impl,
gauss,
random_points,
n_terms_range=n_terms,
corr_length=2)
# Random points exp model
exp_model = gstools.Exponential(dim=random_points.dim, len_scale=len_scale)
impl = GSToolsSpatialCorrelatedField(exp_model)
impl_test_mu_sigma(impl,
exponential,
random_points,
n_terms_range=n_terms,
corr_length=2)
# Grid points gauss model
gauss_model = gstools.Gaussian(dim=grid_points.dim, len_scale=len_scale)
impl = GSToolsSpatialCorrelatedField(gauss_model)
impl_test_mu_sigma(impl,
gauss_model,
grid_points,
n_terms_range=n_terms,
corr_length=2)
# Grid points exp model
exp_model = gstools.Exponential(dim=grid_points.dim, len_scale=len_scale)
impl = GSToolsSpatialCorrelatedField(exp_model)
impl_test_mu_sigma(impl,
exp_model,
grid_points,
n_terms_range=n_terms,
corr_length=2)
def kriging_fill_grid(input):
"""
conditioning data:
input['x'] (array)
input['y'] (array)
input['z'] (array)
grid definition for output field
input['x_start']
input['x_stop']
input['x_step']
input['y_start']
input['y_stop']
input['y_step']
"""
if len(input['x']) == len(input['y']) == len(input['z']):
XI = np.arange(input['x_start'], input['x_stop'], input['x_step'])
YI = np.arange(input['y_start'], input['y_stop'], input['y_step'])
cov_model = gs.Gaussian(dim=2,
len_scale=1,
anis=0.2,
angles=-0.5,
var=0.5,
nugget=0.1)
#pk_kwargs = cov_model.pykrige_kwargs
#OK = OrdinaryKriging(input['x'], input['y'], input['z'], **pk_kwargs)
#ZI, ss = OK.execute("grid", XI, YI)
OK2 = gs.krige.Ordinary(cov_model, [input['x'], input['y']],
input['z'])
ZI, ss = OK2.structured([XI, YI])
return ZI
else:
return None
def setUp(self):
self.cov_model = gs.Gaussian(dim=2, var=1.5, len_scale=4.0)
rng = np.random.RandomState(123018)
x = rng.uniform(0.0, 10, 100)
y = rng.uniform(0.0, 10, 100)
self.field = rng.uniform(0.0, 10, 100)
self.pos = np.array([x, y])
def test_rotation_unstruct_3d(self):
self.cov_model = gs.Gaussian(dim=3,
var=1.5,
len_scale=4.0,
anis=(0.25, 0.5))
x_len = len(self.x_grid_c)
y_len = len(self.y_grid_c)
z_len = len(self.z_grid_c)
x_u, y_u, z_u = np.meshgrid(self.x_grid_c, self.y_grid_c,
self.z_grid_c)
x_u = np.reshape(x_u, x_len * y_len * z_len)
y_u = np.reshape(y_u, x_len * y_len * z_len)
z_u = np.reshape(z_u, x_len * y_len * z_len)
srf = gs.SRF(self.cov_model, mean=self.mean, mode_no=self.mode_no)
field = srf((x_u, y_u, z_u), seed=self.seed, mesh_type="unstructured")
field_str = np.reshape(field, (y_len, x_len, z_len))
self.cov_model.angles = (-np.pi / 2.0, -np.pi / 2.0)
srf = gs.SRF(self.cov_model, mean=self.mean, mode_no=self.mode_no)
field_rot = srf((x_u, y_u, z_u),
seed=self.seed,
mesh_type="unstructured")
field_rot_str = np.reshape(field_rot, (y_len, x_len, z_len))
self.assertAlmostEqual(field_str[0, 0, 0], field_rot_str[-1, -1, 0])
self.assertAlmostEqual(field_str[1, 2, 0], field_rot_str[-3, -1, 1])
self.assertAlmostEqual(field_str[0, 0, 1], field_rot_str[-1, -2, 0])
def setUp(self):
self.cmod = gs.Gaussian(latlon=True,
var=2,
len_scale=777,
rescale=gs.EARTH_RADIUS)
self.lat = self.lon = range(-80, 81)
self.data = np.array([
[52.9336, 8.237, 15.7],
[48.6159, 13.0506, 13.9],
[52.4853, 7.9126, 15.1],
[50.7446, 9.345, 17.0],
[52.9437, 12.8518, 21.9],
[53.8633, 8.1275, 11.9],
[47.8342, 10.8667, 11.4],
[51.0881, 12.9326, 17.2],
[48.406, 11.3117, 12.9],
[49.7273, 8.1164, 17.2],
[49.4691, 11.8546, 13.4],
[48.0197, 12.2925, 13.9],
[50.4237, 7.4202, 18.1],
[53.0316, 13.9908, 21.3],
[53.8412, 13.6846, 21.3],
[54.6792, 13.4343, 17.4],
[49.9694, 9.9114, 18.6],
[51.3745, 11.292, 20.2],
[47.8774, 11.3643, 12.7],
[50.5908, 12.7139, 15.8],
])
def test_meshio(self):
points = np.array([
[0.0, 0.0, 0.0],
[0.0, 1.0, 0.0],
[0.0, 0.0, 1.0],
[1.0, 0.0, 0.0],
])
cells = [("tetra", np.array([[0, 1, 2, 3]]))]
mesh = meshio.Mesh(points, cells)
model = gs.Gaussian(dim=3, len_scale=0.1)
srf = gs.SRF(model)
srf.mesh(mesh, points="points")
self.assertEqual(len(srf.field), 4)
srf.mesh(mesh, points="centroids")
self.assertEqual(len(srf.field), 1)
def test_vario_est(self):
srf = gs.SRF(self.cmod, seed=12345)
field = srf.structured((self.lat, self.lon))
bin_edges = [0.01 * i for i in range(30)]
bin_center, emp_vario = gs.vario_estimate(
*((self.lat, self.lon), field, bin_edges),
latlon=True,
mesh_type="structured",
sampling_size=2000,
sampling_seed=12345,
)
mod = gs.Gaussian(latlon=True, rescale=gs.EARTH_RADIUS)
mod.fit_variogram(bin_center, emp_vario, nugget=False)
# allow 10 percent relative error
self.assertLess(_rel_err(mod.var, self.cmod.var), 0.1)
self.assertLess(_rel_err(mod.len_scale, self.cmod.len_scale), 0.1)
def test_incomprrandmeth(self):
self.cov_model = gs.Gaussian(dim=2, var=0.5, len_scale=1.0)
srf = gs.SRF(
self.cov_model,
mean=self.mean,
mode_no=self.mode_no,
generator="IncomprRandMeth",
mean_velocity=0.5,
)
field = srf((self.x_tuple, self.y_tuple), seed=476356)
self.assertAlmostEqual(field[0, 0], 1.23693272)
self.assertAlmostEqual(field[0, 1], 0.89242284)
field = srf((self.x_grid, self.y_grid),
seed=4734654,
mesh_type="structured")
self.assertAlmostEqual(field[0, 0, 0], 1.07812013)
self.assertAlmostEqual(field[0, 1, 0], 1.06180674)
def setUp(self):
self.cov_model = gs.Gaussian(dim=2, var=1.5, len_scale=4.0)
self.mean = 0.3
self.mode_no = 100
self.seed = 825718662
self.x_grid = np.linspace(0.0, 12.0, 48)
self.y_grid = np.linspace(0.0, 10.0, 46)
self.z_grid = np.linspace(0.0, 10.0, 40)
self.x_grid_c = np.linspace(-6.0, 6.0, 8)
self.y_grid_c = np.linspace(-6.0, 6.0, 8)
self.z_grid_c = np.linspace(-6.0, 6.0, 8)
rng = np.random.RandomState(123018)
self.x_tuple = rng.uniform(0.0, 10, 100)
self.y_tuple = rng.uniform(0.0, 10, 100)
self.z_tuple = rng.uniform(0.0, 10, 100)
def error_test(self):
# try fitting directional variogram
mod = gs.Gaussian(latlon=True)
with self.assertRaises(ValueError):
mod.fit_variogram([0, 1], [[0, 1], [0, 1], [0, 1]])
# try to use fixed dim=2 with latlon
with self.assertRaises(ValueError):
ErrMod(latlon=True)
# try to estimate latlon vario on wrong dim
with self.assertRaises(ValueError):
gs.vario_estimate([[1], [1], [1]], [1], [0, 1], latlon=True)
# try to estimate directional vario with latlon
with self.assertRaises(ValueError):
gs.vario_estimate([[1], [1]], [1], [0, 1], latlon=True, angles=1)
# try to create a vector field with latlon
with self.assertRaises(ValueError):
srf = gs.SRF(mod, generator="VectorField", mode_no=2)
srf([1, 2])
def setUp(self):
self.cov_model_2d = gs.Gaussian(dim=2, var=1.5, len_scale=2.5)
self.cov_model_3d = copy.deepcopy(self.cov_model_2d)
self.cov_model_3d.dim = 3
self.seed = 19031977
self.x_grid = np.linspace(0.0, 10.0, 9)
self.y_grid = np.linspace(-5.0, 5.0, 16)
self.z_grid = np.linspace(-6.0, 7.0, 8)
self.x_tuple = np.linspace(0.0, 10.0, 10)
self.y_tuple = np.linspace(-5.0, 5.0, 10)
self.z_tuple = np.linspace(-6.0, 8.0, 10)
self.rm_2d = IncomprRandMeth(
self.cov_model_2d, mode_no=100, seed=self.seed
)
self.rm_3d = IncomprRandMeth(
self.cov_model_3d, mode_no=100, seed=self.seed
)
def test_nugget(self):
model = gs.Gaussian(
nugget=0.01,
var=0.5,
len_scale=2,
anis=[0.1, 1],
angles=[0.5, 0, 0],
)
krige = gs.krige.Ordinary(model,
self.cond_pos,
self.cond_val,
exact=True)
crf = gs.CondSRF(krige, seed=19970221)
field_1 = crf.unstructured(self.pos)
field_2 = crf.structured(self.pos)
for i, val in enumerate(self.cond_val):
self.assertAlmostEqual(val, field_1[i], places=2)
self.assertAlmostEqual(val, field_2[3 * (i, )], places=2)
def test_auto_fit(self):
x = y = range(60)
pos = gs.generate_grid([x, y])
model = gs.Gaussian(dim=2, var=1, len_scale=10)
srf = gs.SRF(model,
seed=20170519,
normalizer=gs.normalizer.LogNormal())
srf(pos)
ids = np.arange(srf.field.size)
samples = np.random.RandomState(20210201).choice(ids,
size=60,
replace=False)
# sample conditioning points from generated field
cond_pos = pos[:, samples]
cond_val = srf.field[samples]
krige = gs.krige.Ordinary(
model=gs.Stable(dim=2),
cond_pos=cond_pos,
cond_val=cond_val,
normalizer=gs.normalizer.BoxCox(),
fit_normalizer=True,
fit_variogram=True,
)
# test fitting during kriging
self.assertTrue(np.abs(krige.normalizer.lmbda - 0.0) < 1e-1)
self.assertAlmostEqual(krige.model.len_scale, 10.2677, places=4)
self.assertAlmostEqual(
krige.model.sill,
krige.normalizer.normalize(cond_val).var(),
places=4,
)
# test fitting during vario estimate
bin_center, gamma, normalizer = gs.vario_estimate(
cond_pos,
cond_val,
normalizer=gs.normalizer.BoxCox,
fit_normalizer=True,
)
model = gs.Stable(dim=2)
model.fit_variogram(bin_center, gamma)
self.assertAlmostEqual(model.var, 0.6426670183, places=4)
self.assertAlmostEqual(model.len_scale, 9.635193952, places=4)
self.assertAlmostEqual(model.nugget, 0.001617908408, places=4)
self.assertAlmostEqual(model.alpha, 2.0, places=4)
def test_raise(self):
# vector field on latlon
fld = gs.field.Field(gs.Gaussian(latlon=True), value_type="vector")
self.assertRaises(ValueError, fld, [1, 2], [1, 2])
# no pos tuple present
fld = gs.field.Field(dim=2)
self.assertRaises(ValueError, fld.post_field, [1, 2])
# wrong model type
with self.assertRaises(ValueError):
gs.field.Field(model=3.1415)
# no model and no dim given
with self.assertRaises(ValueError):
gs.field.Field()
# wrong value type
with self.assertRaises(ValueError):
gs.field.Field(dim=2, value_type="complex")
# wrong mean shape
with self.assertRaises(ValueError):
gs.field.Field(dim=3, mean=[1, 2])
def setUp(self):
self.cov_model = gs.Gaussian(dim=2, var=1.5, len_scale=4.0)
self.mean = 0.3
self.mode_no = 100
self.seed = 825718662
self.x_grid = np.linspace(0.0, 12.0, 48)
self.y_grid = np.linspace(0.0, 10.0, 46)
self.methods = [
"binary",
"boxcox",
"zinnharvey",
"normal_force_moments",
"normal_to_lognormal",
"normal_to_uniform",
"normal_to_arcsin",
"normal_to_uquad",
]
def test_cov_func_convergence(seed):
# TODO:
# Seems that we have systematic error in covariance function.
# Error seems to grow with distance. About l**0.1 for corr_exp==1,
# faster grow for corr_exp == 2.
# Not clear if it is a selection effect however there is cleare convergence
# of the error to some smooth limit function.
# Using (sum of squares) of absolute error gives systemetic error
# between 0.5 - 4.0, seems o grow a bit with level !! but no grow with distance.
# No influence of uniform vs. normal points. Just more cosy for larger distances
# as there is smaller sample set.
np.random.seed(seed)
np.random.rand(100)
# =========== A structured grid of points: =====================================
bounds = ([0, 0], [40, 30])
random_points = PointSet(bounds, 100)
exponential = 1.0
gauss = 2.0
corr_length = 2
n_terms = (np.inf, np.inf
) # Use full expansion to avoid error in approximation.
impl_test_cov_func(SpatialCorrelatedField,
gauss,
random_points,
n_terms_range=n_terms,
corr_length=corr_length)
impl_test_cov_func(SpatialCorrelatedField,
exponential,
random_points,
n_terms_range=n_terms,
corr_length=corr_length)
len_scale = corr_length * 2 * np.pi
gauss_model = gstools.Gaussian(dim=random_points.dim, len_scale=len_scale)
impl = GSToolsSpatialCorrelatedField(gauss_model)
impl_test_cov_func(impl, gauss, random_points, n_terms_range=n_terms)
# Random points exp model
exp_model = gstools.Exponential(dim=random_points.dim, len_scale=len_scale)
impl = GSToolsSpatialCorrelatedField(exp_model)
impl_test_cov_func(impl, exponential, random_points, n_terms_range=n_terms)
def create_corr_field(model='gauss',
corr_length=0.125,
dim=2,
log=True,
sigma=1):
"""
Create random fields
:return:
"""
len_scale = corr_length * 2 * np.pi
if model == 'fourier':
return cf.Fields([
cf.Field(
'conductivity',
cf.FourierSpatialCorrelatedField('gauss',
dim=dim,
corr_length=corr_length,
log=log)),
])
if model == 'exp':
model = gstools.Exponential(dim=dim, var=sigma**2, len_scale=len_scale)
elif model == 'TPLgauss':
model = gstools.TPLGaussian(dim=dim, var=sigma**2, len_scale=len_scale)
elif model == 'TPLexp':
model = gstools.TPLExponential(dim=dim,
var=sigma**2,
len_scale=len_scale)
elif model == 'TPLStable':
model = gstools.TPLStable(dim=dim, var=sigma**2, len_scale=len_scale)
else:
model = gstools.Gaussian(dim=dim, var=sigma**2, len_scale=len_scale)
return cf.Fields([
cf.Field('conductivity',
cf.GSToolsSpatialCorrelatedField(model, log=log)),
])
setting the estimation directions in 3D. Afterwards we will fit a model to this estimated variogram and show the result. """ import numpy as np import gstools as gs import matplotlib.pyplot as plt from mpl_toolkits.mplot3d import Axes3D ############################################################################### # Generating synthetic field with anisotropy and rotation by Tait-Bryan angles. dim = 3 # rotation around z, y, x angles = [np.deg2rad(90), np.deg2rad(45), np.deg2rad(22.5)] model = gs.Gaussian(dim=3, len_scale=[16, 8, 4], angles=angles) x = y = z = range(50) pos = (x, y, z) srf = gs.SRF(model, seed=1001) field = srf.structured(pos) ############################################################################### # Here we generate the axes of the rotated coordinate system # to get an impression what the rotation angles do. # All 3 axes of the rotated coordinate-system main_axes = gs.rotated_main_axes(dim, angles) axis1, axis2, axis3 = main_axes ############################################################################### # Now we estimate the variogram along the main axes. When the main axes are
"""
Anisotropy and Rotation
=======================
The internally used (semi-) variogram
represents the isotropic case for the model.
Nevertheless, you can provide anisotropy ratios by:
"""
import gstools as gs
model = gs.Gaussian(dim=3, var=2.0, len_scale=10, anis=0.5)
print(model.anis)
print(model.len_scale_vec)
###############################################################################
# As you can see, we defined just one anisotropy-ratio
# and the second transversal direction was filled up with ``1.``.
# You can get the length-scales in each direction by
# the attribute :any:`CovModel.len_scale_vec`. For full control you can set
# a list of anistropy ratios: ``anis=[0.5, 0.4]``.
#
# Alternatively you can provide a list of length-scales:
model = gs.Gaussian(dim=3, var=2.0, len_scale=[10, 5, 4])
model.plot("vario_spatial")
print("Anisotropy representations:")
print("Anis. ratios:", model.anis)
print("Main length scale", model.len_scale)
print("All length scales", model.len_scale_vec)
###############################################################################
Artificial data ^^^^^^^^^^^^^^^ Here we generate log-normal data following a Gaussian covariance model. We will generate the "original" field on a 60x60 mesh, from which we will take samples in order to pretend a situation of data-scarcity. """ import numpy as np import gstools as gs import matplotlib.pyplot as plt # structured field with edge length of 50 x = y = range(51) pos = gs.generate_grid([x, y]) model = gs.Gaussian(dim=2, var=1, len_scale=10) srf = gs.SRF(model, seed=20170519, normalizer=gs.normalizer.LogNormal()) # generate the original field srf(pos) ############################################################################### # Here, we sample 60 points and set the conditioning points and values. ids = np.arange(srf.field.size) samples = np.random.RandomState(20210201).choice(ids, size=60, replace=False) # sample conditioning points from generated field cond_pos = pos[:, samples] cond_val = srf.field[samples] ###############################################################################
Let's create an ensemble of conditioned random fields in 2D.
"""
import numpy as np
import matplotlib.pyplot as plt
import gstools as gs
# conditioning data (x, y, value)
cond_pos = [[0.3, 1.9, 1.1, 3.3, 4.7], [1.2, 0.6, 3.2, 4.4, 3.8]]
cond_val = [0.47, 0.56, 0.74, 1.47, 1.74]
# grid definition for output field
x = np.arange(0, 5, 0.1)
y = np.arange(0, 5, 0.1)
model = gs.Gaussian(dim=2, var=0.5, len_scale=5, anis=0.5, angles=-0.5)
krige = gs.Krige(model, cond_pos=cond_pos, cond_val=cond_val)
cond_srf = gs.CondSRF(krige)
###############################################################################
# We create a list containing the generated conditioned fields.
ens_no = 4
field = []
for i in range(ens_no):
field.append(cond_srf.structured([x, y], seed=i))
###############################################################################
# Now let's have a look at the pairwise differences between the generated
# fields. We will see, that they coincide at the given conditions.
print(m2)
print(fit_m2)
format_ax(ax)
fig.tight_layout()
if save:
fig.savefig(os.path.join("..", "results", "07_matern_tpl_0-5.pdf"),
dpi=300)
fig.show()
# model families
fig, ax = plt.subplots(figsize=[5, 3])
gau = gs.Gaussian(integral_scale=1)
exp = gs.Exponential(integral_scale=1)
nus = [0.5, 0.75, 1.0, 1.5, 2.0]
# ax = exp.plot(ax=ax, x_max=3, linestyle="-.", color="k")
ax = gau.plot(ax=ax, x_max=3, linestyle="-", color="k")
for i, nu in enumerate(nus):
m = gs.Matern(integral_scale=1, nu=nu)
ax = m.plot(
ax=ax,
x_max=3,
label=f"Matern(nu={nu:.2})",
linewidth=2,
dashes=dashes(i),
color="C0",
)
format_ax(ax)
# sphinx_gallery_thumbnail_path = 'pics/GS_pyvista_cut.png' import pyvista as pv import gstools as gs ############################################################################### # We create a structured grid with PyVista containing 50 segments on all three # axes each with a length of 2 (whatever unit). dim, spacing = (50, 50, 50), (2, 2, 2) grid = pv.UniformGrid(dim, spacing) ############################################################################### # Now we set up the SRF class as always. We'll use an anisotropic model. model = gs.Gaussian(dim=3, len_scale=[16, 8, 4], angles=(0.8, 0.4, 0.2)) srf = gs.SRF(model, seed=19970221) ############################################################################### # The PyVista mesh can now be directly passed to the :any:`SRF.mesh` method. # When dealing with meshes, one can choose if the field should be generated # on the mesh-points (`"points"`) or the cell-centroids (`"centroids"`). # # In addition we can set a name, under which the resulting field is stored # in the mesh. srf.mesh(grid, points="points", name="random-field") ############################################################################### # Now we have access to PyVista's abundancy of methods to explore the field. #
In the following we will show the influence of the nugget and
measurement errors.
"""
import numpy as np
import gstools as gs
# condtions
cond_pos = [0.3, 1.1, 1.9, 3.3, 4.7]
cond_val = [0.47, 0.74, 0.56, 1.47, 1.74]
cond_err = [0.01, 0.0, 0.1, 0.05, 0]
# resulting grid
gridx = np.linspace(0.0, 15.0, 151)
# spatial random field class
model = gs.Gaussian(dim=1, var=0.9, len_scale=1, nugget=0.1)
###############################################################################
# Here we will use Simple kriging (`unbiased=False`) to interpolate the given
# conditions.
krig = gs.krige.Krige(
model=model,
cond_pos=cond_pos,
cond_val=cond_val,
mean=1,
unbiased=False,
exact=False,
cond_err=cond_err,
)
krig(gridx)
import pyvista as pv
import gstools as gs
# mainly for setting a white background
pv.set_plot_theme("document")
###############################################################################
# create a uniform grid with PyVista
dims, spacing, origin = (40, 30, 10), (1, 1, 1), (-10, 0, 0)
mesh = pv.UniformGrid(dims=dims, spacing=spacing, origin=origin)
###############################################################################
# create an incompressible random 3d velocity field on the given mesh
# with added mean velocity in x-direction
model = gs.Gaussian(dim=3, var=3, len_scale=1.5)
srf = gs.SRF(model, mean=(0.5, 0, 0), generator="VectorField", seed=198412031)
srf.mesh(mesh, points="points", name="Velocity")
###############################################################################
# Now, we can do the plotting
streamlines = mesh.streamlines(
"Velocity",
terminal_speed=0.0,
n_points=800,
source_radius=2.5,
)
# set a fancy camera position
cpos = [(25, 23, 17), (0, 10, 0), (0, 0, 1)]
def test_raise_error(self):
self.assertRaises(ValueError, gs.CondSRF, gs.Gaussian())
krige = gs.krige.Ordinary(gs.Stable(), self.cond_pos, self.cond_val)
self.assertRaises(ValueError, gs.CondSRF, krige, generator="unknown")
import meshzoo
import meshio
import gstools as gs
# generate a triangulated hexagon with meshzoo
points, cells = meshzoo.ngon(6, 4)
mesh = meshio.Mesh(points, {"triangle": cells})
###############################################################################
# Now we prepare the SRF class as always. We will generate an ensemble of
# fields on the generated mesh.
# number of fields
fields_no = 12
# model setup
model = gs.Gaussian(dim=2, len_scale=0.5)
srf = gs.SRF(model, mean=1)
###############################################################################
# To generate fields on a mesh, we provide a separate method: :any:`SRF.mesh`.
# First we generate fields on the mesh-centroids controlled by a seed.
# You can specify the field name by the keyword `name`.
for i in range(fields_no):
srf.mesh(mesh, points="centroids", name="c-field-{}".format(i), seed=i)
###############################################################################
# Now we generate fields on the mesh-points again controlled by a seed.
for i in range(fields_no):
srf.mesh(mesh, points="points", name="p-field-{}".format(i), seed=i)
.. math:: S(k) = \left(\frac{1}{2\pi}\right)^n \cdot
\frac{(2\pi)^{n/2}}{(bk)^{n/2-1}}
\int_0^\infty r^{n/2-1} C(r) J_{n/2-1}(bkr) r dr
Where :math:`k=\left\Vert\mathbf{k}\right\Vert`.
Depending on the spectrum, the spectral-density is defined by:
.. math:: \tilde{S}(k) = \frac{S(k)}{\sigma^2}
You can access these methods by:
"""
import gstools as gs
model = gs.Gaussian(dim=3, var=2.0, len_scale=10)
ax = model.plot("spectrum")
model.plot("spectral_density", ax=ax)
###############################################################################
# .. note::
# The spectral-density is given by the radius of the input phase. But it is
# **not** a probability density function for the radius of the phase.
# To obtain the pdf for the phase-radius, you can use the methods
# :any:`CovModel.spectral_rad_pdf`
# or :any:`CovModel.ln_spectral_rad_pdf` for the logarithm.
#
# The user can also provide a cdf (cumulative distribution function) by
# defining a method called ``spectral_rad_cdf``
# and/or a ppf (percent-point function)
# by ``spectral_rad_ppf``.