def elliptic_oned_demo(args):
args['PROBLEM-NUMBER'] = int(args['PROBLEM-NUMBER'])
assert 0 <= args['PROBLEM-NUMBER'] <= 1, ValueError('Invalid problem number.')
args['N'] = int(args['N'])
rhss = [ExpressionFunction('ones(x.shape[:-1]) * 10', 1, ()),
ExpressionFunction('(x - 0.5)**2 * 1000', 1, ())]
rhs = rhss[args['PROBLEM-NUMBER']]
d0 = ExpressionFunction('1 - x', 1, ())
d1 = ExpressionFunction('x', 1, ())
parameter_space = CubicParameterSpace({'diffusionl': 0}, 0.1, 1)
f0 = ProjectionParameterFunctional('diffusionl', 0)
f1 = ExpressionParameterFunctional('1', {})
problem = StationaryProblem(
domain=LineDomain(),
rhs=rhs,
diffusion=LincombFunction([d0, d1], [f0, f1]),
dirichlet_data=ConstantFunction(value=0, dim_domain=1),
name='1DProblem'
)
print('Discretize ...')
discretizer = discretize_stationary_fv if args['--fv'] else discretize_stationary_cg
d, data = discretizer(problem, diameter=1 / args['N'])
print(data['grid'])
print()
print('Solve ...')
U = d.solution_space.empty()
for mu in parameter_space.sample_uniformly(10):
U.append(d.solve(mu))
d.visualize(U, title='Solution for diffusionl in [0.1, 1]')
def helmholtz_problem(domain=RectDomain(), rhs=None, parameter_range=(0., 100.),
dirichlet_data=None, neumann_data=None):
"""Helmholtz equation problem.
This problem is to solve the Helmholtz equation ::
- ∆ u(x, k) - k^2 u(x, k) = f(x, k)
on a given domain.
Parameters
----------
domain
A |DomainDescription| of the domain the problem is posed on.
rhs
The |Function| f(x, μ).
parameter_range
A tuple `(k_min, k_max)` describing the interval in which k is allowd to vary.
dirichlet_data
|Function| providing the Dirichlet boundary values.
neumann_data
|Function| providing the Neumann boundary values.
"""
return StationaryProblem(
domain=domain,
rhs=rhs or ConstantFunction(1., dim_domain=domain.dim),
dirichlet_data=dirichlet_data,
neumann_data=neumann_data,
diffusion=ConstantFunction(1., dim_domain=domain.dim),
reaction=LincombFunction([ConstantFunction(1., dim_domain=domain.dim)],
[ExpressionParameterFunctional('-k**2', {'k': ()})]),
parameter_space=CubicParameterSpace({'k': ()}, *parameter_range),
name='helmholtz_problem'
)
def elliptic2_demo(args):
args['PROBLEM-NUMBER'] = int(args['PROBLEM-NUMBER'])
assert 0 <= args['PROBLEM-NUMBER'] <= 1, ValueError(
'Invalid problem number.')
args['N'] = int(args['N'])
rhss = [
ExpressionFunction('ones(x.shape[:-1]) * 10', 2, ()),
ExpressionFunction('(x[..., 0] - 0.5)**2 * 1000', 2, ())
]
rhs = rhss[args['PROBLEM-NUMBER']]
problem = StationaryProblem(
domain=RectDomain(),
rhs=rhs,
diffusion=LincombFunction([
ExpressionFunction('1 - x[..., 0]', 2, ()),
ExpressionFunction('x[..., 0]', 2, ())
], [
ProjectionParameterFunctional('diffusionl', 0),
ExpressionParameterFunctional('1', {})
]),
parameter_space=CubicParameterSpace({'diffusionl': 0}, 0.1, 1),
name='2DProblem')
print('Discretize ...')
discretizer = discretize_stationary_fv if args[
'--fv'] else discretize_stationary_cg
m, data = discretizer(problem, diameter=1. / args['N'])
print(data['grid'])
print()
print('Solve ...')
U = m.solution_space.empty()
for mu in m.parameter_space.sample_uniformly(10):
U.append(m.solve(mu))
m.visualize(U, title='Solution for diffusionl in [0.1, 1]')
def thermal_block_problem(num_blocks=(3, 3), parameter_range=(0.1, 1)):
"""Analytical description of a 2D 'thermal block' diffusion problem.
The problem is to solve the elliptic equation ::
- ∇ ⋅ [ d(x, μ) ∇ u(x, μ) ] = f(x, μ)
on the domain [0,1]^2 with Dirichlet zero boundary values. The domain is
partitioned into nx x ny blocks and the diffusion function d(x, μ) is
constant on each such block (i,j) with value μ_ij. ::
----------------------------
| | | |
| μ_11 | μ_12 | μ_13 |
| | | |
|---------------------------
| | | |
| μ_21 | μ_22 | μ_23 |
| | | |
----------------------------
Parameters
----------
num_blocks
The tuple `(nx, ny)`
parameter_range
A tuple `(μ_min, μ_max)`. Each |Parameter| component μ_ij is allowed
to lie in the interval [μ_min, μ_max].
"""
def parameter_functional_factory(ix, iy):
return ProjectionParameterFunctional(component_name='diffusion',
component_shape=(num_blocks[1], num_blocks[0]),
index=(num_blocks[1] - iy - 1, ix),
name=f'diffusion_{ix}_{iy}')
def diffusion_function_factory(ix, iy):
if ix + 1 < num_blocks[0]:
X = '(x[..., 0] >= ix * dx) * (x[..., 0] < (ix + 1) * dx)'
else:
X = '(x[..., 0] >= ix * dx)'
if iy + 1 < num_blocks[1]:
Y = '(x[..., 1] >= iy * dy) * (x[..., 1] < (iy + 1) * dy)'
else:
Y = '(x[..., 1] >= iy * dy)'
return ExpressionFunction(f'{X} * {Y} * 1.',
2, (), {}, {'ix': ix, 'iy': iy, 'dx': 1. / num_blocks[0], 'dy': 1. / num_blocks[1]},
name=f'diffusion_{ix}_{iy}')
return StationaryProblem(
domain=RectDomain(),
rhs=ConstantFunction(dim_domain=2, value=1.),
diffusion=LincombFunction([diffusion_function_factory(ix, iy)
for ix, iy in product(range(num_blocks[0]), range(num_blocks[1]))],
[parameter_functional_factory(ix, iy)
for ix, iy in product(range(num_blocks[0]), range(num_blocks[1]))],
name='diffusion'),
parameter_space=CubicParameterSpace({'diffusion': (num_blocks[1], num_blocks[0])}, *parameter_range),
name=f'ThermalBlock({num_blocks})'
)
def elliptic2_demo(args):
args['PROBLEM-NUMBER'] = int(args['PROBLEM-NUMBER'])
assert 0 <= args['PROBLEM-NUMBER'] <= 1, ValueError(
'Invalid problem number.')
args['N'] = int(args['N'])
rhss = [
ExpressionFunction('ones(x.shape[:-1]) * 10', 2, ()),
LincombFunction([
ExpressionFunction('ones(x.shape[:-1]) * 10', 2, ()),
ConstantFunction(1., 2)
], [
ProjectionParameterFunctional('mu', 0),
ExpressionParameterFunctional('0.1', {})
])
]
dirichlets = [
ExpressionFunction('zeros(x.shape[:-1])', 2, ()),
LincombFunction([
ExpressionFunction('2 * x[..., 0]', 2, ()),
ConstantFunction(1., 2)
], [
ProjectionParameterFunctional('mu', 0),
ExpressionParameterFunctional('0.5', {})
])
]
neumanns = [
None,
LincombFunction([
ExpressionFunction('1 - x[..., 1]', 2, ()),
ConstantFunction(1., 2)
], [
ProjectionParameterFunctional('mu', 0),
ExpressionParameterFunctional('0.5**2', {})
])
]
robins = [
None,
(LincombFunction(
[ExpressionFunction('x[..., 1]', 2, ()),
ConstantFunction(1., 2)], [
ProjectionParameterFunctional('mu', 0),
ExpressionParameterFunctional('1', {})
]), ConstantFunction(1., 2))
]
domains = [
RectDomain(),
RectDomain(right='neumann', top='dirichlet', bottom='robin')
]
rhs = rhss[args['PROBLEM-NUMBER']]
dirichlet = dirichlets[args['PROBLEM-NUMBER']]
neumann = neumanns[args['PROBLEM-NUMBER']]
domain = domains[args['PROBLEM-NUMBER']]
robin = robins[args['PROBLEM-NUMBER']]
problem = StationaryProblem(domain=RectDomain(),
rhs=rhs,
diffusion=LincombFunction([
ExpressionFunction('1 - x[..., 0]', 2, ()),
ExpressionFunction('x[..., 0]', 2, ())
], [
ProjectionParameterFunctional('mu', 0),
ExpressionParameterFunctional('1', {})
]),
dirichlet_data=dirichlet,
neumann_data=neumann,
robin_data=robin,
parameter_space=CubicParameterSpace({'mu': 0},
0.1, 1),
name='2DProblem')
print('Discretize ...')
discretizer = discretize_stationary_fv if args[
'--fv'] else discretize_stationary_cg
m, data = discretizer(problem, diameter=1. / args['N'])
print(data['grid'])
print()
print('Solve ...')
U = m.solution_space.empty()
for mu in m.parameter_space.sample_uniformly(10):
U.append(m.solve(mu))
m.visualize(U, title='Solution for mu in [0.1, 1]')
def text_problem(text='pyMOR', font_name=None):
import numpy as np
from PIL import Image, ImageDraw, ImageFont
from tempfile import NamedTemporaryFile
font_list = [font_name] if font_name else [
'DejaVuSansMono.ttf', 'VeraMono.ttf', 'UbuntuMono-R.ttf', 'Arial.ttf'
]
font = None
for filename in font_list:
try:
font = ImageFont.truetype(
filename, 64) # load some font from file of given size
except (OSError, IOError):
pass
if font is None:
raise ValueError('Could not load TrueType font')
size = font.getsize(text) # compute width and height of rendered text
size = (size[0] + 20, size[1] + 20
) # add a border of 10 pixels around the text
def make_bitmap_function(
char_num
): # we need to genereate a BitmapFunction for each character
img = Image.new('L',
size) # create new Image object of given dimensions
d = ImageDraw.Draw(img) # create ImageDraw object for the given Image
# in order to position the character correctly, we first draw all characters from the first
# up to the wanted character
d.text((10, 10), text[:char_num + 1], font=font, fill=255)
# next we erase all previous character by drawing a black rectangle
if char_num > 0:
d.rectangle(
((0, 0), (font.getsize(text[:char_num])[0] + 10, size[1])),
fill=0,
outline=0)
# open a new temporary file
with NamedTemporaryFile(
suffix='.png'
) as f: # after leaving this 'with' block, the temporary
# file is automatically deleted
img.save(f, format='png')
return BitmapFunction(f.name,
bounding_box=[(0, 0), size],
range=[0., 1.])
# create BitmapFunctions for each character
dfs = [make_bitmap_function(n) for n in range(len(text))]
# create an indicator function for the background
background = ConstantFunction(1., 2) - LincombFunction(
dfs, np.ones(len(dfs)))
# form the linear combination
dfs = [background] + dfs
coefficients = [1] + [
ProjectionParameterFunctional('diffusion', (len(text), ), (i, ))
for i in range(len(text))
]
diffusion = LincombFunction(dfs, coefficients)
return StationaryProblem(domain=RectDomain(dfs[1].bounding_box,
bottom='neumann'),
neumann_data=ConstantFunction(-1., 2),
diffusion=diffusion,
parameter_space=CubicParameterSpace(
diffusion.parameter_type, 0.1, 1.))
burgers_problem(parameter_range=(1., 1.3)),
burgers_problem_2d(),
burgers_problem_2d(torus=False, initial_data_type='bump', parameter_range=(1.3, 1.5))]
picklable_elliptic_problems = \
[StationaryProblem(domain=RectDomain(), rhs=ConstantFunction(dim_domain=2, value=1.)),
helmholtz_problem()]
non_picklable_elliptic_problems = \
[StationaryProblem(domain=RectDomain(),
rhs=ConstantFunction(dim_domain=2, value=21.),
diffusion=LincombFunction(
[GenericFunction(dim_domain=2, mapping=lambda X, p=p: X[..., 0]**p)
for p in range(5)],
[ExpressionParameterFunctional('max(mu["exp"], {})'.format(m), parameter_type={'exp': ()})
for m in range(5)]
))]
elliptic_problems = picklable_thermalblock_problems + non_picklable_elliptic_problems
@pytest.fixture(params=elliptic_problems + thermalblock_problems +
burgers_problems)
def analytical_problem(request):
return request.param
@pytest.fixture(params=picklable_elliptic_problems +
picklable_thermalblock_problems + burgers_problems)
def picklable_analytical_problem(request):
if __name__ == '__main__':
argvs = sys.argv
parser = OptionParser()
parser.add_option("--dir", dest="dir", default="./")
opt, argc = parser.parse_args(argvs)
print(opt, argc)
rhs = ExpressionFunction('(x[..., 0] - 0.5)**2 * 1000', 2, ())
problem = StationaryProblem(
domain=RectDomain(),
rhs=rhs,
diffusion=LincombFunction(
[ExpressionFunction('1 - x[..., 0]', 2, ()),
ExpressionFunction('x[..., 0]', 2, ())],
[ProjectionParameterFunctional(
'diffusionl', 0), ExpressionParameterFunctional('1', {})]
),
parameter_space=CubicParameterSpace({'diffusionl': 0}, 0.01, 0.1),
name='2DProblem'
)
args = {'N': 100, 'samples': 10}
m, data = discretize_stationary_cg(problem, diameter=1. / args['N'])
U = m.solution_space.empty()
for mu in m.parameter_space.sample_uniformly(args['samples']):
U.append(m.solve(mu))
Us = U * 1.5
plot = m.visualize((U, Us), title='Solution for diffusionl=0.5')