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PINA/examples/problems/parametric_poisson.py
2025-03-19 17:46:33 +01:00

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Python

""" Parametric Poisson problem. """
# ===================================================== #
# #
# This script implements the two dimensional #
# Parametric Poisson problem. The ParametricPoisson #
# class is defined inheriting from SpatialProblem and #
# ParametricProblem. We denote: #
# u --> field variable #
# x,y --> spatial variables #
# mu1, mu2 --> parameter variables #
# #
# ===================================================== #
from pina.domain import CartesianDomain
from pina.problem import SpatialProblem, ParametricProblem
from pina.operators import laplacian
from pina.equation import FixedValue, Equation
from pina import Condition
import torch
class ParametricPoisson(SpatialProblem, ParametricProblem):
# assign output/ spatial and parameter variables
output_variables = ['u']
spatial_domain = CartesianDomain({'x': [-1, 1], 'y': [-1, 1]})
parameter_domain = CartesianDomain({'mu1': [-1, 1], 'mu2': [-1, 1]})
# define the laplace equation
def laplace_equation(input_, output_):
force_term = torch.exp(
- 2*(input_.extract(['x']) - input_.extract(['mu1']))**2
- 2*(input_.extract(['y']) - input_.extract(['mu2']))**2)
return laplacian(output_.extract(['u']), input_, d=['x','y']) - force_term
# problem condition statement
conditions = {
'gamma1': Condition(
location=CartesianDomain({'x': [-1, 1], 'y': 1, 'mu1': [-1, 1], 'mu2': [-1, 1]}),
equation=FixedValue(0.)),
'gamma2': Condition(
location=CartesianDomain({'x': [-1, 1], 'y': -1, 'mu1': [-1, 1], 'mu2': [-1, 1]}),
equation=FixedValue(0.)),
'gamma3': Condition(
location=CartesianDomain({'x': 1, 'y': [-1, 1], 'mu1': [-1, 1], 'mu2': [-1, 1]}),
equation=FixedValue(0.)),
'gamma4': Condition(
location=CartesianDomain({'x': -1, 'y': [-1, 1], 'mu1': [-1, 1], 'mu2': [-1, 1]}),
equation=FixedValue(0.)),
'D': Condition(
location=CartesianDomain({'x': [-1, 1], 'y': [-1, 1], 'mu1': [-1, 1], 'mu2': [-1, 1]}),
equation=Equation(laplace_equation)),
}