63 lines
2.5 KiB
Python
63 lines
2.5 KiB
Python
"""Module for the Equation."""
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import inspect
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from .equation_interface import EquationInterface
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class Equation(EquationInterface):
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"""
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Implementation of the Equation class. Every ``equation`` passed to a
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:class:`~pina.condition.condition.Condition` object must be either an
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instance of :class:`Equation` or
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:class:`~pina.equation.system_equation.SystemEquation`.
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"""
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def __init__(self, equation):
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"""
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Initialization of the :class:`Equation` class.
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:param Callable equation: A ``torch`` callable function used to compute
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the residual of a mathematical equation.
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:raises ValueError: If the equation is not a callable function.
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"""
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if not callable(equation):
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raise ValueError(
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"equation must be a callable function."
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"Expected a callable function, got "
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f"{equation}"
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)
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# compute the signature
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sig = inspect.signature(equation)
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self.__len_sig = len(sig.parameters)
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self.__equation = equation
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def residual(self, input_, output_, params_=None):
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"""
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Compute the residual of the equation.
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:param LabelTensor input_: Input points where the equation is evaluated.
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:param LabelTensor output_: Output tensor, eventually produced by a
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:class:`torch.nn.Module` instance.
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:param dict params_: Dictionary of unknown parameters, associated with a
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:class:`~pina.problem.inverse_problem.InverseProblem` instance.
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If the equation is not related to a
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:class:`~pina.problem.inverse_problem.InverseProblem` instance, the
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parameters must be initialized to ``None``. Default is ``None``.
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:return: The computed residual of the equation.
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:rtype: LabelTensor
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:raises RuntimeError: If the underlying equation signature length is not
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2 (direct problem) or 3 (inverse problem).
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"""
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# Move the equation to the input_ device
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self.to(input_.device)
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# Call the underlying equation based on its signature length
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if self.__len_sig == 2:
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return self.__equation(input_, output_)
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if self.__len_sig == 3:
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return self.__equation(input_, output_, params_)
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raise RuntimeError(
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f"Unexpected number of arguments in equation: {self.__len_sig}. "
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"Expected either 2 (direct problem) or 3 (inverse problem)."
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)
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