Method interpolate

python/dolfinx/fem/function.py:496–544

Interpolate an expression. Args: u0: Callable function, Expression or Function to interpolate. cells0: Cells in mesh associated with ``u0`` to interpolate over. If ``None`` then all cells are interpolated over. cells1: Cells

(
        self,
        u0: Callable | Expression[Scalar] | Function[Scalar],
        cells0: npt.NDArray[np.int32] | None = None,
        cells1: npt.NDArray[np.int32] | None = None,
    )

        )  # type: ignore

    def interpolate(
        self,
        u0: Callable | Expression[Scalar] | Function[Scalar],
        cells0: npt.NDArray[np.int32] | None = None,
        cells1: npt.NDArray[np.int32] | None = None,
    ) -> None:
        """Interpolate an expression.

        Args:
            u0: Callable function, Expression or Function to
               interpolate.
            cells0: Cells in mesh associated with ``u0`` to interpolate
                over. If ``None`` then all cells are interpolated over.
            cells1: Cells in the mesh associated with ``self`` to
                interpolate over. If ``None``, then taken to be the same
                cells as ``cells0``. If ``cells1`` is not ``None`` it
                must have the same length as ``cells0``.
        """

        @singledispatch
        def _interpolate(u0):
            """Interpolate a cpp.fem.Function."""
            self._cpp_object.interpolate(u0, cells0, cells1)

        @_interpolate.register(Function)
        def _(u0: Function):
            """Interpolate a fem.Function."""
            self._cpp_object.interpolate(u0._cpp_object, cells0, cells1)

        @_interpolate.register(int)
        def _(u0_ptr: int):
            """Interpolate using a pointer to a function f(x)."""
            self._cpp_object.interpolate_ptr(u0_ptr, cells0)

        @_interpolate.register(Expression)
        def _(e0: Expression):
            """Interpolate a fem.Expression."""
            self._cpp_object.interpolate_expr(e0._cpp_object, cells0, cells1)

        try:
            # u is a Function or Expression (or pointer to one)
            _interpolate(u0)
        except TypeError:
            # u0 is callable
            assert callable(u0)
            x = _cpp.fem.interpolation_coords(
                self._V.element._cpp_object, self._V.mesh.geometry._cpp_object, cells0
            )
            self._cpp_object.interpolate_f(np.asarray(u0(x), dtype=self.dtype), cells0)

    def copy(self) -> Function[Scalar]:
        """Create a copy of the Function.