Source code for festim.exports.average_surface

from dolfinx import fem

from festim.exports.surface_quantity import SurfaceQuantity




class AverageSurface(SurfaceQuantity):
    """Computes the average value of a field on a given surface

    Args:
        field (festim.Species): species for which the average surface is computed
        surface (festim.SurfaceSubdomain): surface subdomain
        filename (str, optional): name of the file to which the average surface is exported

    Attributes:
        see `festim.SurfaceQuantity`
    """

    @property
    def title(self):
        return f"Average {self.field.name} surface {self.surface.id}"



    def compute(self, ds):
        """
        Computes the average value of the field on the defined surface
        subdomain, and appends it to the data list
        """

        self.value = fem.assemble_scalar(
            fem.form(self.field.solution * ds(self.surface.id))
        ) / fem.assemble_scalar(fem.form(1 * ds(self.surface.id)))
        self.data.append(self.value)