Enumeration to define the function used to mesh the domain
type MeshGrid = enumeration(uniform "Uniform grid with equal spacing between vertices", biotAndUniform "Uniform grid with equal spacing between vertices execpted for boundary segments with a specing from biot number", geometricalGrowth "Grid with geometrical growth spacing between vertices", biotAndGeometricalGrowth "Grid with geometrical growth spacing between vertices execpted for boundary segments with a specing from biot number");