[m11_2]Combine three basic equations in geodynamics with self gravitation item.
Selfgravitation:LINE451-486.%Thisprogramcomplishedtheprocessof2DEulerianadvectionwithmethod%ofMIC(allocatingmemorytemporarily).clearall;clf;%SetparametersNt=2000;output_interval=1;%LengthofmodelLx=100