A novel algorithm is presented for determining the structure function of a discretized
heat diffusion problem. In this approach the thermal capacitances and thermal resistances
defining the structure function are computed as weighted spatial averages of the volumetric
heat capacity and thermal resistivity respectively. This information is able to reveal
the physical meaning of structure function in 3-D heat diffusion problems. Also it
can be exploited, for determining the exact contribution of the thermal resistivity
and volumetric heat capacity in any sub-region of the spatial region in which the
3-D heat diffusion problem is defined, to each resistance and capacitance of the structure
function.
