comparison of an implicit vs. explicit one-dimensional finite differences program for solving the unsteady heat-flow-equation

The heat-flow equation (without source-term):


The input data-file (identical for both programs)

The explicit version (Fortran 77 source code)

The implict version (Fortran 77 source code)

A small programm for comparison of the results (Fortran 77 source code)

New and nicer the same programs as scilab programs: explict, implicit (updated at 2012-03-07).

The programs calculate the heat distribution at a 100m long row in one year, where the row has the following thermal properties:

The results:


explicit solution


implicite solution

The difference

(really small - only at the borders there is a bigger difference probably because of a malfunction of the SY-Subroutine):


Author: Wolfram Rühaak, 28. May 2002