This is a descriptions of the files needed for BEM (Boundary element method) to solve the 2D Laplace equation. (Which needs to be modified to solve the 2D poissonís equation).


By Nasser Abbasi

Sept 7, 2006


First, this again the WORD document send by Professor Atluri called PoissonBIE.doc for reference.


Now for the FORTRAN code.


The code needed is a little confusing. There are 2 sets of files on the site



This is a set of files DEMO files, which can be found at copied the needed files and here they are








These file do compile OK, and could be run. Here is an example output.txt

This is the WINDOWS EXECUTABLE generated. MAIN.EXE


This is the file I used to compile these.


VERSION non-demo




I copied the needed files and here they are



L2LC_T.FOR (the main)



But these requires NAG library to build. (see below for more information if you want to build these sets of files).


This is the file I used to build these files

This is the error I get


$ ./

/cygdrive/c/DOCUME~1/win/LOCALS~1/Temp/ccIuW5W7.o:l2lc_t.for:(.text+0x13ad): undefined reference to `_d01baz_'

/cygdrive/c/DOCUME~1/win/LOCALS~1/Temp/ccIuW5W7.o:l2lc_t.for:(.text+0x13b2): undefined reference to `_d01bbf_'

collect2: ld returned 1 exit status


The problem is that the main program (L2LC_T.FOR) uses NAG routines, which you need. It uses the routines D01BAZ and D01BBF, in NAG library mark 21. see


which one can download for trial here


(If someone has access to NAG library, they can try to build these files).