Inverse of 27x27 sparse matrix with 4 symbols

*To*: mathgroup at smc.vnet.net*Subject*: [mg28963] Inverse of 27x27 sparse matrix with 4 symbols*From*: umud.ozturk at arcelik.com.tr*Date*: Wed, 23 May 2001 01:54:30 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

Hi everyone, I want to find out the inverse of a 27x27 sparse "m" matrix (in the attachment -contact the author to get the attachement -modeator) whose most of the elements are combinations of 4 symbols (d11,d12,d22,d66). I tried simply Inverse[m] but it seems that the 27x27 sparse matrix with 4 symbols is beyond the practical limits. I use Pentium III with 256 MB RAM, and I waited for days but I couldn't have any solution. Does anybody have similar experinces and are there more efficient methods to take inverse of such a matrix (... decomposition, etc)? I really want to take the inverse of larger sized (100x100 even 1000x1000 sparse) matrices which includes the same 4 four variables. When I tried this, I observed that Mathematica does not use more than approximately 1.0 GB total virtual memory (RAM+swap space), does Mathematica 4.1 in PC versions have any problems to adress the virtual memory larger than 1 GB. Thanks in advance. Umud. Umud E. =D6zt=FCrk Ar=E7elik A.S. R&D Center R&D Engineer Phone: +90 (216) 585 85 85 Ext:8432 - 4122 Fax: +90 (216) 585 85 80 nkkkkkkkkk