memory management and pointers

*To*: mathgroup at smc.vnet.net*Subject*: [mg27147] memory management and pointers*From*: Sebastien.deMentendeHorne at electrabel.com*Date*: Thu, 8 Feb 2001 04:40:38 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

Hi, I never heard about pointers in Mathematica but I am facing a problem where it should be nice if Mathematica doesn't allow/free memory every time. For instance: u = ReplacePart[u,1,{1,1}] where u is a very big matrix As I need to do this very often in an algorithm, Mathematica spends a lot of the time by: - creating the new object ReplacePart[u,1,{1,1}] which is as big as u - rebinding u to the new object - freeing the old u object Is it possible to ask Mathematica to do a ReplacePart directly on u without all the hassle of allocation/free of memory. Another example: u = u + f[u] +g[u] where u is again the big matrix will imply a lot of wasted time in memory problems. When Mathematica says that "u += a" is equivalent to "u = u + a" is it true or almost true (difference in memory management)? Thank you very much Sébastien Sébastien de Menten de Horne | ELECTRABEL Tel: ++32 10 48 51 76 | R&D Energy Markets, Fax: ++32 10 48 51 09 | Traverse d'Esope, 6 Gsm: ++32 478 789 444 | B-1348 Louvain-la-Neuve, BELGIUM