Re: matrix operations -- shared data vs copied

*To*: mathgroup at smc.vnet.net*Subject*: [mg65956] Re: matrix operations -- shared data vs copied*From*: "Chris Chiasson" <chris.chiasson at gmail.com>*Date*: Mon, 24 Apr 2006 06:02:16 -0400 (EDT)*References*: <e2fkpu$bo8$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

B=A copies A, it doesn't link to A changing A after this statement doesn't change B otherwise, this would be invalid input: a = 1 a = a + 1 You seem to be using a model of thinking about Mathematica that doesn't really mesh with the way it operates. B=A is really just like a rule B->A that is always active whenever the evaluator finds an expression with B in it B:=A, while it might be tempting to think of as a "link" from B to A, is really a delayed rule B:>A that is always active whenever the evaluator finds an expression with B in it The difference between the two, = and :=, comes into play with patterns and with the state of A when B is encountered. If you don't want to read the Mathematica Book one billion times, I suggest paying someone to instruct you on how to use Mathematica - that way, you'll only have to read the Mathematica book one million times. Maybe try Mathematica classes??