Setting order of variables other than alphabetical.
- To: mathgroup at smc.vnet.net
- Subject: [mg21077] Setting order of variables other than alphabetical.
- From: chesri <chesri at leonis.nus.edu.sg>
- Date: Sun, 12 Dec 1999 23:51:44 -0500 (EST)
- Organization: National University of Singapore
- Sender: owner-wri-mathgroup at wolfram.com
Hello! I am a regular user of MATHEMATICA, and while doing problems in dynamical system theory, I have faced following problem. Consider a term involving power series expansion terms. (These terms too were generated using MATHEMATICA functions.) ( e x10 +d x01+ e^2 x20 + 2 ed x11 + d^2 x02 + ...) ( e x10 +d x01+ e^2 x20 + 2 ed x11 + d^2 x02 + ...) The term in third order should be, for x1 = x10 = x01, e^3 (x1 x2 + x2 x1) but MATHEMATICA re-orders terms in alphabetical order and writes the term as e^3 (2 x1 x2) which is incorrect, if x1 and x2 are (column) vectors in R^n, i.e. x1 x2 [\NOT] = x2 x1. Now it is possible to define a variable as is done to define it to be a real or integer by setting an attribute, in MATHEMATICA as a general condition, but it is not possible to define it as a vector. Does anyone know how to effectively set this problem right? Satish