RE: CirclePlus precedence and bigoplus
- To: mathgroup at smc.vnet.net
- Subject: [mg36171] RE: [mg36138] CirclePlus precedence and bigoplus
- From: "David Park" <djmp at earthlink.net>
- Date: Mon, 26 Aug 2002 04:15:48 -0400 (EDT)
- Sender: owner-wri-mathgroup at wolfram.com
Lucas, I hope that your question will provoke a number of replies because I think it is an interesting topic. First, it would be nice if Mathematica had a ShowPrecedence statement to quickly retrieve a precedence number for any command. It is a bit time consuming to search through the table in Section A.2.7. Next, it would be nice if the user could set the precedence for operators that don't have built-in definitions. Since it appears that you can't do that, is it possible to switch the meanings of Plus and CirclePlus in your theory? Are you depending on the numerical behavior of Plus? Go with the precedence that Mathematica gives you. Or you could use something like VerticalBar or RightTee which have lower precedence than Plus, but perhaps don't have the look that you want. You could try to use the Notation package for your CirclePlus sum. But I always find the Notation package difficult to use and like to use StandardForm as much as possible. One possibility is... \!\(\((\[Sum]\+\(i = 1\)\%5 x[i])\) /. Plus -> CirclePlus\) These are weak answers to your question, but maybe they will bring in more discussion. David Park djmp at earthlink.net http://home.earthlink.net/~djmp/ From: Lucas [mailto:lscharen at d.umn.edu] To: mathgroup at smc.vnet.net Hello, I'm attempting to implement an abstract mathematica package in mathematica that utilized the \[CirclePlus] operator in an unusual way. Specifically, the \[CirclePlus] has a precidence lower than + and introduces barriers in the computation. So, an expression such as a + b \[CirclePlus] c + d --> (a+b) \[CirclePlus] (c+d) The mathematica ouput of a + d + (b \[CirclePlus] c) is incorrect. I've tried playing with the PrecedenceForm[] function, but that does not seem able to produce the desired effect. Also, I would like to introduce a notation like N \[BigCirclePlus] x[[i]] --> x[[1]] \[CirclePlus] x[[2]] \[CirclePlus] .... i=0 analagous to summation, but mathematica does not appear to offer the CirclePlus in a large format. to relate this to the case above, x[1] = (a + b) and x[2] = (c + d), so each indexed element is a subexpression. Finally, I would like to be able to set up the CirclePlus operator such that the following algebraic relations hold: \Sum \BigCirclePlus E = \BigCirclePlus \Sum E i j ij j i ij d d -- \BigCirclePlus E = \BigCirclePlus -- E dx j j j dx j Thanks in advance for any help on the above. -Lucas Scharenbroich -MLS Group / JPL