[R] Treating variables as symbols

2009-10-01 Thread ZeMajik
Hey, I'm trying to find how to perform operations with a variable treated as a symbol. For, an extremely simple, example I want to integrate a*x with respect to x and I want to find the indefinite integral of this, (a*x^2/2), or the definite integral with some interval for x. Another example of

Re: [R] Treating variables as symbols

2009-10-01 Thread Jorge Ivan Velez
Hi Zemajik, Try this: y - function(a) paste(a, '*x', sep=) y(2) [1] 2*x Also, take a look at the Ryacas package. HTH, Jorge On Thu, Oct 1, 2009 at 9:46 AM, ZeMajik wrote: Hey, I'm trying to find how to perform operations with a variable treated as a symbol. For, an extremely simple,

Re: [R] Treating variables as symbols

2009-10-01 Thread Henrique Dallazuanna
Try this: y - function(a) substitute(a * x, list(a = a)) On Thu, Oct 1, 2009 at 10:46 AM, ZeMajik zema...@gmail.com wrote: Hey, I'm trying to find how to perform operations with a variable treated as a symbol. For, an extremely simple, example I want to integrate a*x with respect to

Re: [R] Treating variables as symbols

2009-10-01 Thread ZeMajik
Thanks guys, Ryacas is pretty much what I'm looking for!However, I can't seem to get it to work properly. For example: yacas(Integrate(x) x) Error in parse(text = text, srcfile = NULL) : unexpected numeric constant in / (^ (x ,2 2 Same thing with expressions such as yacas(x*x) However

Re: [R] Treating variables as symbols

2009-10-01 Thread Gabor Grothendieck
Read the troubleshooting section on the home page: http://ryacas.googlecode.com Note, in particular, that it currently only works with an older version of the XML package. library(Ryacas) packageDescription(XML)$Version [1] 1.96-0 x - Sym(x) Integrate(x*x, x) [1] Starting Yacas!