Re: [ROOT] TFormula

From: Pierre-Luc Drouin (pldrouin@physics.carleton.ca)
Date: Mon Aug 05 2002 - 22:28:37 MEST


Hi,

I'm working on a program that reads equations in a dat file and use them
to apply cuts on some SNO events. Users must be able to change cut
equations in the dat file without recompiling QSNO (SNO analysis
program). Cuts may combine more than 4 parameters, that's why I need an
equation interpreter that can interpret formulas with more than 4
variables.

Thank you!

Pierre-Luc Drouin
SNO, Carleton University 

On Mon, 5 Aug 2002, Rene Brun wrote:

> May be you should explain what you want to do !
> Why don't you use CINT directly as an interpreter?
> 
> The convention in TFormula is to use the letters x,y,z,t
> to identify the 1st,2nd,3rd,4th dimension in the expression.
> For sure we could use the 26 characters + upper case.
> I don't think this would be the right way to proceed.
> 
> Rene Brun
> 
> On Mon, 5 Aug 2002, Pierre-Luc Drouin wrote:
> 
> > Hi,
> > 
> > The problem I have is that I'm making a class that must be the most
> > flexible as possible, and it's possible that it needs more than 4
> > variables (perhaps 10, or more). Is there a mean to do that using
> > TFormula? I mean, once an interpreter is able to interpret
> > complex equations like
> > TFormula is able to do, what does limit the number of variables?
> > 
> > Thank you!
> > 
> > Pierre-Luc Drouin
> > 
> > On Mon, 5 Aug 2002, Rene Brun wrote:
> > 
> > > Hi Pierre-Luc
> > > 
> > > TFormula allows up to 4 dimensions. Example:
> > >  root > TFormula f("f","x+y+z+t")
> > >  root > double x[4] = {1,2,3,4}
> > >  root > f.EvalPar(x)
> > > 
> > > The current documentation indicates a max of 3 dimensions.
> > > I have updated the comments in the CVS version.
> > > 
> > > Rene Brun
> > > 
> > > On Mon, 5 Aug 2002, Pierre-Luc Drouin wrote:
> > > 
> > > > Hello,
> > > > 
> > > > I need an equation interpreter that can be used with more than 3
> > > > variables. Is there a class that allows it in ROOT?
> > > > 
> > > > Thank you!
> > > > 
> > > > Pierre-Luc Drouin
> > > > 
> > > 
> > 
> 



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