Re: Approximate Zero Times A Symbol
- To: mathgroup at smc.vnet.net
- Subject: [mg127072] Re: Approximate Zero Times A Symbol
- From: Christoph Lhotka <christoph.lhotka at fundp.ac.be>
- Date: Thu, 28 Jun 2012 04:02:43 -0400 (EDT)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
- References: <201206270811.EAA18698@smc.vnet.net>
Hello, My argumentation would be as follows: 0 x = 0 if (0,x) have infinite precision, while 0. x = 0. since the result has a precision at most of 0., therefore there is no need to keep the x, which has infinite precision: for the expression we only need x up to precision of 0., therefore 0. * approximate x = 0., which is true up to the precision of 0. If I understand well, what you would like to have and if it only concerns the format it is printed, I would define: dis[ex_]:=Plus@@({x,y}*(StringTrim/@ToString/@(PaddedForm[Coefficient[ex,#],{8,8}]&/@{x,y}))) which would give dis/@{0.x+1.y,0.34324324324324324324324x+1.000000000004y} {0.00000000 x+1.00000000 y,0.34324324 x+1.00000000 y} Hope that helps, Christoph On 06/27/2012 10:11 AM, djmpark wrote: > What is the justification for the following? > > > > 0. x + 1. y > > > > 0. + 1. y > > > > I want to display a dynamic weighted sum of x and y and sometimes one of the > coefficients becomes zero. I would like to keep both terms (for a steady > display) and format with NumberForm. If Mathematica is going to drop the x, > why doesn't it at least also drop the approximate zero? > > > > If I use SetPrecision we obtain: > > > > SetPrecision[0. x + 1. y, 10] > > > > 1.000000000 y > > > > which is at least more consistent, but not what I want either. > > > > David Park > > djmpark at comcast.net > > http://home.comcast.net/~djmpark/index.html >
- References:
- Approximate Zero Times A Symbol
- From: "djmpark" <djmpark@comcast.net>
- Approximate Zero Times A Symbol