Re: problems with ContourPlot

*To*: mathgroup at smc.vnet.net*Subject*: [mg33635] Re: [mg33616] problems with ContourPlot*From*: BobHanlon at aol.com*Date*: Thu, 4 Apr 2002 19:39:53 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

In a message dated 4/3/02 8:14:53 PM, hvdosten at lb.netic.de writes: >if I try this: > > >a := 0.5; b := 0.5; c := 0.5; y := 0.0; > >ContourPlot[(x*(x - a) + y*y + z*z)/ (Sqrt[(x*x + y*y + z*z) ** 3]* > Sqrt[((x - a) ** 2 + y*y + z*z) ** 3]) - ((x - a)*(x - a - b >-c) + > y*y + z*z)/ (Sqrt[((x - a) ** 2 + y*y + z*z) ** 3]* > Sqrt[((x - a - b - c) ** 2 + y*y + z*z) ** 3]) - (x*(x - a -b) >+ > y*y + z*z)/ (Sqrt[(x*x + y*y + z*z) ** 3]* > Sqrt[((x - a - b) ** 2 + y*y + z*z) ** > 3]) + ((x - a - b)*(x - a - b - c) + y*y + > z*z)/(Sqrt[((x - a - b) ** 2 + y*y + z*z) ** 3]* > Sqrt[((x - a - b - c) ** 2 + y*y + z*z) ** 3]), {x, -1, 1}, >{z, 0, 1}, Contours -> {0, 1, 5, 10, 50, 100}, ContourShading -> False] > > > > >I receive the error-messages: > > > >[ ...Expression... ] is not a machine-size real number at {x, z} = >{-1.,0.} > > >ContourGraphics::"ctpnt": "The contour is attempting to traverse a cell >in which some of the points have not evaluated to numbers, and it will >be dropped." > > >General::"stop": "Further output of (ContourGraphics :: "ctpnt") will be >suppressed during this calculation." > > > > > >Because I compiled this also with Fortran I know that there are also >results in the range up to 10^6. Is this too much for ContourPlot? Or >did I some crazy things.... ?? At (-1,0.) I cannot find any >singularity... > replace all uses of ** with ^ ** is NonCommutativeMultiply ^ is Power Bob Hanlon Chantilly, VA USA