Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2006
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2006

[Date Index] [Thread Index] [Author Index]

Search the Archive

Problems solving using Solve

  • To: mathgroup at smc.vnet.net
  • Subject: [mg68809] Problems solving using Solve
  • From: "akil" <akomur at wanadoo.nl>
  • Date: Sat, 19 Aug 2006 00:41:17 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

I have a problem suing the following code:

Cone[beta_, v_,rcAB_,rcCD_,ax_,ay_,cx_,cy_,centerOfMassx_,centerOfMassy_] := 
Module[
{betaUsed, vtemp, fx, fy, ex, ey, 
waarde,criticalRC,criticalHeight,xVerplaatsing,ePx2Py2},
      betaUsed = beta ;
      vtemp = v;
      fline[x_] := Tan[betaUsed]x - Tan[betaUsed]vtemp;
      fx = x /. Solve[fline[x] == cd[x,rcCD,cx,cy], x][[1]];
      fy = cd[fx,rcCD,cx,cy];
      criticalRC = (centerOfMassy - fy)/(centerOfMassx - fx);
      criticalHeight = -criticalRC*fx + fy;
      ex = (-ay + rcAB*ax + criticalHeight)/(rcAB + (-criticalRC));
      ey = ab[ex,rcAB,ax,ay];
      xVerplaatsing = ex - vtemp;
      ePx2Py2 = Sqrt[xVerplaatsing^2 + ey^2];
      waarde = xVerplaatsing/ePx2Py2;
      ArcCos[-waarde]
];

afg = 
Simplify[D[Cone[beta,v,rcAB,rcCD,ax,ay,cx,cy,centerOfMassx,centerOfMassy],v], 
TimeConstraint -> 1 ];
Solve[afg== 0, v];

eg.
{ax,ay}= {-44.9376, 36.1678} and {cx,cy}= {17.8329, 122.477} and 
{centerOfMassx,centerOfMassy}={-18.6338,72.3356} and rcAB=-0.166667 and 
rcCD=-0.37931

Doing the Solve[afg== 0, v] takes ages (after an hour I quit it). Is there 
any way I can make it work faster? Is any code in Cone such that it 
unnecessarily makes it run faster? So are there any ways I can try to make 
everything run faster? Using integers it runs, but it takes too long when 
using real cones (made up of four points A B C D and a centerOfMass).

Akil 



  • Prev by Date: Re: NonlinearFit + Sums
  • Next by Date: Re: Re: too many special linear matrices
  • Previous by thread: Re: NonlinearRegress with weight
  • Next by thread: Re: Problems solving using Solve