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Re: Help! on vector field around equilibrium of nonlinear system

  • To: mathgroup at smc.vnet.net
  • Subject: [mg43318] Re: [mg43261] Help! on vector field around equilibrium of nonlinear system
  • From: CAP F <Ferdinand.Cap at eunet.at>
  • Date: Sun, 24 Aug 2003 04:55:20 -0400 (EDT)
  • References: <200308231208.IAA25084@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

sabrina wrote:

> Hello, all:
> I am doing some nonlinear differential equations analysis. I tried to use
> plotvectorfield to plot the vector field and also find the equilibrium of
> this system. It seemed to me it is not so clear to show the vector field (
> kind of jamed in my case :( ) so I decided to plot some lines and arrows
> around the equilibrium so that it is easier for me to visualize if those
> points are saddle points or stable points, etc. Any good ideas of how to
> draw those lines and determine which direction the lines should point to?
> Thanks
>
> Sabrina

Why not use portraits ? For saddle etc points, see p 71 f in the book
mentioned below in the notebooks
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To get the notebook into a Mathematica-compatible application, do
one of the following:

* Save the data starting with the line of stars above into a file
  with a name ending in .nb, then open the file inside the
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* Copy the data starting with the line of stars above to the
  clipboard, then use the Paste menu command inside the application.

Data for notebooks contains only printable 7-bit ASCII and can be
sent directly in email or through ftp in text mode.  Newlines can be
CR, LF or CRLF (Unix, Macintosh or MS-DOS style).

NOTE: If you modify the data for this notebook not in a Mathematica-
compatible application, you must delete the line below containing
the word CacheID, otherwise Mathematica-compatible applications may
try to use invalid cache data.

For more information on notebooks and Mathematica-compatible
applications, contact Wolfram Research:
  web: http://www.wolfram.com
  email: info at wolfram.com
  phone: +1-217-398-0700 (U.S.)

Notebook reader applications are available free of charge from
Wolfram Research.
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