RegionPlot ?
- To: mathgroup at smc.vnet.net
- Subject: [mg23489] RegionPlot ?
- From: "Seth Chandler" <SChandler at uh.edu>
- Date: Fri, 12 May 2000 22:54:28 -0400 (EDT)
- Organization: University of Houston
- Sender: owner-wri-mathgroup at wolfram.com
Right now, the function Experimental`CylindricalAlgebraicDecomposition
yields a list of inequalities. For inequalities with two variables, I would
like to be able to plot the region showing where that inequality is
satisfied.
By way of simple example:
In[69]:=
ecad = Experimental`CylindricalAlgebraicDecomposition[{x + y <= 3, x - y
> -4,
x >= 0, y >= 1}, {x, y}]
Out[69]=
0 <= x < 2 && 1 <= y <= 3 - x || x == 2 && y == 1
What I would like to do is something like:
RegionPlot[ecad,{x,-3,5},{y,-3,7}].
The output would be Polygon primitives, Line primitives, and a Point
primitive
Any thoughts on how to implement this?
Obviously, one could approximate the matter by creating a table of x,y
values and plotting at {x,y} a primitive of some shape and size for each
table element satisfying the set of inequalities. I was hoping someone
might come up with something more elegant, however. (Maybe ContourPlot used
in some way?)