orbits broken




On Wed, 30 Sep 2009, Sheldon Newhouse wrote:

< Hello,
<  I tried the 'orbits' program.  Here is what happened.
< 
< (%i5) loa(%i1) build_info();
< Maxima version: 5.19.2
< Maxima build date: 13:10 9/20/2009
< host type: i686-pc-linux-gnu
< lisp-implementation-type: CMU Common Lisp
< lisp-implementation-version: 19d Fedora release 5.fc8 (19D)
< 
< (%o1)
< (%i2) load(dynamics);
< (%o2)     /usr/local/share/maxima/5.19.2/share/dynamics/dynamics.mac
< (%i3) display2d: false;
< (%o3) false
< (%i4) orbits(x*y*(1-y),.2,100,200,[x,3,4,.01]);
< Graph passed to plot2d...
< Improper name or value in functional position:
< errexp1
< #0: 
< orbits(f=x*(1-y)*y,y0=0.2,n1=100,n2=200,domain=[x,3,4,0.01],options=[])(dynamics.mac 
< line 367)
<  -- an error.  To debug this try debugmode(true);
 
Try a smaller upper bound on x:

orbits(x*y*(1-y),.2,100,200,[x,3,3.4,.1]);

There appear to be some numerical issues near x=4, when orbits may
escape [0,1] due to rounding. I'm running the same version of maxima
with the same cmucl.

Leo

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