strange behavior in "rk": unable to evaluate the predicate errexp1
Subject: strange behavior in "rk": unable to evaluate the predicate errexp1
From: Daniel Lakeland
Date: Wed, 17 Jan 2007 21:38:22 -0800
I was working with the "rk" function just fine, then I re-derived my
expressions using a hopefully more numerically stable expression, and
now:
(%i60) rknumeric;
2 1.5 2 2 1.5
(%o60) [hp, (- 0.016 (hp + 1) vx + 8900. hp vx - 55.62 h hp (hp + 1)
2 1.5 2 1.5
+ 0.041 hp (hp + 1) + 0.29 h (hp + 1) + 55.62 h hp + 0.041 hp)
2 1.5
/(5.67 h (hp + 1) vx - 8900. h hp),
- 2.1522E+7 hp vx - 2.1522E+7 h vp - 134500. h - 100.0]
(%i61) solns:rk(rknumeric,
[h,vx,hp],
ev([h0*3,v0/3,-3e-4],ourproperties,numer,infeval),
[x,0,1,.00002]);
Maxima was unable to evaluate the predicate:
errexp1
(%o61) [[0, 0.0011, 1.9964E-4, - 3.0E-4]]
Any suggestions as to what this means? There is a bit of a pause
before the error.
--
Daniel Lakeland
dlakelan at street-artists.org
http://www.street-artists.org/~dlakelan