Subject: Numerical Methods For Differential Equations
From: Barton Willis
Date: Sun, 25 Sep 2005 10:44:49 -0500
-----Benjamin Good wrote: -----
>Calling load("diffeq") gives me the following error:
>Unknown argument - STATUS:
Try this:
(%i1) status([x]) := 'done$
(%i2) load("diffeq")$
(%i3) f(x,y) := y$
(%i4) runge1(f,0,1,0.5,1);
(%o4) [[0.0,0.5,1.0],[1.0,1.6145833333333333,2.6068793402777777],
[1.0,1.6145833333333333,2.6068793402777777]]
(%i5) f1(x,y1,y2) := y2$
(%i6) f2(x,y1,y2) := -y1$
(%i7) rungen([f1,f2],0,1,0.5,[1,0]);[
(%o7) [[0.0,0.5,1.0],[[1.0,0.0],[0.89583333333333326,-0.48958333333333326],
[0.56282552083333337 ,-0.87717013888888884]],[[0.0,-1.0],
[-0.48958333333333326,-0.89583333333333326],[-0.87717013888888884,-0.56282552083333337]]]
(%i8)
The status function I defined is bogus -- I don't think the Runge--Kutta
functions need a correct status function to work. Of course, we
should fix the status function. Maybe that has already been done in CVS.
Barton