Step Info from NDSolve
- To: mathgroup at smc.vnet.net
- Subject: [mg33624] Step Info from NDSolve
- From: bghiggins at ucdavis.edu (Brian Higgins)
- Date: Wed, 3 Apr 2002 18:08:38 -0500 (EST)
- Sender: owner-wri-mathgroup at wolfram.com
Hi Mathgroup,
Is there anyway to get step information (number of steps, step size)
from NDSolve during the actual integration . The application I have in
mind has the following structure:
NDSolve[{x[t]==F[x[t],y[t],t,1],y'[t]==F[x[t],y[t],t,
2],x[0]==x0,y[0]==y0},{x[t],y[t]},{t,0,tmax}]
where
F[xval_?NumericQ,yval_?NumericQ,tval_?NumericQ,eqnNum_]:=
Module[{}, some code...;
{deriv1,deriv2}[[eqnNum]]]
Thus during integration the RHS values for x'[t] and y'[t] are found
dynamically. This works fine.
Now what I would like to do is take some action inside the function F
depending on the step size and how many steps NDSolve has taken when F
is called.
Is it possible to extract this information from NDSolve dynamically.
Thanks much in advance for any help you can offer,
Brian