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