Re: export differential equation solution obtained through Mathematica

*To*: mathgroup at smc.vnet.net*Subject*: [mg106338] Re: export differential equation solution obtained through Mathematica*From*: dh <dh at metrohm.com>*Date*: Fri, 8 Jan 2010 06:28:45 -0500 (EST)*References*: <hi6t6f$a6k$1@smc.vnet.net>

Hi, obviously the output of NDSolve is a numerical function not an anayltical one. Therefore, the best you can do is to create a table with p and t values. This data you may the export e.g. to a CSV (or other formated), file that can be read by EXCEL. Here is an example: sol = f /. NDSolve[{f' [t] == f[t], f[0] == 1}, f, {t, 0, 1}][[1]] dat = Table[{t, sol[t]}, {t, 0, 1, .1}] Export["d:/tmp/t.dat", dat, "CSV"] Daniel Yun Zhao wrote: > Hi everyone, > > I would like to know if there is a way to export differential equation > solution obtained through Mathematica to microsoft excel. There are several > data processing things that I want to know, that simply plotting the > solution in Mathematica won't suffice. > > I have a system of differential equations like so: > > > sol3=NDSolve[{p'[t]=-0.0491*p[t]-0.0089*p[t],n'[t]=0.0491*p[t]+(0.0491-0.0089)*n[t],p[0]=25000,n[0]=0},{p,n},{t,0,100}] > > When I plotted it in Mathematica using this code: > > Plot[Evaluate[{n[t]+p[t]}/.First[sol3]],{t,0,100}] > > I get a exponential increasing function plotting number vs. time. > > What I want is the values of both the time vector and number vector, and I > want to copy and paste them into two columns in microsoft excel. > > I tried using: > > Export["newdata.dat", Evaluate[{n[t]+p[t]}/.First[sol3]] > > But this gives me a .dat file with the time and number vectors all scrambled > up. > > My question is: > > (1) is there a better way to tell Mathematica what I want to export, because > I don't think Evaluate[{n[t]+p[t]}/.First[sol3] is the correct term to > convey what I want > > (2) How do I properly export differential equation solutions that I can > graph but not display in Mathematica, to spreadsheets software like > Microsoft Excel? > > > > Thank you all very much. > >