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.
>
>