Re: LogLog plot of NDSolve solution
- To: mathgroup at smc.vnet.net
- Subject: [mg52591] Re: LogLog plot of NDSolve solution
- From: Peter Pein <petsie at arcor.de>
- Date: Fri, 3 Dec 2004 03:54:00 -0500 (EST)
- References: <comfv4$5pe$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Adam Getchell wrote:
> Hello all,
>
> I'm solving an ODE via NDSolve (neutron abundance for Big Bang
> Nucleosynthesis -- from "Modern Cosmology", S. Dodelson). The result
> comes out as an InterpolatingFunction, which plots fine using Plot.
> However, if I wish to do a Log-Log plot, neither LogLogPlot nor
> LogLogListPlot work. What am I missing?
>
> \!\(Dodelson := \(\[CapitalChi]'\)[
> x] - \(x\/H\) \(255\/\(\(\[Tau]\_n\) x\^5\)\) \((12 + 6 x +
> x\^2)\) \((\[ExponentialE]\^\(-x\) - \[CapitalChi][
> x] \((1 + \[ExponentialE]\^\(-x\))\))\)\)
>
> In[329]:=
> \!\(\(\(\[IndentingNewLine]\)\(ans =
> NDSolve[{Dodelson \[Equal]
> 0 /. {H \[Rule] 1.13, \[Tau]\_n \[Rule] 886.7}, \[CapitalChi][
> 1.293] \[Equal] .25}, \[CapitalChi], {x, .1, 1.3},
> MaxSteps \[Rule] 10\^6]\)\)\)
>
> Using the Evaluate trick suggested by
> http://www.nhn.ou.edu/~morrison/Mathematica/TipSheets/2Dgraphics.pdf
> doesn't work.
>
> This example doesn't cover LogLogPlots:
> http://documents.wolfram.com/v4/MainBook/3.8.2.html
>
> Other search results on Google haven't turned up anything so far.
>
> Thanks,
>
> --Adam Getchell
>
>
Hello Adam,
maybe you mixed up \[CapitalChi] and X?
This works with Version 4 and should do so with more up to date Versions:
Chi = \[CapitalChi] /. First[ans];
x0 = x /. First@FindRoot[Chi[x], {x, .5, 1}];
LogLogPlot[Chi[x], {x, x0, 1.3}]; (* works fine *)
Have a nice day,
Peter
--
Peter Pein
10245 Berlin