On 04-07-2013, at 18:42, Jannetta Steyn <janne...@henning.org> wrote:
> Hi Ben and others > > I don't quite know how to explain the "doesn't work" in more detail without > any visual aid. You said that R got into an indefinite loop, whatever that maybe. > When you run the two scripts it is easy to see the > difference. MatLab produces a line on x= -55. This is what I expect - a > more or less straight line. R on the other hand the result drops from -55 > (the initial value) to -80 and then goes up to -71.37092. > > The two scripts have exactly the same equations. I don't think so. In the R script you have init = c(v_axon_AB=-55,mNa_axon_AB=1,hNa_axon_AB=0,mK_axon_AB=1) That is not the same as in your Matlab script. To make them the same you should replace the line with init = c(v_axon_AB=-55,mNa_axon_AB=0,hNa_axon_AB=1,mK_axon_AB=0) Using this line gives quite different results. But not the same as Matlab. It seems that you ought to carefully check all your equations. I don't know enough about Matlab/Octave syntax to determine if the results of the two systems are identical. Berend > I have even named the > variables the same in the two scripts and copied the equations across to > make sure I haven't made any typos. > > Can one attach images to posts? I'll try. The flatline image is the plot > from MatLab and the other is the plot from R. > > Thanks > Jannetta > > > On 4 July 2013 16:52, Ben Bolker <bbol...@gmail.com> wrote: > >> Berend Hasselman <bhh <at> xs4all.nl> writes: >> >>> >>> >>> On 04-07-2013, at 17:15, Jannetta Steyn <jannetta <at> henning.org> >> wrote: >>> >>>> Hi folks >>>> >>>> I have implemented a model of a neuron using Hodgkin Huxley equations >> in >>>> both R and MatLab. My preference is to work with R but R is not giving >> me >>>> the correct results. I also can't use ode45 as it just seems to go >> into an >>>> indefinite loop. However, the MatLab implementation work fine with >>>> the same >>>> equations, parameters and initial values and ode45. Below is my R and >>>> MatLab implementations. >>>> >>> >>> No problem in running your R file. Have plot. >>> (Mac mini Core2Duo 2.66Ghz running R 3.0.1 Patched >>> (2013-06-19 r62992) on Mac OS X 10.8.4: 16.5 seconds.) >>> >>> Trying to run your Matlab file in Octave. >>> No success yet because of unavailable ode45. >> >> I'm impressed that you (BH) went to the trouble of checking >> on this vague "doesn't work" question. If you want to go farther >> I think you can get ode45 for octave by installing the odepkg >> package: >> >> http://octave.sourceforge.net/odepkg/index.html >> >> ______________________________________________ >> R-help@r-project.org mailing list >> https://stat.ethz.ch/mailman/listinfo/r-help >> PLEASE do read the posting guide >> http://www.R-project.org/posting-guide.html >> and provide commented, minimal, self-contained, reproducible code. >> > > > > -- > > =================================== > Web site: http://www.jannetta.com > Email: janne...@henning.org > =================================== > <Rplot01.png><MatPlot01.png>______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.