[R] nls plinear formula

I want to fit a nonlinear model of the form: Y=A+B*X1+C*X2+log(X3/(X3+D)) I think that the best way is to use the plinear algorithm, but I don't know how to specify the formula in the nls function. I've tried: Y~cbind(rep(1,times=length(Y)),X1,X2,log(X3/(X3+D))) But this fits the model: Y=A+B*X1

[R] simplex projection and S-Map

I am interested in using the nonlinear forecasting techniques developed by Sugihara et al. In particular the simplex projection and the S-Map (see this website for details and reprints: http://iod.ucsd.edu/simplex/ ). I've looked through CRAN but could not find any package with functions that al