[R] try (nls stops unexpectedly because of chol2inv error

Hi, I am running simulations that does multiple comparisons to control. For each simulation, I need to model 7 nls functions. I loop over 7 to do the nls using try if try fails, I break out of that loop, and go to next simulation. I get warnings on nls failures, but the simulation continues to

[R] cov.unscaled in NLS - how to define cov.scaled to make comparable to SAS proc NLIN output - and theoretically WHY are they different

I am running a 3-parameter nonlinear fit using the default Gauss-Newton method of nls. initialValues.L = list(b=4,d=0.04,t=180); fit.nls.L = nls( myModel.nlm , fData.L, start = initialValues.L, control = nls.control(warnOnly = TRUE), trace=T ); summary.nls.L = summary(fit.nls.L); I run the sam

[R] Variable variables using R ... e.g., looping over data frames with a numeric separator

Hello, I have programmed in PHP a lot, and wanted to know if anyone figured out Variable variables using R. For example, I have several dataframes of unequal sizes that relate to L treatments (1, 2, 3, 4, 5,6, L) ... in this case L=7 fData.1 unique.1 fit.nls.1 summary.nls.1 fit.var.1 summary.var