Blog Archives

A better ‘nls’ (?)

July 5, 2012
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A better ‘nls’ (?)

Those that do a lot of nonlinear regression will love the nls function of R. In most of the cases it works really well, but there are some mishaps that can occur when using bad starting values for the parameters. One of the most dreaded is the “singular gradient matrix at initial parameter estimates” which

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Don’t recycle me!

June 19, 2012
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Don’t recycle me!

For me, one of the most annoying features of R is that by default, rbind,  cbind  and data.frame recycle the shorter vector to the length of the longer vector. I still don’t understand why the standard generics don’t have a parameter like cbind(1:10, 1:5, fill = TRUE) to fill up with ‘NA’s. There may be

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