[Rcpp-devel] [rcpp-devel] Rcpp Gallery Example fastLm vs R native lm

I have a question about the fastLm example in the Gallery
http://gallery.rcpp.org/articles/fast-linear-model-with-armadillo/. I put
the code directly into my package (after renaming it fastLmProto so I don?t
mask the RcppArmadillo function by the same name). After building the
package, I wanted to compare results:

require(datasets)

coef(lm(y1 ~ x1, data = anscombe))

(Intercept)          x1

  3.0000909   0.5000909

coef(fastLmProto(anscombe$y1, as.matrix(anscombe$x1)))

          [,1]

[1,] 0.7968032

coef(fastLm(anscombe$y1, as.matrix(anscombe$x1)))

[1] 1.208169



Should I expect the results to match? Why do fastLmProto and fastLm produce
a single fitted parameter (I would expect two)? Why are they different? Am I
doing something wrong here, or just being na?ve in my assumptions?

coef(lm(y1 ~ x1 - 1, data = anscombe))