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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>I have a question about the fastLm example in the Gallery <a href="http://gallery.rcpp.org/articles/fast-linear-model-with-armadillo/">http://gallery.rcpp.org/articles/fast-linear-model-with-armadillo/</a>. 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:<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Lucida Console";color:blue'>> require(datasets)<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Lucida Console";color:blue'>> coef(lm(y1 ~ x1, data = anscombe))<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Lucida Console";color:black;background:#E1E2E5'>(Intercept) x1 <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Lucida Console";color:black;background:#E1E2E5'> 3.0000909 0.5000909 <o:p></o:p></span></p><pre><span class=gnvmtomcdbb><span style='font-family:"Lucida Console";color:blue;background:#E1E2E5'>> </span></span><span class=gnvmtomchab><span style='font-family:"Lucida Console";color:blue;background:#E1E2E5'>coef(fastLmProto(anscombe$y1, as.matrix(anscombe$x1)))<o:p></o:p></span></span></pre><pre><span style='font-family:"Lucida Console";color:black;background:#E1E2E5'> [,1]<o:p></o:p></span></pre><pre><span style='font-family:"Lucida Console";color:black;background:#E1E2E5'>[1,] 0.7968032<o:p></o:p></span></pre><pre><span class=gnvmtomcdbb><span style='font-family:"Lucida Console";color:blue;background:#E1E2E5'>> </span></span><span class=gnvmtomchab><span style='font-family:"Lucida Console";color:blue;background:#E1E2E5'>coef(fastLm(anscombe$y1, as.matrix(anscombe$x1)))<o:p></o:p></span></span></pre><pre><span style='font-family:"Lucida Console";color:black;background:#E1E2E5'>[1] 1.208169<o:p></o:p></span></pre><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>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 naïve in my assumptions?<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I reviewed the RcppArmadillo documentation and the article <a href="http://dirk.eddelbuettel.com/papers/RcppArmadillo.pdf">http://dirk.eddelbuettel.com/papers/RcppArmadillo.pdf</a> but could not find anything relevant.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Thanks,<o:p></o:p></p><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Dale Smith, Ph.D.<o:p></o:p></span></b></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Senior Financial Quantitative Analyst<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Risk & Compliance<o:p></o:p></span></p><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Fiserv<o:p></o:p></span></b></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Office: 678-375-5315<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><a href="http://www.fiserv.com/"><span style='color:blue'>www.fiserv.com</span></a></span><span style='color:#1F497D'><o:p></o:p></span></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>