plogis seems broken:> xfit<-seq(1,5,.1) > pfit<-pnorm(-(3-xfit)/1) > pfit[1] 0.02275013 0.02871656 0.03593032 0.04456546 0.05479929 0.06680720 [7] 0.08075666 0.09680048 0.11506967 0.13566606 0.15865525 0.18406013 [13] 0.21185540 0.24196365 0.27425312 0.30853754 0.34457826 0.38208858 [19] 0.42074029 0.46017216 0.50000000 0.53982784 0.57925971 0.61791142 [25] 0.65542174 0.69146246 0.72574688 0.75803635 0.78814460 0.81593987 [31] 0.84134475 0.86433394 0.88493033 0.90319952 0.91924334 0.93319280 [37] 0.94520071 0.95543454 0.96406968 0.97128344 0.97724987> pfit<-plogis(-(3-xfit)/1) > pfit[1] 0.0000000 0.0000000 0.0000000 0.0000000 0.0000000 0.0000000 0.0000000 [8] 0.0000000 0.0000000 0.0000000 0.0000000 0.0000000 0.0000000 0.0000000 [15] 0.0000000 0.0000000 0.0000000 0.0000000 0.0000000 0.0000000 0.5000000 [22] 0.5249792 0.5498340 0.5744425 0.5986877 0.6224593 0.6456563 0.6681878 [29] 0.6899745 0.7109495 0.7310586 0.7502601 0.7685248 0.7858350 0.8021839 [36] 0.8175745 0.8320184 0.8455347 0.8581489 0.8698915 0.8807971 notice all the zeros--this is wrong.> myplogis<-function(q){ 1/(1+exp(-q)) }+ + +> pfit<-myplogis((-(3-xfit)/1)) > pfit[1] 0.1192029 0.1301085 0.1418511 0.1544653 0.1679816 0.1824255 0.1978161 [8] 0.2141650 0.2314752 0.2497399 0.2689414 0.2890505 0.3100255 0.3318122 [15] 0.3543437 0.3775407 0.4013123 0.4255575 0.4501660 0.4750208 0.5000000 [22] 0.5249792 0.5498340 0.5744425 0.5986877 0.6224593 0.6456563 0.6681878 [29] 0.6899745 0.7109495 0.7310586 0.7502601 0.7685248 0.7858350 0.8021839 [36] 0.8175745 0.8320184 0.8455347 0.8581489 0.8698915 0.8807971 I actually looked at plogis.c and it looks fine. Not sure what is causing the trouble. Bill Simpson -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-devel-request@stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
On Sun, 5 Apr 1998, Bill Simpson wrote:> plogis seems broken: > > > xfit<-seq(1,5,.1) > > pfit<-pnorm(-(3-xfit)/1) > > pfit > [1] 0.02275013 0.02871656 0.03593032 0.04456546 0.05479929 0.06680720 > [7] 0.08075666 0.09680048 0.11506967 0.13566606 0.15865525 0.18406013 > [13] 0.21185540 0.24196365 0.27425312 0.30853754 0.34457826 0.38208858 > [19] 0.42074029 0.46017216 0.50000000 0.53982784 0.57925971 0.61791142 > [25] 0.65542174 0.69146246 0.72574688 0.75803635 0.78814460 0.81593987 > [31] 0.84134475 0.86433394 0.88493033 0.90319952 0.91924334 0.93319280 > [37] 0.94520071 0.95543454 0.96406968 0.97128344 0.97724987 > > pfit<-plogis(-(3-xfit)/1) > > pfit > [1] 0.0000000 0.0000000 0.0000000 0.0000000 0.0000000 0.0000000 0.0000000 > [8] 0.0000000 0.0000000 0.0000000 0.0000000 0.0000000 0.0000000 0.0000000 > [15] 0.0000000 0.0000000 0.0000000 0.0000000 0.0000000 0.0000000 0.5000000 > [22] 0.5249792 0.5498340 0.5744425 0.5986877 0.6224593 0.6456563 0.6681878 > [29] 0.6899745 0.7109495 0.7310586 0.7502601 0.7685248 0.7858350 0.8021839 > [36] 0.8175745 0.8320184 0.8455347 0.8581489 0.8698915 0.8807971 > notice all the zeros--this is wrong. > > I actually looked at plogis.c and it looks fine. Not sure what is causing > the trouble.I also looked at plogis.c. It looks fine in R-0.61.1, but not in R-snapshot; the difference is an added line if(x < location) return 0; which should not be there. Guess you are running snapshot and looking at plogis.c form another version. Goran Brostrom Statistics Dept, Umea University Umea, Sweden -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-devel-request@stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
From: Goran Brostrom <gb@stat.umu.se> To: Bill Simpson <wsimpson@uwinnipeg.ca> cc: r-devel <r-devel@stat.math.ethz.ch> Subject: Re: plogis bug On Sun, 5 Apr 1998, Bill Simpson wrote: > plogis seems broken: > I also looked at plogis.c. It looks fine in R-0.61.1, but not in R-snapshot; the difference is an added line if(x < location) return 0; which should not be there. Guess you are running snapshot and looking at plogis.c form another version. Exactly right! I just commited the change, thanks. Ross -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-devel-request@stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._