Hi!
I am fitting a plane to a surface:
This works excellent:
---------------------------------
x<-dataframe[,1]
y<-dataframe[,2]
z<-dataframe[,3]
data<-cbind(x,y,z)
# Fit plane to surface
result<-lm(z~x+y,data)
---------------------------------
But I need to rescale the x,y parameters. So:
-----------------------------
x<-dataframe[,1]*149
y<-dataframe[,2]*149
z<-dataframe[,3]
data<-cbind(x,y,z)
# Fit plane to surface
result<-lm(z~x+y,data)
----------------------------------
And surprisingly this does not work. Error message is:
Error in eval(attr(formula, "variables"), data, env) :
sys.frame: not that many enclosing functions
Why does this happen?
kind regards
Tomas Svensson
EVOTEC,Hamburg
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tomsv193 at student.liu.se writes:> Hi! > > I am fitting a plane to a surface: > > This works excellent: > --------------------------------- > x<-dataframe[,1] > y<-dataframe[,2] > z<-dataframe[,3] > data<-cbind(x,y,z) > > # Fit plane to surface > result<-lm(z~x+y,data) > --------------------------------- > > But I need to rescale the x,y parameters. So: > ----------------------------- > x<-dataframe[,1]*149 > y<-dataframe[,2]*149 > z<-dataframe[,3] > data<-cbind(x,y,z) > > # Fit plane to surface > result<-lm(z~x+y,data) > ---------------------------------- > > And surprisingly this does not work. Error message is: > > Error in eval(attr(formula, "variables"), data, env) : > sys.frame: not that many enclosing functions > > Why does this happen?I can confirm this, but not understand it. Certainly looks like a bug. -- O__ ---- Peter Dalgaard Blegdamsvej 3 c/ /''_ --- Dept. of Biostatistics 2200 Cph. N (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help 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-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
Peter Dalgaard BSA <p.dalgaard at biostat.ku.dk> writes:> tomsv193 at student.liu.se writes: > > > Hi! > > > > I am fitting a plane to a surface: > > > > This works excellent: > > --------------------------------- > > x<-dataframe[,1] > > y<-dataframe[,2] > > z<-dataframe[,3] > > data<-cbind(x,y,z) > > > > # Fit plane to surface > > result<-lm(z~x+y,data) > > --------------------------------- > > > > But I need to rescale the x,y parameters. So: > > ----------------------------- > > x<-dataframe[,1]*149 > > y<-dataframe[,2]*149 > > z<-dataframe[,3] > > data<-cbind(x,y,z) > > > > # Fit plane to surface > > result<-lm(z~x+y,data) > > ---------------------------------- > > > > And surprisingly this does not work. Error message is: > > > > Error in eval(attr(formula, "variables"), data, env) : > > sys.frame: not that many enclosing functions > > > > Why does this happen? > > > I can confirm this, but not understand it. Certainly looks like a bug.Ah, got it! The data= argument needs to be a dataframe and you have a matrix. Still looks weird, though. -- O__ ---- Peter Dalgaard Blegdamsvej 3 c/ /''_ --- Dept. of Biostatistics 2200 Cph. N (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help 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-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
I don''t know why one version works and the other doesn''t, but I''ve noticed problems in the past when using "data" as a variable name, and in fact even the first version fails for me when I type it exactly as you did. I suspect the strange behaviour you saw is related to the fact that data is a matrix rather than a data.frame, and indeed everything is fine if I change your code to x<-dataframe[,1]*149 y<-dataframe[,2]*149 z<-dataframe[,3] d<-data.frame(x,y,z) # use data.frame, not cbind # Fit plane to surface result<-lm(z~x+y,d) Duncan Murdoch -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help 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-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
Duncan Murdoch <murdoch at stats.uwo.ca> writes:> I don''t know why one version works and the other doesn''t, but I''ve > noticed problems in the past when using "data" as a variable name, and > in fact even the first version fails for me when I type it exactly as > you did. > > I suspect the strange behaviour you saw is related to the fact that > data is a matrix rather than a data.frame, and indeed everything is > fine if I change your code toI got it now: The problem is that eval accept an integer as its envir argument (as in sys.call()) so lm and friends do too. If you pass a numeric object, like a matrix, the first element is extracted and coerced to integer. That''ll explain why the behaviour changes when a column is multiplied by 149... The reason the example ever worked was that x,y,z from the global env. got picked up. -- O__ ---- Peter Dalgaard Blegdamsvej 3 c/ /''_ --- Dept. of Biostatistics 2200 Cph. N (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help 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-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
> > Duncan Murdoch <murdoch at stats.uwo.ca> writes: > > > I don''t know why one version works and the other doesn''t, but I''ve > > noticed problems in the past when using "data" as a variable name, and > > in fact even the first version fails for me when I type it exactly as > > you did. > > > > I suspect the strange behaviour you saw is related to the fact that > > data is a matrix rather than a data.frame, and indeed everything is > > fine if I change your code to > > I got it now: The problem is that eval accept an integer as its envir > argument (as in sys.call()) so lm and friends do too. If you pass a > numeric object, like a matrix, the first element is extracted and > coerced to integer. That''ll explain why the behaviour changes when a > column is multiplied by 149... > > The reason the example ever worked was that x,y,z from the global env. > got picked up. > --This is a typical example of one of the reasons why I do not trust lm/glm. If the data argument is used, the function should look nowhere else but in the data.frame supplied (as all my functions do with my data objects). As it stands, one is never sure what data are actually being analyzed. I brought this up at the first Vienna meeting, and everyone disagreed with me. Jim> O__ ---- Peter Dalgaard Blegdamsvej 3 > c/ /''_ --- Dept. of Biostatistics 2200 Cph. N > (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 > ~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk) FAX: (+45) 35327907 > -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- > r-help 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-help-request at stat.math.ethz.ch > _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._ >-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help 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-help-request at stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._