[R] unexpected behaviour of 'curve' function
Dear all, curve(x^3*(1-x)^7, from = 0, to = 1) works as expected but, omitting the xlim or the to and from arguments and calling curve more than once: par(mfrow = c(2,2)) for (i in 1:4) curve(x^3*(1-x)^7) gives an expected (al least to me) result. Note also that a pu object is returned by curve pu [1] -0.1802445 1.1802445 The behaviour is reproducible with both R 2.0.0 and R 2.0.1 I can see that a promise of evaluation of pu is made within curve but I cannot understand completely what happens. Thanks in advance, Stefano Guazzetti platform i386-pc-mingw32 arch i386 os mingw32 system i386, mingw32 status major2 minor0.0 year 2004 month10 day 04 language R __ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
Re: [R] unexpected behaviour of 'curve' function
Guazzetti Stefano [EMAIL PROTECTED] writes: Dear all, curve(x^3*(1-x)^7, from = 0, to = 1) works as expected but, omitting the xlim or the to and from arguments and calling curve more than once: par(mfrow = c(2,2)) for (i in 1:4) curve(x^3*(1-x)^7) gives an expected (al least to me) result. Note also that a pu object is returned by curve pu [1] -0.1802445 1.1802445 The behaviour is reproducible with both R 2.0.0 and R 2.0.1 I can see that a promise of evaluation of pu is made within curve but I cannot understand completely what happens. I think the upshot is just that it is taking the from and to from par(usr) from the previous plot and every time you do so, it expands a little (about 4%). Notice that it does not happen if you do this: par(mfrow = c(2,2), xaxs=i) for (i in 1:4) curve(x^3*(1-x)^7) Having pu end up in the global environment looks like a bug in delay() but I don't think it has any influence on this particular effect. -- O__ Peter Dalgaard Blegdamsvej 3 c/ /'_ --- Dept. of Biostatistics 2200 Cph. N (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907 __ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
Re: [R] unexpected behaviour of 'curve' function
On 26 Nov 2004 12:27:35 +0100, Peter Dalgaard [EMAIL PROTECTED] wrote: Guazzetti Stefano [EMAIL PROTECTED] writes: Dear all, curve(x^3*(1-x)^7, from = 0, to = 1) works as expected but, omitting the xlim or the to and from arguments and calling curve more than once: par(mfrow = c(2,2)) for (i in 1:4) curve(x^3*(1-x)^7) gives an expected (al least to me) result. Note also that a pu object is returned by curve pu [1] -0.1802445 1.1802445 The behaviour is reproducible with both R 2.0.0 and R 2.0.1 I can see that a promise of evaluation of pu is made within curve but I cannot understand completely what happens. I think the upshot is just that it is taking the from and to from par(usr) from the previous plot and every time you do so, it expands a little (about 4%). It's not documented what from and to will be when add=FALSE, so this isn't strictly speaking a bug, but I'd say it's undesirable behaviour. I'd much rather see from=0 and to=1 in this case. Notice that it does not happen if you do this: par(mfrow = c(2,2), xaxs=i) for (i in 1:4) curve(x^3*(1-x)^7) Having pu end up in the global environment looks like a bug in delay() but I don't think it has any influence on this particular effect. That's a pretty serious bug in delay(). It's been there at least since 1.9.1. Duncan Murdoch __ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
Re: [R] unexpected behaviour of 'curve' function
On Fri, 26 Nov 2004 18:48:45 -0500, Duncan Murdoch [EMAIL PROTECTED] wrote: On 26 Nov 2004 12:27:35 +0100, Peter Dalgaard [EMAIL PROTECTED] wrote: Having pu end up in the global environment looks like a bug in delay() but I don't think it has any influence on this particular effect. That's a pretty serious bug in delay(). It's been there at least since 1.9.1. Oops, not a bug, behaving as documented (but maybe a design flaw)? delay() is documented as defaulting to the global environment. curve() should have used env=environment(). Duncan Murdoch __ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
Re: [R] unexpected behaviour of 'curve' function
Duncan Murdoch [EMAIL PROTECTED] writes: Oops, not a bug, behaving as documented (but maybe a design flaw)? delay() is documented as defaulting to the global environment. curve() should have used env=environment(). Or not used delay() at all. That code looks a bit warped. AFAICT, you could have 'from' defaulting to lims[1] and 'to' to lims[2], then in the body let if(missing(from) || missing(to)) lims - if(missing(xlim)) if (par(xlog)) 10 ^ par(usr)[1:2] else par(usr)[1:2] else xlim and get the same result (notwithstanding that you probably don't want to use par(usr) in that way) -- O__ Peter Dalgaard Blegdamsvej 3 c/ /'_ --- Dept. of Biostatistics 2200 Cph. N (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907 __ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
