Hmm. After checking my data, both the Spawner and Mtempcv columns are of equal lengths. While I could be wrong, recycling doesn't seem to be the issue.
As a relatively new user of R, I tried to adjust the newdata= issue by adding Mtempcv to the newdata= call (i.e., predict(mod2, list(Spawner=mod2a, Mtempcv=mod2a)). This eliminated the "longer object length is not a multiple..." warning message, but the plot produces only a flat line at 0 on the y axis. My apologies for asking a question about what may be obvious to some. Thanks again for your help, SR Steven H. Ranney Graduate Research Assistant (Ph.D) USGS Montana Cooperative Fishery Research Unit Montana State University PO Box 173460 Bozeman, MT 59717-3460 phone: (406) 994-6643 fax: (406) 994-7479 -----Original Message----- From: Peter Dalgaard [mailto:[EMAIL PROTECTED] Sent: Thu 7/3/2008 3:07 PM To: Ranney, Steven Cc: r-help@r-project.org Subject: Re: [R] lines() warning message Ranney, Steven wrote: > I have data that looks like > > Year,Recruit,Spawner,Mtempcv > 1958,4532,775,0.24125 > 1959,22996,2310,0.16319 > 1960,628,2990,0.46056 > 1961,879,1400,0.33028 > 1962,14747,1130,0.22618 > 1963,13205,790,0.20596 > 1964,31793,1195,0.19229 > 1965,10621,981,0.20363 > 1966,22271,870,0.3452 > 1967,8736,1104,0.27511 > 1968,8761,883,0.10884 > 1969,18885,1421,0.17799 > 1970,10098,1198,0.2106 > 1971,3394,760,0.22098 > 1972,1697,1354,0.39461 > 1973,25159,1308,0.19696 > [truncated] > > with program > > #Ricker Curve > mod2=nls(Recruit~(Spawner*exp((delta+echo*Spawner)+(foxtrot*Mtempcv))), > data=box48, > start=list(delta=4, echo=0, foxtrot=-7), trace=TRUE) > plot(Recruit~Spawner, data=box48, pch=19) > mod2a=seq(369, 3000) > lines(mod2a, predict(mod2, list(Spawner=mod2a)), col="red", lty=2) > > R has no problem finding a solution to the nls() model (only 7 iterations are > needed), but when I try to plot the line on the requested plot, I get the > warning message "Warning message: > In (delta + echo * Spawner) + (foxtrot * Mtempcv) : > longer object length is not a multiple of shorter object length." > > R tries to plot the line, but it appears as just a mess of vertical lines > that get more dense where (I would imagine) the actual line is to go. Any > ideas what may be causing this issue? > > Hmm,,, The predict() call looks dodgy. The model depends on Spawner AND Mtempcv, but you're only giving the former in the newdata= part. So a good guess that one of them is recycled to the length of the other. -- O__ ---- Peter Dalgaard Øster Farimagsgade 5, Entr.B c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907 [[alternative HTML version deleted]]
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