search for: merithew

...st(NULL, c("b0","b1","tau","t0")) attr(model.func, "gradient") <- Z model.func } decay.pl <- nls (amp ~ expn(b0,b1,tau,t0,t), data = decay, start = c(b0=1, b1=7.5, tau=3.5, t0=0.1), trace=T) ---------- thanks, -- Robert Merithew Laboratory of Atomic and Solid State Physics, Clark Hall Cornell University, Ithaca, NY -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]...

...th a non-differentiable function, I had (stupidly) 'simplified' the problem until it became singular. Can I do something to make optim() less sensitive to my initial guess? For this example, I get a lousy solution if I make the initial guess for t0 = min(t) = 0.05. Thanks again, -- Robert Merithew LASSP, Clark Hall Cornell University, Ithaca NY ----------- t <- c(0.05,0.9,1.4,2.38,3.42,5.4,8.31,12.4) amp <- c(1.0,0.85,7.4, 6.1, 4.95, 3.5, 2.3, 1.5) spike <- function (x, t) { b0 <- x[1] b1 <- x[2] tau <- x[3] t0 <- x[4] temp <- exp((-t+t0)/tau) (b0 +...

...t now, expts$temp (for example), is a column of the data frame containing the temperature at which each dataset is taken. I'd love to be able to ask for a plot of all datasets with (expts$temp == 25), for example. Or build a vector of experiment numbers and plot them all... thanks, -- Robert Merithew Laboratory of Atomic and Solid State Physics Cornell University, Ithaca, NY -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe&q...

...d .value }) I think .expr10 should look more like: Q * sqrt((1 - .expr1^2)^2 + (.expr1 * 1/Q)^2) Is there simply a problem with the way the output of deriv() is displayed (missing 2 sets of parentheses)? Finally: Is there a better way to do my lorentzian fits with R? thanks, -- Robert Merithew LASSP, Cornell University -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- 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 !)...

..., I think. I analyze data from solid-state physics experiments, and very little of the analysis is really *statistical*, so it may be that R is the wrong tool for me. If anyone can point me toward documentation covering how to do tasks like the above in R, I'd appreciate it. thanks, -Robert Merithew, PhD rdm28 at cornell.edu LASSP, Cornell University Ithaca, NY -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in t...

...setting. > > I can see a place in the C code where the problem appears to be, but an > attempted quick fix failed. > > Could you please submit a bug report so that I (or someone else) will > remember to have a proper look later? > > Thanks > > Paul Thanks, -- Robert Merithew -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- 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@s...

...ehess.cnrs-mrs.fr Date: Thu, 2 May 2002 12:23:21 +0200 (MET DST) * PR# 1653 * Subject: coplot behaviour From: "RenE J.V. Bertin" <rjvbertin@hotmail.com> Date: Mon, 10 Jun 2002 20:11:02 +0200 * PR# 1654 * Subject: R 1.5.0: axis() does not honor the xaxp argument From: "Robert D. Merithew" <merithew@ccmr.cornell.edu> Date: Tue, 11 Jun 2002 09:29:39 -0400 (EDT) * PR# 1659 * Subject: mtext() alignment of perpendicular text From: p.murrell@auckland.ac.nz Date: Wed, 12 Jun 2002 13:29:45 +1200 (NZST) Directory: In-Out * PR# 1688 * Subject: Maybe a problem in binary read/w...

I think this is a bug; at least this behavior is not documented in plot or plot.default. plot.default resets xaxp, and leaves xaxp reset when it exits: par(xaxp=c(0,1,4)) print(par("xaxp")) plot(c(0,1),c(0.2,0.3)) print(par("xaxp")) R. Woodrow Setzer, Jr. Phone: (919) 541-0128 Experimental Toxicology Division

...ehess.cnrs-mrs.fr Date: Thu, 2 May 2002 12:23:21 +0200 (MET DST) * PR# 1653 * Subject: coplot behaviour From: "RenE J.V. Bertin" <rjvbertin@hotmail.com> Date: Mon, 10 Jun 2002 20:11:02 +0200 * PR# 1654 * Subject: R 1.5.0: axis() does not honor the xaxp argument From: "Robert D. Merithew" <merithew@ccmr.cornell.edu> Date: Tue, 11 Jun 2002 09:29:39 -0400 (EDT) * PR# 1659 * Subject: mtext() alignment of perpendicular text From: p.murrell@auckland.ac.nz Date: Wed, 12 Jun 2002 13:29:45 +1200 (NZST) * PR# 1878 * Subject: close.screen From: Martin.Schlather@uni-bayreuth.de D...

...ehess.cnrs-mrs.fr Date: Thu, 2 May 2002 12:23:21 +0200 (MET DST) * PR# 1653 * Subject: coplot behaviour From: "RenE J.V. Bertin" <rjvbertin@hotmail.com> Date: Mon, 10 Jun 2002 20:11:02 +0200 * PR# 1654 * Subject: R 1.5.0: axis() does not honor the xaxp argument From: "Robert D. Merithew" <merithew@ccmr.cornell.edu> Date: Tue, 11 Jun 2002 09:29:39 -0400 (EDT) * PR# 1659 * Subject: mtext() alignment of perpendicular text From: p.murrell@auckland.ac.nz Date: Wed, 12 Jun 2002 13:29:45 +1200 (NZST) * PR# 1878 * Subject: close.screen From: Martin.Schlather@uni-bayreuth.de D...

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