search for: nlsfit

Dear R-helpers, I am using confint() within a function, and I want to turn off the message it prints: x <- rnorm(100) y <- x^1.1+rnorm(100) nlsfit <- nls(y ~ g0*x^g1, start=list(g0=1,g1=1)) > confint(nlsfit) Waiting for profiling to be done... 2.5% 97.5% g0 0.4484198 1.143761 g1 1.0380479 2.370057 I cannot find any way to turn off 'Waiting for. .." I tried options(max.print=0) and even sink(tempfile()) confin...

...------------------------------------------------------- #The experimental data : http://r.789695.n4.nabble.com/file/n4634705/nlstest_data.txt nlstest_data.txt #The script library(lattice) dftest<-read.table("nlstest_data.txt", sep=";", dec=".", as.is=T, header=T) nlsfit<-coefficients(nls(y ~ F+A*(x-1)+B*log(x)+C*(x-1)*(x-1)+D*log(x)*log(x), data=dftest, start = list(A=-0.06,B=0.48,C=0.89,D=0.03,F=1), control=list(maxiter=200, tol=0.01))) # Coefficients : # A B C D F # -...

...###### # define some constants smallc <- 0.0001 t <- seq(0,1,0.001) t0 <- 0.5 tau1 <- 0.02 # generate yy(t) yy <- 1/2 * ( 1- tanh((t - t0)/smallc) * exp(-t / tau1) ) + rnorm(length(t))*0.01 # show the curve plot(x=t, y=yy, pch=18) # prepare data dd <- data.frame(y=yy, x=t) nlsfit <- nls(data=dd, y ~ 1/2 * ( 1- tanh((x - ttt)/smallc) * exp(-x / tau2) ), start=list(ttt=0.4, tau2=0.1) , trace=TRUE) # get error: # Error in nls(data = dd, y ~ 1/2 * (1 - tanh((x - ttt)/smallc) * exp(-x/tau2)), : # singular gradient -- Jonas Stein <news at jonasstein.de>

...ta. This is my data set: y <- c(37047647,27083970,23944887,22536157,20133224, 20088720,18774883,18415648,17103717,13580739,12350767, 8682289,7496355,7248810,7022120,6396495,6262477,6005496, 5065887,4594147,2853307,2745322,454572,448397,275136,268771) and this is the fit I'm trying to do: nlsfit <- nls(y ~ a * x^k * b^x, start=list(a=5,k=1,b=3)) (It's a Yule distribution.) However, I keep getting: "Error in nls(y ~ a * x^k * b^x, start = list(a = 5, k = 1, b = 3)) : singular gradient" I guess this has something to do with the parameter start values. I was wondering,...

I have an inquire about the RNG in R It is known that when we use the " rnorm " function , we pass the arguments : 1- number of variables to be generated 2- mean vector of the normal random errors. 3- standard deviation vector of the normal random errors. my question is the following Is the a way (a function) in R that we could specify the covariance matrix in step 3, instead of the

I have data vectors x and y both with 179 observations. I'm trying to fit a nonlinear model with five parameters using nls. The formula is only defined within a range of x-values, it should be zero otherwise, thus my attempted use of ifelse: > df<-data.frame(x,y) > nlsfit<-nls(y~ifelse(x>m&x<m+abs(s),abs(a)*d*abs(s)*exp(-(1/2)*(g+d*log((x-m)/(-x+m+abs(s)))^2))/(sqrt(2*pi)*(x-m)*(-x+m+abs(s))),0),data=df,start=list(a=0.37,g=0,d=1,m=0.42,s=0.24)) Error in nlsModel(formula, mf, start, wts) : singular gradient matrix at initial parameter estimates In addi...

...#convert to seconds b2 <- 1-(0.196/(0.06/0.01131)) #relationship between soil moisture and the size of the ring infiltrometer (6 cm radius by 113.1 cm2 cross sectional area) theta <- 0.196 #difference in residual soil water and field capacity Here is the formula: #Where a = K_fs and b=psi_f nlsfit <- nls(time.s~(theta/a*b2)*((cumul.m/theta)-(((0.16-b)/b2)*log(1+((cumul.m*b2)/(theta*(0.16-b)))))), data = df, start=list (a=1, b=0.5), trace=TRUE) ----- I am likely "over parameterizing", but I must admit, that I am not entirely sure what that means. Any help offered would be great...

...d coefficient, its standard error, t-statistic and corresponding (two- sided) p-value. so try summary(fit.lm)$coefficients[,1:2] to get the coefficients and their SEs. For nls, it takes a bit more digging, as the documentation is a bit sparse. Something like: summary(nlsfit)$parameters[,1:2] will give what you want. Cheers, Andy -----Original Message----- From: Antonio Olinto [mailto:aolinto at bignet.com.br] Sent: Wednesday, October 30, 2002 11:05 AM To: R-Help Subject: [R] extracting Std. Error value from lm/nls Hi, How to extract Std. Error values from a lm o...