Displaying 20 results from an estimated 3000 matches similar to: "Predicting from an nls model"
2008 Dec 18
2
Contextstack overlow
All -
I have a number of rows that I am assigning length classes to via
l.class<-with(wae,
ifelse((Length>=120)&(Length<130),"125",
ifelse((Length>=130)&(Length<140),"135",
ifelse((Length>=140)&(Length<150),"145",
ifelse((Length>=150)&(Length<160),"155",
2008 Jun 10
3
newbie nls question
I'm tyring to fit a relatively simple nls model to some data, but keep coming up against the same error (code follows):
Oto=nls(Otolith ~ Linf*(1-exp(-k(AGE-to))),
data = ages,
start = list(Linf=1000, k=0.1, to=0.1),
trace = TRUE)
The error message I keep getting is "Error in eval(expr, envir, enclos) : could not find function "k"". I've used this
2008 Jun 13
2
Quartile regression question
I have data that looks like
lake,loglength,logweight
1,2.369215857,1.929418926
1,2.426511261,2.230448921
1,2.434568904,2.298853076
1,2.437750563,2.298853076
1,2.442479769,2.230448921
1,2.445604203,2.356025857
...
102,2.722633923,3.310268367
102,2.781755375,3.502153893
102,2.836324116,3.683407299
102,2.802773725,3.583312152
102,2.790285164,3.546419267
102,2.806179974,3.599118565
2008 Sep 02
2
nls.control()
All -
I have data:
TL age
388 4
418 4
438 4
428 5
539 10
432 4
444 7
421 4
438 4
419 4
463 6
423 4
...
[truncated]
and I'm trying to fit a simple Von Bertalanffy growth curve with program:
#Creates a Von Bertalanffy growth model
VonB=nls(TL~Linf*(1-exp(-k*(age-t0))), data=box5.4,
start=list(Linf=1000, k=0.1, t0=0.1), trace=TRUE)
#Scatterplot of the data
plot(TL~age, data=box5.4,
2008 Aug 22
2
Newbie programming help
All -
Not sure if this is a real programming question, but here goes:
I have data that looks like
Lake Length Weight
1 158 45
1 179 70
1 200 125
1 202 150
1 206 145
1 209 165
1 210 140
1 215 175
1 216 152
1 220 150
1 221 165
...
where lake goes from 1 - 84 and the number of rows for each lake is variable (but > ~20).
I'm trying to do two things: 1) build a simple linear model of the
2010 Aug 23
2
Quantile Regression and Goodness of Fit
All -
Does anyone know if there is a method to calculate a goodness-of-fit
statistic for quantile regressions with package quantreg?
Specifically, I'm wondering if anyone has implemented the
goodness-of-fit process developed by Koenker and Machado (1999) for R?
Though I have used package quantreg in the past, I may have overlooked
this function, if it is included.
Citation:
Koenker, R. and
2008 Jul 03
1
lm() question
I have data that looks like
YC Age Num
82 11 2
83 10 0
84 9 8
85 8 21
86 7 49
87 6 18
88 5 79
89 4 28
90 3 273
91 2 175
with a program
mod1=lm(log(Num+1)~YC, data=box44)
plot(log(Num+1)~YC, data=box44, pch=19, xlab="Year Class",
ylab="Loge Number at age", ylim=c(0,6), xlim=c(91,82))
abline(lm(log(Num+1)~YC), col="blue", lwd=2)
summary(mod1)
I need to
2008 Aug 29
1
lm() and dffits
All -
My question is a bit involved, so bear with me.
I have some data that looks like:
Lake LL LW
81 2.176091259 1.342422681
81 2.176091259 1.414973348
81 2.176091259 1.447158031
81 2.181843588 1.414973348
81 2.181843588 1.447158031
81 2.184691431 1.462397998
81 2.187520721 1.447158031
81 2.187520721 1.477121255
81 2.187520721 1.505149978
...
[truncated]
I'm trying to:
1) fit a simple
2008 Jul 03
1
lines() warning message
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
2008 Aug 01
1
Confidence intervals with nls()
I have data that looks like
O.lengthO.age
176 1
179 1
182 1
...
493 5
494 5
514 5
606 5
462 6
491 6
537 6
553 6
432 7
522 7
625 8
661 8
687 10
704 10
615 12
(truncated)
with a simple VonB growth model from within nls():
plot(O.length~O.age, data=OS)
Oto = nls(O.length~Linf*(1-exp(-k*(O.age-t0))), data=OS,
start=list(Linf=1000, k=0.1, t0=0.1), trace=TRUE)
mod <- seq(0, 12)
2008 Aug 19
1
Histogram binning
I am trying to produce frequencies in defined intervals however I can't seem
to figure out how to get R to bin my data the way I want it to.
I have several thousand lengths of fish that I want to be binned as follows:
Ex.
Length Bin
209 200
219 210
431 430
727 720
That is, bins with any length equal to or greater than the lower
2007 Jun 11
1
Rearranging Capture History Data in R
What code can i use to convert a table like this:
Tag# Date
1 1
2 1
3 1
4 1
2 2
4 2
1 3
2 3
4 4
Into one like this:
Tag 1 2 3 4 #Date header
1 1 0 0 1
2 1 1 1 0
3 1 0 0 0
4 1 1 0 1
Thanks,
Ben Cox
Research Assistant (M.S.)
Montana Cooperative
2008 Oct 24
4
gfortran optimization problems
Colleagues,
I have a routine in package labdsv that calls a FORTRAN subroutine.
Recently, I was informed that it sometimes gives different results on a
PC and Mac, and that the PC version is clearly wrong. I tested it on
linux (because I don't have a PC), and I get the same (incorrect)
behavior as the PC.
Simply by inserting debug WRITE statements in the FORTRAN I would get
different,
2005 Nov 30
8
Solving Systems of Non-linear equations
I am trying to write a function that will solve a simple system of
nonlinear equations for the parameters that describe the beta
distribution (a,b) given the mean and variance.
mean = a/(a+b)
variance = (a*b)/(((a+b)^2) * (a+b+1))
Any help as to where to start would be welcome.
--
Scott Story
Graduate Student
MSU Ecology Department
319 Lewis Hall
Bozeman, Mt 59717
406.994.2670
sstory at
2010 Nov 19
1
TukeyHSD error
All -
I think I'm being dense, but for the life of me, I can't figure out
why I get error message with the code below.
I have data that looks like
param level perc.surv asin.tran
DO 3 0.6864407 0.9764544
DO 3 0.1250000 0.3613671
DO 3 0.8738739 1.2077299
DO 4 0.4615385 0.7468986
DO 4 0.5691057 0.8547258
DO 4 0.8504673 1.1737517
DO 6 0.5494505 0.8349297
DO
2005 Jun 13
3
To many NA's from mean(..., na.rm=T) when a column is all NA's
Dear R-help folks,
I am seeing unexpected behaviour from the function mean
with option na.rm =TRUE (which is removing a whole column of a data frame
or matrix.
example:
testcase <- data.frame( x = 1:3, y = rep(NA,3))
mean(testcase[,1], na.rm=TRUE)
[1] 2
mean(testcase[,2], na.rm = TRUE)
[1] NaN
OK, so far that seems sensible. Now I'd like to compute both means at
once:
2008 Dec 22
3
Summary information by groups programming assitance
All -
I have data that looks like
psd Species Lake Length Weight St.weight Wr
Wr.1 vol
432 substock SMB Clear 150 41.00 0.01 95.12438
95.10118 0.0105
433 substock SMB Clear 152 39.00 0.01 86.72916
86.70692 0.0105
434 substock SMB Clear 152 40.00 3.11 88.95298
82.03689 3.2655
435 substock SMB Clear
2006 Sep 08
4
Any Rails Developers in Montana?
Any Rails Developers in Montana? Especially Helena or Bozeman?
I don''t expect there''s enough of us to form a user group, but it might
be nice to talk shop ''offline'' every once and a while.
Eric
(in Helena)
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2005 Jul 19
1
deriv - accessing numeric output listed under gradient attribute
Hi,
I am interested in using the numeric output from the "gradient" attribute of
deriv's output in subsequent analyses.
But, I have so far been unable to determine how to do so.
I will use the example from the deriv help to illustrate.
> ## function with defaulted arguments:
> (fx <- deriv(y ~ b0 + b1 * 2^(-x/th), c("b0", "b1", "th"),
2010 Mar 26
1
Trouble loading package
I am trying to load a package called Rmark, but when I run
library(Rmark)
I get the following:
> library(RMark)
Error in !character.only : invalid argument type
Error in library(RMark) : .First.lib failed for 'RMark'
When I try to load Rmark from the packages menu, I get:
> local({pkg <- select.list(sort(.packages(all.available = TRUE)))
+ if(nchar(pkg)) library(pkg,