similar to: finite difference scheme for 2D differential equations

Hi everyone,I have a data daily data (x) for 10 years starting from 04-01-1995 to 03-31-2005. I was able to get the yearly sum for the ten years using aggregate(x, years, sum). But this gave me the yearly sum for 1995 (Apr- Dec); 1996 (Jan-Dec) ---------2005 (Jan-Mar). But I want to get the aggregates for Apr-1995 to Mar 1996, Apr 1996- mar 1997 and so on. your help will be higly appreciated.

Hello everybody, I have two datasets, observed and predicted. Since my observed dataset is not in regular intervals, I need to filter my predicted dataset based on the measurement date of my observed data. Here, is an example similar to what I have library(chron);library(zoo) DATE<- seq(as.Date("2009-01-01"), as.Date("2009-05-01"), by = 1) mydat<- rnorm(length(DATE),

Hello Everyone,I think this is a very simple problem, I have been struggling with it for a few days now. I have a 10-year daily data in the following format. Date A B C D E 1978-10-22 18 20.64 0.0 0.176 -1.76 1978-10-23 15 17.06 0.4 0.147 2.52 1978-10-24 3 7.588 0.0 0.068 -6.86 1978-10-25 9 11.491 0.0 0.102

Hello everyone, I am trying to use while loop to iterate a function until convergence. But I am having problem when I try to use a fixed number of iterations. Say I want to use maximum iteration of 150. If the value don't converge within maximum iteration, show warning of no convergence. Currently I don't have non- convergence problem so I think my code works fine. But in future I may

Hi everyone, This might be a very petty thing but Its not working for me. I want to export an output to a txt file but without indexing. Here is what I have tried to do outfile<- function(Time, var.names, output) { var.names = c(names(para)) for(i in 1: ncol(output)){ cat(length(var.names), '\n') cat("A", "S", "C", "I", '\n')

Hello, I have a question regarding a way to control the appreance of output exported by R when I use capture.output( x, file = "Directory/file.txt") , I get a text file which when I paste to a word file looks like the first table below. The following table has its clumns spaced closely so when I paste it to a word file it looks continuous. Is there any option in R to make the outputs

Hello everyone, I have a data generated in a way similar to the following library(chron);library(zoo) date<- seq(as.Date("1990-01-01"),, as.Date("2000-12-31"), by = 1) obs<- zoo(rnorm(length(date), mean = 10, sd = 2.5), order.by = date) monthly<- function(date) as.Date(as.yearmon(Date)) result<- data.frame ( Date = obs = aggregate(obs, monthly, sum)) Now, I want

Hi everyone, I was trying to mode the following exercise using R. The question: Set up a one pool model using numericintegration. The model will run from time 1 to time 30 using a time step of 1.The pool (A) will be fed by flux "inA" at a rate of 5 units per hour anddrained by flux "outA" at a rate of 20% per hour. At time 0, A has 5units. At time 30, what is the pool size of

Dear List,I am trying to use rep function in the following conditions A = c( 5, 6, 7, 11, 9, 12, 10, 15) B = c(12,15, 21, 31, 25, 27,32, *34*,13,12, 34, 33, 24, 29, 26, *28*,22,14,27,22,21,12,32, 16) I need to repeat each element of A, as many times as each element of B, for the entire length of B. for example, repeat 5, for 12 times, 6 for 15 times,........, 15 for 34 times, and then, again, 5

Hi all R users, I have problems with my second loop for drawing the three curves in the same graphic. I need help please Thank you in advance ######################################################################### simulation <- function(k, n){ conc <- seq(0,100,by=0.5) #choixg <- seq(1, length(conc)) choixg <- rep(0,length(conc)) for (i in 1:length(conc)){ choixg[i] <- (k

Hello all R users, My simulation function works correctly, but I have problems with plot function. You will find the following code using it. Thank you for your help ##################################################" simulation <- function(k, n){ conc <- seq(0,10,by=0.5) #choixg <- seq(1, length(conc)) choixg <- rep(0,length(conc)) for (i in 1:length(conc)){ choixg[i]

#how do I break these up into first two letters (RM), number, and then the last part #is there an easily accessible regex tutorial on the internet? v = (structure(1:122, .Label = c("RM215Temp", "RM215SpCond", "RM215DO.Conc", "RM215Depth", "RM215pH", "RM215ORP", "RM215Turbidity.", "RM215Battery", "RM215DO.",

Hi, I think you're misunderstanding which set of variables go on either side of the formula. Is this what you're looking for? > aggregate(OD ~ Time + Target + Conc, data = df, FUN = "mean") Time Target Conc OD 1 1 BACT 1 765.3333 2 1 BACT 2 745.3333 3 1 BACT 3 675.0000 > aggregate(ODnorm ~ Time + Target + Conc, data = df, FUN =

Hallo Everybody How do you specify arguments for a function used within another function? Here is my problem: I am reconstructing a calculator for the burden of disease due to air pollution from publications and tools published by the WHO. The calculations make use of published dose-response relationships for particular health end-points. This is then applied to populations with known or

Also, > aggregate(cbind(OD, ODnorm) ~ Time + Target + Conc, data = df, FUN = "mean") Time Target Conc OD ODnorm 1 1 BACT 1 765.3333 108.33333 2 1 BACT 2 745.3333 88.33333 3 1 BACT 3 675.0000 18.00000 (You might wish for "cbind(OD,ODnorm) ~ . - Well", but aggregate.formula is not smart enough for that.) -pd > On 24 Oct 2023, at

Dear Colleagues: Through your help an R related installation issue was resolved, but I now have the following usage issue. On any "get.var.ncdf" usage I am seeing: Error: in routine alloca() there is a stack overflow: thread 0, max 535822282KB, used 0KB, request 24B The same error is posted on a file as small as 50MB and as large as 500GB, with ulimit set to unlimited. I

I have used Sweave a lot the latest year, but never really used any long function calls. If I have code which look like this ------------------------------------------------------------- gof <- benthic.flux(ID="Gulf of Finland", meas.conc=conc, bw.conc=bw.conc, time=times,

I am having trouble fitting correlation structures within nlme. I would like to fit corCAR1, corGaus and corExp correlation structures to my data. I either get the error "step halving reduced below minimum in pnls step" or alternatively R crashes. My dataset is similar to the CO2 example in the nlme package. The one major difference is that in my case the 'conc' steps are

Hi I have measured the UV absorbance (abs) of 10 solutions of a substance at known concentrations (conc) and have used a linear model to plot a calibration graph with confidence limits. I now want to predict the concentration of solutions with UV absorbance results given in the new.abs data.frame, however predict.lm only appears to work for new "conc" variables not new "abs"

Dear R experts! I'd to fit data by 'nls' with me-supplied function 'fcn'. 1) I'd like 'fcn' to accept arbitrary arguments, i.e. I defined it as f(...) {<body>}. (Ok, that's not actually impotant). 2) Second, I would NOT like to supply every parameter in the formula. To illustrate this, let's look at the last example of 'nls' help