similar to: Solving tridiagonal matrix in R

I need to find solutions to a tridiagonal system. By this I mean a set of linear equations Ax = d where A is a square matrix containing elements A[i,i-1], A[i,i] and A[i,i+1] for i in 1:nrow, and zero elsewhere. R is probably not the ideal way to do this, but this is part of a larger problem that requires R. In my application it is much easier (and much faster) to generate the diagonal and

Hello, I have a big number lets say of around hundred digits. I want to subset that big number into consecutive number of 5 digits and find the product of those 5 digits. For example my first 5 digit number would be 73167. I need to check the product of the individual numbers in 73167 and so on. The sample number is as follows:

Hello R users, I am trying to use R to do the low pass filter analysis for the tidal data. I am a novice in R and so far been doing only simple stuffs on R. I found a package called signal but couldn't find the proper tutorial for the low pass filter. Could anyone point me to the proper tutorial or starting point on how to do low pass filter analysis in R ? Thank you so much. Janesh

I have created a graph with basic R plot with 2 rows and 3 columns. With the basic plot feature of R I had to write several lines of code to come up with the graph https://www.dropbox.com/s/f7d6ei6krtcrtti/hello.png I was wondering whether we can plot multiple series in each plot using ggplot as created in the above link. If anyone could give me any suggestion then I could try on ggplot. I

Hi , I am trying to convert the date as factor to date using "as.date" function in R. I have the date in the following format 2008-01-01 02:30 I tried to use the following command : as.Date(mydata$Date, format="%y-%m-%d ") Can somebody help me with this ? I was able to convert the format with no hour but getting difficulty with hour included. Thank you.

Hi, I am generating large Kac matrices (also known as Clement matrix). This a tridiagonal matrix. I was wondering whether there is a vectorized solution that avoids the `for' loops to the following code: n <- 1000 Kacmat <- matrix(0, n+1, n+1) for (i in 1:n) Kacmat[i, i+1] <- n - i + 1 for (i in 2:(n+1)) Kacmat[i, i-1] <- i-1 The above code is fast, but I am curious about

Hello All, I have a data with two columns. In one column it is date and in another column it is flow data. I was able to read the data as date and flow data. I used the following code: creek <- read.csv("creek.csv") library(ggplot2) creek[1:10,] colnames(creek) <- c("date","flow") creek$date <- as.Date(creek$date, "%m/%d/%Y") The link to my data

Hello All, I have plotted a scatter plot in ggplot2 and added a regression line and a regression equation. But the processing is very very slow. One reason might be because I have so many data pairs. Is there any way to speed up this code ? I need to create a multiple layout as well. The code I have used is as follows: setwd("C:/Users/jzd0009/Documents/R software") mydata <-

Hello All, I have a discontinuous dataset and I used spplot to plot the points. I was wondering whether it is possible to show the legend of the plot as color ramp. I saw that on continuous data. If anyone could tell me that would be great. Another thing I would like to know is how can we create the horizontal legend. By default, the legend is vertical. I was able to shift the legend inside

Hi, I am trying to solve a model that consists of rather stiff ODEs in R. I use the package ODEsolve (lsoda) to solve these ODEs. To speed up the integration, the jacobian is also specified. Basically, the model is a one-dimensional advection-diffusion problem, and thus the jacobian is a tridiagonal matrix. The size of this jacobian is 100*100. In the original package

Dear R users, I am working on a data-set with 3 species. They are apple, orange and banana. I want to annotate the facets only on the bottom panel. However, by default I am getting annotations on all the plots. I was able to get text annotation only on the desired plot. However, I am confused what I need to do for the arrows / segments. Here is my code: library(ggplot2) library(grid) tempobs

Dear R Users, I have data for more than 3 years. For each year I want to find the day corresponding to Jaunary 1 of that year. For example: > x <- c('5/5/2007','12/31/2007','1/2/2008') > #Convert to day of year (julian date) - > strptime(x,"%m/%d/%Y")$yday+1 [1] 125 365 2 I want to know how to do the same thing but with time added. But I still

Hi, I have sparse (tridiagonal) matrices, and I use the Matrix package for handling them. For certain computations, I need to either set the first row to zero, or double the last row. I find that neither operation preserves sparsity, eg > m <- Diagonal(5) > m 5 x 5 diagonal matrix of class "ddiMatrix" [,1] [,2] [,3] [,4] [,5] [1,] 1 . . . . [2,] . 1

Hello All, I have a data file in a text format and there are two data sets. The data set are continuous. For each data set there is a header which has the number of data rows and the name of data series. For example first data set has "6240 Terry Cove-Model". Then the data for that series follows upto 6240 rows. Then another data would start and it will have the header such as

Dear All, Which package/function could i use to solve following linear least square problem? A over determined system of linear equations is given. The nnls-function may would be a possibility BUT: The solving is constrained with a inequality that all unknowns are >= 0 and a equality that the sum of all unknowns is 1 The influence of the equations according to the solving process is

Dear R-users, I have a dataset as like below, and I want to subtotal the values of rice,wheat and maize by year for each fid. fid      year     rice     wheat      maize ------------------------------------------------ 1        1995      5        NA           NA 1        1995      NA        3           NA 1        1995      NA       NA           2 1        1996      4        NA           NA 1  

Hi, I have done the interpolation for my data and I was able to create the contours in multipanel with the help of Pascal. Now, I want to clip the contour with the shapefile. I want only the portion of contour to be displayed which falls inside the boundary of the shapefile. The data mydata.csv can be found on https://www.dropbox.com/s/khi7nv0160hi68p/mydata.csv The data for shapefile can be

Good day, I would like to know if there is an efficient and accurate method for computing the power of a tridiagonal matrix in R? The "obvious" method would be eigen-decomposition, but I find that this is not very accurate, probably because the dimensions of the matrix I am considering are large and the eigenvectors are not well approximated. Here is an example of what I am trying to

I am trying to solve an integral in R. However, I am getting an error when I am trying to solve for that integral. The equation that I am trying to solve is as follows: $$ C_m = \frac{{abs{x}}e^{2x}}{\pi^{1/2}}\int_0^t t^{-3/2}e^{-x^2/t-t}dt $$ [image: enter image description here] The code that I am using is as follows: a <- seq(from=-10, by=0.5,length=100) ## Create a function to compute

Hello All, I am trying to do the comparison of my observed and modeled data sets for two stations. One station is called station "red" and another is called "blue". I was able to create the facets but when I tried to add two series in one facet then only one facet got updated while other didn't. The data watersurf1.csv can be downloaded from