Displaying 20 results from an estimated 4000 matches similar to: "generalized least squares with empirical error covariance matrix"
2007 Dec 05
2
kalman filter random walk
Hi,
I'm trying to use the kalman filter to estimate the variable drift of a
random walk, given that I have a vector of time series data. Anyone have
any thoughts on how to do this in R?
Thanks,
Alex
[[alternative HTML version deleted]]
2017 Jul 30
0
Kalman filter for a time series
> structSSM
Is no longer part of KFAS. All you needed to do was:
library(KFAS)
?KFAS
and you would have seen that if you went to the index. A structural state space model is now built up from its components, much like in LM. Look at;
?SSModel
-Roy
> On Jul 29, 2017, at 9:26 PM, Staff <rbertematti at gmail.com> wrote:
>
> I found an example at
>
2017 Jul 30
4
Kalman filter for a time series
I found an example at
http://www.bearcave.com/finance/random_r_hacks/kalman_smooth.html shown
below. But it seems the structSSM function has been removed from KFAS
library so it won't run. Does anyone know how to fix the code so that it
runs?
library(KFAS)
library(tseries)
library(timeSeries)
library(zoo)
library(quantmod)
getDailyPrices = function( tickerSym, startDate, endDate )
{
2012 Mar 23
2
Fwd: The StructTS method
To whomever it may concern,
I'm a young Industrial Engineer working on Senior Design at Georgia Tech and have found the StructTS method to be excellent for the training set for my forecasting project. There's only one problem: I don't actually understand what a Structural Time Series IS. I've looked up resources on it, and get that essentially you're dividing the Time
2017 Jun 01
5
Reversing one dimension of an array, in a generalized case
Hi All:
I have been looking for an elegant way to do the following, but haven't found it, I have never had a good understanding of any of the "apply" functions.
A simplified idea is I have an array, say:
junk(5, 10, 3)
where (5, 10, 3) give the dimension sizes, and I want to reverse the second dimension, so I could do:
junk1 <- junk[, rev(seq_len(10), ]
but what I am
2017 Jun 01
0
Reversing one dimension of an array, in a generalized case
How about this:
f <- function(a,wh){ ## a is the array; wh is the index to be reversed
l<- lapply(dim(a),seq_len)
l[[wh]]<- rev(l[[wh]])
do.call(`[`,c(list(a),l))
}
## test
z <- array(1:120,dim=2:5)
## I omit the printouts
f(z,2)
f(z,3)
Cheers,
Bert
Bert Gunter
"The trouble with having an open mind is that people keep coming along
and sticking things into
2017 Jun 01
2
Reversing one dimension of an array, in a generalized case
My error. Clearly I did not do enough testing.
z <- array(1:24,dim=2:4)
> all.equal(f(z,1),f2(z,1))
[1] TRUE
> all.equal(f(z,2),f2(z,2))
[1] TRUE
> all.equal(f(z,3),f2(z,3))
[1] "Attributes: < Component ?dim?: Mean relative difference: 0.4444444 >"
[2] "Mean relative difference: 0.6109091"
# Your earlier example
> z <- array(1:120, dim=2:5)
>
2017 Jun 01
3
Reversing one dimension of an array, in a generalized case
Here is an alternative approach using apply(). Note that with apply() you are reversing rows or columns not indices of rows or columns so apply(junk, 2, rev) reverses the values in each column not the column indices. We actually need to use rev() on everything but the index we are interested in reversing:
f2 <- function(a, wh) {
dims <- seq_len(length(dim(a)))
dims <-
2017 Jun 01
3
Reversing one dimension of an array, in a generalized case
> On 1 Jun 2017, at 22:42, Roy Mendelssohn - NOAA Federal <roy.mendelssohn at noaa.gov> wrote:
>
> Thanks to all for responses/. There was a question of exactly what was wanted. It is the generalization of the obvious example I gave,
>
>>>> junk1 <- junk[, rev(seq_len(10), ]
>
>
> so that
>
> junk[1,1,1 ] = junk1[1,10,1]
> junk[1,2,1] =
2017 Jun 01
0
Reversing one dimension of an array, in a generalized case
??
> z <- array(1:24,dim=2:4)
> all.equal(f(z,3),f2(z,3))
[1] "Attributes: < Component ?dim?: Mean relative difference: 0.4444444 >"
[2] "Mean relative difference: 0.6109091"
In fact,
> dim(f(z,3))
[1] 2 3 4
> dim(f2(z,3))
[1] 3 4 2
Have I made some sort of stupid error here? Or have I misunderstood
what was wanted?
Cheers,
Bert
Bert Gunter
2017 Jun 01
0
Reversing one dimension of an array, in a generalized case
On the off chance that anyone is still interested, here is the corrected function using aperm():
z <- array(1:120,dim=2:5)
f2 <- function(a, wh) {
idx <- seq_len(length(dim(a)))
dims <- setdiff(idx, wh)
idx <- append(idx[-1], idx[1], wh-1)
aperm(apply(a, dims, rev), idx)
}
all.equal(f(z, 1), f2(z, 1))
# [1] TRUE
all.equal(f(z, 2), f2(z, 2))
# [1] TRUE
2017 Jun 01
1
Reversing one dimension of an array, in a generalized case
Thanks again. I am going to try the different versions. But I probably won't be able to get to it till next week.
This is probably at the point where anything further should be sent to me privately.
-Roy
> On Jun 1, 2017, at 1:56 PM, David L Carlson <dcarlson at tamu.edu> wrote:
>
> On the off chance that anyone is still interested, here is the corrected function using
2017 Jun 01
0
Reversing one dimension of an array, in a generalized case
Thanks to all for responses/. There was a question of exactly what was wanted. It is the generalization of the obvious example I gave,
>>> junk1 <- junk[, rev(seq_len(10), ]
so that
junk[1,1,1 ] = junk1[1,10,1]
junk[1,2,1] = junk1[1,9,1]
etc.
The genesis of this is the program is downloading data from a variety of sources on (time, altitude, lat, lon) coordinates, but all
2018 Jan 02
4
httr::content without message
Hi All:
I am using httr to download files form a service, in this case a .csv file. When I use httr::content on the result, I get a message. Since this will be in a package. I want to suppress the message, but haven't figured out how to do so.
The following should reproduce the result:
myURL <-
2017 Oct 17
2
ggridges help
yes, thanks, and I was getting close to that. One thing I found is the manual says the height is the distance above the y-line, which should be, but doesn't have to be positive. In fact, the time series are estimates of a cycle, and has negative values, which unfortunately are not included in my sub-sample. And the negative values are not handled properly (the series disappears for
2017 Aug 29
3
RMarkdown question
Hi All:
In creating a R Notebook I know that in the text I can link to a (sub) section by using the command:
[Header 1](#anchor)
and putting the appropriate anchor name at the appropriate header. But can the same be done for code chunks, if the code chunk is named? What I want to do is say that such and such code chunk is an example of how to do something, and have that link to the
2017 Oct 17
2
ggridges help
I have tried:
ggplot(plotFrame, aes(x = time, y = cycle, height = cycle, group = depth)) + geom_ridgeline()
ggplot(plotFrame, aes(x = time, y = depth, height = cycle, group = depth)) + geom_ridgeline()
ggplot(plotFrame, aes(x = time, y = depth, group = depth)) + geom_density_ridges()
none are producing a plot that was a ridgeline for each depth showing the time series at that depth. The plot
2017 Oct 17
0
ggridges help
The min_height = -0.25 is there to make it show cycle values down to -1/4.
You may want to change it to -1 so it shows more of the cycle values.
Bill Dunlap
TIBCO Software
wdunlap tibco.com
On Tue, Oct 17, 2017 at 1:26 PM, Roy Mendelssohn - NOAA Federal <
roy.mendelssohn at noaa.gov> wrote:
> yes, thanks, and I was getting close to that. One thing I found is the
> manual says the
2017 Oct 17
0
ggridges help
Does the following work for you?
ggplot2::ggplot(plotFrame, aes(x = time, y = depth, height = cycle,
group = depth)) + ggridges::geom_ridgeline(fill="red", min_height=-0.25)
Bill Dunlap
TIBCO Software
wdunlap tibco.com
On Tue, Oct 17, 2017 at 12:43 PM, Roy Mendelssohn - NOAA Federal <
roy.mendelssohn at noaa.gov> wrote:
> I have tried:
>
> ggplot(plotFrame, aes(x =
2017 Oct 17
2
ggridges help
Hi All:
I am just not understanding ggridges. The data I have are time series at different depths in the ocean. I want to make a joy plot of the time series by depth.
If I was just doing a ggplot2 line plot I would be doing:
ggplot(plotFrame, aes(x = time, y = cycle, group = depth)) + geom_line()
but translating that to ggridges has not worked right. Below is the result from dput() of a