Displaying 20 results from an estimated 1000 matches similar to: "Data assimilation / inverse modeling in R"
2006 Apr 05
2
gsub in data frame
Hello,
I have this data frame:
### begin
d <-data.frame(matrix(c("1","--","bla",2),2,2))
d
# I want to replace the "--" by "\N" and still get a data frame.
# I tried:
out <-gsub("--","\\\\N",as.matrix(d)) #using as.matrix to get rid of factors
out
cat(out)
# But I lost my data frame
### end
Any idea?
Regards,
2006 Apr 24
2
Change the language of the labels in a graph
Hello,
How do you change the language of the labels in a graph. In this example, I
want to get French labels by changing Sys.putenv. I should get "Mai"
instead of "May".
Sys.putenv(LANGUAGE="fr")
x <- as.Date(c("1jan1960", "2jan1960", "31mar1960", "30jul1960"), "%d%b%Y")
y <-1:4
plot(x,y)
Regards,
Pierre
2006 Mar 14
2
Multi-line paste function
Here's my contribution to R.
When R interacts with external programs (MySQL, cURL, etc.), it often
requires a pasted string that is sent to these programs. For readability
reasons, it is often preferable to have complex commands (SQL for example)
spread on several lines. However, the normal paste function requires to add
additional ' ", ' at the end of each line and another '
2006 Jul 19
1
How would you export a 3-dimensional array to an SQL database?
Hello,
How would you export a 3-dimensional array to an SQL database?
a<-array(1:24, 2:4)
Is there an open source DB that would be more adequate for this type of
operation?
Is there a way to reshape/flatten a 3-dimensional array?
Regards,
Pierre Lapointe
**************************************************
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2006 Nov 07
1
Gregexpr - extract results with lapply
Gregexpr - extract results with lapply
Hello,
I need to extract sequences of three upper case letters in a string. In
other words, in this string:
str <-c("ABC", "this WOUld be gOOD")
The result I'm looking for is ABC WOU OOD.
With gregexpr, I can get the position and length of the sequences
gregexpr('[A-Z]{3}',str,perl=TRUE)
[[1]]
[1] 1
2007 Jan 16
1
system(mysql... Does not recognize < as passing an attribute (No HTML)
Hi,
This is my command line request: mysql -u root -ppassword -D quant
<c:/cline.txt
This line works from the command line in windows.
In R, when I try to use the system function, it does not work,
> system(paste('mysql -u root -ppassword -D quant
<c:/cline.txt'),show.output.on.console = TRUE)
ERROR 1102 (42000): Incorrect database name '<c:/cline.txt'
It seems
2007 Jan 16
1
system(mysql... Does not recognize < as passing an attribute
Hi,
This is my command line request: mysql -u root -ppassword -D quant
<c:/cline.txt
This line works from the command line in windows.
In R, when I try to use the system function, it does not work,
> system(paste('mysql -u root -ppassword -D quant
<c:/cline.txt'),show.output.on.console = TRUE)
ERROR 1102 (42000): Incorrect database name '<c:/cline.txt'
It seems
2006 Nov 06
2
grep searching for sequence of 3 consecutive upper case letters
Hello,
I need to identify all elements which have a sequence of 3 consecutive upper
case letters, anywhere in the string.
I tested my grep expression on this site: http://regexlib.com/RETester.aspx
But when I try it in R, it does not filter anything.
str <-c("AGH", "this WOUld be good", "Not Good at All")
str[grep('[A-Z]{3}',str)] #looking for a
2006 Jun 09
3
sqlSave() and rownames=TRUE makes my Rgui crash
Hello,
I created a table in MySQL with this command
CREATE TABLE example (pk INT NOT NULL AUTO_INCREMENT,PRIMARY KEY(pk),
id VARCHAR(30),col1 VARCHAR(30),col2 VARCHAR(30))
### In R, I can connect to this table:
library(DBI)
library(RODBC)
chan <- odbcConnect("MySQL51", uid="root", pwd="xxx")
first <- sqlQuery(chan, "select * from example")
2012 Jul 11
2
Modifying the design matrix X in GAMS to suit data assimilation
I have a data assimilation problem that might be amenable to the use of GAMS, but I am not sure how feasible it is to implement. I was told the R mailing list was a great resource.
My observations are spatiotemporal salinity in the San Francisco Bay at a number of instruments over a few days. The thing that I want to fit is the initial condition for a salt transport model at the beginning of this
2010 Nov 14
5
kalman filter
Hello,
I would like use Kalman filter for estimating parameters of a stochastic
model. I have developed the state space model but I don’t know the correct
way use Kalman filter for parameter estimation. Has anybody experience in
work with Kalman filter in R.
I don’t know the correct function. Maybe it is
- KalmanLike; but what is the correct Input?
- tsmooth?
-
2005 May 22
4
Calling R from R and specifying "wait until script is finished"
Hello,
Let's say I have 50 R scripts to run. What would be the most efficient way
to run them?
I thought I could do multiple Rterms in a DOS batch file:
Ex:
Rterm <1.R> 1.txt
Rterm <2.R> 2.txt
...
Rterm <50.R> 50.txt
However, I'm afraid they will all open at the same time. I know I could
pause the batch file with something like:
PING 1.1.1.1 -n 1 -w 60000
2005 May 25
1
Plot: Distance between tick and tick label on y-axis
Hello,
I want to reduce the distance between my ticks and their labels. I managed
to do it for the x-axis, but the y-axis puzzles me. Here's an example where
there is no space between the x-asix ticks and labels.
par(las=1)
plot(runif(50), type="l",xaxt="n",yaxt="n",ylab="", bty="l")
axis(2)
axis(1,padj=-1.5)
#However,
axis(2,padj=-1.5)
2005 May 26
1
Useful tip: Use Google to find R scripts
Hello,
Ever wondered how people use a particular function in their programs? Use
Google to find actual scripts:
filetype:R boxplot
will return real R scripts using the boxplot function.
Regards,
Pierre Lapointe
Assistant Market Strategist
***********************************************************************************
AVIS DE NON-RESPONSABILITE:\ Ce document transmis par
2005 Jun 08
1
RODBC question: problem importing series with blank cells
Hello,
I have an excel file that I load through RODBC. Some of my columns are
blank. They are equity time series and the stocks did not exist at the
earlier dates. My problem is that the whole column becomes <NA> even though
there are numbers at later dates.
Here's my excel file
http://www.tradebit.com/download.php/35699
<http://www.tradebit.com/download.php/35699>
And
2008 Feb 26
2
Kalman Filter
Hi
My name is Vladimir Samaj. I am a student of Univerzity of Zilina. I am
trying to implement Kalman Filter into my school work. I have some problems
with understanding of R version of Kalman Filter in package stats( functions
KalmanLike, KalmanRun, KalmanSmooth,KalmanForecast).
1) Can you tell me how are you seting the initial values of state vector in
Kalman Filter? Are you using some method?
2005 May 19
5
Arranging Plots
Dear all,
I'd appreciate any hints how to arrange some plots.
I have three plots. I would like to arrange them in the following order:
- Plot 1 and Plot 2 should be in the upper row
- Plot 3 should be in the lower row but centered in the middle.
I hope the following sketch will help understanding my problem
================
| === === |
|| P1| |P2 | |
|| | | | |
| === === |
2006 Jan 26
0
XML Request in R: Pointers/examples needed
Hello R-helpers,
I'm new to XML. I have been using an application for some time, but now I
wish to automate my downloads with R. When I use the web interface of their
XML application, I'm able to read the response in R with the XML package.
My problem now is to send the requests directly from R. Here below are two
XML request scripts that come from the applicaton help file. My
2005 Jun 14
1
Matrix stability problem
Hello,
This is not a problem with R, the calculated results are mathematically
correct. This a matrix stability problem. Because of measuring errors, my
matrix solution is a bit off.
Here is what my equations look like:
A11 x11+A12 x12 +A13 x13 = b1
A21 x21+A22 x21 +A23 x23 = b2
A31 x31+A32 x31 +A33 x33 = b3
A is a reading, X is a measured weight, and b is total. The 3 experiments
give
2006 Dec 20
2
Kalman Filter in Control situation.
I am looking for a Kalman filter that can handle a control input. I thought
that l.SS was suitable however, I can't get it to work, and wonder if I am
not using the right function. What I want is a Kalman filter that accepts
exogenous inputs where the input is found using the algebraic Ricatti
equation solution to a penalty function. If K is the gain matrix then the
exogenous input