Displaying 20 results from an estimated 6000 matches similar to: "Transformation of Y changes the 'lm' object?"
2008 May 06
2
To preserve the class "Matrix"
Hi,
Suppose
a=matrix(1:9,3,3)
> a
[,1] [,2] [,3]
[1,] 1 4 7
[2,] 2 5 8
[3,] 3 6 9
Now,
> class(a[1:2,])
[1] "matrix"
> class(a[1:3,])
[1] "matrix"
> class(a[,1:2])
[1] "matrix"
> class(a[,1:3])
[1] "matrix"
But,
> class(a[1,])
[1] "integer"
> class(a[,1])
[1]
2008 May 13
2
Remove an object by the reference
Hi R,
A simple question, but don't know the answer...
x="a"
a=5
I need to remove the object "a" by using only x. something like rm(somefunction(x))...Is this possible?
Shubha Karanth | Amba Research
Ph +91 80 3980 8031 | Mob +91 94 4886 4510
Bangalore * Colombo * London * New York * San José * Singapore * www.ambaresearch.com
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2008 May 24
1
Solving 100th order equation
Hi R,
I have a 100th order equation for which I need to solve the value for x. Is there a package to do this?
For example my equation is:
(x^100 )- (2*x^99) +(10*x^50)+.............. +(6*x ) = 4000
I have only one unknown value and that is x. How do I solve for this?
BR, Shubha
Shubha Karanth | Amba Research
Ph +91 80 3980 8031 | Mob +91 94 4886 4510
Bangalore *
2008 Nov 07
2
Mismatch in logical result?
Hi R,
I have certain checkings, which gives FALSE, but actually it is true. Why does this happen? Note that the equations that I am checking below are not even the case of recurring decimals...
> 1.4^2 == 1.96
[1] FALSE
> 1.2^3==1.728
[1] FALSE
Thanks in advance, Shubha
Shubha Karanth | Amba Research
Ph +91 80 3980 8031 | Mob +91 94 4886 4510
Bangalore * Colombo *
2008 Feb 06
1
wilderSum
Hi,
Can somebody tell me the formula for "?wilderSum" in TTR package? I mean how are these calculated?
BR, Shubha
Shubha Karanth | Amba Research
Ph +91 80 3980 8031 | Mob +91 94 4886 4510
Bangalore * Colombo * London * New York * San José * Singapore * www.ambaresearch.com
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2008 Sep 08
1
To find vector X under contraints
Hi R,
I have the variance-covariance matrix,
>V=matrix(c(0.011119238, 0.002407527, 0.002407527, 0.020739401),2,2)
I need to find a vector X=c(x1,x2), such that
1) X'VX is equal to a constant 2 (say) and
2) sum(x) should be equal to a another constant 1.5 (say).
How do we do this in R?
BR, Shubha
Shubha Karanth | Amba Research
Ph +91 80 3980 8031 | Mob +91 94
2010 May 11
1
Creating R exe files
Hi all,
Just like Fortran creates EXE files for a code, can R also do the same? Thanks for the info.
Thanks and Regards,
Shubha Karanth | Amba Research
Ph +91 80 3980 8283 | Mob +91 94 4886 4510
Bangalore * Colombo * London * New York * San José * Singapore * www.ambaresearch.com
This e-mail may contain confidential and/or privileged i...{{dropped:13}}
2008 May 13
3
Regular Expressions
Hi R,
Again struck with regular expressions...
Suppose,
S=c("World_is_beautiful", "one_two_three_four","My_book")
I need to extract the last but one element of the strings. So, my output should look like:
Ans=c("is","three","My")
gsub() can do this...but wondering how do I give the regular expression....
2008 Jun 19
2
Comparison between R and MATLAB
Hi R,
Can I get a comparison between R and MATLAB? How is R efficient than MATLAB? Or what are the weaknesses of R compared to MATLAB?
Thank you very much for your help,
Shubha
Shubha Karanth | Amba Research
Ph +91 80 3980 8031 | Mob +91 94 4886 4510
Bangalore * Colombo * London * New York * San José * Singapore * www.ambaresearch.com
This e-mail may contain confidential and/or
2008 Jun 19
2
Calling R functions into C# or C++
Hi R,
I have a request...
Can I call R functions/routines from C# or C++? If so, how do I do this? Do I need to have some knowledge on DLL to do this?
Thanks a lot for your help,
Shubha
Shubha Karanth | Amba Research
Ph +91 80 3980 8031 | Mob +91 94 4886 4510
Bangalore * Colombo * London * New York * San José * Singapore * www.ambaresearch.com
This e-mail may contain
2008 Feb 28
0
RMysql question
R users,
I have a problem in RMysql. The error I get is:
> library(RMySQL)
> library(RMySQL)
>options(expressions=10000)
> MySQL(max.con = 16, fetch.default.rec = 500, force.reload = FALSE)
Error: protect(): protection stack overflow
I have no idea of why the error is. Can anyone help on this?
Many Thanks,
Shubha
Shubha Karanth | Amba Research
Ph +91 80 3980
2008 Jun 11
0
Polynomial Goal Programming
Hello R,
Is there a package to perform Polynomial goal programming in R?
BR, Shubha
Shubha Karanth | Amba Research
Ph +91 80 3980 8031 | Mob +91 94 4886 4510
Bangalore * Colombo * London * New York * San José * Singapore * www.ambaresearch.com
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2010 Feb 21
0
Time series cross-sectional regression analysis
Hi all,
Is there a package in R to perform time series cross-sectional regression analysis (like the TSCSREG procedure in SAS)? Thanks for the info.
Thanks and Regards,
Shubha Karanth | Amba Research
Ph +91 80 3980 8283 | Mob +91 94 4886 4510
Bangalore * Colombo * London * New York * San José * Singapore * www.ambaresearch.com
This e-mail may contain confidential and/or
2008 Apr 09
11
Number of words in a string
Hi R,
A quick question: How do we find the number of words in a string?
Example:
C="Have a nice day"
And the number of words should be 4. any built in function or?...
Thanks, Shubha
Shubha Karanth | Amba Research
Ph +91 80 3980 8031 | Mob +91 94 4886 4510
Bangalore * Colombo * London * New York * San José * Singapore * www.ambaresearch.com
This e-mail may contain
2006 Nov 24
1
Fwd: Dates Conversion/write.foreign
---------- Forwarded message ----------
From: Shubha Vishwanath Karanth <shubhak at ambaresearch.com>
Date: Nov 24, 2006 7:54 PM
Subject: Dates Conversion/write.foreign
To: Shubha Karanth <shubhakaranth at gmail.com>, Shubha Vishwanath
Karanth <shubhak at ambaresearch.com>
Hi R experts,
I need an urgent help...
I have an a dataframe caled idat. Below i give a snapshot
2008 Sep 10
4
re flecting a line
Suppose x and y are numeric vectors of the same length.
plot(x,y) #scatterplot
lmObj1 <- lm(y~x) # best fit line
abline(lmObj1) # good
lmObj2 <- lm(x~y) #get best fit but with axes interchanged
abline(lmObj2) # not what I want. I want the correct line, drawn on the same
graph, but with
# response and predictor variables interchanged
One way to proceed would be to
2007 Jan 23
4
Vector to Matrix transformation
Hi R,
I have a vector V1 of unknown length, say n. I need to convert this into
a matrix C of row size=5, and accordingly the column should be updated.
I tried with:
C=as.matrix(V1,5,n/5)
But it is not working...Could somebody help me on this?
Thanks in advance...
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2007 Sep 18
0
FW: ISIN numbers into Bloomberg tickers
Hi David,
I tried the following and get the below error messages....
con =
blpConnect(show.days="trading",na.action="previous.days",periodicity="da
ily")# connecting Bloomberg
> dat <- blpGetData(con,"US4009703799
Equity","PX_LAST",start=as.chron(as.Date("01/01/2005",
2010 Aug 14
2
Stepwise Regression + entry/exit significance level
Hi R,
Does the "step" function used to perform stepwise regression has the
option to specify the entry/exit significance levels for the independent
variables? (This is similar to the 'slentry' and 'slstay' option in
'Proc reg' of SAS.). Or do we have any other package which does the
above? Thanks.
Thanks and Regards,
Shubha
This e-mail may
2010 Jun 17
3
R user interface
Hi R,
I have a an excel file with a lot of data. I need to create an user
interface in R, which has one single screen. It needs to contain a right
pane containing the click buttons for different countries (say). If the
user clicks a country, then a chart needs to be created for that
country, taking the data from Excel. Is this possible and which package
helps me in doing this? Many thanks in