Displaying 20 results from an estimated 10000 matches similar to: "Cost-benefit/value for money analysis"
2004 Sep 01
1
error in mle
Friends
I'm trying fit a survival model by maximum likelihood estimation using this function:
flver=function(a1,a2,b1,b2)
{
lver=-(sum(st*log(exp(a1*x1+a2*x2)))+sum(st*log(hheft(exp(b1*x1+b2*x2)*t,f.heft)))
-(exp(a1*x1+a2*x2)/exp(b1*x1-b2*x2))*sum(-log(1-pheft(exp(b1*x1+b2*x2)*t,f.heft))))
}
emv=mle(flver,start=list(a1=0,a2=0,b1=0,b2=0))
where hheft and pheft are functions defined in
2012 Sep 07
6
splitting character vectors into multiple vectors using strsplit
Hi folks,
Suppose I create the character vector charvec by
> charvec<-c("a1.b1","a2.b2")
> charvec
[1] "a1.b1" "a2.b2"
and then I use strsplit on charvec as follows:
> splitlist<-strsplit(charvec,split=".",fixed=TRUE)
> splitlist
[[1]]
[1] "a1" "b1"
[[2]]
[1] "a2" "b2"
I was wondering
2009 Nov 29
3
Plotting observed vs. Predicted values, change of symbols
Dear Wiz[R]ds,
I am deeply grateful for the help from Duncan Murdoch, Gray Calhoun, and
others. We are almost there. For whatever reason, I can't change the symbol
from a circle to a triangle in the upright posture plots. Any ideas? I have
included the problem in full.
# tritiated (3H)-Norepinephrine(NE) disappearance from plasma
# concentrations supine and upright
# supine
datasu <-
2012 Apr 19
3
How to "flatten" a multidimensional array into a dataframe?
Hi,
I have a three dimensional array, e.g.,
my.array = array(0, dim=c(2,3,4), dimnames=list( d1=c("A1","A2"),
d2=c("B1","B2","B3"), d3=c("C1","C2","C3","C4")) )
what I would like to get is then a dataframe:
d1 d2 d3 value
A1 B1 C1 0
A2 B1 C1 0
.
.
.
A2 B3 C4 0
I'm sure there is one function to do
2013 Feb 23
1
how to calculate left kronecker product?
For an application, I have formulas defined in terms of a left Kronecker
product of matrices,
A,B, meaning
A \otimes_L B = {A * B[i,j]} -- matrix on the left multiplies each
element on the right.
The standard kronecker() function is the right Kronecker product,
A \otimes_R B = {A[i,j] * B} -- matrix on the right multiplies each
element on the left.
The example below shows the result of
2007 Jul 31
5
extract columns of a matrix/data frame
Hello all,
I have a matrix whose column names look like
a1 a2 b1 b2 b3 c1 c2
1 2 3 7 1 3 2
4 6 7 8 1 4 3
Now, I can have any number of a's. not just two as shown above and same goes for b's and c's. I need to extract all the a's columns and put them in another matrix, extract all b's columns and put them in some matrix
2009 Oct 29
3
Removing & generating data by category
Dear R users,
Basically, from the following arbitrary data set:
a <-
data.frame(id=c(c("A1","A2","A3","A4","A5"),c("A3","A2","A3","A4","A5")),loc=c("B1","B2","B3","B4","B5"),clm=c(rep(("General"),6),rep("Life",4)))
> a
2010 Jul 17
4
sort file names in numerical order
Hello,
I get some file names by list.files().
These names are in alphabetical order.
I want to change it to logical numeric order.
Example:
> fileNames <- c("A10", "A1", "A2", "B1", "B2", "B10")
> sort(fileNames)
[1] "A1" "A10" "A2" "B1" "B10" "B2"
I want to have:
2007 Nov 13
7
combine two dataframe
I have two data frame A and B adn want to cross them.
A has format as:
a1 a2 a3
1 2 3
2 3 1
1 3 2
...
B:
b1 b2
1 2
2 1
...
the combine result shall be something like
a1 a2 a3 b1 b2
1 2 3 1 2
1 2 3 2 1
2 3 1 1 2
2 3 1 2 1
1 3 2 1 2
1 3 2 2 1
....
is there a function able of doing this instead of loops?
Thanks,
Sun
2005 Aug 15
2
queer data set
I have a dataset that is basically structureless. Its dimension varies
from row to row and sep(s) are a mixture of tab and semi colon (;) and
example is
HEADER1 HEADER2 HEADER3 HEADER3
A1 B1 C1 X11;X12;X13
A2 B2 C2 X21;X22;X23;X24;X25
A3 B3 C3
A4 B4 C4 X41;X42;X43
A5 B5 C5 X51
etc., say. Note that a blank
2009 Nov 29
1
Plotting observed vs. fitted values
Dear Wiza[R]ds,
I am very grateful to Duncan Murdoch for his assistance with this problem.
His help was invaluable. However, the problem has become a little more
complicated for me. Now, in each plot, I need to plot the observed and
fitted values of a supine and upright posture experiment. Here is what I
have and how far I got.
# tritiated (3H)-Norepinephrine(NE) disappearance from plasma
#
2013 Mar 13
5
string split at xth position
Hi,
I have a vector of strings like:
c("a1b1","a2b2","a1b2") which I want to spilt into two parts like:
c("a1","a2","a2") and c("b1","b2,"b2"). So there is
always a first part with a+number and a second part with b+number.
Unfortunately there is no separator I could use to directly split
the vectors.. Any idea
2009 Mar 20
4
how to make aggregation in R ?
Hi,
I am trying to aggregate the sum of my test data.frame as follow:
testDF <- data.frame(v1 = c("a", "a", "a", "a", "a", "b", "b", "b", "b",
"b", "c", "c", "c", "c", "c", "d", "d", "d", "d",
2003 Oct 04
2
mixed effects with nlme
Dear R users:
I have some difficulties analizing data with mixed effects NLME and the
last version of R. More concretely, I have a repeated measures design with
a single group and 2 experimental factors (say A and B) and my interest is
to compare additive and nonadditive models.
suj rv A B
1 s1 4 a1 b1
2 s1 5 a1 b2
3 s1 7 a1 b3
4 s1 1 a2
2012 Oct 18
7
summation coding
I would like to code the following in R: a1(b1+b2+b3) + a2(b1+b3+b4) +
a3(b1+b2+b4) + a4(b1+b2+b3)
or in summation notation: sum_{i=1, j\neq i}^{4} a_i * b_i
I realise this is the same as: sum_{i=1, j=1}^{4} a_i * b_i - sum_{i=j} a_i
* b_i
would appreciate some help.
Thank you.
--
View this message in context: http://r.789695.n4.nabble.com/summation-coding-tp4646678.html
Sent from the R
2013 Mar 12
2
big edge list to adjacency matrix
I have huge list of edges with weights.
a1 b1 w1
a2 b2 w2
a3 b3 w3
a1 b1 w4
a3 b1 w5
I have to convert it into 2 dim matrix
b1 b2 b3
a1 max(w1,w4) 0 0
a2 0 w2 0
a3 w5 0 w3
if edges repeated take the maximum weights. How do this efficiently without
using for loop? Any idea.
thanks
Avi
[[alternative
2019 Nov 28
2
SLP example not being vectorized
Hi,
I am new to llvm with a particular interested in the optimization area,
specially on SLP. While working through the tutorial, I ran this example
[1] with the hope to see SLP vectorization in action but for some
reason, I do not see it on the LLVM assembly as seen below. Is there
anything I am missing? I am using Clearlinux as build machine and this
has clang version 9.0.0.
2007 Feb 25
1
Repeated measures logistic regression
Dear all,
I'm struggling to find the best (set of?) function(s) to do repeated
measures logistic regression on some data from a psychology experiment.
An artificial version of the data I've got is as follows. Firstly,
each participant filled in a questionnaire, the result of which is a
score.
> questionnaire
ID Score
1 1 6
2 2 5
3 3 6
4 4 2
...
2010 Jul 07
3
How do I test against a simple null that two regressions coefficients are equal?
Hi there,
I run two regressions:
y = a1 + b1 * x + e1
y = a2 + b2 * z + e2
I want to test against the null hypothesis: b1 = b2. How do I design the test?
I think I can add two equations together and divide both sides by 2:
y = 0.5*(a1+a2) + 0.5*b1 * x + 0.5*b2 * z + e3, where e3 = 0.5*(e1 + e2).
or just y = a3 + 0.5*b1 * x + 0.5*b2 * z + e3
If I run this new regression, I can test against
2000 Nov 09
2
simple mixture
Dear All,
I am trying to do some simple mixture analyses. For instance, I have a
sample of n observations and I suspect they come from two different
exponential distributions with parameters rate1 and rate2, respectively.
So, I want to estimate rate1, rate2, and the proportions of both kinds of
individuals in the sample. I had a look at the packages mda and mclust, but
they do not seem to do this