Displaying 20 results from an estimated 8000 matches similar to: "Confusing concept of vector and matrix in R"
2010 Sep 17
2
Is there a project to compile R scripts into stand-alone executable file?
I know Matlab's M file can be converted to a stand-alone executable file. I
wonder if there is a project aimed at compiling R scripts into stand-alone
executable file. I think it will be very promising for R to be more widely
used in different fields.
--
View this message in context:
2011 Oct 01
7
Poor performance of "Optim"
I used to consider using R and "Optim" to replace my commercial packages:
Gauss and Matlab. But it turns out that "Optim" does not converge
completely. The same data for Gauss and Matlab are converged very well. I
see that there are too many packages based on "optim" and really doubt if
they can be trusted!
--
View this message in context:
2016 Jun 25
2
strange behavior in 'inherits' check for loaded S4 object
Hi,
(sorry for the wall of text; the issue here appears to be rather complicated)
I'm seeing a somewhat strange case where checking whether an S4 object
inherits from a parent class defined from another package with
'inherits' fails if that object is materialized through a call to
'load'. That's a mouthful, so I've put together a relatively small
reproducible example
2004 Nov 04
3
keep dimension of a sub matrix
Hi,
is there any way to keep a sub matrix dimension?
exemple :
i1<-1; i2<-1
j1<-2; j2<-3;
ret <-matrix(1,4,4)[i1:i2,j1:j2] ;
dim(ret) is NULL because the submatrix single col or single row is coerce to a vector automaticaly.
How can i bypass this cast : submatrix->vector ???????
Thank you.
---------------------------------
[[alternative HTML version
2016 Jul 29
2
strange behavior in 'inherits' check for loaded S4 object
I should add one more item that may be related here -- calling
'methods:::.requirePackage' returns a different result based on
whether the package namespace is already loaded or not.
If the package namespace is not loaded, the package is loaded and
attached, and the package environment is returned:
> methods:::.requirePackage("digest")
Loading required package:
2012 Aug 23
1
Why was my R process killed spontaneously?
I tried to use gpuCor function in the gputools package of R to calcuate the
pairwise correlations of a matrix of 40,000 columns.
Becuase there would be memory issues if I use the whole matrix at a time, I
splitted the matrix into submatrix of 10,000 columns and then calculate the
pairwise correlation of different submatrices. There are altogether 4
submatrices, so I need to calculate the pearson
2000 Feb 11
1
Creating efficiently a subset of a matrix
Dear R-helpers
I have the following problem: given a m x n matrix A, I want to have just a
m x k submatrix B, with B[i,] = A[i, offset[i] + 1:k], e.g. from
> offset <- c(0, 0, 1)
> a <- matrix(1:9, 3)
> a
[,1] [,2] [,3]
[1,] 1 4 7
[2,] 2 5 8
[3,] 3 6 9
the submatrix b
1 4
2 5
6 9
I can do this with a for loop or with sapply
> b <-
2004 Dec 17
2
Matrix and rownames problem
Hi,
I'm quite new to R, so excuse me if this problem has a simple solution.
I'm working with an array, lets say
i <- array(c(1:3,3:1), dim=c(3,2))
Then I want to give the rows and the columns names:
rownames(i)<-c("a","b","c")
colnames(i)<-c("d","e")
The result is given below:
d e
a 1 3
b 2 2
c 3 1
Here comes my problem.
2016 Jul 31
2
strange behavior in 'inherits' check for loaded S4 object
(Just returning from the "wilds" of Canada, so not able to comment on the specifics, but ...)
There is a basic point about generic functions that may be related to the "private" class question and my earlier remarks that Martin alluded to.
R (and S4 before it) allows packages to define methods for a generic function in another package. Say, for plot() in graphics.
The
2002 Oct 10
2
tapply for matrices
Does anyone have something like tapply that is extremely fast for matrices when there is a very large number of levels of the grouping variable?
I'm referring to, for example,
tapply(x, grouping.variable, function.operating.on.submatrix)
where x is a matrix and the submatrix is a subset of the rows of x. The grouping variable's length equals the number of rows of x.
--
Frank E
2007 Apr 25
1
for loops
Hello everybody
I'm very new at using R so probably this is a very stupid question.
I have a matrix of "p" columns and I have to calculate for each of them the "two sample t-statistic" and p-value and to save the results into two different vectors.
I have divided my matrix into two submatrices: submatrix A containing the first "n1" rows (p columns) and submatrix B
2004 Feb 09
5
simple question on picking out some rows of a matrix/data frame
Hi,
I have a simple question about matrix/data frame manipulation. I have
a data frame that looks a something like this
X Y Z
1 0 "apples"
-1 -1 "oranges"
...
0 -1 "bananas"
and I'd like to pull out all the rows for which X and Y are (un)equal
into a submatrix.
How can I do that?
Many thanks,
Roger Levy
2007 Oct 15
2
Get data from matrix
Hi,
I have a matrix that has a variable number of columns. I do not know, a
priori, the number of columns.
How can I get a sub matrix, for example, from row 10 to the end of the
columns?
In MatLab I would use something like this: SubMatrix = Matrix[10, 1:end]
Thanks a lot.
--
View this message in context: http://www.nabble.com/Get-data-from-matrix-tf4629336.html#a13218653
Sent from the R
2003 Oct 13
2
colnames from submatrix?
Hi R-Wizards:
I've looking through the R docs and have yet to find what I'm looking for
and have tried a few intermediate steps to now avail yet and rather than
spend another few hours looking for the solution, I figured I would post a
message.
I have a matrix (actually a set of them) that I want to pull all the names
of the non-zero columns into a vector/list for further processing:
2004 Sep 15
2
efficient submatrix extraction
Hi,
I have a matrix of say 1024x1024 and I want to look at it in chunks.
That is I'd like to divide into a series of submatrices of order 2x2.
| 1 2 3 4 5 6 7 8 ... |
| 1 2 3 4 5 6 7 8 ... |
| 1 2 3 4 5 6 7 8 ... |
| 1 2 3 4 5 6 7 8 ... |
...
So the first submatrix would be
| 1 2 |
| 1 2 |
the second one would be
| 3 4 |
| 3 4 |
and so on. That is I want the matrix to be evenly divided
2010 Jan 18
1
Sub-matrixes that are linked to the "Base matrix"
Hello,
I'm am in the process of trying to port a RATS functions to R and have
the problem, that RATS allows for the creation of submatrixes that are
linked to their basematrix.
Basically it should work like this:
a = matrix(1:(4*3),4,3)
a
# [,1] [,2] [,3]
# [1,] 1 5 9
# [2,] 2 6 10
# [3,] 3 7 11
# [4,] 4 8 12
# This of course doesnt work :)
b =
2006 Sep 20
2
Unexpected behavior of apply() over a 3d array
Dear listeRs,
I'm finding that apply() behaves strangely when used on a 3-d array. For
example:
> at <- array(1:27,dim=c(3,3,3))
> at
, , 1
[,1] [,2] [,3]
[1,] 1 4 7
[2,] 2 5 8
[3,] 3 6 9
, , 2
[,1] [,2] [,3]
[1,] 10 13 16
[2,] 11 14 17
[3,] 12 15 18
, , 3
[,1] [,2] [,3]
[1,] 19 22 25
[2,] 20 23 26
2002 Feb 01
3
matrix with ncol=1
Hello list,
I try to optimize some R code and it turns out that the function as.matrix
takes a lot of time in my code. There is only one reason why I need
as.matrix: My code should work for matrices with ncol=p and p should be
allowed to be 1 or larger.
Now I have a matrix x with dim(x)=(n,p), and
I need to work with the submatrix y <-x[gv,], (gv a vector of
n logicals) and to calculate
1998 Apr 09
1
0-extent matrices?
Is there a good reason not to allow matrix extents to be zero? I have been
writing a function which fits glms under certain linear constraints. I
fit the model with a reduced set of variables and then transform back to
the original set. This involves operating on submatrices of the
covariance matrix and subsets of the coefficients. Sometimes these subsets
are empty. A zero-length subset of the
2011 Apr 13
1
Extracting selected rows from a matrix to a submatix
I have a matrix M
> dim(M)
[1] 30380 561
I have another list L contains , that contains some row names of matrix M
str (L)
chr [1:21037]
Now I want to extract the submatrix subM (21037 , 561) from the matrix M by matching the rownames (M) to the 21037 rownames o f L
How do I do that ?
Thanks and regards,
Pankaj Barah
Pankaj Barah Department of Biology
Norwegian University