Displaying 20 results from an estimated 77 matches for "subspac".
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subspace
2011 Apr 14
2
Krylov subspace computations of matrix exponentials
I use the very nice expm functions available from the expm and Matrix
packages. My understanding is that for large sparse matrices the
currently best methods available are Krylov subspace methods, but
they are as far as I can tell not implemented in either of the packages
mentioned, nor in any other R package I have found.
Does anybody know if Krylov subspace methods are available from
any R package?
If not, is there anybody working on this or planning to do so?
If not, I might...
2005 Nov 30
0
Running Continuum/Subspace
As of version 0.9.2 the program continuum has started, and not failed right
at the beginning like it did in 0.9.1. Now, due to its anti cheating
measures, it goes through many kernel32, ntdll, gdi32, advapi32, and
comctl32 calls along with some winex11drv calls. For some reason, when i
try to log it to a file, it grows to 2 GB or greater. I haven't waited for
it to finish, as i don't
2005 Aug 29
1
lme and ordering of terms
Dear R users,
When fitting a lme() object (from the nlme library), is it possible to
test interactions *before* main effects? As I understand, R
conventionally re-orders all terms such that highest-order interactions
come last - but I??d like to know if it??s possible (and sensible) to
change this ordering of terms.
I??ve tried the terms() command (from aov) but I don??t know if something
2004 Aug 06
2
icecast cvs patch
.... but that could be used maliciously to override other
> (important) values in the stats core, like "number of users", etc. So to do
> this we'd need to put all the metadata fields into some sub-namespace in the
> stats core, which I don't think is currently possible?
Subspaces were sort of the point, exactly for this reason. Did I forget
to build that in? I'm pretty sure it's doable, or else I was an idiot.
Either is possible, of course.
In any case, putting ALL metadata into the stats is hte right solution I
think, and if that means subspaces, so be it :)
j...
2009 Oct 11
2
Why H1=1? (H's the hat matrix)
Suppose I have the following hat matrix:
H=X(X'X)^{-1}X'
X is a n by p matrix, where n >= p and X_{i,1} = 1
I'm wondering why H1 = 1. (Here, 1 is column vector, whose each
element is the number 1)
Thank you!
2010 Feb 08
3
Hypercube in R
Dear all,
Does anybody have an idea or suggestion how to construct (plot)
4-dimensional hypercube in R.
Thanks in advance for any pointers.
Regards, Andrej
2011 Mar 02
2
Vector manipulations
I have a question regarding the most efficient way to select a substring of
a vector:
I have a vector of value v, and I want to select a subspace of this vector
called w such that:
w=v[1:n]
where
sum(w) = x
I am interested in what you thing would be the most efficient way to do this
- I would like to avoid slowing down my simulations as much as possible.
Thank you very much for any help that anyone is able to give.
[[alternative HTML...
2012 Feb 13
3
mgcv: increasing basis dimension
hi
Using a ts or tprs basis, I expected gcv to decrease when increasing the
basis dimension, as I thought this would minimise gcv over a larger
subspace. But gcv increased. Here's an example. thanks for any comments.
greg
#simulate some data
set.seed(0)
x1<-runif(500)
x2<-rnorm(500)
x3<-rpois(500,3)
d<-runif(500)
linp<--1+x1+0.5*x2+0.3*exp(-2*d)*sin(10*d)*x3
y<-rpois(500,exp(linp))
sum(y)
library(mgcv)
#basis dimension k=5...
2004 Aug 06
2
icecast cvs patch
> A patch that put _configurable_ extra fields from vorbis comment headers into
> the stats core might be a good idea, though. Want to do that?
Or perhaps a patch which puts all fields into the stats core. Why be
selective?
jack.
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2004 Aug 06
0
icecast cvs patch
...usly to override other
> > (important) values in the stats core, like "number of users", etc. So
> to do
> > this we'd need to put all the metadata fields into some sub-namespace
> in the
> > stats core, which I don't think is currently possible?
>
>Subspaces were sort of the point, exactly for this reason. Did I forget
>to build that in? I'm pretty sure it's doable, or else I was an idiot.
>Either is possible, of course.
>
>In any case, putting ALL metadata into the stats is hte right solution I
>think, and if that means subsp...
2006 May 30
1
when dimensionality is larger than the number of observations?
Hi, there:
Can anyone here kindly point some good reference or links on this topic?
Esp. some solutions from BioConductor or R, when dealing with
microarray-like, "fat" data?
thanks,
--
Weiwei Shi, Ph.D
"Did you always know?"
"No, I did not. But I believed..."
---Matrix III
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2005 Mar 14
1
r: eviews and r // eigen analysis
hi all
i have a question that about the eigen analysis found in R and in
eviews.
i used the same data set in the two packages and found different
answers. which is incorrect?
the data is:
aa ( a correlation matrix)
1 0.9801 0.9801 0.9801 0.9801
0.9801 1 0.9801 0.9801 0.9801
0.9801 0.9801 1 0.9801 0.9801
0.9801 0.9801 0.9801 1 0.9801
0.9801 0.9801 0.9801 0.9801 1
now
> svd(aa)
$d
[1] 4.9204
2008 Jul 17
2
[LLVMdev] Casting between address spaces and address space semantics
...de. This means that, for example, i32 addrspace(1) * 100 points
to a different piece of memory than i32 addrspace(2) * 100. Also, this means
that a bitcast from one address space to another (possibly 0), makes the
pointer point to something different when loaded.
b) Every address space is really a subspace of the full range of addresses,
but always disjoint. This means that, for example, i32 addrspace(1) * 100
points to the same memory as i32 addrspace(2) * 100, though one, or possibly
both of them can be invalid (since the pointer lies outside of that address
space). This also means that bitcasting...
2011 Jan 06
1
Splitting a Vector
...e others colinear with it. Then, using
that information to split the vector (explanatory variable) in question,
into two new vectors, one should correspond to the fitted values and one
the residuals of the (I think you could call it nested) model. One
vector therefore should be aligned with the subspacespace defined by the
other variables colinear with it, and the other will be residual, and so
orthogonal to the subspace of the colinear variables. Then by including
these two variables in the origional model - the one that showed the
order dependency, you can see how much explanatory power the...
2004 Jul 02
3
How to get the normal direction to a plane?
Dear All
Maybe the following is a stupid question.
Assume I have 3 coordinate points (not limited to be in 2D or 3D space)
a, b, c.
It is known that these 3 points will define a plane.
The problem is how to get the normal direction that is orthogonal to
this plane.
Is there an easy way to calculate it using the values of a, b, and c?
Thanks for any point or help on this.
Fred
2004 Dec 17
3
How to interpret and modify "plot.svm"?
Dear R people,
I am trying to plot the results from running svm in library(e1071). I
use plot.svm. After searching through the help archives and FAQ, I
still have several questions:
1. In default, crosses indicate support vectors. But why are there
two colors of crosses? What do they represent?
2. I want to draw a white-gray colored plot and modify the different
colored crosses or circles by
2008 Jul 17
0
[LLVMdev] Casting between address spaces and address space semantics
...example, i32 addrspace(1) * 100 points
> to a different piece of memory than i32 addrspace(2) * 100. Also, this means
> that a bitcast from one address space to another (possibly 0), makes the
> pointer point to something different when loaded.
>
> b) Every address space is really a subspace of the full range of addresses,
> but always disjoint. This means that, for example, i32 addrspace(1) * 100
> points to the same memory as i32 addrspace(2) * 100, though one, or possibly
> both of them can be invalid (since the pointer lies outside of that address
> space). This also m...
2005 May 31
2
Null space (or kernel) and image of a matrix
Hello!
Does anyone now if there exist a function that would compute a "null space"
(or "kernel" - "Ker") of a matrix and maybe also one that would compute an
"image" ("Im") of a matrix.
I tried R-site search and google, However I found notnihg useful!
Thanks for any sugestions! I am also not sure what an "image" of a matrix
is, so
2011 Nov 14
2
How to compute eigenvectors and eigenvalues?
Hello.
Consider the following matrix:
mp <- matrix(c(0,1/4,1/4,3/4,0,1/4,1/4,3/4,1/2),3,3,byrow=T)
> mp
[,1] [,2] [,3]
[1,] 0.00 0.25 0.25
[2,] 0.75 0.00 0.25
[3,] 0.25 0.75 0.50
The eigenvectors of the previous matrix are 1, 0.25 and 0.25 and it is not a diagonalizable matrix.
When you try to find the eigenvalues and eigenvectors with R, R responses:
> eigen(mp)
$values
[1]
2018 Aug 08
2
vctrs: a type system for the tidyverse
...ry
> wary of taking away the thing about factors that makes them fundamentally
> not characters, and removing the effectiveness of the level restriction, in
> practice, does that.
For what it's worth, I always thought about factors as fundamentally
characters, but with restrictions: a subspace of all possible strings.
And I'd say that a non-negligible number of R users may think about
them in a similar way.
In fact, if you search "concatenation factors", you'll see that back
in 2008 somebody asked on R-help [1] because he wanted to do exactly
what Hadley is describing...