the second
(partial) derivatives of the loss function. Or do I miss something? Moreover, I
would expect smaller standard errors of the estimated parameters when
additional constraints are included, and it is not the case in the given
example.
De: "Ivan Krylov"
À: "CAMARDA Car
In the commented snippet below, a behavior of the solnp() I cannot fully
explain: when a constraint is added, hessian matrix is obviously changing, but
in a way I don't understand. I know that the model below could be estimated
differently and in a much efficient way. However I wanted to pres
Dear R-users,
let's assume a simple linear model in which to each original observation one
attaches random response and covariate, but with weights that are practically
zero. If one runs a linear model to both original and augmented data, one
obtains the same estimates, but obviously differe
Dear R-users,
I have a matrix with a series of "not-overlapping in a row dimension" vectors
in a given structure. Something like:
|a1, 0, 0, 0|
| 0, a2, a3, 0|
|a4, 0, 0, a5|
where "ai" are column-vectors of the equal length, m.
My aim is to construct a new matrix formed by diagona
2.14.1 (2011-12-22)
From: William Dunlap [wdun...@tibco.com]
Sent: Monday, April 22, 2013 6:25 PM
To: Camarda, Carlo Giovanni; Greg Snow
Cc: r-h...@stat.math.ethz.ch
Subject: RE: [R] extracting the diagonal of an inverse matrix
You could save the space required to store t
1)
P2a <- kronecker(t(P2)%*%P2, diag(m))
P <- 1000 * P1a + 1000 * P2a
## final matrix A
A <- D + P
## solving A
B <- solve(A)
## what I just actually need
diag(B)
From: Greg Snow [538...@gmail.com]
Sent: Saturday, April 20, 2013 12:16 AM
To
Dear R-users,
I would like to know whether there is a way to extract a diagonal of an inverse
matrix without computing the inverse of the matrix itself. The size of my
matrices are really huge and, also using sparse matrix, computing the inverse
leads to storage problems and low speed.
In othe
Dear R-users,
in the last days I have been trying to estimate a normal linear model with
equality and inequality constraints.
Please find below a simple example of my problem.
Of course, one could easily see that, though the constraints are consistent,
there is some redundancy in the specific
ize other parts of my model.
Thanks again,
Giancarlo
From: Uwe Ligges [lig...@statistik.tu-dortmund.de]
Sent: Saturday, February 09, 2013 8:04 PM
To: Camarda, Carlo Giovanni
Cc: r-h...@stat.math.ethz.ch
Subject: Re: [R] impossible to invert a spam-object,
Dear R-users,
a question concerning sparse matrices in package "spam" (spam_0.29-2).
On one hand I have a spam object (n X n) from which I cannot compute the
inverse. On the other hand, if I convert this object in a plain matrix, I can
find the inverse without any problem.
Specifically I get t
Dear R-users,
would it be a better way to construct the matrix below without using any
for-loop or model.matrix? preferably with some matrix algebra?
Thanks in advance,
Carlo Giovanni Camarda
## dimensions
m <- 3
n <- 4
mn <- m*n
k <- m+n-1
## with a for-loop
X <- matrix(0, mn, k)
for(i in 1:
Dear R-users,
I'd like to use an xyplot(lattice) in which in each panel I have points with
different point-character and color, and additional lines with the same color.
Please find below a toy example in which I did not manage to change such
parameters, and the associated basic plot() in which
Dear R-users,
Is there any R-function for fitting generalized additive mixed
models for ordinal data? Do they actually make some sense? I can fit a
generalized linear mixed model for ordinal data using the function
clmm(ordinal) and I'm able to cope with generalized additive model for
ordi
-
From: Duncan Murdoch [mailto:murd...@stats.uwo.ca]
Sent: Wednesday, April 08, 2009 5:13 PM
To: Camarda, Carlo Giovanni
Cc: r-h...@stat.math.ethz.ch
Subject: Re: [R] persp3d and rgl.viewpoint for rotating 3D plots
On 4/8/2009 11:01 AM, Camarda, Carlo Giovanni wrote:
> Dear R-users,
Dear R-users,
within the rgl-package, I would have a question about the usage of persp3d
in combination of rgl.viewpoint.
I am not able to figure out how to let a 3D plot rotating around likewise the
example in ?rgl.viewpoint. It seems that when I use persp3d(...) I see
something on my scr
Dear R-users,
I would like to place two 3D plots side-by-side in a rgl-setting. It
would nice to have something like "par(mfrow=c(1,2))" for basic plots, or an
array framework for wireframe(lattice) (see example below). I only managed to
overlap two persp3d plots.
My final idea would be
Thursday, March 12, 2009 4:25 PM
To: Camarda, Carlo Giovanni
Cc: r-h...@stat.math.ethz.ch
Subject: Re: [R] matrix multiplication, tensor product, block-diagonal and fast
computation
On Wed, 11 Mar 2009, Camarda, Carlo Giovanni wrote:
> Dear R-users,
>
> I am searching to the "bes
Dear R-users,
I am searching to the "best" way to compute a series of n matrix
multiplications between each matrix (mXm) in an array (mXmXn), and each
column of a matrix (mXn).
Please find below an example with four possible solutions.
The first is a simple for-loop which one might avoid; the se
Dear R-users,
I coded two equivalent ways to perform (in a simplified version)
some matrix multiplications I would like to use in a more general
framework.
In the first case I used Kronecker product and vectorization of a
certain matrix. This approach takes less time, but, as you may guess
Dear R-users,
I would have a question regarding the multiplication between a
matrix (A, mXn) and a block-diagonal matrix, B, (m*n)X(m*n).
The easy solution would be to, first, vectorize A and use simple matrix
multiplication, but my aim is to avoid such vectorization. Is it
possible?
Pleas
Dear UseRs,
please find below a simple example which exemplifies my question.
In words, I'd like to write a function which prints formula and outcomes only
when results are not assigned or recalling the already assigned object, as e.g.
glm.
I'm sure a solution is rather simple and straightforwa
Dear R-users,
is there any way to sum up the elements of the "diagonals" of a matrix
without using a for-loop? While there is a simple way over rows and
columns, I don't see a straightforward multiplication for the diagonals,
am I too demanding? Or, more likely, I'm lack some algebra trick? Is
the
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