Displaying 20 results from an estimated 7000 matches similar to: "matrix algebra for constructing a special matrix?"
2009 Apr 08
1
persp3d and rgl.viewpoint for rotating 3D plots
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 screen, which is different from what I get when it's rotating. Is there any different behavior between
2009 Mar 19
1
two plots side-by-side with persp3d(rgl)
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 to animate both surfaces using play3d(rgl).
Thanks in advance for any help.
Best,
Carlo Giovanni
2004 Jul 30
1
optimisation procedure with flat log-likelihood
Dear R-friends,
I use
optim(par=c(mystartingpoints), fn=myloglikelihoodfunction, gr=NULL,
method=c("L-BFGS-B"), ## I would like to do not use any
bounds
control=list(trace=6, ## just to see what it's going on
maxit=c(20000)), ## to be sure the it
doesn't stop reaching the max iterations
2005 May 15
1
Save parameters from optim during iteration procedure
Dear R-users,
I am going to try to be as clearer as possible, showing also an example.
1) I have a function (in my real case it's much more complex)
2) I use "optim" to minimize
3) I want to use as method L-BFGS-B for several reasons
4) I know I could use "trace=6" (in "control") in order to see "live"
the procedure
5) I would like to see separately the
2006 May 16
1
optim with specific constraints on possible values
Dear R-users,
I am working with some grid-search optimization for 13 values of an
object function.
At glance one may compute the object function for each possible
combination of set of parameters, but in my case would not be feasible:
taking for example 13 possible values for each parameters like, in
logarithm scale, 10^seq(-3,3,.5) will lead to 13^13 combinations of
results.
As a second trial
2006 Jan 30
3
Subsetting a matrix without for-loop
Dear R-users,
I'm struggling in R in order to "squeeze" a matrix without using a
for-loop.
Although my case is a bit more complex, the following example should
help you to understand what I would like to do, but without the slow
for-loop.
Thanks in advance,
Carlo Giovanni Camarda
A <- matrix(1:54, ncol=6) # my original matrix
A.new <- matrix(nrow=3, ncol=6) # a new
2013 Apr 19
3
extracting the diagonal of an inverse matrix
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 other words, given a square matrix A, I aim to know diag(B), where B=solve(A), without computing solve(A).
2005 Oct 12
1
Historical England and Wales Shape Files
Dear R-user,
I would like to apply spatial statistics on some historical data, in
particular from 1850 to 1900 by registration district of England and
Wales.
I have searched in the R-archive, but unsuccessfully.
Do you know whether R contains those shape files? Or where would be
possible to download and use in R?
Thanks in advance,
Carlo Giovanni Camarda
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2005 Oct 18
1
Solid and dotted lines saving an xyplot
Dear R-users,
I would a small problem saving a graph with postscript after using
xyplot.
Whereas in the R-screen the two lines are solid, once the image is saved
as .eps file the second lines (blue in the following example) is dotted.
Here there is a simple example.
Thanks in advance for your help,
Carlo Giovanni Camarda
# creating data
a1 <- sort(runif(10))
a2 <- sort(runif(10))
a3 <-
2005 Jun 14
2
Plotting rows (or columns) from a matrix in different graphs, not using "par"
Dear R-users,
I would like to ask whether it's possible (for sure it would be), to
plot each rows (or columns) in different graphs and in the same figure
region without using the function "par" and then struggling around with
"axes" and labels etc.
Luckily, I would always have "rows + columns = even number" and the same
"ylim".
The next one could be a
2006 Jul 28
2
Extracting from a matrix w/o for-loop
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indicato...
Nome: non disponibile
Url: https://stat.ethz.ch/pipermail/r-help/attachments/20060728/957eb23c/attachment.pl
2008 Feb 26
2
Summing up diagonals w/o for-loop
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2009 Mar 11
1
matrix multiplication, tensor product, block-diagonal and fast computation
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 second
solution employs the tensor product but then manually selects the right
outcomes. The
2005 Jul 12
2
how to generate argument from a vector automatically
hi netters
i have a vector NAMES containing a series of variable names:
NAMES=c(x,r,z,m,st,qr,.....nn).
i wanna fit a regression tree by using the code:
my.tree<-tree(y~x+r+z+m+....nn,my.dataframe)
but i don't want to type out "x+r+z+m+....+nn" one by one, as there are so
many variables. besides, sometimes i wanna put the code in a function. so i
need to have the
2006 Feb 01
1
glm-logistic on discrete-time methods with individual and aggregated data
Dear R-Users,
without going into details I tried to prepare a simple example to show
you where I would need help.
In particular I prepare two examples-template for a study I'm conduction
on discrete-time methods for survival analysis.
Each of this example has two datasets which are basically equal, with
the exception that in the former one has individual data and in the
latter one aggregated
2004 Aug 30
3
Generalized Singular Value Decomposition (GSVD)
Dear R-users,
I couldn't find a function or some help in R-project web about the
Generalized Singular Value Decomposition. In MatLab there is a simple
function for this algebric issue (gsvd). Is there anything like that in R?
And, if not, could you help me to apply this method in R?
Thanks in advance, Giancarlo
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2017 Jun 28
1
[PATCH v4] nv110/exa: update sched codes
Hi,
On Wed, Jun 28, 2017 at 12:53 PM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
> BTW, you can drop those explicit "depbar" ops. I think they're only
> needed when you're doing something weird with barriers. Blob doesn't
> use them (anymore)
>
Gotcha. Should I remove them in the same patch or a different one? It seems
like the depbar removal is
2017 Jun 10
2
[PATCH v3] nv110/exa: update sched codes
This patch adds proper delays to maxwell exa shaders. rendercheck tests
seem consistent with/without this patch. I haven't extensively tested
them though.
Trello:
https://trello.com/c/6LPB2EIS/174-update-maxwell-shaders-with-proper-delays
Signed-off-by: Aaryaman Vasishta <jem456.vasishta at gmail.com>
---
src/shader/exac8nv110.fp | 10 +++++-----
src/shader/exac8nv110.fpc | 18
2017 Jun 03
2
[PATCH v2] nv110/exa: update sched codes
v2: Add missing delays
This patch adds proper delays to maxwell exa shaders. rendercheck tests
seem consistent with/without this patch. I haven't extensively tested
them though.
Trello:
https://trello.com/c/6LPB2EIS/174-update-maxwell-shaders-with-proper-delays
Signed-off-by: Aaryaman Vasishta <jem456.vasishta at gmail.com>
---
src/shader/exac8nv110.fp | 10 +++++-----
2017 Jun 07
2
[PATCH v2] nv110/exa: update sched codes
On Tue, Jun 6, 2017 at 7:15 AM, Samuel Pitoiset <samuel.pitoiset at gmail.com>
wrote:
> Nice work!
>
> See my comments below, and double-check if some of them can be applied to
> the shaders I didn't review yet.
>
> I recommend you to test your work because if one sched code is wrong, you
> are likely going to kill your card and reboot your box. :-)
>
>
>