Displaying 20 results from an estimated 1000 matches similar to: "Matrix decomposition: orthogonal complement"
2009 Mar 27
1
constraint optimization: solving large scale general nonlinear problems
Hi
I need advice regarding constraint optimization with large number of
variables.
I need to solve the following problem
max f(x1,...,xn)
x1,..xn
x1=g1(x1,...,xn)
.
.
xn=gn(x1,...,xn)
I am using Rdonlp2 package which works well until 40 variables in my
case. I need to solve this problem with over 300 variables. In this case
Rdonlp2 is very very slowly. I know
2009 Mar 27
4
A beginner's question
I am a new R-language user. I have set up a data frame "mydata",one of
the colume of which is "skill". Now I want to select the observations
whose "skill" value is equal to 1,by what command can I get it?
2006 Sep 16
1
[LLVMdev] cpp program linking error
Hi,
i have compile and built the llvm-gcc4 and llvm 1.8a in my machine, but
there is some problem about llvm-gcc4. It can not compile a
cpp code like this:
#include <iostream>
using std::cout;
using std::endl;
int main()
{
cout << "Hello" << endl;
}
$llvm-g++ hello.cc -o hello
/developer/zsth/llvm-gcc/install/bin/../lib/gcc/i686-pc-linux-gnu/4.0.1/../../..
2020 Sep 14
2
[PATCH 07/17] 53c700: improve non-coherent DMA handling
Switch the 53c700 driver to only use non-coherent descriptor memory if it
really has to because dma_alloc_coherent fails. This doesn't matter for
any of the platforms it runs on currently, but that will change soon.
To help with this two new helpers to transfer ownership to and from the
device are added that abstract the syncing of the non-coherent memory.
The two current bidirectional cases
2000 Apr 04
0
stochastic process transition probabilities estimation
Hi all,
I'm new with R (and S), and relatively new to statistics (I'm a
computer scientist), so I ask sorry in advance if my question is silly.
My problem is this: I have a (sample of a) discrete time stochastic
process {X_t} and I want to estimate
Pr{ X_t | X_{t-l_1}, X_{t-l_2}, ..., X_{t-l_k} }
where l_1, l_2, ..., l_k are some fixed time lags. It will be enough for
me to compute
2004 Dec 12
2
Help : generating correlation matrix with a particular structure
Hi,
I would like to generate a correlation matrix with a
particular structure. For example, a 3n x 3n matrix :
A_(nxn) aI_(nxn) bI_(nxn)
aI_(nxn) A_(nxn) cI_(nxn)
aI_(nxn) cI_(nxn) A_(nxn)
where
- A_(nxn) is a *specified* symmetric, positive
definite nxn matrix.
- I_(nxn) is an identity matrix of order n
- a, b, c are (any) real numbers
Many attempts have been unsuccessful because a
2009 May 26
1
interactive file choosing in Linux?
I am used to using the [R] function choose.files() for interactive file selection in MS-Windows.
What is the comparable function in Linux? I expected the function file.choose() to display similar behavior, i.e., a graphical interface diplaying a file listing, but all I seem to get is a "text input prompt". This does not seem correct.
> file.choose()
Enter file
2013 Feb 18
3
Generating QFs from same sample
Dear All
I am kind of stuck up with a code a part of which seems to be causing a
problem, or at least I think so. May be the community can help me. It’s
simple but I suppose I am missing something.
I generate a data matrix X, say of order n*p, where n represents
independent row-vectors and p correlated col vectors. Let the row
representation be X = (X’_1, . . ., X’_n)’. I generate the
2006 Oct 19
3
Time conversion from Win32 64bit FILETIME?
Windows-32 has a time structure called FILETIME, a 64-bit value
representing the number of 100-nanosecond intervals since January 1,
1601 (UTC). That is not a typo, the year is 1601.
Does anyone have a clue(or algorhithm)for how this is converted to
something a little more POSIX-like ?
Thank you,
Derek
--
Derek N. Eder
Gothenburg University
VINKLA - Vigilance and Neurocognition
2007 Sep 12
1
Verifying understanding of backup-dir vs compare-dest
Hello,
Say one starts with creating an archive
rsync work -> archive
and periodically (below, i = 1 to N) does
rsync --backup-dir=a_<i> work -> archive
and rsync --compare-dest=archive work -> b_<i>
Then suppose one wants to recover the work directory as it was at
time k.
Using the b_<i> directories, one would merely merge
2010 Apr 10
1
minimization function
Hi all,
I am trying to minimize the quardratic form w'Aw, with certain
constraints.
In particular,
(1) A=(a_{ij}) is n by n matrix and it is symmetric positive definite,
a_{ii}=1 for all i;
and 0<a_{ij}<1 for i not equal j.
(2) w'1=n;
(3) w_{i}>=0
Analytically, for n=2, it is easy to come up with a result. For larger n, it
seems
difficult to obtain
2014 Feb 21
6
[LLVMdev] make check issue with llvm-cov
rkotler at mipsswbrd006-le:~/caviumllvm/build/test$ make
Making LLVM 'lit.site.cfg' file...
Making LLVM unittest 'lit.site.cfg' file...
( ulimit -t 600 ; ulimit -d 512000 ; ulimit -m 512000 ; ulimit -s 8192 ; \
/usr/bin/python /home/rkotler/workspace/llvm/utils/lit/lit.py -s
-v . )
XPASS: LLVM :: tools/llvm-cov/llvm-cov.test (8916 of 9784)
******************** TEST
2012 May 23
1
numerical integration
Greetings,
Sorry, the last message was sent by mistake! Here it is again:
I encounter a strange problem computing some numerical integrals on [0,oo).
Define
$$
M_j(x)=exp(-jax)
$$
where $a=0.08$. We want to compute the $L^2([0,\infty))$-inner products
$$
A_{ij}:=(M_i,M_j)=\int_0^\infty M_i(x)M_j(x)dx
$$
Analytically we have
$$
A_{ij}=1/(a(i+j)).
$$
In the code below we compute the matrix
2001 May 19
2
calculations on diagonals of a matrix
Given an nxm matrix A I want to compute the nxm matrix B whose ij-th
element is the sum of the elements of A lying on the diagonal that ends
with element ij, i.e.,
b_ij = a_ij + a_(i-1)(j-1) + a_(i-2)(j-2) + ...
In APL (which I no longer use), I would use the 'rotate' operator to derive
an array whose columns are diagonals of the given array and then cumulate
down columns. Is
2010 Jul 26
1
O/T good c/c++ code for LU decomposition
Dear R People:
Could someone recommend a good c/c++ code (or Fortran) for LU
decomposition, please?
Sorry to bother about this. I'm trying to do some "non-R" work that
requires a matrix inversion.
Thanks,
Erin
--
Erin Hodgess
Associate Professor
Department of Computer and Mathematical Sciences
University of Houston - Downtown
mailto: erinm.hodgess at gmail.com
2012 May 15
2
R
To all moderators i guess, my question was probably not clear this is not a homework, i am trying to understand R by doing some exercise in my book.
I will however participate a course in R in august and thought it could be good to have some
knowledge before. I hoped for help from you since i have no instructor to ask, that would have been
my first choice.
thanks anyway
Lotta
2004 Mar 22
3
Distributed computing
Dear all,
does anyone know if there exists an effort to bring some kind of
distributed computing to R? The most simple functionality I'm after is
to be able to explicitly perform a task on a computing server. Sorry if
this is a non-informed newbie question...
Best regards
Anders Sj?gren
PhD Student
Dept. of Mathematical Statistics
Chalmers University of Technology
Gothenburg, Sweden
2012 Feb 14
3
Wildcard for indexing?
Hi,
I'd like to know if it is possible to use wildcards * for indexing...
E.g. I have a vector of strings. Now I'd like to select all elements
which start with A_*? I'd also need to combine that with logical operators:
"Select all elements of a vector that start with A (A*) OR that start with B (B*)"
Probably that is quite easy. I looked into grep() which I think might
2002 Dec 12
1
Rejoining domain with W2K
I have successfully installed Samba 2.2.7a as a PDC and has added the
"add user script" to automatically create machine accounts. This
worked very well when I added my client machine the first time. It
successfully joined the domain and I was able to login as a user.
I then removed the machine from the domain and put it in an unrelated
workgroup and then tried to re-join the Samba
2008 Mar 27
1
functions
I wrote some functions for multiway CANDECOMP, i.e. for least
squares fitting of
a_{i_1\cdots i_m}\approx\sum_{s=1}^p x^1_{i_1s}x^1_{i_1s}\cdots
x^m_{i_ms}
with arrays of arbitrary dimension. Reminded me of the good old APL
days. I could not find this in the archives, but if it's already there,
I would appreciate if someone let me know.