Displaying 20 results from an estimated 1000 matches similar to: "minimization function"
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
2001 Jan 02
0
mdct explanation
...as promised.
This describes the mdct used in my d.m.l patch. I think it is the
same as the Lee fast-dct.
I typed it in a kind of pseudo-TeX, 'cause the ascii art would
kill me. Hope you can read TeX source; if not, ask someone who
can to make a .ps/.gif/.whatever of the TeX output, and put it
on a webpage or something. I'm to lazy to do it (and besides, I
don't have access to TeX,
2011 Jan 03
1
Greetings. I have a question with mixed beta regression model in nlme.
*Dear R-help:
My name is Rodrigo and I have a question with nlme package
in R to fit a mixed beta regression model. The details of the model are:
Suppose that:*
*j in {1, ..., J}* *(level 1)*
*i in {1, ..., n_j}* *(level 2)*
*y_{ij} ~ Beta(mu_{ij} * phi_{ij}; (1 - mu_{ij}) * phi_{ij})
y_{ij} = mu_{ij} + w_{ij}
*
*with*
*logit(mu_{ij}) = Beta_{0i} + Beta_{1i} * x1_{ij} + b2 * x2_{ij}
2011 Jan 03
0
Greetings. I have a question with mixed beta regression model in nlme (corrected version).
*Dear R-help:
My name is Rodrigo and I have a question with nlme package
in R to fit a mixed beta regression model. I'm so sorry. In the last
email, I forgot to say that W is also a unknown parameter in the mixed
beta regression model. In any case, here I send you the correct formulation.
**
Suppose that:*
*j in {1, ..., J}* *(level 1)*
*i in {1, ..., n_j}* *(level 2)*
*y_{ij} ~
2012 Jun 25
4
do.call or something instead of for
Dear R users,
I'd like to compute X like below.
X_{i,t} = 0.1*t + 2*X_{i,t-1} + W_{i,t}
where W_{i,t} are from Uniform(0,2) and X_{i,0} = 1+5*W_{i,0}
Of course, I can do this with "for" statement, but I don't think it's good
idea because "i" and "t" are too big.
So, my question is that
Is there any better idea to avoid "for" statement
2009 Nov 15
2
lme model specification
Dear all
this is a question of model specification in lme which I'd for which I'd greatly appreciate some guidance.
Suppose I have data in long format
gene treatment rep Y
1 1 1 4.32
1 1 2 4.67
1 1 3 5.09
. . . .
. . . .
. . . .
1 4 1 3.67
1 4 2 4.64
1 4 3 4.87
.
2012 May 23
0
numerical integrals
Greetings,
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 $A_{i,j}$, $1\leq i,j\leq 5$, numerically
and check against the known
2010 Oct 04
0
spatial interaction (gravity) model as Poisson regression
Dear list,
I posted essentially this same question to the r-sig-geo mailing list
last week with no response :( Unfortunately I am no closer to reaching
a solution, so I now post it here (with some clarifications) in the
hope that someone following this list might have an answer for me:
Has anyone had much experience with spatial interaction (or gravity)
models, specifically in the form of
2007 Apr 14
6
[LLVMdev] Regalloc Refactoring
On Thu, 12 Apr 2007, Fernando Magno Quintao Pereira wrote:
>> I'm definitely interested in improving coalescing and it sounds like
>> this would fall under that work. Do you have references to papers
>> that talk about the various algorithms?
>
> Some suggestions:
>
> @InProceedings{Budimlic02,
> AUTHOR = {Zoran Budimlic and Keith D. Cooper and Timothy
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 Nov 02
2
Matrix decomposition: orthogonal complement
Hello,
How I can compute in R the orthogonal complement of one matrix?
If A (n x m ) matrix of full column rank (n>m), its orthogonal
complement is denoted by A_ .
A_ is n X (n-m) matrix of full column rank and such that A'A_=0.
I need to compute A_. How I can compute A_ in R?
Best Regards,
/Florin
--
Florin G. Maican
Ph.D. candidate, Department of Economics
School of
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
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
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
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
2009 Nov 29
1
optim or nlminb for minimization, which to believe?
I have constructed the function mml2 (below) based on the likelihood function described in the minimal latex I have pasted below for anyone who wants to look at it. This function finds parameter estimates for a basic Rasch (IRT) model. Using the function without the gradient, using either nlminb or optim returns the correct parameter estimates and, in the case of optim, the correct standard
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