Displaying 20 results from an estimated 700 matches similar to: "OT -- isotonic regression subject to bound constraints."
2009 Oct 01
1
Help for 3D Plotting Data on 'Irregular' Grid
Dear All,
Here is what I am trying to achieve: I would like to plot some data in 3D.
Usually, one has a matrix of the kind
y_1(x_1) , y_1(x_2).....y_1(x_i)
y_2(x_1) , y_2(x_2).....y_2(x_i)
...........................................
y_n(x_1) , y_n(x_2)......y_n(x_i)
where e.g. y_2(x_1) is the value of y at time 2 at point x_1 (see that
the grid in x is the same for the y values at all times).
2013 Feb 25
3
Empirical Bayes Estimator for Poisson-Gamma Parameters
Dear Sir/Madam,
I apologize for any cross-posting. I got a simple question, which I thought
the R list may help me to find an answer. Suppose we have Y_1, Y_2, ., Y_n ~
Poisson (Lambda_i) and Lambda_i ~Gamma(alpha_i, beta_i). Empirical Bayes
Estimator for hyper-parameters of the gamma distr, i.e. (alpha_t, beta_t)
are needed.
y=c(12,5,17,14)
n=4
What about a Hierarchal B ayes
2005 Sep 15
1
Coefficients from LM
Hi everyone,
Can anyone tell me if its possibility to extract the coefficients from the
lm() command?
For instance, imagine that we have the following data set (the number of
observations for each company is actually larger than the one showed...):
Company Y X1 X2
1 y_1 x1_1 x2_1
1 y_2 x1_2 x2_2
1 y_3 x1_3 x2_3
(...)
2 y_4 x1_4 x2_4
2 y_5 x1_5 x2_5
2 y_6 x1_6 x2_6
(...)
n y_n x1_n x2_n
n
2008 Nov 01
2
sampling from Laplace-Normal
Hi,
I have to draw samples from an asymmetric-Laplace-Normal distribution:
f(u|y, x, beta, phi, sigma, tau) \propto exp( - sum( ( abs(lo) +
(2*tau-1)*lo )/(2*sigma) ) - 0.5/phi*u^2), where lo = (y - x*beta) and
y=(y_1, ..., y_n), x=(x_1, ..., x_n)
-- sorry for this huge formula --
A WinBUGS Gibbs sampler and the HI package arms sampler were used with the
same initial data for all parameters. I
2008 Aug 04
2
Multivariate Regression with Weights
Hi all,
I'd like to fit a multivariate regression with the variance of the error term porportional to the predictors, like the WLS in the univariate case.
y_1~x_1+x_2
y_2~x_1+x_2
var(y_1)=x_1*sigma_1^2
var(y_2)=x_2*sigma_2^2
cov(y_1,y_2)=sqrt(x_1*x_2)*sigma_12^2
How can I specify this in R? Is there a corresponding function to the univariate specification lm(y~x,weights=x)??
2010 Jan 26
3
Problem with "nls" function
Dear R users,
I have a response variable in a csv file called "y" and a matrix of
predictor variables in a csv file called "mat". I have used the function
"nls" I have specified the nonlinear relation between these variable.The
code I have witten is called Rprog which begins with the phrase:
L.minor.m1<-nls(Y~a ....etc..
The program when I execute the program, I
2006 Dec 14
3
Model formula question
Hi all,
I'm not familiar with R programming and I'm trying to reproduce a
result from a paper.
Basically, I have a dataset which I would like to model in terms of
successive increments, i.e. (y denote empirical values of y)
y_1 = y1,
y_2 = y1 + delta1,
y_3 = y1 + delta1 + delta2.
...
y_m = y1 + sum_2^m delta j
where delta_j donote successive increments in the y-values, i.e.
delta
2005 May 18
1
dse VAR models
Hi,
Can anyone tell me how to construct a simple VAR(1) time series with two
variables using the dse package? I would like to end up with two time series
y_1t = \phi_11 y_1,t-1 + \phi_12 y_2,t-1 + e_1t
y_2t = \phi_21 y_1,t-1 + \phi_22 y_2,t-1 + e_2t
Best regards,
Sam.
2008 May 02
0
isotonic/ordered heterogeneity tests
dear R-help:
one of my students is struggling to test an ordered alternative
hypothesis on a set of groups (e.g., mu_a <= mu_b <= mu_c).
There has been some literature on this topic -- a lot of
this goes back to Bartholomew (1961); Gaines and Rice
(see refs below) are the ones who've popularized it in the
ecology community. The topic is closely related to isotonic regression,
but
2007 Feb 02
1
multinomial logistic regression with equality constraints?
I'm interested in doing multinomial logistic regression with equality
constraints on some of the parameter values. For example, with
categorical outcomes Y_1 (baseline), Y_2, and Y_3, and covariates X_1
and X_2, I might want to impose the equality constraint that
\beta_{2,1} = \beta_{3,2}
that is, that the effect of X_1 on the logit of Y_2 is the same as the
effect of X_2 on the
2008 Aug 13
1
The standard deviation of measurement 1 with respect to measurement 2
Hi,
I have two (different types of) measurements, say X and Y, resulting from
the same set of experiments. So X and Y are paired: (x_1, y_1), (x_2, y_2),
...
I am trying to calculate the standard deviation of Y with respect to X. In
other words, in terms of the scatter plot of X and Y, I would like to divide
it into bins along the X-axis and for each bin calculate the standard
deviation along
2011 Feb 13
1
calculate phase/amplitude of fourier transform function in R
I did a fourier transform on a function in time domain to get the following
functions in frequency domain (in latex):
$Y_1[\omega] = \frac{1}{1-\phi_1 e^{-jw}}$
$Y_2[\omega] = \frac{1}{1-(\phi_1 + \phi_2)e^{-jw} +\phi_1\phi_2e^{-2jw}}$
How do I find the spectrum of this function for given $\phi_1$ and $\phi_2$
coefficients and in the discretization interval $w = [-\pi:.1*\pi: \pi]$?
Then, how
2003 Nov 10
1
ts package function filter: mismatch between function action and help (PR#5017)
Dear people,
I'm running
RedHat 9.0
and
R : Version 1.7.1 (2003-06-16)
from the help file
# Usage:
#
# filter(x, filter, method = c("convolution", "recursive"),
# sides = 2, circular = FALSE, init)
# init: for recursive filters only. Specifies the initial values of
# the time series just prior to the start value, in reverse
# time
2004 Dec 03
1
isotonic regression
Hi,
Has anyone written code for isotonic regression on ordered rectangular
grids?
Nathan
Nathan Leon Pace, MD, MStat
University of Utah
Salt Lake City, UT 84132
Office: 801.581.6393
Fax: 801.581.4367
Cell: 801.558.3987
Pager: 801.291.9019
Home: 801.467.2925
[[alternative text/enriched version deleted]]
2001 Oct 31
0
isotonic regression
Dear R-users
Do you know of an easy way in R of performing "isotonic (unimodal)"
regression ala BBBB, Barlow, Bartolomew, Brenner and Brunk.
best regards
Helgi
--
Helgi Tomasson FAX: 354-552-6806
University of Iceland PHONE:354-525-4571
Faculty of Economics and Business Administration email:helgito at
2015 Feb 03
2
Seed in 'parallel' vignette
Hi,
This is most likely only a minor technicality, but I saw the
following: On page 6 of the 'parallel' vignette
(http://stat.ethz.ch/R-manual/R-devel/library/parallel/doc/parallel.pdf),
the random-number generator "L'Ecuyer-CMRG" is said to have seed
"(x_n, x_{n-1}, x_{n-2}, y_n, y_{n-1}, y_{n-2})". However, in L'Ecuyer
et al. (2002), the seed is given with
2014 Feb 08
3
[PATCH 1/2] arm: Use the UAL syntax for ldr<cc>h instructions
On Fri, 7 Feb 2014, Timothy B. Terriberry wrote:
> Martin Storsjo wrote:
>> This is required in order to build using the built-in assembler
>> in clang.
>
> These patches break the gcc build (with "Error: bad instruction").
Ah, right, sorry about that.
> Documentation I've seen is contradictory on which order ({cond}{size} or
> {size}{cond}) is correct.
2014 Aug 21
2
[LLVMdev] Alias Analysis Semantics
Hi Daniel,
Sorry for taking so long to respond. I spoke with a colleague more
familiar with llvm who thought he could clear up my confusion, but we both
came out of the conversation confused. I will try my best to explain the
ambiguity.
In an DAG, alias queries would be completely unambiguous. Every
instruction would only be executed once, and every SSA value really would
have a single static
2014 Aug 21
2
[LLVMdev] Alias Analysis Semantics
Hi Hal,
Thank you for your email, that makes a lot of sense to me. I am working on
some tools to use memory profiling to speculatively replace memory loads
and stores with value forwarding in hardware implementations. I'd like to
compare the profiled data to static alias analysis, so it would be super
useful if there was a way to answer the questions about aliasing across
backedges that
2014 Feb 08
0
[PATCH v2] arm: Use the UAL syntax for instructions
This is required in order to build using the built-in assembler
in clang.
---
I squashed the two changes since it would break the normal gcc
build otherwise.
---
celt/arm/arm2gnu.pl | 2 ++
celt/arm/celt_pitch_xcorr_arm.s | 18 +++++++++---------
2 files changed, 11 insertions(+), 9 deletions(-)
diff --git a/celt/arm/arm2gnu.pl b/celt/arm/arm2gnu.pl
index eab42ef..5c24758 100755
---