Displaying 20 results from an estimated 10000 matches similar to: "Bayesian constrained regression method?"
2010 Nov 30
2
Adding noise
Hello,
I have some discrete pvalues and I would like to sort them. Then add random
noise so that they are ordered the same way as the original pvalues. Off
course I don't want any pvalues less than 0 or greater than 1. Any ideas on
how to do this in R?
--
Thanks,
Jim.
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2010 Oct 31
2
Constrained Regression
Hello everyone,
I have 3 variables Y, X1 and X2. Each variables lies between 0 and 1. I want
to do a constrained regression such that a>0 and (1-a) >0
for the model:
Y = a*X1 + (1-a)*X2
I tried the help on the constrained regression in R but I concede that it
was not helpful.
Any help is greatly appreciated
--
Thanks,
Jim.
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2007 Jul 12
1
how to estimate treatment-interaction contrasts
Hello, R experts,
Sorry for asking this question again again since I really want a help!
I have a two-factor experiment data and like to calculate estimates of
interation contrasts say factor A has levels of a1, a2, and B has
levels of b1, b2, b3, b4, and b5 with 3 replicates. I am not sure the
constrast estimate I got is right using the script below:
2010 Jun 22
1
Bayesian Code for contingency tables
Hello,
Is there anywhere I can find some Bayesian Code for 2 by 2 tables or even
the non-central hypergeometric distribution in R? Packages would be helpful
but the actual coding in R is much better.
Thanks,
Thanks Jim
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2011 Apr 24
1
EM vs Bayesian
Hello,
Is there any literature there that says that the EM is better/worse than a
Baysian model when it comes to differentiating univariate mixture of normal
distributions?
--
Thanks,
Jim.
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2011 Mar 16
2
Re; Fitting a Beta distribution
I want to fit some p-values to a beta distribution. But the problem is some
of the values have 0s and 1's. I am getting an error if I use the MASS
function to do this. Is there anyway to get around this?
--
Thanks,
Jim.
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2012 Oct 21
1
Linear discriminant function analysis based median as group centroid and nonparametric scale estimators???
Dear All,
I am using a specific approach for my master thesis. In essence, a
supervised reclassification is used as an intermediate step to find chemical
parameters which are able to reclassify defined groups. These variables will
be used in a next step where location and scale estimators of the groups are
important. Traditionally linear discriminant analysis is used for
reclassification which
2008 Mar 05
6
box-constrained
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Nom : non disponible
Url : https://stat.ethz.ch/pipermail/r-help/attachments/20080305/80536e8c/attachment.pl
2005 Mar 17
1
Optimization of constrained linear least-squares problem
Dear R-ians,
I want to perform an linear unmixing of image pixels in fractions of
pure endmembers. Therefore I need to perform a constrained linear
least-squares problem that looks like :
min || Cx - d || ? where sum(x) = 1.
I have a 3x3 matrix C, containing the values for endmembers and I have a
3x1 column vector d (for every pixel in the image). In theory my x
values should all be in the
2010 Nov 17
2
How to catch warnings
Hello when my code executes I receive the message that were some warnings. I want to catch warning messages at run time so to print some local variables and try to understand why this warning happens.
I searched on internet and I tried withCallingHandlers(
which seems to work but as I used Rkward the result is awful. I get a prompt to copy paste a value only while at the same time my background
2006 Sep 27
2
Constrained OLS regression
Hello R helpers,
I am trying to do a linear OLS regression of y on two variables x1 and
x2. I want to constrain the coefficients of x1 and x2 to sum up to 1.
and therefore run a constrained OLS. Can anybody help with this? (I have
seen some answers to similar questions but it was not clear to me what I
need to do) - I have tried the lm function with offset but I must not
have used it properly.
2011 Aug 22
3
Changing data scales
I have data that ranges from 0.3 to 2 and I want to change the scale to be
from 0 to 1.
Can this be done in R?
--
Thanks,
Jim.
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2007 Nov 28
2
fit linear regression with multiple predictor and constrained intercept
Hi group,
I have this type of data
x(predictor), y(response), factor (grouping x into many groups, with 6-20
obs/group)
I want to fit a linear regression with one common intercept. 'factor'
should only modify the slopes, not the intercept. The intercept is expected
to be >0.
If I use
y~ x + factor, I get a different intercept for each factor level, but one
slope only
if I use
y~ x *
2010 Sep 23
3
accumulation curves
Hi,
I am trying to fit a logarithmic trendline to a scatterplot of a
species accumulation curve. I've tried abline, lines, curve and
scatter.smooth but none of these work.
Can anyone help please,
Kyran
2009 Nov 04
3
Constrained Optimization
Hi All,
I'm trying to do the following constrained optimization example.
Maximize x1*(1-x1) + x2*(1-x2) + x3*(1-x3)
s.t. x1 + x2 + x3 = 1
x1 >= 0 and x1 <= 1
x2 >= 0 and x2 <= 1
x3 >= 0 and x3 <= 1
which are the constraints.
I'm expecting the answer x1=x2=x3 = 1/3.
I tried the "constrOptim" function in R and I'm running into some issues.
I first start off
2003 Oct 31
1
constrained nonlinear optimisation in R?
Hello. I have searched the archives but have not found anything. I
need to solve a constrained optimisation problem for a nonlinear
function (“maximum entropy formalism”). Specifically,
Optimise: -1*SUM(p_ilog(p_i)) for a vector p_i of probabilities,
conditional on a series of constraints of the form:
SUM(T_i*p_i)=k_i for given values of T_i and k_i (these are
constraints on
2012 Jan 13
0
New package ‘bcrm’ to implement Bayesian continuous reassessment method designs
Dear R users,
I am pleased to announce the release of a new packaged called `bcrm?
(version 0.1), now available on CRAN.
The package implements a wide range of Bayesian continuous reassessment
method (CRM) designs to be used in Phase I dose-escalation trials. The
package is fully documented and highlights include
? A choice of 1-parameter working models or the 2-parameter logistic
model.
2012 Jan 13
0
New package ‘bcrm’ to implement Bayesian continuous reassessment method designs
Dear R users,
I am pleased to announce the release of a new packaged called `bcrm?
(version 0.1), now available on CRAN.
The package implements a wide range of Bayesian continuous reassessment
method (CRM) designs to be used in Phase I dose-escalation trials. The
package is fully documented and highlights include
? A choice of 1-parameter working models or the 2-parameter logistic
model.
2010 Aug 24
1
Constrained non-linear optimisation
I'm relatively new to R, but I'm attempting to do a non-linear maximum
likelihood estimation (mle) in R, with the added problem that I have a
non-linear constraint.
The basic problem is linear in the parameters (a_i) and has only one
non-linear component, b, with the problem being linear when b = 0 and
non-linear otherwise. Furthermore, f(a_i) <= b <= g(a_i) for some
(simple) f
2011 Jan 11
3
Generation of Normal Random Numbers
Dear R helpers
I have a data frame as given below
df = data.frame(A = c(776,827,836,995,855,1026,1203,1363,965,1195),
B = c(806,953,1049,1056,1243,764,1148,1162,948,1154),
C = c(959,1155,1193,1163,863,1070,1087,877,1132,944),
D = c(906,760,978,1170,1009,883,1007,960,828,113))
# Actually the real data has number of vectors and