Displaying 20 results from an estimated 30000 matches similar to: "smallest/biggest number"
2009 Mar 19
2
find the index of the smallest or biggest number in a vetor or data.frame
Dear R experts,
How to find out the index of minimum or maxmum number in a vetor or
data.frame?
For example,
a=
n price
1 50
-2 100
0 200
-1 300
......
I want to find out the row which the n is the smallest or largestest and
extract the price.
Thanks
Ted
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2010 Dec 08
1
how to find smallest non-negative and biggest non-positive number in a matrix column ?
so it could be zero in both cases when given column has 0 set in it
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2014 Sep 17
2
Generating unordered, with replacement, samples
Hello,
I am trying to interface in my teaching some elementary probability with Monte Carlo ideas. In sampling from a finite population, the number of distinct samples of size 'k' from a population of size 'n' , when individuals are selected with replacement and the selection order does not matter, is choose(n + k -1, k). Does anyone have a suggestion about how to simulate
2008 Aug 21
1
HELP: how to add weight to a [x,y] coordinate
Anyone who can help me with the following question?
How can I add weight to [x,y] coordinates on a graph/scatterplot?
Background:
Monte Carlo simulation generated 730,000 [x,y] coordinates with a weight attached (from 0-0.5).
Both x and y are rounded and fit on a raster with x-axis 0-170 months (smalles unit = 1 month) and y-axis 0-6 (smallest unit=0.1).
I would like every [x,y] to add its
2005 Dec 15
1
precision of rnorm
How many distinct values can rnorm return?
I assume that rnorm manipulates runif in some way, runif uses the Mersenne
Twister, which has a period of 2^19937 - 1. Given that runif returns a 64
bit precision floating point number in [0,1], the actual period of the
Mersenne Twister in a finite precision world must be significantly less.
One of the arguments for Monte Carlo over the bootstrap is
2009 Apr 09
1
puzzling lm.fit errors
Hi everyone, I am running a monte carlo and am getting an error that I
haven't the slightest clue where to begin figuring it out. The error
is as follows:
Error in lm.fit(x, y, offset = offset, singular.ok = singular.ok, ...) :
0 (non-NA) cases
In addition: Warning message:
In ltm.fit(X, betas, constraint, formula, con) :
Hessian matrix at convergence is not positive definite;
2016 Sep 26
2
Publication & Project: Verificarlo: checking floating point accuracy through Monte Carlo Arithmetic
Hi,
We have recently published a paper on floating point accuracy analysis
through Monte Carlo Arithmetic. We also released the open-source tool
Verificarlo (https://github.com/verificarlo/verificarlo) that relies on
LLVM for instrumenting floating point operations.
Could you please add our paper to http://llvm.org/pubs/ ?
Verificarlo: checking floating point accuracy through Monte Carlo
2007 Nov 20
2
Plotting Non Numeric Data
Hi,
Is there a way to plot non numerical data in R?
Specifically, I have an array, say with 1000 entries, where each entry
is a string of 4 characters (in any order, 24 possibilities in my
case). I would like on the y-axis all the strings that are in the
array as labels. The x-axis I would like labeled 0 to 1000. The line
is to show how the strings change as we move through the array.
2013 Mar 27
1
Conditional CCA and Monte Carlo - Help!
Hi All,
I am using canonical correspondence analysis to compare a community
composition matrix to a matrix of sample spatial relationships and
environmental variables. In order to parse out how much variance is
explained purely by space (S/E) or the environment (E/S) I am using a
conditional (partial) CCA. I want to test significance via Monte Carlo but
I can not find a way to do this with a
2005 Aug 13
2
monte carlo simulations/lmer
Hi - I am doing some monte carlo simulations comparing bayesian (using
Plummer's jags) and maximum likelihood (using lmer from package lme4
by Bates et al).
I would like to know if there is a way I can flag nonconvergence and
exceptions. Currently the simulations just stop and the output reads
things like:
Error in optim(.Call("lmer_coef", x, 2, PACKAGE = "Matrix"), fn,
2009 May 06
2
NLMINB() produces NaN!
I am having the same problem as one Rebecca Sela(see bellow).
On 21/12/2007 12:07 AM, Rebecca Sela wrote:
>* I am trying to optimize a likelihood function using NLMINB. After running without a problem for quite a few iterations (enough that my intermediate output extends further than I can scroll back), it tries a vector of parameter values NaN. This has happened with multiple Monte Carlo
2010 Aug 12
2
Difference in Monte Carlo calculation between chisq.test and fisher.test
Hello all,
I would like to know what the difference is between chisq.test and
fisher.test when using the Monte Carlo method with simulate.p.value=TRUE?
Thank you
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2010 Oct 28
2
Please help me about Monte Carlo Permutation
> Dear R experts,
>I am sorry for my inability.
>I have the following dataset:
> Qtot Itot
>1 73 684
>2 64 451
>3 71 378
>4 65 284
>5 47 179
>6 31 117
>7 19 69
>
>Now I need to perform Monte Carlo Pertutation test underlaying the
following condition.
>
>
>Condition
>
>In order to choose randomly (5000 times) for the Qtot
2004 Sep 28
3
slow loops in Monte Carlo Simulations
Hi there,
I am running Monte Carlo Simulations in R using ordinary "while
(condition)" loops. Since the number of iterations is something like
100.000 and within each iteration a given subsample is extended
sequentially it takes hours to run the simulation.
Does anyone know if there is either a way to avoid using loops in
Monte Carlo Simulations or how to include possible faster
2012 Jun 20
2
Figure title
Hi,
I created several figures and their titles should appear like this:
Figure 1: Monte Carlo results for alternative estimators of structural
parameters (N = 100, T = 5)
Because N and T change across figures, my code includes the following lines:
N.set <- 100
T.set <- 5
mtext(“Figure 1: Monte Carlo results for alternative estimators of
structural
2010 Mar 24
2
Monte Carlo simulation in R
Hi, R-helpers,
I'm trying to use R to do a Monte Carlo simulation and need the help. What I
have is a matrix that consists of the probabilities for the persons to
choose zones. For example, in the matrix shown below, each column represents
a person, and each row represents a zone. So, the probability that the first
person will choose the 2nd zone is 30%.
25% 30% 10% 30% 20% 0% 20% 50% 60%
2005 Aug 04
2
p-values
HI R-users,
I am trying to repeat an example from Rayner and Best "A contingency
table approach to nonparametric testing (Chapter 7, Ice cream example).
In their book they calculate Durbin's statistic, D1, a dispersion
statistics, D2, and a residual. P-values for each statistic is
calculated from a chi-square distribution and also Monte Carlo p-values.
I have found similar p-values
2010 Jul 15
2
replace negative numbers by smallest positive value in matrix
Hi Group,
I have a matrix, and I would like to replace numbers less than 0 by
the smallest minimum number. Below is an
small matrix, and the loop I used. I would like to get suggestions on
the "R way" to do this.
Thanks,
Juliet
# example data set
mymat <- structure(c(-0.503183609420937, 0.179063475173256, 0.130473004669938,
-1.80825226960127, -0.794910626384209, 1.03857280868547,
2012 Dec 04
3
monte carlo simulation on R
Hello,
How can I make a monte carlo simulation on R?
Regards
Adel
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Tunisia
tel: +216 97 246 706 (+33640302046 jusqu'au 15/6)
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2015 Apr 22
3
distribucion de IRWIN HALL
.... Un código más optimizado para la aproximación Monte Carlo de la distribución de IH
N=10000 # tamaño simulación Monte Carlo
n=5 # numero de uniformes
cdf.IH <-function(x,n,N) {
z=replicate(N,sum(runif(n)))
apply(outer(x,z,">="),1,mean)
}
x=seq(0,5,.1)
y=cdf.IH(x,n=n,N=N)
plot(x,y,type="l")
Un saludo. Olivier
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