Displaying 20 results from an estimated 500 matches similar to: "[Fwd: Re: optimization subject to constraints]"
2010 Apr 28
1
function which saves an image of a dgtMatrix as png
Hi,
I'm getting crazy:
This does work:
library(Matrix)
a1<-b1<-c(1,2)
c1<-rnorm(2)
aDgt<-spMatrix(ncol=3,nrow=3,i=a1,j=b1,x=c1)
png("myImage.png")
image(aDgt)
dev.off()
But this doesn't !!!
f<-function(x){
png("myImage.png")
image(x)
dev.off()
}
f(aDgt)
My image is saved as a text file and contains nothing at all !!!
Thanks in advance,
Gildas Mazo
2012 Mar 06
2
Numerical Inversion of Cumulative Distribution Function
Dear R users,
Given a user-defined cumulative distribution function F, I want to compute F^{-1}(x). How is that possible with R?
Best Regards,
--
Gildas Mazo
PhD student
MISTIS team at INRIA
Grenoble, France
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2010 Jul 22
4
SQL/R
Dear R users,
I want to aggregate data in the following way:
###
X <- data.frame(u = c("T1","T1","T1","T2"), v=c("a","a","b","a"))
X
library(sqldf)
sqlOut <- sqldf("select count(distinct(v)) from X group by u")
sqlOut
###
Now I want to get the same result without using SQL. How can I achieve
that ?
2010 Jun 04
2
Build Design Matrix with avoiding loops
Dear R users,
I'd like to build a simple design matrix in a efficient way. I naively
wrote the code below.
####
n = 15
k = 3
nbPerGrp = c(5,5,5)
xT <- list()
for (i in 1:k){
xT[[i]] <- rep(0, k)
xT[[i]][i] <- 1
}
X <- matrix(nrow = n, ncol = k) #design matrix
for (i in 1:nbPerGrp[1]){
X[i,] <- xT[[1]]
}
for (i in 1:k-1){
for (j
2010 Aug 09
2
optimization subject to constraints
Dear R users,
I'm looking for tools to perform optimization subject to constraints,
both linear and non-linear. I don't mind which algorithm may be used, my
primary aim is to get something general and easy-to-use to study simples
examples.
Thanks for helping,
Gildas
2012 Sep 20
1
optim and "the function should not" advice
Dear R users,
I'm using optim to optimize a pretty complicated function. This function takes the parameter vector "theta" and within its body I use instructions like
sigma<-theta[a:b]; computations with sigma...
out<-c()
for (i in 1:d){
a<-theta[(3*d+i):c]
out[i]<-evaluation of an expression involving 'a' (I use symbolic differentiation)
}
Unfortunately
2012 Mar 22
4
Plotting patient drug timelines using ggplot2 (or some other means) -- Help!!!
Hello All,
Want very much to learn how to plot patient drug timelines. Trouble is I need to figure out how to do this today. So not much time for me to struggle with it. Hoping someone can just help me out a bit.
Below are some sample data and code that produces what I think is the beginning of a very nice graph.
Need to alter the code to:
1. Get the lines for the drugs to appear on the
2010 Mar 25
3
Absolutely No idea how to plot my Spatial Data
Hi,
I have a data set of points which are represented by 3 variables x,y,z where
x is the position of the point on the x-absciss and y on the y-absciss. Each
of my points has a value z, which I want to be displayed as follows: the
more z is high, the more the color on the map is dark.
How can I achieve this ?
Thanks for your help
--
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2013 Feb 10
3
Constrained Optimization in R (alabama)
Dear List,
I'm trying to solve this simple optimization problem in R. The parameters
are the exponents to the matrix mm. The constraints specify that each row
of the parameter matrix should sum to 1 and their product to 0. I don't
understand why the constraints are not satisfied at the solution. I must be
misinterpreting how to specify the constrains somehow.
library(alabama)
ff <-
2011 Dec 21
1
constrOptim and further arguments
Dear List,
I have the code below, where I am using the constrained optimisation
package, 'constrOptim.nl' to find the values of two values, b0 and b1.
I have no problems when I enter further variable information DIRECTLY into
the functions, fn, and heq. In this instance I require fn to have -0.0075
appended to it, and in the case of heq, h[1] has -0.2.
library(alabama)
2010 Sep 21
2
Trouble with Optimization in "Alabama" Package
Hello,
This is my first post to the help request list, so I'm going to err on the
side of giving too much information.
I'm working on writing a simulation in which agents will make repeated
production and exchange decisions with randomly chosen partners.
The idea is, all agents can produce two goods which they want to consume,
they choose a value t in [0,10] which sets their production
2010 Oct 28
1
Rsolnp examples
I'm interested in the Rsolnp package. For their primary function
"solnp", one example is given, and there is a reference to "unit
tests". Anyone know where these can be found? Also, Rsolnp is
used in a few other packages (e.g., depmixS4), but I cannot seem
to find source illustrating its call sequence, and the precise
definition of the functions passed.
Can anyone help?
2020 Nov 04
2
sprintf, check number of parameters
Dear Tomas,Thank you.Regarding the "unnumbered" arguments, i.e. sprintf('%f %f', 1, 2, 3). This was the case I wanted to report, here a warning can be very useful.Regarding the "numbered" arguments, that is, sprintf('%$1f %$3f', 1, 2, 3). Here, omission of an argument might be intended, for example, in an application with support for multiple languages.
2017 Sep 02
2
Strange lazy evaluation of default arguments
Another way to avoid the problem is to not redefine variables that are
arguments. E.g.,
> Su3 <- function(u=100, l=u, mu=0.53, sigma2=4.3^2, verbose)
{
if (verbose) {
print(c(u, l, mu))
}
uNormalized <- u/sqrt(sigma2)
lNormalized <- l/sqrt(sigma2)
muNormalized <- mu/sqrt(sigma2)
c(uNormalized, lNormalized, muNormalized)
}
> Su3(verbose=TRUE)
2005 Aug 15
0
RE: has_many_belongs_to_many insert issues [CLOSED]
Found the issue.
In the association table (categories.products) it is very important to
use lowercase column names.
I.e, product_id and category_id.
I had Product_id and Category_id in SQL....
Gildas
-----Original Message-----
From: rails-bounces-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org
[mailto:rails-bounces-1W37MKcQCpIf0INCOvqR/iCwEArCW2h5@public.gmane.org] On Behalf Of Cherruel,
2017 Sep 02
6
Strange lazy evaluation of default arguments
Dear R developers,
sessionInfo() below
Please have a look at the following two versions of the same function:
1. Intended behavior:
> Su1 = function(u=100, l=u, mu=0.53, sigma2=4.3^2)
+ {
+ print(c(u, l, mu)) # here, l is set to u?s value
+ u = u/sqrt(sigma2)
+ l = l/sqrt(sigma2)
+ mu = mu/sqrt(sigma2)
+ print(c(u, l, mu))
+ }
>
> Su1()
[1] 100.00 100.00 0.53
[1]
2020 Sep 20
2
sprintf, check number of parameters
Dear R developers,
I am wondering if this should raise an error or a warning.
> sprintf('%.f, %.f', 1, 2, 3)
[1] "1, 2"
I am aware that R has ?numbered? sprintf arguments (sprintf('%1$.f', ?), and in that case, omissing of specific arguments may be intended. But in the usual syntax, omission of an argument is probably a mistake.
Thank you for your consideration.
2017 Sep 02
0
Strange lazy evaluation of default arguments
Dear Bill,
All makes perfect sense (including the late evaluation). I actually discovered the problem by looking at old code which used your proposed solution. Still I find it strange (and, hnestly, I don?t like R?s behavior in this respect), and I am wondering why u is not being copied to L just before u is assigned a new value. Of course, this would require the R interpreter to track all these
2011 Oct 17
5
Install the rugarch-package
Hi,
i am unable to install the rugarch package.
More than that i do not even find this package in my list of possible
packages.
Its possible than the name has changed, or the package is not longer
availiable?
Is there a similar package avaliable for garch modelling except the fGarch
what i am using now?
many Thanks
Roland
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2012 Feb 22
1
line width in legend of interaction.plot
Dear R developers,
The following command produces an interaction plot with lwd=2.
interaction.plot(c(1, 2, 1, 2), c(1, 1, 2, 2), 1:4, lwd=2)
In the legend, however, lwd seems to be 1, which does not seem
to be intended behavior. Probably the lwd is not correctly forwarded
to legend:
from the interaction.plot source:
legend(xleg, yleg, legend = ylabs, col = col, pch = if (type %in%