Displaying 20 results from an estimated 200 matches similar to: "Toying with neural networks"
2013 Oct 29
3
Ayuda con Mice con polyreg
Saludo gente, antes que nada gracias por la ayuda que puedan aportarme, soy
iniciante en R, estoy usando el paquete Mice para realizar imputaciones
múltiples sobre variables en su mayoría categóricas. El problema está que
cuando expresó este comando imp <- mice(dataset,method="polr",maxit=1)
donde el dataset es un data.frame me tirá este error :
iter imp variable
1 1 pial1a
2010 Jul 14
1
Changing model parameters in the mi package
I am trying to use the mi package to impute data, but am running into
problems with the functions it calls.
For instance, I am trying to impute a categorical variable called
"min.func." The mi() function calls the mi.categorical() function to
deal with this variable, which in turn calls the nnet.default()
function, and passes it a fixed parameter MaxNWts=1500. However, as
2005 Apr 11
4
R: function code
HI
sorry to be a nuisance to all!!!
how can i see the code of a particular function?
e.g. nnet just as an example
2011 Jan 07
1
Adjusting MaxNwts in MICE Package
Hi,
I'm trying to impute a large data set using mice but I keep getting this:
Error in nnet.default(X, Y, w, mask = mask, size = 0, skip = TRUE, softmax =
TRUE, :
too many (2944) weights
nnet.default uses the argument MaxNWts to set a maximum number of weights.
I've tried to change nnet.default to get around this, but mice is somehow
still passing an argument that sets the maximum
2008 Feb 15
2
Softmax in nnet
Hi R help,
I run my data in nnet with skip layer, factor response (with 0 & 1
values) and explicitly put softmax=T to compare the result of the
default nnet with no softmax specification. I assume this should give
me the same result. I got the result the default one, but not the
softmax version and I got the error message that I did not quite
understand.
test6.nn.skipT.softm.Yfac <-
2003 Jul 11
2
Nonliner Rgression using Neural Nnetworks
Hi,
I am an old hand at chemistry but a complete beginner at statistics
including R computations.
My question is whether you can carry out nonlinear
multivariate regression analysis in R using neural networks, where the
output variable can range from -Inf to + Inf., unlike discriminant
analysis where the output is confined to one or zero. The library nnet
seems to work only in the latter
2013 Jan 14
0
Changing MaxNWts with the mi() function (error message)
Hello,
I am trying to impute data with the mi() function (mi package) and
keep receiving an error message. When imputing the variable, "sex,"
the mi() function accesses the mi.categorical() function, which then
accesses the nnet() function. I then receive the following error
message (preceded by my code below):
> imputed.england=mi(england.pre.imputed, n.iter=6, add.noise=FALSE)
2010 Jun 02
1
nnet: cannot coerce class c("terms", "formula") into a data.frame
Dearest all,
Objective: I am now learning neural networks. I want to see how well can
train an artificial neural network model to discriminate between the two
files I am attaching with this message.
http://r.789695.n4.nabble.com/file/n2240582/3dMaskDump.txt 3dMaskDump.txt
http://r.789695.n4.nabble.com/file/n2240582/test_vowels.txt test_vowels.txt
Question: when I am attempting to run
2012 Dec 18
1
multi dimensional optim problem
I am attempting to use optim to solve a neural network problem. I would like to optimize coefficients that are currently stored in a matrix
Y=270 x 1
X= 27- x 14
b1= 10x14
b2= 11x1
V= 10 x 14 set of prior variances.
I have the following function:
posterior.mode1=function(y,X,b_0,b2,V) {
log.like=function(b1) {
a_g=compute(b1)
z_g=tanh(a_g);
z_g=cbind(1,z_g)
2012 Jan 05
2
difference of the multinomial logistic regression results between multinom() function in R and SPSS
Dear all,
I have found some difference of the results between multinom() function in
R and multinomial logistic regression in SPSS software.
The input data, model and parameters are below:
choles <- c(94, 158, 133, 164, 162, 182, 140, 157, 146, 182);
sbp <- c(105, 121, 128, 149, 132, 103, 97, 128, 114, 129);
case <- c(1, 3, 3, 2, 1, 2, 3, 1, 2, 2);
result <- multinom(case ~ choles
2013 Oct 30
2
disculpe las molestias ...ayuda con MICE
Saludo gente, antes que nada gracias por la ayuda que puedan aportarme, soy
iniciante en R, estoy usando el paquete Mice para realizar imputaciones
múltiples sobre variables en su mayoría categóricas. El problema está que
cuando expresó este comando imp <- mice(dataset,method="polr",maxit=1)
donde el dataset es un data.frame me tirá este error :
iter imp variable
1 1 pial1a
2013 Mar 06
1
CARET and NNET fail to train a model when the input is high dimensional
The following code fails to train a nnet model in a random dataset using
caret:
nR <- 700
nCol <- 2000
myCtrl <- trainControl(method="cv", number=3, preProcOptions=NULL,
classProbs = TRUE, summaryFunction = twoClassSummary)
trX <- data.frame(replicate(nR, rnorm(nCol)))
trY <- runif(1)*trX[,1]*trX[,2]^2+runif(1)*trX[,3]/trX[,4]
trY <-
2003 Sep 22
0
Neural Network Question
Hi,
I'm using the R nnet package to train a classifier to recognise items which belong to a particular class and those which don't belong to the class.
I'm supplying nnet with a matrix x containing training examples (in each row) and a matrix y of targets. The training set is made up of 200 positive examples and 1000 negative examples. I want to train the network on the same
2012 Jun 26
1
Error in mice
Hi all,
I am imputing missingness of 90 columns in a data frame using mice.
But "mice" gives back :
Error in nnet.default(X, Y, w, mask = mask, size = 0, skip = TRUE, softmax = TRUE, : too many (1100) weights
Any idea to solve this error is welcome,
Anera
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2013 Oct 29
0
Fwd: Ayuda con Mice con polyreg
Saludo gente, antes que nada gracias por la ayuda que puedan aportarme, soy
iniciante en R, estoy usando el paquete Mice para realizar imputaciones
múltiples sobre variables en su mayoría categóricas. El problema está que
cuando expresó este comando imp <- mice(dataset,method="polr",maxit=1)
donde el dataset es un data.frame me tirá este error :
iter imp variable
1 1 pial1a
2010 Oct 12
1
need help with nnet
HI, Dear R community,
My data set has 2409 variables, the last one is response variable. I have
used the nnet after feature selection and works. But this time, I am using
nnet to fit a model without feature selection. I got the following error
information:
> dim(train)
[1] 1827 2409
nnet.fit<-nnet(as.factor(out) ~ ., data=train, size=3, rang=0.3,
decay=5e-4, maxit=500) # model
2013 Oct 30
1
disculpe las molestias ...ayuda con MICE
Muchas gracias, pero claro en una muestra de 50 datos se ejecuta, en la
muestra original de 1000 registros
me tira error :(
2013/10/30 daniel <daniel319@gmail.com>
> Amalia,
>
> No obtengo tus resultados. Corrí tus formulas y datos y el resultado es
> x <- structure(list(ï..psraid = c(202517L, 202518L, 202520L, 202523L,
> + 202527L, 202537L, 202543L, 202544L, 202551L,
2000 Mar 28
2
Logistic ridge regression ...
Hi
I have some data (v. large amount) with a (0,1) response where I want to
minimise the errors in the betas rather than SS or deviance.
So can anyone point me to a ridge regression function or equivalent for
such a logistic regression case?
John
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2007 Jun 21
2
Multinomial models
Hello,
I am VERY new to R (one week) and I am trying to run a multinomial logit model.
The model I am using is
> model1 <- multinom(Y ~ X1 + X2 + , ..., Xn)
if I put in
> summary(model1)
I get
#Error in function (classes, fdef, mtable) :
unable to find an inherited method for function "fitted", for
signature "multinom"
and if I put in
> coef(model1)
2012 May 30
1
caret() train based on cross validation - split dataset to keep sites together?
Hello all,
I have searched and have not yet identified a solution so now I am sending
this message. In short, I need to split my data into training, validation,
and testing subsets that keep all observations from the same sites together
? preferably as part of a cross validation procedure. Now for the longer
version. And I must confess that although my R skills are improving, they
are not so