Problem
I am using R 3.3.3 on Windows 10 (x64 bit). I get the following prediction output from the glmmPQL prediction function as follows:
library(MASS)
library(nlme)
library(dplyr)
model<-glmmPQL(a ~ b + c + d, data = trainingDataSet, family = binomial, random = list( ~ 1 | e), correlation = corAR1())
The prediction values are given as follows:
p <- predict(model, newdata=testingDataSet, type="response",level=0) (1.0)
The output it gives is as follows:
I then try to measure the performance of this output using the following code:
pr <- prediction(p, testingDataSet$a)(1.1)
It gives us the following error as follows:
Error in prediction(p, testingDataSet$a) :
Format of predictions is invalid. (1.2)
I have successfully been able to use the prediction method in R using other functions (glm,svm,nn) when the data looks something like as follows:
model<-glm(a ~ b + c + e, family = binomial(link = 'logit'), data = trainingDataSet)
p <- predict(model, newdata=testingDataSet, type="response") (1.3)
Attempts
I believe the fix to the above problem is to get it into the format shown below (1.3). I have tried the following things using R and have been failing.
I have tried casting p in 1.0 using as.numeric() and as.list() and other things. I want to get look like the p R object in 1.3. In other words, I believe the format is reason why things not working for me?
No matter what mutate or casting I try, I can't seem to get it into the form in 1.3 and image shown as desired. Especially with the index as columns features.
I'm coming up empty handed on stackoverflow and the R help files. When I use the command class(p) both tell me they are numeric.
Question
Give the above, can someone tell me how I can use R to get the output from glmmPQL in a format that the prediction function can use as shown above please?
In other words, how can I make sure the output in 1.0 can made to match the output in 1.3 in R? My attempts have failed and I would deeply appreciate someone more skilled in R to point out where I am failing?
If you use as.numeric(p) then you'll get the values you want - then the only difference is that the GLM output has names. You can add these in with something like:
p <- as.numeric(p)
names(p) <- 1:length(p)
If this doesn't work, you can use str(p) to examine the structure of the object in more depth.
Related
I am very new to R, and this is my first time of encountering the eval() function. So I am trying to use the med and boot.med function from the following package: mma. I am using it to conduct mediation analysis. med and boot.med take in models such as linear models, and dataframes that specify mediators and predictors and then estimate the mediation effect of each mediator.
The author of the package gives the flexible option of specifying one's own custom.function. From the source code of med, it can be seen that the custom.function is passed to the eval(). So I tried insert the gbmt function as the custom function. However, R kept giving me error message: Error during wrapup: Number of trees to be used in prediction must be provided. I have been searching online for days and tried many ways of specifying the number of trees parameter n.trees, but nothing works (I believe others have raised similar issues: post 1, post 2).
The following codes are part of the source code of the med function:
cf1 = gsub("responseY", "y[,j]", custom.function[j])
cf1 = gsub("dataset123", "x2", cf1)
cf1 = gsub("weights123", "w", cf1)
full.model[[j]] <- eval(parse(text = cf1))
One custom function example the author gives in the package documentation is as follows:
temp1<-med(data=data.bin,n=2,custom.function = 'glm(responseY~.,data=dataset123,family="quasibinomial",
weights=weights123)')
Here the glm is the custom function. This example code works and you can replicate it easily (if you have mma installed and loaded). However when I am trying to use the gbmt function on a survival object, I got errors and here is what my code looks like:
temp1 <- med(data = data.surv,n=2,type = "link",
custom.function = 'gbmt(responseY ~.,
data = dataset123,
distribution = dist,
train_params = start_stop,
cv_folds=10,
keep_gbm_data = TRUE,
)')
Anyone has any idea how the argument about number of trees n.trees can be added somewhere in the above code?
Many thanks in advance!
Update: in order to replicate the example code, please install mma and try the following:
library("mma")
data("weight_behavior") ##binary x #binary y
x=weight_behavior[,c(2,4:14)]
pred=weight_behavior[,3]
y=weight_behavior[,15]
data.bin<-data.org(x,y,pred=pred,contmed=c(7:9,11:12),binmed=c(6,10), binref=c(1,1),catmed=5,catref=1,predref="M",alpha=0.4,alpha2=0.4)
temp1<-med(data=data.bin,n=2) #or use self-defined final function
temp1<-med(data=data.bin,n=2, custom.function = 'glm(responseY~.,data=dataset123,family="quasibinomial",
weights=weights123)')
I changed the custom.function to gbmt and used a survival object as responseY and the error occurs. When I use the gbmt function on my data outside the med function, there is no error.
I am trying to run a simple naive bayes model (trying to redo what I have seen the datacamp course).
I am using the R naivebayes package.
The training dataset is where9am which looks like this:
My first problem is the following... when I have several predictions in a dataframe thursday9am...
... and I use the following code:
locmodel <- naive_bayes(location ~ daytype, data = where9am)
my_pred <- predict(locmodel, thursday9am)
I get a series of <NA> while it works well with the correct prediction if the thursday9am dataframe only contains a single observation.
The second problem is the following: when I use the following code to get the associated probabilities...
locmodel <- naive_bayes(location ~ daytype, data = where9am, type = c("class", "prob"))
predict(locmodel, thursday9am , type = "prob")
... even if I have only one observation in thursday9am, I get a series of <NaN>.
I am not sure what I am doing wrong.
I'm fairly new to using the caret library and it's causing me some problems. Any
help/advice would be appreciated. My situations are as follows:
I'm trying to run a general linear model on some data and, when I run it
through the confusionMatrix, I get 'the data and reference factors must have
the same number of levels'. I know what this error means (I've run into it before), but I've double and triple checked my data manipulation and it all looks correct (I'm using the right variables in the right places), so I'm not sure why the two values in the confusionMatrix are disagreeing. I've run almost the exact same code for a different variable and it works fine.
I went through every variable and everything was balanced until I got to the
confusionMatrix predict. I discovered this by doing the following:
a <- table(testing2$hold1yes0no)
a[1]+a[2]
1543
b <- table(predict(modelFit,trainTR2))
dim(b)
[1] 1538
Those two values shouldn't disagree. Where are the missing 5 rows?
My code is below:
set.seed(2382)
inTrain2 <- createDataPartition(y=HOLD$hold1yes0no, p = 0.6, list = FALSE)
training2 <- HOLD[inTrain2,]
testing2 <- HOLD[-inTrain2,]
preProc2 <- preProcess(training2[-c(1,2,3,4,5,6,7,8,9)], method="BoxCox")
trainPC2 <- predict(preProc2, training2[-c(1,2,3,4,5,6,7,8,9)])
trainTR2 <- predict(preProc2, testing2[-c(1,2,3,4,5,6,7,8,9)])
modelFit <- train(training2$hold1yes0no ~ ., method ="glm", data = trainPC2)
confusionMatrix(testing2$hold1yes0no, predict(modelFit,trainTR2))
I'm not sure as I don't know your data structure, but I wonder if this is due to the way you set up your modelFit, using the formula method. In this case, you are specifying y = training2$hold1yes0no and x = everything else. Perhaps you should try:
modelFit <- train(trainPC2, training2$hold1yes0no, method="glm")
Which specifies y = training2$hold1yes0no and x = trainPC2.
I have a linear model1<-lm(divorce_rate~marriage_rate+median_age+population) for which the leverage plot shows an outlier at 28 (State variable id for "Nevada"). I'd like to specify a model without Nevada in the dataset. I tried the following but got stuck.
data<-read.dta("census.dta")
attach(data)
data1<-data.frame(pop,divorce,marriage,popurban,medage,divrate,marrate)
attach(data1)
model1<-lm(divrate~marrate+medage+pop,data=data1)
summary(model1)
layout(matrix(1:4,2,2))
plot(model1)
dfbetaPlots(lm(divrate~marrate+medage+pop),id.n=50)
vif(model1)
dataNV<-data[!data$state == "Nevada",]
attach(dataNV)
model3<-lm(divrate~marrate+medage+pop,data=dataNV)
The last line of the above code gives me
Error in model.frame.default(formula = divrate ~ marrate + medage + pop, :
variable lengths differ (found for 'medage')
I suspect that you have some glitch in your code such that you have attach()ed copies that are still lying around in your environment -- that's why it's really best practice not to use attach(). The following code works for me:
library(foreign)
## best not to call data 'data'
mydata <- read.dta("http://www.stata-press.com/data/r8/census.dta")
I didn't find divrate or marrate in the data set: I'm going to speculate that you want the per capita rates:
## best practice to use a new name rather than transforming 'in place'
mydata2 <- transform(mydata,marrate=marriage/pop,divrate=divorce/pop)
model1 <- lm(divrate~marrate+medage+pop,data=mydata2)
library(car)
plot(model1)
dfbetaPlots(model1)
This works fine for me in a clean session:
dataNV <- subset(mydata2,state != "Nevada")
## update() may be nice to avoid repeating details of the
## model specification (not really necessary in this case)
model3 <- update(model1,data=dataNV)
Or you can use the subset argument:
model4 <- update(model1,subset=(state != "Nevada"))
I have an error when evaluating a simple test set with evaluate_Weka_classifier. Trying to learn how the interface works from R to Weka with RWeka, but I still don't get this.
library("RWeka")
iris_input <- iris[1:140,]
iris_test <- iris[-(1:140),]
iris_fit <- J48(Species ~ ., data = iris_input)
evaluate_Weka_classifier(iris_fit, newdata = iris_test, numFolds=5)
No problems here, as we would assume (It is ofcourse a stupit test, no random holdout data etc). But now I want to simulate missing data (alot). So i set Petal.Width as missing:
iris_test$Petal.Width <- NA
evaluate_Weka_classifier(iris_fit, newdata = iris_test, numFolds=5)
Which gives the error:
Error in .jcall(evaluation, "S", "toSummaryString", complexity) :
java.lang.IllegalArgumentException: Can't have more folds than instances!
Edit: This error should tell me that I have not enough instances, but I have 10
Edit: If I use write.arff, it can be exported and read in by Weka. Change Petal.Width {} into Petal.Width numeric to make the two files exactly the same. Then it works in Weka.
Is this a thinking error? When reading Machine Learning, Practical machine learning tools and techniques it seems to be legit. Maybe I just have to tell RWeka that I want to use fractions when a split uses a missing variable?
Thnx!
The issue is that you need to tell J48() what to do with missing values.
library(RWeka)
?J48()
#pertinent output
J48(formula, data, subset, na.action,
control = Weka_control(), options = NULL)
na.action tells R what to do with missing values. When following up on na.action you will find that "The ‘factory-fresh’ default is na.omit". Under this setting of course there are not enough instances!
Instead of leaving na.action as the default omit, I have changed it as follows,
iris_fit<-J48(Species~., data = iris_input, na.action=NULL)
and it works like a charm!