similar to: Calculating AUC from ROCR

Displaying 20 results from an estimated 2000 matches similar to: "Calculating AUC from ROCR"

2009 May 12
1
ROCR: auc and logarithm plot
Hi, I am quite new to R and I have two questions regarding ROCR. 1. I have tried to understand how to extract area-under-curve value by looking at the ROCR document and googling. Still I am not sure if I am doing the right thing. Here is my code, is "auc1" the auc value? " pred1 <- prediction(resp1,label1) perf1 <- performance(pred1,"tpr","fpr") plot(
2007 Nov 24
3
help in plotting
Dear list, I want to combine several plots in one graph. I did this: plot(a1); plot(a2, add=TRUE); ...plot(a5, add=TRUE) The problem is the more plot we put, the more complex the graph. Is there any way to label each line; or other way just to make sure I know which one which? Thank you for the help, Ilham [[alternative HTML version deleted]]
2012 Dec 19
2
pROC and ROCR give different values for AUC
Packages pROC and ROCR both calculate/approximate the Area Under (Receiver Operator) Curve. However the results are different. I am computing a new variable as a predictor for a label. The new variable is a (non-linear) function of a set of input values, and I'm checking how different parameter settings contribute to prediction. All my settings are predictive, but some are better. The AUC i
2010 Jan 22
2
Computing Confidence Intervals for AUC in ROCR Package
Dear R-philes, I am plotting ROC curves for several cross-validation runs of a classifier (using the function below). In addition to the average AUC, I am interested in obtaining a confidence interval for the average AUC. Is there a straightforward way to do this via the ROCR package? plot_roc_curve <- function(roc.dat, plt.title) { #print(str(vowel.ROC)) pred <-
2008 Jan 05
1
AUC values from LRM and ROCR
Dear List, I am trying to assess the prediction accuracy of an ordinal model fit with LRM in the Design package. I used predict.lrm to predict on an independent dataset and am now attempting to assess the accuracy of these predictions. >From what I have read, the AUC is good for this because it is threshold independent. I obtained the AUC for the fit model output from the c score (c =
2011 Mar 13
1
use of ROCR package (ROC curve / AUC value) in a specific case versus integral calculation
Hello, I would like to use the ROCR package to draw ROC curves and compute AUC values. However, in the specific context of my application, the true positive rates and false positive rates are already provided by some upstream method. Of course, I can draw a ROC plot with the following command : plot(x=FPrate, y=TPrate, "o", xlab="false positive rate", ylab="true
2006 Nov 24
1
How to find AUC in SVM (kernlab package)
Dear all, I was wondering if someone can help me. I am learning SVM for classification in my research with kernlab package. I want to know about classification performance using Area Under Curve (AUC). I know ROCR package can do this job but I found all example in ROCR package have include prediction, for example, ROCR.hiv {ROCR}. My problem is how to produce prediction in SVM and to find
2011 Jan 20
2
auc function
Hi, there. Suppose I already have sensitivities and specificities. What is the quick R-function to calculate AUC for the ROC plot? There seem to be many R functions to calculate AUC. Thanks. Yulei [[alternative HTML version deleted]]
2007 Jul 26
5
ROC curve in R
Hi, I need to build ROC curve in R, can you please provide data steps / code or guide me through it. Thanks and Regards Rithesh M Mohan [[alternative HTML version deleted]]
2009 Jul 25
4
ROCR package question
I use ROCR to plot multiple runs' performance. Using the sample code as example: # plot ROC curves for several cross-validation runs (dotted # in grey), overlaid by the vertical average curve and boxplots # showing the vertical spread around the average. data(ROCR.xval) pred <- prediction(ROCR.xval$predictions, ROCR.xval$labels) perf <- performance(pred,"tpr","fpr")
2007 Dec 13
2
Function for AUC?
Hello Is there an easy way, i.e. a function in a package, to calculate the area under the curve (AUC) for drug serum levels? Thanks for any advice -- Armin Goralczyk, M.D. -- Universit?tsmedizin G?ttingen Abteilung Allgemein- und Viszeralchirurgie Rudolf-Koch-Str. 40 39099 G?ttingen -- Dept. of General Surgery University of G?ttingen G?ttingen, Germany -- http://www.chirurgie-goettingen.de
2012 Feb 09
2
AUC, C-index and p-value of Wilcoxon
Dear all, I am using the ROCR library to compute the AUC and also the Hmisc library to compute the C-index of a predictor and a group variable. The results of AUC and C-index are similar and give a value of about 0.57. The Wilcoxon p-value is <0.001! Why the AUC is showing small value and the p-value is high significant? The AUC is based on Wilcoxon calculation? Many thanks, Lina
2009 Mar 19
1
Prediction-class ROCR
Hi, I'm involved in a bioinformatics project at my university, and we're doing a comparison paper between some methods of classification of nc-RNA. I've been encharged of ploting the ROC curves' graphs. But I'm new on working with R and I'm having some difficulty with the prediction-class. I don't get where the values of ROCR.simple$predictions, for example, came from
2011 Apr 27
2
ROCR for combination of markers
Dear list   I have 5 markers that can be used to detect an infection in combination. Could you please advise me how to use functions in ROCR/ other package to produce the ROC curve for a combination of markers?   I have used the following to get ROC statistics for each marker. pred <- prediction(y$marker1, y$infectn) perf <-performance(pred,"tpr","fpr")
2006 Mar 15
1
How to compare areas under ROC curves calculated with ROCR package
Dear all, I try to compare the performances of several parameters to diagnose lameness in dogs. I have several ROC curves from the same dataset. I plotted the ROC curves and calculated AUC with the ROCR package. I would like to compare the AUC. I used the following program I found on R-help archives : From: Bernardo Rangel Tura Date: Thu 16 Dec 2004 - 07:30:37 EST
2007 Nov 16
2
creating discretized data
Hi, Ia m working in discretized data. Here my data: x <- c(2,1,3, 5), and I want to make (0,1) data based on the length of each component in x. So the new data should like: y = (0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 1). I spent too much time with "seq", "rep". Still didn't get it. Any help? Thanks Ilham [[alternative HTML version deleted]]
2009 Feb 07
2
Question about ROCR package
Hi, I have a question about ROCR package. I got the ROC curve plotted without any problem following the manual. However, I don't know to extract the values, e.g. y.values ( I think it is the area under the curve auc measure). The return is an object of class "performance" which have Slots and one of the slot is "y.values". I type the object and I can see them in
2007 Nov 24
1
how to label multiple plots
Dear R-list, I want to combine several plots in one graph. I did this: plot(a1); plot(a2, add=TRUE); ...plot(a5, add=TRUE) The problem is the more plot we put, the more complex the graph. Is there any way to label each line; or other way just to make sure I know which one which? Thanks, Ilham [[alternative HTML version deleted]]
2013 May 27
1
Question about subsetting S4 object in ROCR
Dear list I'm testing a predictor and I produced nice performance plots with ROCR package utilizing the 3 standard command pred <- prediction(predictions, labels) perf <- performance(pred, measure = "tpr", x.measure = "fpr") plot(perf, col=rainbow(10)) The pred object and the perfo object are S4 with the following slots An object of class "performance"
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 <-