Displaying 20 results from an estimated 1000 matches similar to: "Como construir una curva ROC"
2014 Jun 23
2
Resumen de R-help-es, Vol 64, Envío 33
Hola, Marta,
Por lo que he podido ver tus datos ya tienen calculados las tasas de verdaderos y falsos positivos (TPR y FPR). También parece que los tienes ordenados por la variable FishSpeed y supongo que también por las que parecen marcas de tiempo. No necesitas ROCR porque con un simple plot te sale algo parecido a una curva. Eso sí, veo que son medidas repetidas en el tiempo para cada valor de
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(
2017 Sep 01
2
Area bajo la curva
Buenas noches.
Quisiera saber si existe una libreria o función que me calcule el área bajo
la curva de dos vectores de números. Ademas esta debe tener en cuenta si
existen datos faltantes o NaN.
Por ejemplo calcular el área bajo la curva del vector en el eje x:
x<- c(1,2,3,4,5,6,7,8,9,10)
y el vector en el eje y:
y<-c(0,2,15,30,50,NaN,NaN,10,2,1)
Muchas gracias.
--
*Wilmer
2009 Feb 25
3
Using package ROCR
I am trying to use package ROCR to analyze classification accuracy,
unfortunately there are some problems right at the beginning.
Question 1)
When I try to run demo I am getting the following error message
> library(ROCR)
> demo(ROCR)
> if(dev.cur() <= 1) .... [TRUNCATED]
Error in get(getOption("device")) : wrong first argument
When I issue the command
> dev.cur()
it
2017 Sep 01
2
Area bajo la curva
Estimado Wilmer Contreras Sepulveda
Me parece buena la sugerencia de Jorge, hay muchas formas, yo aparte de la sugerencia que le hicieron le agrego otras dos, en cualquier buscador las palabras claves son R AUC, y el artículo https://www.r-bloggers.com/calculating-auc-the-area-under-a-roc-curve/ , lógicamente aparecerán tantas alternativas que puede llegar a confundirse respecto a cuál es
2009 Sep 24
3
pipe data from plot(). was: ROCR.plot methods, cross validation averaging
All,
I'm trying again with a slightly more generic version of my first question. I can extract the
plotted values from hist(), boxplot(), and even plot.randomForest(). Observe:
# get some data
dat <- rnorm(100)
# grab histogram data
hdat <- hist(dat)
hdat #provides details of the hist output
#grab boxplot data
bdat <- boxplot(dat)
bdat #provides details of the boxplot
2012 Feb 09
2
ROCR crashes for simple recall plot
I'm trying to use ROCR to create a simple cutoff vs recall plot
(recall at p) on the example ROCR.simple dataset:
library(ROCR)
data(ROCR.simple)
pred <- prediction(ROCR.simple$predictions, ROCR.simple$labels)
perf <- performance(pred, "rec")
plot(perf)
But R crashes on me on the last line.
I'm using R 2.14.1, ROCR 1.0-4. ?Any ideas? Thanks in advance.
--
Yang Zhang
2008 May 22
1
Extracting slots from ROCR prediction objects
Hi,
I have an object from the prediction function from the ROCR package and I would like to extract one of the slots from the object, for example the cutoffs slot. However the usual techniques ($, [["name"]]) of subsetting don't work. How can I assess the lists in the slots?
Here is an example of what I am working with:
library(ROCR)
data(ROCR.simple)
pred <-
2012 Nov 22
2
ROCR package not installing
I have tried installing the package (ROCR) with this command:
Install.packages(ROCR)
And with this command on the command line
R CMD INSTALL ROCR_1.0-4.tar.gz
But both times I get exactly the same error shown below, I don't understand
what is wrong, is this an error in the package code?
Thank you
Philip
probinson@bioinform08:/tmp/RtmpO0rFbx/downloaded_packages$ R CMD
2020 Sep 30
4
Graficar una curva de tendencia potencial.
AF_E PS_E
90.838 2.206
83.139 1.751
134.272 3.710
84.043 2.076
105.184 2.788
157.249 3.783
50.280 1.027
96.973 2.355
123.582 3.398
60.417 1.236
123.501 3.315
90.128 1.566
193.783 5.167
116.036 2.994
100.289 2.216
56.943 1.106
102.272 2.692
145.579 3.810
53.105 1.202
127.212 3.061
102.838 2.383
126.352 2.723
13.661 0.190
164.352 4.870
159.945 4.160
54.382 0.884
128.253 3.598
181.208 4.767
145.118
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
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")
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
2009 Jul 23
1
ROCR - confidence interval for Sens and Spec
Dear List,
I am new to ROC analysis and the package ROCR. I want to compute the confidence intervals of sensitivity and specificity for a given cutoff value. I have used the following to calculate sensitivity and specificity:
data(ROCR.simple)
pred <- prediction(ROCR.simple$predictions, ROCR.simple$labels)
se.sp <- function (cutoff, performance) {
sens <-
2012 May 15
6
Curva dosis-respuesta
Buenos dias R-help-es,
Estoy interesado en estimar una curva dosis-respuesta para un conjunto de
datos y para ello, estoy utilizando la libreria "drm". Hasta ahi todo bien.
Me gustaria automatizar algunas cosas y el primer paso para ello es la
estimacion del modelo. Si la estimacion funciona, todo lo demas funciona;
de lo contrario, todo fallara. Tengo algunas lineas que mitigan un
2009 Mar 27
1
ROCR package finding maximum accuracy and optimal cutoff point
If we use the ROCR package to find the accuracy of a classifier
pred <- prediction(svm.pred, testset[,2])
perf.acc <- performance(pred,"acc")
Do we?find the maximum accuracy?as follows?(is there a simplier way?):
> max(perf.acc at x.values[[1]])
Then to find the cutoff point that maximizes the accuracy?do we do the
following?(is there a simpler way):
> cutoff.list <-
2012 Jun 08
1
Problems when install ROCR
I meet lots of problem when installing the package ROCR, do you have meet such problems?
1, biocLite("ROCR")
2, biocLite("gplots")
3, biocLite("Rgraphviz")
4, sudo apt-get install graphviz
oh, no, unlimited question, what's wrong with R in ROCR or gplots or et al
Error : object ‘nobs’ is not exported by 'namespace:gdata'
installation of package
2010 Aug 17
1
ROCR predictions
Hi everybody,
I am having a problem building a ROC curve with my data using the ROCR
package.
I have 10 lists of proteins such as attached (proteinlist.xls). each of the
lists was calculated with a different p-value.
The goal is to find the optimal p-value for the highest number of true
positives as well as lowaest number of false positives.
As far as I understood the explanations from the
2014 Jun 27
2
error:max not meaningful for factors
Hola a todos,
Estoy intentando utilizar este script para hacer un plot con valores x
,y,z; representando los valores TP(y) y FP(x) y en funcion de la velocidad
que seria el factor alpha.
Y me da este en el ultimo punto de hacer el plot, alguien sabe que
significa?
library(ROCR)
data(ROCR.simple)
pred <- prediction( ROCR.simple$predictions, ROCR.simple$labels )
perf <- performance( pred,
2013 Nov 18
1
Ajuste curva
Hola,
quiero ajustar una curva sinoidal de la forma "f(x)=k/( 1+(c/log(x))^n)"
mediante la función 'nls' pero me da error el siguiente código:
>datos<-read.table(file="datos.csv", header=TRUE,sep=";",dec=",")
>library(nls)
>fit <- nls(y ~ k/(1+(c/log(x))^n), datos, start = list (k=100 , c
=5*10^(-6), n=1))
Error en