Displaying 20 results from an estimated 3000 matches similar to: "PCA on high dimentional data"
2008 Jan 18
2
plotting other axes for PCA
Hi R-community,
I am doing a PCA and I need plots for different combinations of axes (e.g.,
PC1 vs PC3, and PC2 vs PC3) with the arrows indicating the loadings of each
variables. What I need is exactly what I get using biplot (pca.object) but
for other axes.
I have plotted PC2 and 3 using the scores of the cases, but I don't get the
arrows proportional to the loadings of each variables on
2010 Apr 02
2
Biplot for PCA using labdsv package
Hi everyone,
I am doing PCA with labdsv package. I was trying to create a biplot graphs
in order to observe arrows related to my variables. However when I run the
script for this graph, the console just keep saying:
*Error in nrow(y) : element 1 is empty;
the part of the args list of 'dim' being evaluated was:
(x)*
could please someone tell me what this means? what i am doing
2007 Jun 27
1
Condensed PCA Results
Hello all,
I'm currently using R to do PCA Analysis, and was wondering if anyone knew the
specific R Code that could limit the output of the PCA Analysis so that you
only get the Principal Component features as your output and none of the
extraneous words or numbers that you don't want.
If that was unclear, let me use linear regression as an example:
"lm(y~x)" is the normal
2008 Sep 15
1
how to plot PC2 vs PC 3 in PCA
Hi everybody,
I am doing principal component analysis (PCA) using "prcomp' function. When i did "Biplot", i did not found interesting result and it is based on Principal component (PC) 1 vs PC2. Now, i want to see"Biplot" in combination of either PC1 vs PC3 or PC2 vs PC 3. I did not get the ideas.
Does any one have ideas ?
I am optimistic on getting some idea.
2007 Jun 05
2
biplot package
Dears,
I've been learning biplot (Gabriel, 1971) and I found the function 'biplot', inside of the package 'stats',
useful but, a bit limited.
So, I'm thinking to start a colaborative package to enhance this methods to other multivariate methods. In this
way, I would like to start it, making public a new function (biplot.pca, still in development, but running)
that make
2008 Jun 11
3
Finding Coordinate of Max/Min Value in a Data Frame
Hi,
Suppose I have the following data frame.
__BEGIN__
> library(MASS)
> data(crabs)
> crab.pca <- prcomp(crabs[,4:8],retx=TRUE)
> crab.pca$rotation
PC1 PC2 PC3 PC4 PC5
FL 0.2889810 0.3232500 -0.5071698 0.7342907 0.1248816
RW 0.1972824 0.8647159 0.4141356 -0.1483092 -0.1408623
CL 0.5993986 -0.1982263 -0.1753299 -0.1435941 -0.7416656
CW
2009 Nov 09
4
prcomp - principal components in R
Hello, not understanding the output of prcomp, I reduce the number of
components and the output continues to show cumulative 100% of the
variance explained, which can't be the case dropping from 8 components
to 3.
How do i get the output in terms of the cumulative % of the total
variance, so when i go from total solution of 8 (8 variables in the data
set), to a reduced number of
How to use PC1 of PCA and dim1 of MCA as a predictor in logistic regression model for data reduction
2011 Aug 17
4
How to use PC1 of PCA and dim1 of MCA as a predictor in logistic regression model for data reduction
Hi all,
I'm trying to do model reduction for logistic regression. I have 13
predictor (4 continuous variables and 9 binary variables). Using subject
matter knowledge, I selected 4 important variables. Regarding the rest 9
variables, I tried to perform data reduction by principal component
analysis (PCA). However, 8 of 9 variables were binary and only one
continuous. I transformed the data by
2007 Jan 30
2
R and S-Plus got the different results of principal component analysis from SAS, why?
Dear Rusers,
I have met a difficult problem on explaining the differences of principal
component analysis(PCA) between R,S-PLUS and SAS/STATA/SPSS, which wasn't
met before.
Althought they have got the same eigenvalues, their coeffiecients were
different.
First, I list my results from R,S-PLUS and SAS/STATA/SPSS, and then show
the original dataset, hoping sb. to try and explain it.
2007 Jul 02
2
Question about PCA with prcomp
Hello All,
The basic premise of what I want to do is the following:
I have 20 "entities" for which I have ~500 measurements each. So, I
have a matrix of 20 rows by ~500 columns.
The 20 entities fall into two classes: "good" and "bad."
I eventually would like to derive a model that would then be able to
classify new entities as being in "good
2017 Sep 15
3
Regarding Principal Component Analysis result Interpretation
Dear Sir/Madam,
I am trying to do PCA analysis with "iris" dataset and trying to interpret
the result. Dataset contains 150 obs of 5 variables
Sepal.Length Sepal.Width Petal.Length Petal.Width Species
1 5.1 3.5 1.4
0.2 setosa
2 4.9 3.0 1.4
0.2 setosa
2005 May 29
2
"text"-function: adding text in an x,y-plot
Hello R-friends,
i have a question to the "text"-function.
a little test-dataset for better understanding:
-the dataset was imported with read.table(....,header=TRUE)
s1-s10 are the samplenames
var1 var2 var3
s1 1 1 2
s2 2 3 1
s3 2 2 3
s4 5 4 3
s5 4 2 3
s6 6 3 2
s7 8 5 4
s8 7 2 1
s9 9 3 2
2011 Sep 09
2
prcomp: results with reversed sign in output?
Dear All,
when I'm running a PCA with
prcomp(USArrests, scale = TRUE)
I get the right principal components, but with the wrong sign infront
Rotation:
PC1 PC2 PC3 PC4
Murder 0.5358995 -0.4181809 0.3412327 0.64922780
Assault 0.5831836 -0.1879856 0.2681484 -0.74340748
UrbanPop 0.2781909 0.8728062 0.3780158 0.13387773
Rape 0.5434321 0.1673186 -0.8177779 0.08902432
instead of
PC1 PC2 PC3 PC4
2007 Nov 19
1
print matrix content on plot
Hi,
I saved as a matrix a summary of a PCA analysis and I've used barplot to plot the PCA variances. I would like to print on the same graphic the values of my matrix m1 - in other words the summary of my PCA analysis. I can do it very painstaking with text for each row and make sure that everything aligns and so on but i wonder if there is a better method than that.
My summary follows:
2017 Sep 15
0
Regarding Principal Component Analysis result Interpretation
First, see the example at https://isezen.github.io/PCA/
> On 15 Sep 2017, at 13:43, Shylashree U.R <shylashivashree at gmail.com> wrote:
>
> Dear Sir/Madam,
>
> I am trying to do PCA analysis with "iris" dataset and trying to interpret
> the result. Dataset contains 150 obs of 5 variables
>
> Sepal.Length Sepal.Width Petal.Length Petal.Width
2009 Mar 10
1
Using napredict in prcomp
Hello all,
I wish to compute site scores using PCA (prcomp) on a matrix with
missing values, for example:
Drain Slope OrgL
a 4 1 NA
b 2.5 39 6
c 6 8 45
d 3 9 12
e 3 16 4
...
Where a,b... are sites.
The command
> pca<-prcomp(~ Drain + Slope + OrgL, data = t, center = TRUE, scale =
TRUE, na.action=na.exclude)
works great, and from
2009 Nov 07
1
after PCA, the pc values are so large, wrong?
rm(list=ls())
yx.df<-read.csv("c:/MK-2-72.csv",sep=',',header=T,dec='.')
dim(yx.df)
#get X matrix
y<-yx.df[,1]
x<-yx.df[,2:643]
#conver to matrix
mat<-as.matrix(x)
#get row number
rownum<-nrow(mat)
#remove the constant parameters
mat1<-mat[,apply(mat,2,function(.col)!(all(.col[1]==.col[2:rownum])))]
dim(yx.df)
dim(mat1)
#remove columns with numbers of
2016 Apr 18
1
project test data into principal components of training dataset
Hi there,
I've a training dataset and a test dataset. My aim is to visually
allocate the test data within the calibrated space reassembled by the
PC's of the training data set, furthermore to keep the training data set
coordinates fixed, so they can serve as ruler for measurement for
additional test datasets coming up.
Please find a minimum working example using the wine dataset below.
2009 Mar 31
3
Factor Analysis Output from R and SAS
Dear Users,
I ran factor analysis using R and SAS. However, I had different outputs from
R and SAS.
Why they provide different outputs? Especially, the factor loadings are
different.
I did real dataset(n=264), however, I had an extremely different from R and
SAS.
Why this things happened? Which software is correct on?
Thanks in advance,
- TY
#R code with example data
# A little
2016 Mar 25
2
summary( prcomp(*, tol = .) ) -- and 'rank.'
> On 25 Mar 2016, at 10:41 am, peter dalgaard <pdalgd at gmail.com> wrote:
>
> As I see it, the display showing the first p << n PCs adding up to 100% of the variance is plainly wrong.
>
> I suspect it comes about via a mental short-circuit: If we try to control p using a tolerance, then that amounts to saying that the remaining PCs are effectively zero-variance, but