Displaying 20 results from an estimated 7000 matches similar to: "PCA functions"
2007 May 25
2
R-About PLSR
hi R help group,
I have installed PLS package in R and use it for princomp & prcomp
commands for calculating PCA using its example file(USArrests example).
But How I can use PLS for Partial least square, R square, mvrCv one more
think how i can import external file in R. When I use plsr, R2, RMSEP it
show error could not find function plsr, RMSEP etc.
How I can calculate PLS, R2, RMSEP, PCR,
2005 Jul 08
2
extract prop. of. var in pca
Dear R-helpers,
Using the package Lattice, I performed a PCA.
For example
pca.summary <- summary(pc.cr <- princomp(USArrests, cor = TRUE))
The Output of "pca.summary" looks as follows:
Importance of components:
Comp.1 Comp.2 Comp.3 Comp.4
Standard deviation 1.5748783 0.9948694 0.5971291 0.41644938
Proportion of Variance 0.6200604
2003 Oct 16
1
princomp with more coloumns than rows: why not?
As of R 1.7.0, princomp no longer accept matrices with more coloumns
than rows. I'm curious: Why was this decision made?
I work a lot with data where more coloumns than rows is more of a rule
than an exception (for instance spectroscopic data). To me, princomp
have two advantages above prcomp: 1) It has a predict method, and 2)
it has a biplot method.
A biplot method shouldn't be too
2005 Apr 25
2
Pca loading plot lables
Dear colleagues,
I a m a beginner with R and I would like to add labels (i.e. the variable names) on a pca loading plot to determine the most relevant variables. Could you please tell me the way to do this kind of stuff.
The command I use to draw the pca loading plot is the following :
Plot(molprop.pc$loading[,1] ~ molprop.pc$loading[,2])
Thanks for your help
Fred Ooms
2010 Jun 30
3
Factor Loadings in Vegan's PCA
Hi all,
I am using the vegan package to run a prcincipal components analysis
on forest structural variables (tree density, basal area, average
height, regeneration density) in R.
However, I could not find out how to extract factor loadings
(correlations of each variable with each pca axis), as is straightforwar
in princomp.
Do anyone know how to do that?
Moreover, do anyone knows
2011 Jun 30
2
sdev value returned by princomp function (used for PCA)
Dear all,
I have a question about the 'sdev' value returned by the princomp function (which does principal components analysis).
On the help page for princomp it says 'sdev' is 'the standard deviations of the principal components'.
However, when I calculate the principal components for the USArrests data set, I don't find this to be the case:
Here is how I
2005 May 23
1
Can't reproduce clusplot princomp results.
Dear R folk:
Perhaps I'm just dense today, but I am having trouble reproducing the
principal components plotted and summarized by clusplot. Here is a brief
example using the pluton dataset. clusplot reports that the first two
principal components explain 99.7% of the variability. But this is not what
princomp is reporting. I would greatly appreciate any advice.
With best regards,
-- Tom
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
2015 Aug 24
3
Build optimized R : openblas, MKL, ATLAS
On Mon, Aug 24, 2015 at 11:29 AM, Bj?rn-Helge Mevik
<b.h.mevik at usit.uio.no> wrote:
> arnaud gaboury <arnaud.gaboury at gmail.com> writes:
>
>> - Intel MKL: this is part of Intel Parallel Studio and is a paid
>> software. Now, there is the MKL package distributed by
>> Revolutionanalytics, but I am not certain how this can be distributed
>> for free. Is
2004 Mar 01
1
pca scores for newdata
Hi
I used princomp on a dataset x[!sub,]. How can I get the scores for
another dataset, say x[sub,]? I didn't succeed using predict()
thanks for a hint
cheers
christoph
--
Christoph Lehmann <christoph.lehmann at gmx.ch>
2012 Oct 19
1
factor score from PCA
Hi everyone,
I am trying to get the factor score for each individual case from a principal component analysis, as I understand, both princomp() and prcomp() can not produce this factor score, the principal() in psych package has this option: scores=T, but after running the code, I could not figure out how to show the factor score results. Here is my code, could anyone give me some advice please?
2015 Aug 22
2
Build optimized R : openblas, MKL, ATLAS
I want to build R optimized, with either MKL, OpenBLAS or ATLAS.
My OS: Fedora 22
Hardware: CPU op-mode(s): 32-bit, 64-bit Byte Order: Little Endian
CPU(s): 8 Thread(s) per core: 2 Vendor ID: GenuineIntel Model name:
Intel(R) Core(TM) i7-2600K CPU @ 3.40GHz
I am a little confused when it comes to choose a method and would like
to hear your experiences. If I am right, I have 3 possibilities:
-
2004 Nov 03
2
Princomp(), prcomp() and loadings()
In comparing the results of princomp and prcomp I find:
1. The reported standard deviations are similar but about 1% from
each other, which seems well above round-off error.
2. princomp returns what I understand are variances and cumulative
variances accounted for by each principal component which are
all equal. "SS loadings" is always 1.
3. Same happens
2009 Jan 14
6
Removing duplicates from a list
For a list say;
list1<-{1,2,3,4,5,2,1}
How do I remove the duplicates please?
My real list is 20,000 obs long of dates with many duplicates
Regards
Glenn
[[alternative HTML version deleted]]
2009 Nov 25
1
which to trust...princomp() or prcomp() or neither?
According to R help:
princomp() uses eigenvalues of covariance data.
prcomp() uses the SVD method.
yet when I run the (eg., USArrests) data example and compare with my own
"hand-written" versions of PCA I get what looks like the opposite.
Example:
comparing the variances I see:
Using prcomp(USArrests)
-------------------------------------
Standard deviations:
[1] 83.732400 14.212402
2012 Apr 20
1
Quick question about princomp/biplot
Hi everyone.
I performing a simple PCA using the princomp function. Then, I use the
biplot function to show it. However, the function use line number to
represent samples. I would like to know if there's a way to use a dot
(point) instead of the line number when using the biplot function.
With regards,
Phil
--
View this message in context:
2009 Jan 19
3
Month tick marks on a plot()
Hi All,
I have a small dataframe [dates, values) I am plotting with
plot(df,type=²l²)
And the date date covers a year. The graph only have marks at Œ2008¹ and
Œ2009¹.
How do I get the months labeled at the bottom please
Thanks as always
Glenn
[[alternative HTML version deleted]]
2008 Nov 03
1
Input correlation matrix directly to princomp, prcomp
Hello fellow Rers,
I have a no-doubt simple question which is turning into a headache so
would be grateful for any help.
I want to do a principal components analysis directly on a correlation
matrix object rather than inputting the raw data (and specifying cor =
TRUE or the like). The reason behind this is I need to use polychoric
correlation coefficients calculated with John Fox's
2008 Sep 09
4
PCA and % variance explained
After doing a PCA using princomp, how do you view how much each component
contributes to variance in the dataset. I'm still quite new to the theory of
PCA - I have a little idea about eigenvectors and eigenvalues (these
determine the variance explained?). Are the eigenvalues related to loadings
in R?
Thanks,
Paul
--
View this message in context:
2008 Jul 03
2
PCA on image data
Dear R users,
i would like to apply a PCA on image data for data reduction.
The image data is available as three matrices for the
RGB values. At the moment i use
x <- data.frame(R,G,B)#convert image data to data frame
pca<-princomp(x,retx = TRUE)
This is working so far.
>From this results then i want to create a new matrix
from the first (second..) principal component. Here i stuck.