Displaying 20 results from an estimated 3000 matches similar to: "Princomp(), prcomp() and loadings()"
2008 Jan 13
1
What is the 'scale' in princomp() function?
Dear R users,
When I tried to use princomp() from stats packages to do Principal
Components Analysis, I am not very clear what is the "scale".
And the scores are different from "PROC PRINCOMP" procedure from SAS.
Using the example data from this package:
restpc <- princomp(USArrests, cor = TRUE)
> restpc$scale
Murder Assault UrbanPop Rape
4.311735 82.500075
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
2005 Sep 16
1
About princomp
Hi,
I run the example for princomp for R211
I got the following error for biplot
> ## The variances of the variables in the
> ## USArrests data vary by orders of magnitude, so scaling is appropriate
> (pc.cr <http://pc.cr> <- princomp(USArrests)) # inappropriate
Erreur dans cov.wt(z) : 'x' must contain finite values only
> princomp(USArrests, cor = TRUE) # =^=
2012 Aug 21
1
make check fails two tests on RHEL 6 build
I am installing R 2.15.1 onto RHEL 6, using gcc 4.7.0 with Intel MKL
10.3.7 and the following environment:
export BLAS_LIBS="-Wl,--start-group
/usr/caen/intel-12.1/mkl/lib/intel64/libmkl_gf_lp64.a
/usr/caen/intel-12.1/mkl/lib/intel64/libmkl_sequential.a
/usr/caen/intel-12.1/mkl/lib/intel64/libmkl_core.a -Wl,--end-group
-lpthread"
export LAPACK_LIBS="-Wl,--start-group
2008 Mar 06
0
Help with colinearity problem in multiple linear regression
Hello,
For basic linear regression lm() does the job well, for datasets that are
larger than memory biglm() seems to work.
I'm working on a parallel implementation of multiple linear regression for
datasets that are too large for memory.
Currently I am working over least squares:
calculating: t(X) %*% X and t(X) %*% y
separately in parallel on each node
This generates a
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?
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
2009 Dec 23
1
prcomp : plotting only explanatory axis arrows
Dear all,
I have a very large dataset (1712351 , 20) and would like
to plot only the arrows that represent the
contribution of each variables.
On the sample below I woild like to plot
only the explanatory variables (Murder, Assault..)
and not the sites.
prcomp(USArrests) # inappropriate
prcomp(USArrests, scale = TRUE)
prcomp(~ Murder + Assault + Rape, data = USArrests, scale = TRUE)
2000 Jul 20
1
Installing R-1.1.0 (PR#612)
Dear R-developers,
I finally got around to install R 1.1.0 but had problems at the `make
check' stage.
After compiling the released R 1.1.0 version the `make check' stage
stopped while checking the examples in base. There was some problem
with the quantile function and the check stopped complaining that NA's
are not allowed.
But I assume that this problem is already known because
2017 Aug 09
1
arithmetic with zero-column data.frames
So as often there is more to it than you first think.
Let's consider this an RFC (for experienced long time R users) :
>>>>> Martin Maechler <maechler at stat.math.ethz.ch>
>>>>> on Wed, 9 Aug 2017 10:45:56 +0200 writes:
>>>>> William Dunlap via R-devel <r-devel at r-project.org>
>>>>> on Tue, 8 Aug 2017 11:59:45
2010 Nov 25
1
RODBC
Hi,
I am running the RODBC examples form the help guide. I am trying to
UPDATE a table in an Access data base but I am having an error.
library(RODBC)
library(termstrc)
path = getwd()
setwd(getwd())
dbName = "data.mdb"
pathdbname = paste(path,"/",dbName,sep="")
accesChannel = odbcConnectAccess(pathdbname, uid = "", pwd = "")
2009 Jan 13
1
PCA loadings differ vastly!
hi, I have two questions:
#first (SPSS vs. R):
I just compared the output of different PCA routines in R (pca, prcomp,
princomp) with results from SPSS. the loadings of the variables differ
vastly! in SPSS the variables load constantly higher than in R.
I made sure that both progr. use the correlation matrix as basis. I
found the same problem with rotated values (varimax rotation and rtex=T
2003 Apr 02
1
RODBC sqlSave problem.
Dear list,
Being new to both the postgres database, ODBC and the RODBC interface, I
am somewhat confused by some of the problems I am experiencing trying to
connect R to the database.
Whai I am trying is basically the example part of the help file for the
sqlSave function:
> library(RODBC)
> odbcConnect("theodor") -> channel
> data(USArrests)
> sqlSave(channel,
2009 Apr 30
1
Creating datasets in packages
I am developing an R package which includes datasets. The build and
install works correctly. However, when I access the dataset
("BowRiver"), I get:
> data(BowRiver)
> BowRiver
Error: object "BowRiver" not found. However, I can access the dataset
from
> data
Example R datasets (such as USArrests) are loaded and can be accessed by
the dataset name:
>
2004 Nov 25
3
Searching for a string in RSQLite
I'd like to search for a particular string in an SQLite database using
RSQLite, but I'm running into problems constructing the query
properly, because of embedded quotes and parens in the string.
Is there a function that escapes these for me, or some other fixup
that would let me do the queries below? In the real situation I don't
have control over what strings get searched for.
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
2004 Feb 17
1
Comparison of % variance explained by each PC before AND after rotation
Hello again-
Thanks to Prof. Ripley for responding to my previous question.
I would like to clarify my question using sample code. I will use some
sample code taken from ?prcomp
Again, I would like to compare the % variance explained by each PC
before and after rotation.
< code follows >
data(USArrests)
pca = prcomp(USArrests, scale = TRUE)
# proportion variance explained by each
2000 Apr 26
1
Factor Rotation
How does one rotate the loadings from a principal component analysis?
Help on function prcomp() from package mva mentions rotation:
Arguments
retx a logical value indicating whether the rotated
variables should be returned.
Values
rotation the matrix of variable loadings (i.e., a matrix
whose olumns contain the eigenvectors). The
function princomp returns this in the element
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
2004 Nov 25
0
Problem with ODBC access to SQL database
I have the following problem in getting the "sqlSave" function from the
example code in the R package RODBC to work with MySQL as ODBC server:
- a new database is created, but no data is written to it
- the example code works just fine when I use MS Access as ODBC server.
----------- offending code and output -------------------
> library(RODBC);
> channel <-