Displaying 20 results from an estimated 2000 matches similar to: "eof and svd calculus with NA's"
2002 Jun 26
1
aic calculus for glm models
I am trying to know exactly the formulas used to calculate aic for glm
models. In glm.fit, the calculus of aic is:
aic.model <- aic(y, n,mu, weights, dev) + 2 * fit$rank
where 2 * fit$rank is (may be am i wrong?) twice the numbers of
parameters p and aic(y, n, mu, weights, dev)
refers to the function defined in the family function (which is for
Gamma family, for instance)
aic
2003 Feb 06
6
Confused by SVD and Eigenvector Decomposition in PCA
Hey, All
In principal component analysis (PCA), we want to know how many percentage
the first principal component explain the total variances among the data.
Assume the data matrix X is zero-meaned, and
I used the following procedures:
C = covriance(X) %% calculate the covariance matrix;
[EVector,EValues]=eig(C) %%
L = diag(EValues) %%L is a column vector with eigenvalues as the elements
percent
2002 Nov 05
2
eigenvectors order
Hi,
How the eigenvectors output by the eigen() function are ordered. The
first column corresponds to the largest eigenvalue? or is the last
column as in Octave?
I'm performing a spatial-temporal analysis of some climatic variables
so my matrices are MxN (locations*time)and I'm looking for the leading
EOF's. As I have understand the eigenvectors columns represent those
EOF's
2010 Jul 27
2
Introductory statistics and introduction to R
Hi,
I have a bright, diligent second-year graduate student who wants to
learn statistics and R and will, in effect, be taking a tutorial from me
on these subjects. (If you've seen some of my questions on this list,
please don't laugh.) As an undergrad he majored in philosophy, so this
will be his first foray into computer programming and statistics.
I'm thinking of having him use
2003 Jun 17
1
books
Dear All,
using R is noticed that I would benefit by going back to the books and
"refresh" my linear algebra and calculus.
Has anybody suggestions on which books are better as reference on the two
these two topics?
I was thinking to get Lang's "A First Course in Calculus", but I I have no
idea what could be a good one for linear algebra. Something detailed and
clear
2009 Feb 05
3
The Origins of R AND CALCULUS
An amusing afterthought : What is a rival software (ahem!) was planting
this, hoping for a divide between S and R communities.or at the very minimum
hoping for some amusement. an assumption or even a pretense of stealing
credit is one of the easiest ways of sparking intellectual discord
Most users of softwares don't really care about who gets credit ( Who wrote
Windows Vista ,or Mac OS or
2006 Sep 09
2
duplication matrix
Dear R-list members,
Just wondering if there is any way to compute the duplication matrix in R.
I tried to search for it but only found functions "xpnd" and "vech".
Basically for a symmetric n by n matrix A, the duplication matrix D_n is
a matrix of dimension n^2 by n(n+1)/2 such that
D_n vech(A)= c(A), where c(A) just vectorizes A.
The duplication matrix is defined on page
2006 Apr 04
1
imaging and contouring
Dear R'Helpers and Colleagues,
I have looked in the documentation, asked to some colleagues in the
lab, but was unable to solve the following difficulty.
I am running R on a iMac G5 with OS 10.4.
The file below (73 rows x 144 col) shows the values of a climatic
index on the globe with a grid of 2,5 ? x 2,5 ? (NA = no value):
?
With image() and map() and running the following
2009 Mar 31
0
[LLVMdev] adjust address calculus for an architecture that does not address bytes
Christian Sayer wrote:
> Hi,
> my target architecture has a kind of "16bit addressing mode", i.e. one address does not address 8 bit but a 16bit chunk. Consequently, every constant used to calculate effective addresses must be divided by two.
> So far this is not such a problem for stack objects since FrameIndexes, function arguments etc. have a lot of custom lowering code where
2009 Apr 01
2
[LLVMdev] adjust address calculus for an architecture that does not address bytes
> > At first I thought this could be handled when lowering
> loads and stores, but I realize that I can only catch the
> targeted addresses of loads/stores here - however address
> calculation nodes may occur anywhere in a DAG.
> >
> > So my first impulse would be to adjust the constants when
> the GEP instructions are transformed to ADDs. Afaics his
> would mean
2005 May 18
1
fast matrix update
Hello,
I use extensively m[i0:i1,j0:j1] = ... to update matrices parts.
This writing is very convenient, but, since I'm doing this
calculus many many times, I would like to know if there is a way
(a hope ?) to do the same operation faster ?
Thanks for any advice or pointer.
Vincent
2004 Dec 18
1
erro in SVM (packsge "e1071")
Hello,
I am using SVM under e1071 package for nu-regression with 18 parameters. The
variables are ordered factors, factors, date or numeric datatypes. I use the
linear kernel.
It gives the following error that I cannot solve. I tryed debug, browser and
all that stuff, but no way.
The error is:
Error in get(ctr, mode = "function", envir = parent.frame())(levels(x), :
2005 May 19
1
Log-likelihood calculation in lme
On a real data set, running the lme function, I get
parameters estimation and a log-likelihood value.
Nevertheless, the variance-covariance matrix in this
case had a determinant close to zero. So, I could not
calculate the log-likelihood myself with the classical
expression.
What is the calculus made in lme?
Thanks for all suggestions.
Tessa P-J
(student)
2007 Jan 11
1
maximum likelihood, 1st and 2nd derivative
Hi guys again, it seems I haven't been doing the maximum likelihood
estimation correctly. I quote below, can someone explain to me please what
does it mean that the 2nd and 3rd derivatives of the function equals zero
and how to compute that in R.
"We have our initial estimated, subjective parameters for the gamma mixture
and we have our likelihood that is the mixture of negative
2009 Mar 31
2
[LLVMdev] adjust address calculus for an architecture that does not address bytes
Hi,
my target architecture has a kind of "16bit addressing mode", i.e. one address does not address 8 bit but a 16bit chunk. Consequently, every constant used to calculate effective addresses must be divided by two.
So far this is not such a problem for stack objects since FrameIndexes, function arguments etc. have a lot of custom lowering code where this can be done.
But when it comes
2005 Jul 08
1
explained deviance in multinom
Hi:
I'm working with multinomial models with library nnet, and I'm trying to get the explained deviance (pseudo R^2) of my models.
I am assuming that:
pseudo R^2= 1 - dev(model) / dev (null)
where dev(model) is the deviance for the fitted model and dev(null) is the deviance for the null model (with the intercept only).
library(nnet)
full.model<- multinom(cbind(factor1,
2020 Mar 16
3
GSOC Projects
Hey, I am Swapnil Raj I am student in Trinity College Dublin and I am interested
in working on LLVM. I am really interested in two projects listed, the first
one is the extending the clang AST with template information and the second is
finding smart null pointer dereferences. I am passionate about compilers and
interpreters, I have written a few small language based on lambda calculus. I am
2002 Oct 29
0
patch to mva:prcomp to use La.svd instead of svd (PR#2227)
Per the discussion about the problems with prcomp() when n << p, which
boils down to a problem with svd() when n << p,
here is a patch to prcomp() which substitutes La.svd() instead of svd().
-Greg
(This is really a feature enhancement, but submitted to R-bugs to make sure
it doesn't get lost. )
*** R-1.6.0/src/library/mva/R/prcomp.R Mon Aug 13 17:41:50 2001
---
2002 Apr 01
3
svd, La.svd (PR#1427)
(I tried to send this earlier, but it doesnt seem to have come through,
due to
problems on my system)
Hola:
Both cannot be correct:
> m <- matrix(1:4, 2)
> svd(m)
$d
[1] 5.4649857 0.3659662
$u
[,1] [,2]
[1,] -0.5760484 -0.8174156
[2,] -0.8174156 0.5760484
$v
[,1] [,2]
[1,] -0.4045536 0.9145143
[2,] -0.9145143 -0.4045536
> La.svd(m)
$d
[1]
2002 Feb 08
3
need help from fs guru
Hello
I just brought my machine back up from a very nasty crash. Not sure what
caused it yet but whatever happeed cause the journal to be foobared.
fsck dropped the journal and then proceeded to check the fs. I have a
directory called websites which fsck unlinked. however when i look in
debugfs i see this..
622669 40755 0 0 4096 13-Jan-2002 22:39 home3
2133571369 --- error ---