Displaying 20 results from an estimated 43553 matches for "solves".
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solve
2000 Apr 28
3
Matrix inverse
I haven't found a function that directly calculates the matrix inverse, does it exist? Otherwise what would be the fastest way to do it?
Patrik Waldmann
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2000 May 01
1
solve vs. qr.solve
...underlying C code to find out
> what "solve.default" is, and when which method is used. I have
> looked around in R-1.0.1/src/* with no great success. Can I
> get a hint where to search?
Try listing the functions: they are identical. solve.qr takes the
QR decomposition of A, solves Ax=b as QAx = Rx = Qb (or possibly Q' here).
--
Brian D. Ripley, ripley at stats.ox.ac.uk
Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/
University of Oxford, Tel: +44 1865 272861 (self)
1 South Parks Road, +44 1865 27286...
2010 Jun 12
1
sharing experience - installing R Spatial Views
Hi Guys,
I would like to share my experience when installing the Spatial views
packages for R. I could not install 32 packages which are parts of the
Spatial views, and I use google-search and search to solve ALL those
problems for about 2 days. I hope maybe somebody would benefit from my
experience.
I admitted that I do not have excellent programming skills at all. So,
perhaps some of
2009 Oct 14
1
using mapply to avoid loops
Hello, I would like to use mapply to avoid using a loop but for some reason, I can't seem to get it to work. I've included copies of my code below. The first set of code uses a loop (and it works fine), and the second set of code attempts to use mapply but I get a "subscript out of bounds" error. Any guidance would be greatly appreciated. Xj, Yj, and Wj are also lists, and s2,
2003 Oct 30
3
Change in 'solve' for r-patched
The solve function in r-patched has been changed so that it applies a
tolerance when using Lapack routines to calculate the inverse of a
matrix or to solve a system of linear equations. A tolerance has
always been used with the Linpack routines but not with the Lapack
routines in versions 1.7.x and 1.8.0. (You can use the optional
argument tol = 0 to override this check for computational
2010 Sep 01
2
What solve() does?
Hello!
Can anyone explain me what solve() function does: Gaussian elimination
or iterative, numeric solve? In addition, I would need both the Gaussian
elimination and iterative solution for the course. Are the two built in R?
Thanks!
PM
2016 Apr 20
6
Solving sparse, singular systems of equations
I have a situation in R where I would like to find any x (if one exists) that solves the linear system of equations Ax = b, where A is square, sparse, and singular, and b is a vector. Here is some code that mimics my issue with a relatively simple A and b, along with three other methods of solving this system that I found online, two of which give me an error and one of which succe...
2012 Dec 11
2
Catching errors from solve() with near-singular matrices
Dear all,
The background is that I'm trying to fix this bug in the geometry
package:
https://r-forge.r-project.org/tracker/index.php?func=detail&aid=1993&group_id=1149&atid=4552
Boiled down, the problem is that there exists at least one matrix X for
which det(X) != 0 and for which solve(X) fails giving the error "system
is computationally singular: reciprocal condition
2007 Dec 22
1
using solve.qp without a quadratic term
I was playing around with a simple example using solve.qp ( function is in the quadprog package ) and the code is below. ( I'm not even sure there if there is a reasonable solution because I made the problem up ).
But, when I try to use solve.QP to solve it, I get the error that D in the quadratic function is not positive
definite. This is because Dmat is zero
because I don't have a
2009 Jun 17
1
Inverting a square matrix using solve() with LAPACK=TRUE (PR#13762)
Full_Name: Ravi Varadhan
Version: 2.8.1
OS: Windows
Submission from: (NULL) (162.129.251.19)
Inverting a matrix with solve(), but using LAPACK=TRUE, gives erroneous
results:
Here is an example:
hilbert <- function(n) { i <- 1:n; 1 / outer(i - 1, i, "+") }
h5 <- hilbert(5)
hinv1 <- solve(qr(h5))
hinv2 <- solve(qr(h5, LAPACK=TRUE))
all.equal(hinv1, hinv2) #
2009 May 15
1
Matrix package,solve() errors and crashes Please help
>
> Hello All,
>
Please help me with this problem.I have been having this problem for over a
month now and I could not find any information.I later realised that error
is with MATRIX package.
I am working on graph object using IGRAPH version 0.5.2-2 package & wanted
to do Bonacich Power.
What I have is undirected GRAPH.
This is my graph object.
The file 'Bonacich
2010 Jan 05
4
solving cubic/quartic equations non-iteratively
To R-helpers,
R offers the polyroot function for solving mentioned equations
iteratively.
However, Dr Math and Mathworld (and other places) show in detail how to
solve mentioned equations non-iteratively.
Do implementations for R that are non-iterative and that solve mentioned
equations exists?
Regards, Mads Jeppe
2016 Apr 20
0
Solving sparse, singular systems of equations
...u really want to proceed. See also ?svd and package irlba.
--
Sent from my phone. Please excuse my brevity.
On April 20, 2016 4:22:34 AM PDT, A A via R-help <r-help at r-project.org> wrote:
>
>
>
>I have a situation in R where I would like to find any x (if one
>exists) that solves the linear system of equations Ax = b, where A is
>square, sparse, and singular, and b is a vector. Here is some code that
>mimics my issue with a relatively simple A and b, along with three
>other methods of solving this system that I found online, two of which
>give me an error and on...
2016 Apr 20
0
Solving sparse, singular systems of equations
> On 20 Apr 2016, at 13:22, A A via R-help <r-help at r-project.org> wrote:
>
>
>
>
> I have a situation in R where I would like to find any x (if one exists) that solves the linear system of equations Ax = b, where A is square, sparse, and singular, and b is a vector. Here is some code that mimics my issue with a relatively simple A and b, along with three other methods of solving this system that I found online, two of which give me an error and one of which succe...
2016 Apr 20
0
Solving sparse, singular systems of equations
...matrix into a dense one before doing
any linear algebra).
Bill Dunlap
TIBCO Software
wdunlap tibco.com
On Wed, Apr 20, 2016 at 4:22 AM, A A via R-help <r-help at r-project.org>
wrote:
>
>
>
> I have a situation in R where I would like to find any x (if one exists)
> that solves the linear system of equations Ax = b, where A is square,
> sparse, and singular, and b is a vector. Here is some code that mimics my
> issue with a relatively simple A and b, along with three other methods of
> solving this system that I found online, two of which give me an error and
>...
2004 Feb 16
4
Matrix mulitplication
ABCD are four matrix.
A * Inverse((Transpose(A)*Tranpose(B)*B*A+C)) * Transpose(A) * Transpose(B) * D
how to write in R in an efficient way?
---------------------------------
[[alternative HTML version deleted]]
2003 Aug 07
3
ginv vs. solve
Why do
x<-b%*%ginv(A)
and
x<-solve(A,b)
give different results?. It seems that I am missing some basic feature of
matrix indexing.
e.g.:
A<-matrix(c(0,-4,4,0),nrow=2,ncol=2)
b<-c(-16,0)
x<-b%*%ginv(A);x
x<-solve(A,b);x
Thanks in advance,
Angel
2002 Sep 26
3
error with complex solve (PR#2068)
Full_Name: John Peters
Version: 1.5.1
OS: Windows 2000
Submission from: (NULL) (130.155.2.3)
solve(a,b) with two arguments gives an error if a is complex and b is a vector:
> a_matrix(c(1,2+3i,3,2),ncol=2)
> a
[,1] [,2]
[1,] 1+0i 3+0i
[2,] 2+3i 2+0i
> b_c(2,2+1i)
> solve(a,b)
Error in solve.default(a, b) : A must be a complex matrix
> is.complex(a)
[1] TRUE
>
2005 Feb 02
0
Not reproducing GLS estimates
Dear List:
I am having some trouble reproducing some GLS estimates using matrix
operations that I am not having with other R procedures. Here are some
sample data to see what I am doing along with all code:
mu<-c(100,150,200,250)
Sigma<-matrix(c(400,80,16,3.2,80,400,80,16,16,80,400,80,3.2,16,80,400),n
c=4)
sample.size<-100
temp <-
2007 Nov 26
3
Fwd: Empty list to use in a for cycle
? stato filtrato un testo allegato il cui set di caratteri non era
indicato...
Nome: non disponibile
Url: https://stat.ethz.ch/pipermail/r-help/attachments/20071126/35b0349a/attachment.pl