search for: solves

Displaying 20 results from an estimated 43553 matches for "solves".

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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 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-help mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the
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 &gt...
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