Displaying 6 results from an estimated 6 matches for "ainv".
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2005 Oct 05
2
eliminate t() and %*% using crossprod() and solve(A,b)
Hi
I have a square matrix Ainv of size N-by-N where N ~ 1000
I have a rectangular matrix H of size N by n where n ~ 4.
I have a vector d of length N.
I need X = solve(t(H) %*% Ainv %*% H) %*% t(H) %*% Ainv %*% d
and
H %*% X.
It is possible to rewrite X in the recommended crossprod way:
X <- solve(quad.form(Ainv, H),...
2003 Mar 26
1
Solving equations
Hello,
Does somebody knows if there exists a function which solves a set of
equation, say f(vars),
for the variables vars (similar to Solve in mathematica).
The functions I am considering are of the form f(t) ~ A*exp(B*t), where
A and B are matrices.
Thanks Thomas
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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(in the
2015 Mar 25
4
F77_CALL/NAME problem
...GESV subroutine into C. Here it is the relevant
part of the C file I am currently writing
#include<stdio.h>
#include<R.h>
#include<Rmath.h>
#include<math.h>
void F77_NAME(DGESV)( int*, int*, double*, int*, int*, double*, int*, int*);
void solve( int *p, double *A, double *Ainv)
{
...
F77_CALL(DGESV)(p, p, Ain, p, ipiv, Bin, p, &info);
}
In order to create the ".so" file to load in R I downloaded the dgesv.f file
as well as the dependencies (dgetf2.f dgetrf.f dgetrs.f dlaswp.f). As I was
used to I ran in a terminal
R CMD COMPILE *.f
R CMD SHLIB MY...
2004 Apr 01
1
Use R function in C code
I want to use R function Matrix inverse in my c code, please tell me how I can.
If there is a sample which can tell me how it works. It will be fantastic.
2000 May 01
1
solve vs. qr.solve
> Date: Mon, 1 May 2000 16:25:11 +0200 (CEST)
> From: gb <gb at stat.umu.se>
>
> On 1 May 2000, Douglas Bates wrote:
> > gb <gb at stat.umu.se> writes:
> >
> > > How about 'Ainv <- qr.solve(A)'?
> > >
> > > I happened to read the help page for 'qr.solve' the other day, and there I
> > > found that qr.solve(A, b) "is == but much better than solve(A) %*% b".
> > > (I guess that 'better than' refers to nume...