b is nearly singular. Note that one of its eigenvalues is -2.935e-8
which is close to zero. We can use the generalized inverse from
MASS to get one solution, x, but any multiple of the eigenvector
corresponding to the near-zero eigenvalue when added to that
will also give a solution as shown:
> eigen(b)
$values
[1] 1.614539e+01 -2.935343e-08
$vectors
[,1] [,2]
[1,] -0.1394858 -0.9902241
[2,] -0.9902241 0.1394858
> library(MASS)
> x <- ginv(b) %*% a
> a
[1] 0.8109437 5.7569740
> # bx gives a showing x is a solution
> b %*% x
[,1]
[1,] 0.8109438
[2,] 5.7569740
> # but b(x + e) where e is 2nd eigenvector is also solution
> b %*% (x + eigen(b)$vectors[,2])
[,1]
[1,] 0.8109438
[2,] 5.7569740
On 8/28/06, Nongluck Klibbua <[EMAIL PROTECTED]> wrote:
> Dear R-users,
> I try to use "solve" to get the solution of this matrix.But it has error
> happen below.
> How I can solve this problem.
> [1] "a"
> [,1]
> [1,] 0.8109437
> [2,] 5.7569740
> [1] "b"
> [,1] [,2]
> [1,] 0.3141293 2.230037
> [2,] 2.2300367 15.831264
>
> Error in solve.default(b, a) : system is computationally singular:
> reciprocal condition number = 1.37415e-018
>
> Thanks
> Luck
>
> ______________________________________________
> R-help@stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
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