[R] Error in the inverse of a diagonal matrix?
Manuel Castejon Limas
manuel.castejon at dim.unirioja.es
Mon Feb 14 10:18:29 CET 2000
I´m new to R so maybe this issue has been asked before and I still could not read the complete set of past messages sent to the list.
I found a weird behabiour that I will explain with a simple example. Lets consider the following block of commands:
> x <- diag(c(1,4,10))
> x
[,1] [,2] [,3]
[1,] 1 0 0
[2,] 0 4 0
[3,] 0 0 10
> invx <- x^-1
> invx
[,1] [,2] [,3]
[1,] 1 Inf Inf
[2,] Inf 0.25 Inf
[3,] Inf Inf 0.1
I would really appreciate if the result would have been
[,1] [,2] [,3]
[1,] 1 0 0
[2,] 0 0.25 0
[3,] 0 0 0.1
most of all because
> x %*% invx
[,1] [,2] [,3]
[1,] NaN NaN NaN
[2,] NaN NaN NaN
[3,] NaN NaN NaN
does not really satisfies me :-)
I´m using version 0.90.1.
Is this what it was meant to be?
Is this a known bug?
Am I doing something wrong?
Anybody knows a workaround (for a general matrix, not for a diagonal one)?
I would really appreciate your help and support.
Thanks in advance.
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Manuel Castejon Limas.
Manuel.Castejon at dim.unirioja.es
Departamento de Ingenieria Mecanica. | Mechanical Engineering Department.
Area de Proyectos de Ingenieria. | Project Management Area.
Universidad de La Rioja. | University of La Rioja.
España. | Spain.
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