Hi Noah,

Could you please show us what you did?  I can not reproduce your problem
(sessionInfo below):

> m <- matrix(scan(), ncol = 4, byrow = TRUE)
1: 0.99252358 0.93715047 0.7540535 0.4579895
5: 0.01607797 0.09616267 0.2452471 0.3088614
9: 0.09772828 0.58451468 1.4907090 1.8773815
13: -0.01000000 0.00000000 0.0900000 0.1700000
17:
Read 16 items
> m
            [,1]       [,2]      [,3]      [,4]
[1,]  0.99252358 0.93715047 0.7540535 0.4579895
[2,]  0.01607797 0.09616267 0.2452471 0.3088614
[3,]  0.09772828 0.58451468 1.4907090 1.8773815
[4,] -0.01000000 0.00000000 0.0900000 0.1700000

> solve(m)
           [,1]      [,2]     [,3]        [,4]
[1,]  1.4081192  -7826819  1287643  21.5115344
[2,] -0.3987761  18796863 -3092403 -25.7757002
[3,] -0.1208272 -18836093  3098860  -0.9159397
[4,]  0.1467979   9511648 -1564829   7.6326466


> sessionInfo()
R version 2.11.1 Patched (2010-05-31 r52180)
x86_64-apple-darwin9.8.0

locale:
[1] en_US.UTF-8/en_US.UTF-8/C/C/en_US.UTF-8/en_US.UTF-8

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base

other attached packages:
[1] fortunes_1.4-0

loaded via a namespace (and not attached):
[1] tools_2.11.1

HTH,
Jorge


On Sat, Nov 20, 2010 at 11:55 PM, Noah Silverman <> wrote:

> Hi,
>
> I'm trying to use the solve() function in R to invert a matrix.  I get
> the following error, "Lapack routine dgesv: system is exactly singular"
>
> However, My matrix doesn't appear to be singular.
>
>            [,1]       [,2]      [,3]      [,4]
> [1,]  0.99252358 0.93715047 0.7540535 0.4579895
> [2,]  0.01607797 0.09616267 0.2452471 0.3088614
> [3,]  0.09772828 0.58451468 1.4907090 1.8773815
> [4,] -0.01000000 0.00000000 0.0900000 0.1700000
>
>
> Can anyone help me understand what is happening here?
>
> Thanks!
>
> -N
>
> ______________________________________________
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> PLEASE do read the posting guide
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> and provide commented, minimal, self-contained, reproducible code.
>

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