[Rd] Concerns with SVD

[J C Nash]

Better check your definitions of SVD -- there are several forms, but all I
am aware of (and I wrote a couple of the codes in the early 1970s for the SVD)
have positive singular values.

JN


On 2023-07-16 02:01, Durga Prasad G me14d059 wrote:
> Respected Development Team,
> 
> This is Durga Prasad reaching out to you regarding an issue/concern related
> to Singular Value Decomposition SVD in R software package. I am attaching a
> detailed attachment with this letter which depicts real issues with SVD in
> R.
> 
> To reach the concern the expressions for the exponential of a matrix using
> SVD and
> projection tensors are obtained from series expansion. However, numerical
> inconsistency is observed between the exponential of matrix obtained using
> the function(svd()) used in R software.
> 
> However, it is observed that most of the researchers fraternity is engaged
> in utilising R software for their research purposes and to the extent of my
> understanding such an error in SVD in R software might raise the concern
> about authenticity of the simulation results produced and published by
> researchers across the globe.
> 
> Further, I am very sure that the R software development team is well versed
> with the happening and they have any specific and resilient reasons for
> doing so. I would request you kindly, to guide me through the concern.
> 
> Thank you very much.
> 
> 
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