## First time using Eigen, 2 questions

hasuchobe
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### First time using Eigen, 2 questions

Sat Mar 16, 2013 8:17 pm
For sparse matrices... what is meant by outerstarts? I don't understand what this page is talking about.
http://eigen.tuxfamily.org/dox/Tutorial ... e_BasicOps

Second, does eigen support complex matrices? Is there an example on how to do this?

edit: Turns out all you need to do for complex operations is specify complex type from the standard library for the template.

thnx
ggael
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### Re: First time using Eigen, 2 questions

Sat Mar 16, 2013 9:08 pm
For a column major matrix, the nonzeros are sequentially stored as pairs (rowId,value). The outerstarts[j] tells where is the first non-zero for the j-th column. I don't know how to explain it differently. If that's still unclear you might look at this page http://netlib.org/utk/papers/templates/node92.html, where outerstarts==col_ptr.
hasuchobe
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### Re: First time using Eigen, 2 questions

Sat Mar 16, 2013 9:25 pm
ggael wrote:For a column major matrix, the nonzeros are sequentially stored as pairs (rowId,value). The outerstarts[j] tells where is the first non-zero for the j-th column. I don't know how to explain it differently. If that's still unclear you might look at this page http://netlib.org/utk/papers/templates/node92.html, where outerstarts==col_ptr.

That page you linked clarified it. Thanks! Eigen is such a nice library

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