Re: [eigen] A piece of code that has me confused

[Christoph Hertzberg <chtz@xxxxxxxxxxxxxxxxxxxxxxxx>]

On 20.07.2011 21:05, Douglas Bates wrote:
> In the file unsupported/Eigen/src/SparseExtra/SimplicialCholesky.h the
> method _solve uses the template keyword in a way I have not seen
> before:
>
>
> 	  if(m_matrix.nonZeros()>0) // otherwise L==I
> 	      m_matrix.template triangularView<UnitLower>().solveInPlace(dest);
>
> Can anyone point me to documentation on that usage?

Short answer: Since the compiler does not know the actual type of 
m_matrix, it can't be sure whether triangularView is a member variable 
or a templated function, by using template it is told that it is the latter.

Here is a pretty good answer to that question:

http://stackoverflow.com/questions/610245/where-and-why-do-i-have-to-put-template-and-typename-on-dependent-names

HTH
Christoph



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Dipl.-Inf. Christoph Hertzberg
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