Re: [Getfem-users] use of gmm::col_matrix< gmm::wsvector<double> > for assembly operation

[Yves Renard]

On Friday 07 December 2007 16:24, mikael gueguen wrote:
> hello
>
> i use the type gmm::col_matrix< gmm::wsvector<double> > matrix for
> assembly operation.
> This is my global matrix, and i use a dynamic array  for elementary
> operation
> (i interface a fortran subroutine with my c++ code).
> for a problem with six hundred finite elements (the size of global
> matrix is 12000x12000),
> i notice that the access time  increase strongly during the assembly.
> is it normal?
>
> best regards.

The gmm::wsvector<double> is based on a std::map object so the insertion of a 
new nonzero component is of computational cost log(N) where N is the number 
of nonzero components already present. Thus the access time should not 
increase a lot, event if you hav a nearly full column.

You mean that you need to use your matrix in a fortran code ?

Best regards,

Yves. 


-- 

  Yves Renard (address@hidden)       tel : (33) 04.72.43.87.08
  Pole de Mathematiques, INSA de Lyon          fax : (33) 04.72.43.85.29
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  69621 Villeurbanne Cedex, FRANCE
  http://math.univ-lyon1.fr/~renard

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