# Re: st: RE: Adding Matrices generated from a loop

 From "Nadeem Shafique" To statalist@hsphsun2.harvard.edu Subject Re: st: RE: Adding Matrices generated from a loop Date Fri, 24 Aug 2007 18:16:19 +0500

```Respected Nick Cox,

Sorry for not providing complete information, I am trying it using
Mata. Following is the code i am trying to execute.

********************************************************************************************
for (i=1; i<=rows(info); i++)
{
v_i =
panelsubmatrix(v, i, info)
m_i = panelsubmatrix(m,i,info)
n_i = panelsubmatrix(s,i,info)
n = mean(n_i)
t_i=v_i*m_i*n

}

****************** I want to sum all these t_i in one matrix say "t"
******************

********************************************************************************************

Best Regards,

On 8/24/07, Nick Cox <n.j.cox@durham.ac.uk> wrote:
> There may be subtleties here I am missing, but
> I would initialise
>
>        sum <- first_matrix
>
> and then loop over the other matrices
>
>        sum <- sum + next_matrix
>
> This is pseudocode.
>
> Otherwise I can't tell what's troubling you about
> this. As the details will depend on whether
> you are using Stata or Mata, your naming structure,
> what else you are doing with these matrices,
> whether the number is predictable in advance, etc.,
> none of which is indicated, I'll leave it there.
>
> Nick
> n.j.cox@durham.ac.uk
>
>
> > I want to add several matrices (say K) of the same order, suppose the
> > matrices to be added are comming from a loop, how can i calculate the
> > following
> >
> >                 K
> >                 Sum    X_i
> >                 i=1
> > where X_i is the ith Matix
>
> *
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> *   http://www.stata.com/support/faqs/res/findit.html
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>

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