OK. Jamie's solution is still presumably better
in Stata 8. When Jeroen and then I wrote
some crude matrix add-ons in 1997-2000,
-vec()- had not been implemented, I believe.
STB-56 dm79 . . . . . . . . . . . . . . . . . . Yet more new matrix commands
(help matcorr, matewmf, matvsort, svmat2 if installed) . . N. J. Cox
7/00 pp.4--8; STB Reprints Vol 10, pp.17--23
commands to produce a correlation matrix, elementwise monadic
function of another matrix, selected subsets of matrix rows
and columns, vec or vech of a matrix, elements sorted within
a vector, matrix from a vector, and commands to save matrices
STB-50 dm69 . . . . . . . . . . . . . . . . . . Further new matrix commands
(help matdelrc, matewm, matmad, matpow if installed) . . . N. J. Cox
7/99 pp.5--9; STB Reprints Vol 9, pp.29--34
collection of new matrix commands providing additional matrix
checking, management, element-wise operators, maximum absolute
difference, and power
STB-39 dm49 . . . . . . . . . . . . . . . . . . . . Some new matrix commands
(help matfunc, varfunc if installed) . . . . . . . . . . . J. Weesie
9/97 pp.17--20; STB Reprints Vol 7, pp.43--48
collection of new matrix commands; several for explicit matrices
and a few for implicit matrices (i.e., variables)
Nick
[email protected]
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]]On Behalf Of
> R.E. De Hoyos
> Sent: 08 November 2005 18:15
> To: [email protected]
> Subject: st: Re: RE: Re: RE: summing up matrix elements
>
>
> > Offhand, I can't think of any reason why anyone
> > with Stata 9 would prefer that. Nor, I imagine,
> > would Jeroen if he were to be asked.
>
> I have access to Stata 9 only when I am in the University, in
> my laptop I
> have version 8.
>
> Rafa
>
> ----- Original Message -----
> From: "Nick Cox" <[email protected]>
> To: <[email protected]>
> Sent: Tuesday, November 08, 2005 5:59 PM
> Subject: st: RE: Re: RE: summing up matrix elements
>
>
> > You may be thinking of Jeroen Weesie's -matsum-.
> > Offhand, I can't think of any reason why anyone
> > with Stata 9 would prefer that. Nor, I imagine,
> > would Jeroen if he were to be asked.
> >
> > STB-39 dm49 . . . . . . . . . . . . . . . . . . . . Some
> new matrix
> > commands
> > (help matfunc, varfunc if installed) . . . . . . .
> . . . . J.
> > Weesie
> > 9/97 pp.17--20; STB Reprints Vol 7, pp.43--48
> > collection of new matrix commands; several for
> explicit matrices
> > and a few for implicit matrices (i.e., variables)
> >
> > Nick
> > [email protected]
> >
> > R.E. De Hoyos
> >
> >> Both your solutions work fine, thanks a lot.
> >> I though there was a non-mata matrix function similar to
> >> mata's -sum(C)-
> >
> > Nick Cox
> >
> > . mata : sum_r = (sum(C) - trace(C)) / 2
> >
> > R.E. De Hoyos
> >
> >> >> > Is there a way to to get a scalar containing the sum of the
> >> >> > off-diagonal
> >> >> > elements of a pre-defined matrix?
> >> >> >
> >> >> > For instance, define matrix C as a correlation matrix. I
> >> >> > want to know what
> >> >> > is the sum of correlations between the various elements in C.
> >> >> > Therefore I
> >> >> > need the sum of all elements in C minus the sum of the
> >> >> > diagonal elements
> >> >> > (-trace(C)-) and finally divide it by 2 (I am assuming
> >> matric C is
> >> >> > symetric).
*
* For searches and help try:
* http://www.stata.com/support/faqs/res/findit.html
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
