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Re: st: Re:Turn lower diagonal matrix


From   "Bianca B." <bianca268@yahoo.com>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: Re:Turn lower diagonal matrix
Date   Thu, 1 Nov 2012 11:33:36 -0700 (PDT)

I transposed my original matrix without using mata:

 matrix list S2

S2[2,2]
    var1  var2
r1     0     .
r2     1     0

 mat S2t = S2'

. matrix list S2t

S2t[2,2]
      r1  r2
var1   0   1
var2   .   0

Is it possible to combine S2 and S2t for obtaining

       r1  r2
var1   0   1
var2   1   0

?



--- On Thu, 11/1/12, Nick Cox <njcoxstata@gmail.com> wrote:

> From: Nick Cox <njcoxstata@gmail.com>
> Subject: Re: st: Re: Stata matrix to Mata matrix form - Turn lower diagonal matrix
> To: statalist@hsphsun2.harvard.edu
> Date: Thursday, November 1, 2012, 11:05 AM
> Then the missing . should have
> carried over to Mata and should have
> been displayed, which is not visible in your previous
> report. More
> importantly, -makesymmetric()- works:
> 
> . mat li S2
> 
> S2[2,2]
>     c1  c2
> r1   0   .
> r2   1   0
> 
> . mata
> ------------------------------------------------- mata (type
> end to
> exit) --------------------------------------------
> : S2 = st_matrix("S2")
> 
> : S2
>        1   2
>     +---------+
>   1 |  0   .  |
>   2 |  1   0  |
>     +---------+
> 
> : makesymmetric(S2)
> [symmetric]
>        1   2
>     +---------+
>   1 |  0      |
>   2 |  1   0  |
>     +---------+
> 
> :
> What you may be missing is that -makesymmetric()- shows the
> result of
> making a matrix symmetric; it does not itself change the
> argument.
> That can be done by assignment or by using
> -_makesymmetric()-
> 
> : _makesymmetric(S2)
> 
> : S2
> [symmetric]
>        1   2
>     +---------+
>   1 |  0      |
>   2 |  1   0  |
>     +---------+
> 
> 
> 
> On Thu, Nov 1, 2012 at 5:57 PM, Bianca B. <bianca268@yahoo.com>
> wrote:
> > The elements in row 1 are 0 and . (i.e. missing value),
> in row 2 1 and 0.
> > Then I converted my original stata matrix into mata.
> >
> >
> >
> > --- On Thu, 11/1/12, Nick Cox <njcoxstata@gmail.com>
> wrote:
> >
> >> From: Nick Cox <njcoxstata@gmail.com>
> >> Subject: Re: st: Re: Stata matrix to Mata matrix
> form - Turn lower diagonal matrix
> >> To: statalist@hsphsun2.harvard.edu
> >> Date: Thursday, November 1, 2012, 10:11 AM
> >> I mean what is the element in row 1
> >> and column 2 of your matrix?
> >>
> >> mat_s2[1,2]
> >>
> >> will display it in Mata.
> >>
> >> I may be missing something important, but I don't
> understand
> >> how your
> >> matrix can display like that unless it is
> symmetric.
> >>
> >> Nick
> >>
> >> On Thu, Nov 1, 2012 at 4:46 PM, Bianca B. <bianca268@yahoo.com>
> >> wrote:
> >>
> >> > mat_S2[1,2] is the name of the matrix.
> >> >
> >> >   mat_S2
> >> >
> >> >    1   2
> >> >    +---------+
> >> >  1 |  0      |
> >> >    |  1   0
> >> >    |
> >> >> >+---------+
> >> > I found this old post
> >> > http://www.stata.com/statalist/archive/2007-02/msg00156.html
> >> >
> >> > where there is exactly my same question that
> is to turn
> >> my lower-triangular matrix, named mat_S2, into a
> symmetrical
> >> matrix by reflecting the lower triangular elements
> across
> >> the diagonal.
> >> >
> >> > I tried to use mata makesymmetric function but
> I do not
> >> obtain the matrix I wish and that I report below
> >> >
> >> >         
> 1   2
> >> >       +---------+
> >> >     1 |
> >> 0   1  |
> >> >     2 |
> >> 1   0  |
> >> >       +---------+
> >> >
> >> >
> >> >
> >> > --- On Thu, 11/1/12, Nick Cox <njcoxstata@gmail.com>
> >> wrote:
> >> >
> >> >> From: Nick Cox <njcoxstata@gmail.com>
> >> >> Subject: Re: st: Re: Stata matrix to Mata
> matrix
> >> form
> >> >> To: statalist@hsphsun2.harvard.edu
> >> >> Date: Thursday, November 1, 2012, 9:34 AM
> >> >> You've lost me. What is mat_S2[1,2]?
> >> >>
> >> >> Nick
> >> >>
> >> >> On Thu, Nov 1, 2012 at 3:39 PM, Bianca B.
> <bianca268@yahoo.com>
> >> >> wrote:
> >> >> > Nick, you're right, I'm sorry. I
> didn't
> >> specify that I
> >> >> need to turn my lower-triangular matrix
> into a
> >> symmetrical
> >> >> matrix by reflecting the lower triangular
> elements
> >> across
> >> >> the diagonal. So starting from this
> matrix
> >> >> >
> >> >> > mat_S2
> >> >> >
> >> >> >
> >> >>    1   2
> >> >> >      +---------+
> >> >> >    1 |  0
> >> |
> >> >> >    2 | 
> 1   0
> >> >> >      |
> >> >> >      +---------+
> >> >> >  I'd like to obtain a matrix
> like that
> >> >> >
> >> >> >
> >> >>    1   2
> >> >> >      +---------+
> >> >> >    1 |
> >> 0   1  |
> >> >> >    2 |
> >> 1   0  |
> >> >> >      +---------+
> >> >> >
> >> >> >
> >> >> >
> >> >> >
> >> >> > --- On Thu, 11/1/12, Nick Cox <njcoxstata@gmail.com>
> >> >> wrote:
> >> >> >
> >> >> >> From: Nick Cox <njcoxstata@gmail.com>
> >> >> >> Subject: Re: st: Re: Stata matrix
> to Mata
> >> matrix
> >> >> form
> >> >> >> To: statalist@hsphsun2.harvard.edu
> >> >> >> Date: Thursday, November 1, 2012,
> 8:29 AM
> >> >> >> Looks symmetric to me.
> >> >> >>
> >> >> >> If a matrix is symmetric, Stata
> says so,
> >> and only
> >> >> displays
> >> >> >> the lower
> >> >> >> half (including the principal
> diagonal).
> >> >> >>
> >> >> >> In your case, Stata is doing
> exactly
> >> that.
> >> >> >>
> >> >> >> Here is another example:
> >> >> >>
> >> >> >> . mata : I(3)
> >> >> >> [symmetric]
> >> >> >>
> >> >> >>
> >> >> 1   2   3
> >> >> >> 
>    +-------------+
> >> >> >>   1 |  1
> >> >>     |
> >> >> >>   2 |
> >> >> 0   1     
> |
> >> >> >>   3 |
> >> >> >>
> >> 0   0   1  |
> >> >> >> 
>    +-------------+
> >> >> >>
> >> >> >> If this is not what you mean,
> you'll have
> >> to
> >> >> explain what
> >> >> >> "doesn't
> >> >> >> work" means exactly.
> >> >> >>
> >> >> >> Nick
> >> >> >>
> >> >> >> On Thu, Nov 1, 2012 at 3:16 PM,
> Bianca B.
> >> <bianca268@yahoo.com>
> >> >> >> wrote:
> >> >> >> > Dear Nick,
> >> >> >> >
> >> >> >> > Thanks a lot. I converted a
> >> lower-triangular
> >> >> matrix
> >> >> >> from stata to mata form to apply
> the mata
> >> >> makesymmetric
> >> >> >> command but it doesn't work.
> >> >> >> > The command is
> >> >> >> >
> >> >> >> > : makesymmetric(mat_S2)
> >> >> >> > [symmetric]
> >> >> >> >
> >> >> 1   2
> >> >> >> > 
>    +---------+
> >> >> >> >   1 | 
> 0
> >> >>   |
> >> >> >> >   2 |
> >> >> 1   0
> >> >> >> |
> >> >> >> > 
>    +---------+
> >> >> >> >
> >> >> >> > Would you have any
> suggestion?
> >> >> >> > Best,
> >> >> >> > Bianca
> >> >> >> >
> >> >> >> >
> >> >> >> >
> >> >> >> > . mat foo = J(6,7,42)
> >> >> >> >
> >> >> >> > . mat li foo
> >> >> >> >
> >> >> >> > foo[6,7]
> >> >> >> >     c1
> >> c2  c3
> >> >> >> c4  c5  c6  c7
> >> >> >> > r1  42  42 
> 42
> >> 42
> >> >> 42
> >> >> >> 42  42
> >> >> >> > r2  42  42 
> 42
> >> 42
> >> >> 42
> >> >> >> 42  42
> >> >> >> > r3  42  42 
> 42
> >> 42
> >> >> 42
> >> >> >> 42  42
> >> >> >> > r4  42  42 
> 42
> >> 42
> >> >> 42
> >> >> >> 42  42
> >> >> >> > r5  42  42 
> 42
> >> 42
> >> >> 42
> >> >> >> 42  42
> >> >> >> > r6  42  42 
> 42
> >> 42
> >> >> 42
> >> >> >> 42  42
> >> >> >> >
> >> >> >> > . mata : mat_foo =
> st_matrix("foo")
> >> >> >> >
> >> >> >> > . mata : mat_foo
> >> >> >> >
> >>    1
> >> >> >> 2    3    4
> >>   5
> >> >> >> 6    7
> >> >> >> >
> >> >> >>
> >> >> +------------------------------------+
> >> >> >> >   1 |
> >> >> >>
> >> >>
> >>
> 42   42   42   42   42   42   42
> >> >> >> |
> >> >> >> >   2 |
> >> >> >>
> >> >>
> >>
> 42   42   42   42   42   42   42
> >> >> >> |
> >> >> >> >   3 |
> >> >> >>
> >> >>
> >>
> 42   42   42   42   42   42   42
> >> >> >> |
> >> >> >> >   4 |
> >> >> >>
> >> >>
> >>
> 42   42   42   42   42   42   42
> >> >> >> |
> >> >> >> >   5 |
> >> >> >>
> >> >>
> >>
> 42   42   42   42   42   42   42
> >> >> >> |
> >> >> >> >   6 |
> >> >> >>
> >> >>
> >>
> 42   42   42   42   42   42   42
> >> >> >> |
> >> >> >> >
> >> >> >>
> >> >> +------------------------------------+
> >> >> >> >
> >> >> >> > . mata : st_matrix("foo",
> mat_foo :/
> >> 7)
> >> >> >> >
> >> >> >> > . mat li foo
> >> >> >> >
> >> >> >> > foo[6,7]
> >> >> >> >     c1
> >> c2  c3
> >> >> >> c4  c5  c6  c7
> >> >> >> >
> >> >> >>
> >> >>
> >>
> r1   6   6   6   6   6   6   6
> >> >> >> >
> >> >> >>
> >> >>
> >>
> r2   6   6   6   6   6   6   6
> >> >> >> >
> >> >> >>
> >> >>
> >>
> r3   6   6   6   6   6   6   6
> >> >> >> >
> >> >> >>
> >> >>
> >>
> r4   6   6   6   6   6   6   6
> >> >> >> >
> >> >> >>
> >> >>
> >>
> r5   6   6   6   6   6   6   6
> >> >> >> >
> >> >> >>
> >> >>
> >>
> r6   6   6   6   6   6   6   6
> >> >> >> >
> >> >> >> > --- On Thu, 11/1/12, Bianca
> B. <bianca268@yahoo.com>
> >> >> >> wrote:
> >> >> >> >
> >> >> >> >> From: Bianca B. <bianca268@yahoo.com>
> >> >> >> >> Subject: Stata matrix to
> Mata
> >> matrix form
> >> >> >> >> To: statalist@hsphsun2.harvard.edu
> >> >> >> >> Date: Thursday, November
> 1, 2012,
> >> 7:25 AM
> >> >> >> >> Hi Stata users,
> >> >> >> >>
> >> >> >> >> Does anyone know how can
> I get
> >> stata
> >> >> matrix in mata
> >> >> >> matrix?
> *
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> 

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