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Re: st: Re: Stata matrix to Mata matrix form - Turn lower diagonal matrix
From
Nick Cox <[email protected]>
To
[email protected]
Subject
Re: st: Re: Stata matrix to Mata matrix form - Turn lower diagonal matrix
Date
Thu, 1 Nov 2012 17:11:46 +0000
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. <[email protected]> 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 <[email protected]> wrote:
>
>> From: Nick Cox <[email protected]>
>> Subject: Re: st: Re: Stata matrix to Mata matrix form
>> To: [email protected]
>> 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. <[email protected]>
>> 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 <[email protected]>
>> wrote:
>> >
>> >> From: Nick Cox <[email protected]>
>> >> Subject: Re: st: Re: Stata matrix to Mata matrix
>> form
>> >> To: [email protected]
>> >> 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. <[email protected]>
>> >> 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. <[email protected]>
>> >> wrote:
>> >> >
>> >> >> From: Bianca B. <[email protected]>
>> >> >> Subject: Stata matrix to Mata matrix form
>> >> >> To: [email protected]
>> >> >> 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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