# st: RE: absolute values from a matrix

 From "Nick Cox" To Subject st: RE: absolute values from a matrix Date Thu, 9 Nov 2006 15:07:51 -0000

```Use Mata.

: x = uniform(3,3) :- 0.5

: x
1              2              3
+----------------------------------------------+
1 |   .3714490768   -.2448501205   -.4554811986  |
2 |  -.0758442807    .3983461575    .0219247625  |
3 |   .3414094402   -.2889923407    .0644091703  |
+----------------------------------------------+

: y = abs(x)

: y
1             2             3
+-------------------------------------------+
1 |  .3714490768   .2448501205   .4554811986  |
2 |  .0758442807   .3983461575   .0219247625  |
3 |  .3414094402   .2889923407   .0644091703  |
+-------------------------------------------+

If you are on Stata <9, then do say so in your postings.

In that case, one inelegant but functional tool
is -matmap- from SSC.

Nick
n.j.cox@durham.ac.uk

Tom Boonen

> is there an elegant way to create a matrix that contains the absolute
> values of the entries of another matrix?
>
> Something like:
>
> matrix w = (1 , -1 \ 2,	-2)
> matrix list w
>
> *w[2,2]
> *c1  c2
> *r1   1  -1
> *r2   2  -2
>
> * But then:
>
> . matrix w = abs(w)
> type mismatch
> r(109);

*
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```