Re: st: absolute values from a matrix

[Phil Schumm <pschumm@uchicago.edu>]

On Nov 9, 2006, at 8:59 AM, Tom Boonen wrote:
> is there an elegant way to create a matrix that contains the  
> absolute values of the entries of another matrix?

Mata is elegant.  For example, Mata's scalar functions (like abs())  
will all operate on matrices element-wise.  Thus, to use your example  
(from the Mata prompt):


: foo = (1, -1 \ 2, -2)

: abs(foo)
       1   2
    +---------+
  1 |  1   1  |
  2 |  2   2  |
    +---------+


Type -help mata- to learn more.  If you prefer instead to work within  
Stata, you can use a single Mata call to do what you want, like this:


. mat foo = (1, -1 \ 2, -2)

. mata: st_matrix("absfoo",abs(st_matrix("foo")))

. mat li absfoo

absfoo[2,2]
    c1  c2
r1   1   1
r2   2   2


-- Phil

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