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Re: st: absolute values from a matrix


From   Phil Schumm <pschumm@uchicago.edu>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: absolute values from a matrix
Date   Thu, 9 Nov 2006 23:53:17 -0600

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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