Minimum of symetrics elements

[Charlie Joyez]

Dear all,

I have a square matrix A, and I'd like to create a matrix W such as : w_ij = w_ji = min(a_ij , a_ji)
I've thought about comparing A and A' (because w_ij also corresponds to min(a_ij, a'_ij) ), but I can't find a way, the minmax functions in Mata only work within a matrix (or rows/colums) and not between two.

Here is an example :

. mata A =(0,3, 10\ 2, 0, 5\ 1, 1, 0)

. mata A
        1    2    3
    +----------------+
  1 |   0    3   10  |
  2 |   2    0    5  |
  3 |   1    1    0  |
    +----------------+

. mata A'
        1    2    3
    +----------------+
  1 |   0    2    1  |
  2 |   3    0    1  |
  3 |  10    5    0  |
    +----------------+

I'd like to end up with :

. mata W
[symmetric]
       1   2   3
    +-------------+
  1 |  0          |
  2 |  2   0      |
  3 |  1   1   0  |
    +-------------+

Any ideas would be welcome.
Thanks,
Charlie

[Niels Henrik Bruun]

Hi Charlie
Q&D:

: A =(0,3, 10\ 2, 0, 5\ 1, 1, 0)
: A :* (A :< A') + A' :* (A' :< A)
[symmetric]
       1   2   3
    +-------------+
  1 |  0          |
  2 |  2   0      |
  3 |  1   1   0  |
    +-------------+

This can probably be refined. And I haven't checked it for speed.
But here it is

[Charlie Joyez]

Many thanks Henrik,
It works fine, even with a larger matrix of 167x167, so no speed improvement is needed.

Best,
Charlie