On Wed, Dec 2, 2009 at 5:11 PM, Robert O'Boyle <[email protected]> wrote:
> I have an arbitrary matrix
> I want to average only specific rows and columns of this matrix. Here is the
> Boolean mask

I would not want to create the filtered rows, instead just compute a
general weighted average like this:

   mask (+/"1...@[%~[:+/"1*) mat
2 7 0 16.5

Ambrus
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm

Reply via email to