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From: rrr@hpdmd48.boi.hp.com (Rudi Rynders)
Newsgroups: comp.lang.apl
Subject: Re:  "over" and "by"
Message-ID: <15160010@hpdmd48.boi.hp.com>
Date: 10 Jan 91 20:14:02 GMT
Organization: Hewlett Packard - Boise, ID
Lines: 20


 The  "OVER" and  "BY" constructs mentioned in my previous
 note are defined as follows:

    over =.;@({.;}.)&":@,

    by =.(,~"_1' '&;&;)~


  Using these one can neatly produce the result of the APL
  outer product function, as in A jot.+ B for instance.
  It glues the A vector on to the result as the first column
  as well as displaying the B vector accross the top.
  The command is:

    A by B over A+/B
  
  but how this it work?

  Rudi Rynders (rrr@hpdmd48.boi.com)