True, if an assumption is missing about the non-zero element. I suggest 1. ------------------------------------------------------------------------ |\/| Randy A MacDonald | APL: If you can say it, it's done.. (ram) |/\| [EMAIL PROTECTED] | |\ | | The only real problem with APL is that BSc(Math) UNBF'83 | it is "still ahead of its time." Sapere Aude | - Morten Kromberg Natural Born APL'er | Demo website: http://156.34.82.188/ -----------------------------------------------------(INTP)----{ gnat }-
----- Original Message ----- From: "Roger Hui" <[EMAIL PROTECTED]> To: "Programming forum" <[email protected]> Sent: Saturday, February 03, 2007 10:07 AM Subject: Re: [Jprogramming] Spare Matrix from Index Matrix > 4$.s is not invertible. > > > > ----- Original Message ----- > From: ramacd <[EMAIL PROTECTED]> > Date: Saturday, February 3, 2007 6:07 am > Subject: Re: [Jprogramming] Spare Matrix from Index Matrix > > > It seems Roger is a mortal; > > > > s=: ?4 4$2 > > (4&$.)^:_1 (4 $. s) > > |domain error > > (4&$.)^:_1(4 $.s) > > > > ...or is my copy of J too old? > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
