Somewhere I have seen Ken suggest line and page (and even book and library), but I can't find where. The Primer (click on Pri at the top of the Vocabulary page) has sections Atom, List, Table, Array (just after Checkpoint D).
Sent from my iPad On Sep 7, 2012, at 3:03 AM, "Linda Alvord" <lindaalv...@verizon.net> wrote: > Did you happen to notice David's use of the word "pages" at the end of his > message? It makes a great visual image to explain the array. > > I was wondering if it has been used in this context before, or does it have > a long and checkered APL or J history? > > Linda > > > -----Original Message----- > From: programming-boun...@forums.jsoftware.com > [mailto:programming-boun...@forums.jsoftware.com] On Behalf Of David Ward > Lambert > Sent: Wednesday, September 05, 2012 9:57 PM > To: programming > Subject: Re: [Jprogramming] duplicate row of matrix > > Right! "Matrix multiplication" usually means something else. > You want a sort of element-by-corresponding-element multiplication. > > B ; A > +-------+-------+ > |1 1 0 0|1 1 1 1| > |0 0 1 1|1 1 2 2| > | |1 1 3 3| > | |1 1 4 4| > +-------+-------+ > > A solution uses rank conjunction twice. I couldn't begin to understand it > the first time I saw this sort of construction. Then one day I wrote rank > rank and retrospectively realized what I'd written and understood. > I practiced rank with sentences like 'abc' "2 i. 2 3 4 > > My thoughts to construct this sentence: > First I realized that you need to multiply row by row. > The ("1) adverb ensures this. The frames of these two matrices disagree > because there are 2 rows in B and 4 in A. The next adverb ("_ 1) means > (because ultimately the final verb is dyadic) "use all of the left array > with each row of the right hand array". > > B * ("1) ("_ 1) A > 1 1 0 0 > 0 0 1 1 > > 1 1 0 0 > 0 0 2 2 > > 1 1 0 0 > 0 0 3 3 > > 1 1 0 0 > 0 0 4 4 > > Finally, inserting append between the pages gives > > ,/B*"1"_ 1 A > 1 1 0 0 > 0 0 1 1 > 1 1 0 0 > 0 0 2 2 > 1 1 0 0 > 0 0 3 3 > 1 1 0 0 > 0 0 4 4 > > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
