I do not recall using this word this way, for whatever that is worth... -- Raul
On Fri, Sep 7, 2012 at 4:03 AM, Linda Alvord <[email protected]> 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: [email protected] > [mailto:[email protected]] 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
