Excuses for this I have 2 x 4: 2 4$1 1 0 0 0 1 1 1 and for simplicity I said 4 x 4 but I want the same 8 x 4 matrix I would consider each doubled row as one element and multiply them by the 2 x 4 one. so each doubled row has size of 2 x 4 and the multiplier as well. I would like to do array by array multiplication on doubled rows, so If I have the following doubled row in the original matrix: 1 1 2 2 1 1 2 2
what should get in the resultant matrix: 1 1 0 0 0 1 2 2 and do that for all the pairs Henry Rich wrote: > > I'm not clear about what you want. > > You start with 4x4 > > You then double the rows to get 8x4 > > You then do something else, leaving 8x4 (?) > > You then multiply by 4x2, leaving 8x2 (?) > > Now you want to get back to 4x4? Do you just want to run each pair of > rows together to make one row of the result? > > If so, > > _2 ,\ i. 8 2 > > > Henry Rich > > > On 9/5/2012 6:36 PM, pascha wrote: >> >> >> >> Henry Rich wrote: >>> >>> >>> >>> On 9/5/2012 6:18 PM, pascha wrote: >>>> >>>> sorry for quick posts by me.. I am newbie in J >>>> I want to solve a linear system of equation and I want to get a >>>> desirable >>>> design matrix for the equation >>>> considering a simple case of 4 x 4 matrix i. 4 4: >>>> 0 1 2 3 >>>> 4 5 6 7 >>>> 8 9 10 11 >>>> 12 13 14 15 >>>> >>>> could you give a strategy to duplicate each row and get a 8 x 4 matrix, >>>> e.g. >>>> : >>>> 0 1 2 3 >>>> 0 1 2 3 >>>> 4 5 6 7 >>>> 4 5 6 7 >>>> 8 9 10 11 >>>> 8 9 10 11 >>>> 12 13 14 15 >>>> 12 13 14 15 >>>> >>> >>> Just do >>> >>> 2 # mtx >>> >>> >>>> At the end for each duplicate array I want to multiply them by another >>>> 2 >>>> x 4 >>>> matrix (say, 1 1 0 0,. 0 1 1 1) and get the final design matrix. Is >>>> the >>>> solution come with the concept of boxing in this situation? >>>> >>> >>> Boxing may not be needed. Matrix multiply is >>> >>> +/ . * >>> >>> and you can just >>> >>> mp =: +/ . * >>> >>> mtx mp (1 1 0 0,. 0 1 1 1) >>> >>> >>> Henry Rich >>> >>> Thanks >>> well, I want to do array by array multiplication: >>> so If I have i. 4 4 the result should be again a 4 x 4 or 4 x 8 matrix, >>> like this: >>> 0 1 0 0 >>> 0 5 6 7 >>> 8 9 0 0 >>> 0 13 14 15 >>> >>> that's why I though about boxing >>> >>> ---------------------------------------------------------------------- >>> For information about J forums see http://www.jsoftware.com/forums.htm >>> >>> > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > > -- View this message in context: http://old.nabble.com/duplicate-row-of-matrix-tp34394924s24193p34395056.html Sent from the J Programming mailing list archive at Nabble.com. ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
