Is the ,. (stitch) what you are looking for?
   pauliX (+/ .*) qb1,. qb1,. qb0,. qb0
1 1 0 0
0 0 1 1

I think that the mathematical definition of dot product already suggests the right argument is operated in a column-wise manner.

Pascal Heus wrote:
Hi:
I'm new to J and am trying to apply a unitary transformation to a
collection of column vectors in a single operation. This would probably
take a second to the J gurus out there....

Something like:
| 0 1 |     |1| |0| |0| |1|
| 1 0 | dot |0| |1| |1| |0|
where "dot" is the matrix product

For example, I have defined a 2x2 matrix:
pauliX   =: 2 2 $ (0 1 1 0)

a couple of column vectors
qb0 =: 2 1 $ 1 0
qb1 =: 2 1 $ 0 1

and the matrix product
dot =: 4 : ' x +/ . *  y'

and would like to write something like
pauliX dot qb1 qb1 qb0 qb0

which should then return four column vectors with their value inverted
(or a 2x4 matrix).

Should I define a 2xN matrix first? How can I then apply the dot product
a 2x2 matrix to each column of a 2xN matrix?

Any help/suggestion would be appreciated.

thanks
Pascal



--
regards,
bill
----------------------------------------------------------------------
For information about J forums see http://www.jsoftware.com/forums.htm

Reply via email to