x=: 2 2$0 1 1 0 y=: 2 4$1 0 0 1 0 1 1 0 x 0 1 1 0 y 1 0 0 1 0 1 1 0 x +/ .* y 0 1 1 0 1 0 0 1
The following J Wiki essay may be of interest: http://www.jsoftware.com/jwiki/Essays/LU_Decomposition ----- Original Message ----- From: Pascal Heus <[EMAIL PROTECTED]> Date: Sunday, April 1, 2007 2:17 pm Subject: [Jprogramming] Matrices operation 9rookie question) > 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 > probablytake 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 > producta 2x2 matrix to each column of a 2xN matrix? ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
