Hello Everybody, Just when I thought I was out of the hook/fork fog they pulled me back in.
I was trying to construct a verb for a covariance matrix: http://stattrek.com/matrix-algebra/covariance-matrix.aspx ]data=. 5 3 $ 90 60 90 90 90 30 60 60 60 60 60 90 30 30 30 mean=: +/%# mp=: +/ . * covmat=: ((mp~|:)(-"1 mean))%# NB. divede by n not n-1 to comply with the example covmat data 504 360 180 360 360 0 180 0 720 The result seems to be ok but I am confused with the verb. Isn't it a fork with two hooks on the left and a primitive on the right If I put a cap before the two hooks covmat2=: ([:(mp~|:)(-"1 mean))%# It gives the same answer covmat2 data 504 360 180 360 360 0 180 0 720 I can't figure out why it works whether the cap is there or not. Esa ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
