Perhaps I'm missing the point, but I would say: R =: ((cos , -@sin) ,: sin , cos)
R 1r6p1 0.866025 _0.5 0.5 0.866025 Ben On Fri, 18 Dec 2020 at 18:59, Francesco Pedulla' <mel...@gmail.com> wrote: > Dear all, > I need to represent the 2D rotation matrix 'R' > > R = |cos(t) -sin(t)| > |sin(t) cos(t)| > > and compute it for different values of the rotation angle 't'. I am aware > the matrix of function can be represented as a gerund, which I like: > > R =: 2 2$cos`(-@sin)`sin`cos . > > To compute R(t), I wrote the following definition: > > mf =: conjunction : '($x)$,(,x)/.((+/$x)$y)' > > > so that "R mf pi%4" returns R(pi/4). But I find the code for 'mf' not very > elegant. Is there a better way to achieve this? > Thanks in advance for any hint, > > Francesco > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
