My note was in Journal of J, vol. 1 no. 2 http://www.journalofj.com/
On Tue, Jan 14, 2020 at 9:40 AM Devon McCormick <[email protected]> wrote: > Images can be 3D if you manipulate them in terms of RGB planes. > > Cliff Reiter had an interesting algo for drawing Penrose tiles by taking a > high-dimensional (>3D) projection of grid points closest to a > hyper-cylinder and mapping them to two dimensions, which I believe is " The > pentagrid method, introduced by N.G. de Bruijn, allows us to generate > Penrose tilings by taking a slice of the integer lattice in > five-dimensional space." (http://www.cs.williams.edu/~bailey/06le.pdf). > > Unfortunately, I have not been able to find Cliff's J code for doing this. > > > On Tue, Jan 14, 2020 at 8:45 AM Michal Wallace <[email protected]> > wrote: > > > For an upcoming talk, I was thinking through an inventory of common array > > "patterns" - > > or like generic classes of things which are naturally represented as > > arrays. > > > > Here's what I came up with so far: > > > > Rank 1: > > > > - arbitrary lists of data (row/column in a table, sound file, bytes of a > > string, etc) > > - shape of a space/array (as in $) > > - coordinates inside a space/array (including boxed indices for amend) > > - selections (unboxed indices) > > - permutation vectors > > - keys for grouping another vector > > - coefficients of polynomial (also prime exponents, hypergeometric, etc) > > (I think dyadic # kind of fits into the "coefficient" pattern) > > - numeric base and "digits" (as in #. and #:) > > - intervals (I.) > > - tree structure > > > > Rank 2: > > > > - arbitrary tables of data (esp images) > > - matrix (as a tool for transforming other arrays) > > - sparse matrix / list of coordinates > > - connected / weighted graphs / state machine > > > > What are some that I'm missing? > > > > Are there interesting patterns at rank 3 or above? > > > > -Michal > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > > > > > -- > > Devon McCormick, CFA > > Quantitative Consultant > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
